Comprehensive Review in Clinical Neurology: A Multiple Choice Question Book for the Wards and Boards

Chapter 3. Neurocritical Care

Question

Questions 1–2

  1. A 57-year-old man presents with sudden onset of headache, nausea, vomiting, and change in mental status. A scan is obtained and is shown in Figure 3.1. The patient had a normal CT scan obtained 3 months earlier as part of a workup for headaches. Brain edema occurring in the setting of the condition shown in the scan has which of the following characteristics?

FIGURE 3.1 Axial CT

      a.  It is interstitial edema

      b.  It occurs from N-K ATPase pump failure

      c.  It is cytotoxic edema

      d.  It is vasogenic edema

      e.  The pathogenesis is associated with blood-brain barrier disruption

  2. A 62-year-old patient is found to have a brain mass. An image of his MRI is shown in Figure 3.2. What are the characteristics of the surrounding cerebral edema?

FIGURE 3.2 Axial T2-weighted MRI

      a.  It is caused by disruption of the CSF flow

      b.  It occurs from N-K ATPase pump failure

      c.  It is cytotoxic edema

      d.  It is vasogenic edema

      e.  It is caused by obstructive hydrocephalus

  3. A 52-year-old man suffered a cardiac arrest associated with ventricular fibrillation and required cardiopulmonary resuscitation (CPR) for 10 minutes. On arrival to the hospital, the patient is unconscious. He gets intubated and is admitted to the ICU. Which of the following is incorrect?

      a.  The patient should be treated with hypothermia for 12 to 24 hours

      b.  The target temperature with hypothermic therapy should be 32°C to 34°C

      c.  There is strong evidence to support the use of hypothermic therapy in cardiac arrest from ventricular fibrillation, pulseless electrical activity, and asystole

      d.  Temperatures lower than 28°C can be harmful without significant benefit

      e.  In a patient such as the one depicted in this case, neurologic outcome improves with hypothermic therapy

  4. A patient suffers a large intracranial hemorrhage. On examination, he has a right fixed dilated pupil and seems to be hemiparetic on the left side. Which type of herniation does this patient have?

      a.  Uncal herniation

      b.  Subfalcine herniation

      c.  Tonsillar herniation

      d.  Central transtentorial herniation

      e.  Transcalvarial herniation

  5. Which of the following is not a cause of cerebral edema?

      a.  Prolonged cardiac arrest

      b.  Hypernatremia

      c.  Liver failure

      d.  Lead intoxication

      e.  Rapid ascent into high altitude

  6. A patient is admitted to the neurocritical care unit with an acute neurological condition and a Glasgow Coma Scale score of 7. His brain CT scan is shown in Figure 3.3. A decision is made to place an ICP monitor. Which device is the best option in this case?

FIGURE 3.3 Axial CT.

      a.  A parenchymal catheter

      b.  An epidural device

      c.  A subarachnoid bolt

      d.  An intraventricular catheter

      e.  Based on the images, an ICP monitor should not be placed

Questions 7–8

  7. A 20-year-old man was involved in a motor vehicle accident and suffered traumatic brain injury. He is intubated and admitted to the neurocritical care unit. An ICP monitor is placed measuring an ICP of 35 mm Hg. Hyperventilation is started, and 60 g of mannitol are given intravenously. Which of the following is correct regarding therapies for increased ICP?

      a.  Hyperventilation will produce a change in the CSF osmolarity, favoring the shift of fluid from neurons into the CSF

      b.  Hyperventilation is a short-lived therapy, and a rebound increase in the ICP may occur

      c.  Hyperventilation should target a partial pressure of CO2 of 15 to 20 mm Hg

      d.  Mannitol increases CSF osmolarity, creating an osmotic gradient that will drive fluid from the intravascular compartment into the CSF

      e.  Mannitol can be given in a continuous infusion and should be used to target a serum osmolarity of more than 330 mOsm/L

  8. The patient described in question 7 deteriorates, and his ICP remains persistently elevated. He is currently sedated on propofol and receiving hypertonic saline. Barbiturate coma is induced. Regarding these therapies, which of the following is correct?

      a.  Barbiturates decrease the ICP by reducing cerebral metabolic activity, thereby reducing cerebral blood flow and blood volume

      b.  Barbiturates should be titrated to an EEG pattern of continuous β activity

      c.  Hypertonic saline reduces the ICP by producing vasoconstriction and a reduction in cerebral blood flow

      d.  Complications of propofol use include hypertension and metabolic alkalosis

      e.  Propofol has a long half-life and has no effects on the ICP

  9. A patient is found in a “sleep-like” state, not responsive to verbal stimuli, and poorly responsive to tactile stimuli, but he can be aroused by constant and continuous stimulation. When aroused, his cognitive function is significantly impaired. Which of the following states of consciousness correlates with the findings on this patient?

      a.  Coma

      b.  Stupor

      c.  Locked-in state

      d.  Persistent vegetative state

      e.  Delirium

10. A 48-year-old man is found comatose after not being seen for at least 2 days. He requires endotracheal intubation on the way to the hospital and is admitted to the neurocritical care unit. His CT scan is shown in Figure 3.4 Which of the following is correct regarding the treatment of this patient?

      a.  Endovascular reperfusion therapy is the next step in treatment

      b.  Anticoagulation with intravenous heparin is indicated to prevent expansion of the stroke

      c.  Early hemicraniectomy improves survival

      d.  An intraventricular catheter should be placed

      e.  Dexamethasone should be started at a dose of 4 mg intravenously every 6 hours

FIGURE 3.4 Axial CT.

Questions 11–12

11. A 45-year-old patient with history of hypertension and end stage renal disease on hemodialysis presents with altered mental status and a blood pressure of 210/118 mm Hg. While in the emergency room he has a generalized tonic clonic seizure and requires endotracheal intubation. He is then admitted to the neurocritical care unit. His brain MRI is shown in Figure 3.5. Which of the following is the most likely diagnosis?

FIGURE 3.5 Axial FLAIR MRI.

      a.  Embolic strokes

      b.  Acute disseminated encephalomyelitis

      c.  Intracerebral hemorrhage

      d.  Viral encephalitis

      e.  Posterior reversible encephalopathy syndrome

12. Which of the following is incorrect regarding the condition of the patient depicted in question 11?

      a.  Specific immunosuppressive therapies have been implicated in the etiology of this condition

      b.  There has been an association with cancer chemotherapy and this condition

      c.  Hyperlipidemia is intimately linked with this condition

      d.  This condition is seen in association with eclampsia

      e.  Hypertensive encephalopathy is intimately linked with this condition

13. A patient with severe hypertension is treated with an intravenous infusion of sodium nitroprusside. Which of the following is correct regarding this medication?

      a.  It lowers the ICP and improves cerebral perfusion pressure

      b.  It improves renal perfusion, and therefore is useful in patients with renal disease

      c.  Sodium thiosulfate is used to treat the toxicity from one of its metabolites

      d.  It is a calcium channel blocker resulting in direct vasodilation and negative cardiac chronotropism and inotropism

      e.  Cyanide and thiocyanate are depleted with the use of sodium nitroprusside

14. Corticosteroids are used for the treatment of intracranial hypertension associated with which of the following etiologies?

      a.  Traumatic brain injury

      b.  Intracerebral hemorrhage

      c.  Ischemic stroke

      d.  Acute obstructive hydrocephalus

      e.  Brain tumors

15. A patient is admitted after suffering head trauma. His head CT is shown in Figure 3.6. Regarding this condition, which of the following is correct?

FIGURE 3.6 Axial CT.

      a.  The hemorrhage originates from tearing of cerebral surface bridging veins

      b.  The hemorrhage originates from rupture of the middle meningeal artery

      c.  It is associated with Charcot Bouchard aneurysms

      d.  Lipohyalinosis is present in cerebral vessels in this condition

      e.  Coiling or clipping of the culprit aneurysm will prevent rebleeding

16. A patient presents with nontraumatic SAH. On admission, he is drowsy and confused but moving all four extremities, with slight weakness on the right side. He is found to have a left MCA aneurysm and undergoes endovascular coiling on day 2. About 6 days later, his mental status declines and his right arm and leg become weaker. Which of the following is the most likely cause of his new symptoms?

      a.  Acute hydrocephalus

      b.  Rebleeding

      c.  Mass effect from the hematoma

      d.  Vasospasm

      e.  Uncal herniation

17. A 32-year-old man went whitewater rafting with his friends. They did not hire a tour guide, and there were not enough helmets. On the last rapid he fell out of the boat and hit his head on a rock. His friends brought him back on the boat and noticed that he was slightly confused, but minutes later he came back to normal and finished the ride. Six hours later he became lethargic and his left side was not moving properly. He was taken to the emergency room of a local hospital. The CT scan showed an epidural hematoma. What is the vessel ruptured and through which foramen does it enter the skull?

      a.  Jugular vein, through the jugular foramen

      b.  Middle meningeal artery, through the foramen lacerum

      c.  Jugular vein, through the foramen spinosum

      d.  Carotid artery, through the carotid canal

      e.  Middle meningeal artery, through the foramen spinosum

18. An 18-year-old man is involved in a motor vehicle accident. By the time emergency medical services arrive, he is dead. His autopsy shows evidence of diffuse axonal injury. Regarding this pathology, which of the following is correct?

      a.  Contusion is the main cause of diffuse axonal injury

      b.  It is more often seen in the site of contrecoup

      c.  Evidence of intracranial hemorrhage is required to make the diagnosis

      d.  Histopathologically, there is evidence of destroyed axonal cytoskeleton and retraction bulbs

      e.  The outcome is invariably fatal

19. Which of the following is incorrect regarding ICP monitor waveforms?

      a.  Lundberg A waves are associated with intracranial hypertension

      b.  B waves have amplitudes of 20 to 50 mm Hg

      c.  C waves last for 4 to 5 minutes and have amplitudes of less than 20 mm Hg

      d.  A waves last 1 to 2 minutes and are less sustained than B and C waves

      e.  B and C waves are seen in normal individuals

Questions 20–21

20. A 16-year-old girl is involved in a motorcycle accident while riding with her boyfriend. She was not wearing a helmet. On examination, she is comatose, has bruising around her eyes and behind her right ear, and drainage of clear fluid from the nose and the right ear. Based on the findings, which of the following is most likely present in this case?

      a.  Epidural hematoma

      b.  Skull base fracture

      c.  Intraparenchymal hemorrhage

      d.  SAH

      e.  Subdural hematoma

21. The boyfriend of the patient in question 20 was wearing a helmet. However, he suffered lung contusions, left sided pneumothorax, multiple fractures, and splenic laceration. He remained comatose, and his examination a few days after admission demonstrated multiple petechial hemorrhages throughout the skin, particularly in the axillary region. The patient died a few days later. On autopsy, the brain showed multiple diffuse petechial hemorrhages. Which of the following causes explain the neuropathologic findings?

      a.  Fat embolization

      b.  Diffuse axonal injury

      c.  Meningococcal meningitis

      d.  Coup and contrecoup injury

      e.  SAH

22. A 34-year-old man presents with ascending paralysis occurring 2 weeks after a diarrheal illness. On examination he has weakness of all four limbs, more distally than proximally, and deep tendon reflexes are absent. Analysis of CSF shows 1 μL WBCs (normal up to 5 lymphocytes/μL) and a protein level of 114 mg/dL (normal up to 45 mg/dL). Regarding this condition, which of the following is incorrect?

      a.  Corticosteroids are not indicated

      b.  Vital capacity should be measured frequently

      c.  Hypercapnia on arterial blood gas is the most sensitive indicator of the need for intubation

      d.  Blood pressure and heart rate monitoring is necessary in these patients

      e.  Intravenous immunoglobulin therapy or plasmapheresis can be used in this case

23. A 55-year-old woman was found on the floor with a left frontal scalp laceration. No other history could be obtained. On examination, she is lethargic and difficult to arouse. Her brain CT scan is shown in Figure 3.7. Which of the following is the most likely mechanism of this injury?

FIGURE 3.7 Axial CT

      a.  Fat embolization

      b.  Diffuse axonal injury

      c.  Aneurysmal rupture

      d.  Coup and contrecoup injury

      e.  Extension through the subdural space

Questions 24–25

24. A 45-year-old woman with no preceding history of trauma is admitted with sudden onset of severe headache and rapidly deteriorating alteration in mental status. On examination she is drowsy and confused, moving all four extremities but slightly weaker on the right side. No abnormal posturing is seen. Her brain CT scan is shown in Figure 3.8. Which of the following is the most likely cause of this condition?

      a.  Arteriovenous malformation

      b.  Aneurysmal rupture

      c.  Rupture of bridging veins

      d.  Laceration of the middle meningeal artery

      e.  Hypertensive hemorrhage

FIGURE 3.8 Axial CT.

25. In which of the following classifications would the patient in question 24 fall into?

      a.  Fisher 4

      b.  Hunt Hess 5

      c.  Hunt Hess 3

      d.  Fisher 1

      e.  World Federation of Neurological Surgeons Grading Scale 2

26. A 50-year-old woman with a history of alcoholism, depression, and congestive heart failure presents to your clinic with dysarthria and dysphagia. She had been admitted to an ICU 3 months earlier; details surrounding that admission are not clear, but the dysphagia and dysarthria had been present since then. An MRI of the brain is obtained and is shown in Figure 3.9. Regarding this condition, which of the following is not correct?

      a.  It is caused by rapid correction of hyponatremia

      b.  It is seen in liver transplant patients

      c.  It is associated with alcoholism

      d.  This condition is limited to the pons

      e.  It may be seen in patients with extensive burns

27. A 54-year-old woman with myasthenia gravis gets admitted to the hospital with cough, diarrhea, and generalized weakness. On examination her heart rate is 56, blood pressure is 120/68 mm Hg, she is alert and oriented, but looks anxious and sweaty, her pupils are small and sluggish, extraocular movements are normal, there is generalized weakness, and she has muscle fasciculations. Which of the following is the most likely diagnosis?

FIGURE 3.9 A. Axial FLAIR MRI; B. Sagittal T1-weighted MRI.

      a.  Myasthenic crisis

      b.  Botulism

      c.  Cholinergic crisis

      d.  Adrenergic crisis

      e.  Thyrotoxicosis

28. Which of the following is correct regarding the treatment of patients with SAH?

      a.  Hypertensive therapy should be avoided until the aneurysm is secure

      b.  Prophylaxis with antiepileptic agents is not indicated

      c.  Hypotonic fluids should be used for hemodilution

      d.  Nifedipine is the calcium channel blocker of choice to prevent vasospasm

      e.  Intraventricular catheter is standard of care for SAH Fisher grade 2

Questions 29–30

29. Which of the following findings will be seen in a comatose patient with a brainstem lesion and pinpoint pupils?

      a.  No response to pain on motor examination and ataxic breathing

      b.  Apneustic breathing pattern

      c.  Hyperventilation pattern with decorticate posture

      d.  Cheyne Stokes breathing

      e.  Hyperventilation

30. Which of the following conditions is associated with ataxic breathing (irregular gasping respiration)?

      a.  Hepatic coma

      b.  Pontine lesions

      c.  Medullary lesions

      d.  Forebrain impairment

      e.  Uremia

31. Which of the following is correct regarding diagnostic tests used for SAH?

      a.  The sensitivity of CT scan increases with time, being higher at 7 days than at 3 days from onset of hemorrhage

      b.  A four-vessel angiogram should be performed in all cases of nontraumatic SAH

      c.  The brain MRI is more sensitive than the CT scan in detecting the hemorrhage

      d.  The presence of xanthochromia in the CSF decreases with time, and this study is more sensitive in the first 6 hours from onset of hemorrhage

      e.  A lumbar puncture should be performed in all cases

Questions 32–33

32. A 60-year-old man with history of hypertension and atrial fibrillation on warfarin, suffers a sudden onset of headache and left hemiparesis. On arrival to the emergency room his initial blood pressure is 230/136 mm Hg and his Glasgow Coma Scale score is 6. His CT scan is shown in Figure 3.10. There is no living will and the family wants “everything done.” Which is the next step in the treatment of this patient?

FIGURE 3.10 Axial CT

      a.  Decompressive hemicraniectomy

      b.  External ventricular drain

      c.  Blood pressure control

      d.  Endotracheal intubation

      e.  Vitamin K and fresh frozen plasma

33. The patient depicted in question 32 has an INR of 6. Regarding the treatment of warfarin-related intracranial hemorrhage, which of the following is incorrect?

      a.  Vitamin K should be given intravenously

      b.  Fresh frozen plasma should be given

      c.  The use of recombinant Factor VIIa is associated with thromboembolic events

      d.  Recombinant Factor VIIa reduces hematoma expansion and accelerates correction of the INR

      e.  Protamine sulfate should be given

34. Which of the following is the best means of monitoring respiratory function in a patient with Guillain-Barré syndrome?

      a.  Arterial partial pressure of oxygen (pO2)

      b.  Negative inspiratory force and vital capacity

      c.  Asking the patient if he is dyspneic

      d.  Pulse oximetry

      e.  Arterial partial pressure of carbon dioxide (pCO2)

35. A 63-year-old woman who is admitted to the medical ICU with asthma exacerbation and pneumonia, develops septic shock. She is intubated and sedated, and given her bronchial constriction and difficulty ventilating she is administered paralytics. Broad-spectrum antibiotics are started, and bronchodilators are used along with steroids. She develops acute respiratory distress syndrome and her hospital course is complicated and prolonged. Over the next 3 weeks she improves; however, neurologic consultation is requested because the patient has severe weakness and areflexia in all four limbs, as well as difficulty weaning from the ventilator. A nerve conduction study is performed, showing normal latencies and conduction velocities and reduced compound motor and SNAP. Needle EMG shows numerous trains of fibrillation potentials and positive sharp waves in proximal muscles. What is the most likely diagnosis?

      a.  Acute inflammatory demyelinating polyneuropathy

      b.  Amyotrophic lateral sclerosis

      c.  Chronic inflammatory demyelinating polyneuropathy

      d.  Critical illness polyneuropathy and myopathy

      e.  Polymyositis

36. A 20-year-old man is noted to be febrile and have a depressed level of consciousness. His roommate brings him to the emergency room in his car, and while en route, he has a generalized tonic clonic seizure. By the time he reaches the emergency room, he has been seizing for 35 minutes. Besides ventilatory and hemodynamic support, the treatment of this patient should have the following sequence:

      a.  Lorazepam → Levetiracetam → Pentobarbital → Phenytoin

      b.  Fosphenytoin → Lorazepam → Phenobarbital → Repeat Fosphenytoin

      c.  Lorazepam → Midazolam → Pentobarbital → Fosphenytoin

      d.  Lorazepam → Fosphenytoin → Pentobarbital → Propofol

      e.  Lorazepam → Fosphenytoin → Propofol → Pentobarbital

37. Which of the following is the best predictor of outcome after cardiac arrest?

      a.  Bilateral absence of the N20 response on somatosensory-evoked potentials with median nerve stimulation

      b.  Creatine kinase BB isoenzyme

      c.  Duration of cardio-pulmonary resuscitation

      d.  Absent ocular movements within the first 24 hours

      e.  Absence of brain edema on CT scan

38. A 71-year-old man suffers a massive intracranial hemorrhage, and no brainstem reflexes are present on examination. The following is not consistent with a diagnosis of brain death:

      a.  Apnea test with no respiratory movements observed at a partial pressure of carbon dioxide (pCO2) level of 45 mm Hg with a core body temperature of 31°C

      b.  Absent brainstem reflexes

      c.  Cerebral angiography showing absent filling of contrast in the Circle of Willis

      d.  No cerebral electrical activity on an EEG recorded for 30 minutes

      e.  Absent signals on transcranial doppler

39. Which of the following correlates with decorticate rigidity?

      a.  Associated with pinpoint pupils

      b.  Lesion below the vestibular nucleus with facilitation of the rubrospinal tract

      c.  Lesion below the level of the red nucleus with facilitation of the vestibulospinal tract

      d.  Disinhibition of the red nucleus with facilitation of the rubrospinal tracts and lateral vestibulospinal tracts

      e.  Decreased activity of the rubrospinal tracts

40. Based on the CT scan shown in Figure 3.11, what type of herniation does this patient have?

FIGURE 3.11 Axial CT

      a.  Uncal herniation

      b.  Subfalcine herniation

      c.  Tonsillar herniation

      d.  Central transtentorial herniation

      e.  Transcalvarial herniation

41. Which of the following is incorrect regarding ICP volume and flow dynamics?

      a.  Hypercapnia produces an increase in ICP

      b.  Mean arterial pressure and ICP determine the cerebral perfusion pressure

      c.  The relation between intracranial volume and ICP is linear

      d.  Cerebral blood flow autoregulation is effective between mean arterial pressures of 60 and 150 mm Hg

      e.  A decrease in the hematocrit favors cerebral blood flow

42. Which of the following is incorrect regarding decompressive hemicraniectomy for ischemic stroke?

      a.  Outcomes are worse in patients older than 60 years of age

      b.  Hemispheric language dominance should be taken into account when discussing outcome with the family

      c.  Patients operated on earlier have better outcomes than those operated on later

      d.  Smaller and narrower bone flaps have better clinical results than larger bone flaps

      e.  This surgical procedure improves survival in patients with large hemispheric strokes

43. Which of the following is the most common cause of status epilepticus in adults?

      a.  Noncompliance with antiepileptic drugs

      b.  Central nervous system infection

      c.  Febrile seizures

      d.  Stroke

      e.  Tumors

44. Which of the following statements regarding principles of medical ethics is incorrect?

      a.  Beneficence is the principle of offering to patients diagnostic testing or interventions that would be of benefit to them

      b.  Nonmaleficence, or “do no harm,” is the principle of refraining from providing patients with treatments that will be harmful

      c.  In medicine, practicing beneficence and nonmaleficence often entails weighing risks against benefits, since some medical interventions, while perceived as being beneficial, carry potential risks

      d.  Justice is the principle of fair and equitable distribution of benefits to individuals

      e.  Autonomy is the principle of providing patients with limited options so that they are not confused by all the possibilities

45. A 40-year-old woman on no medications at home undergoes open cholecystectomy. About 45 minutes into the surgery, the end tidal partial pressure of carbon dioxide (PCO2) is increased in spite of increasing the respiratory rate. Her heart rate is also elevated, and her blood pressure becomes labile. Her temperature increases, reaching 104°F and generalized muscle rigidity is noticed. Which of the following is correct?

      a.  Inhaled anesthetic should be increased

      b.  Bromocriptine is the treatment of choice

      c.  This patient most likely has neuroleptic malignant syndrome

      d.  This patient most likely has serotonin syndrome

      e.  Dantrolene is the treatment of choice

Answer Key

1. a

2. d

3. c

4. a

5. b

6. d

7. b

8. a

9. b

10. c

11. e

12. c

13. c

14. e

15. a

16. d

17. e

18. d

19. d

20. b

21. a

22. c

23. d

24. b

25. c

26. d

27. c

28. a

29. b

30. c

31. b

32. d

33. e

34. b

35. d

36. e

37. a

38. a

39. d

40. b

41. c

42. d

43. a

44. e

45. e

Answers

1. a, 2. d

The patient depicted in question 1 has hydrocephalus, a condition associated with interstitial edema.

The patient depicted in question 2 has a brain tumor, a condition associated with vasogenic edema.

There are three types of cerebral edema: vasogenic, cytotoxic, and interstitial.

The patient depicted in question 1 has an acute onset of symptoms suggestive of increased ICP, and a CT scan of the brain showing hydrocephalus. Given the rapid progression of the symptoms, the patient most likely has an acute obstructive hydrocephalus, in which there is disturbance in the normal flow of CSF within the ventricular system and/or from the ventricles to the subarachnoid space. The type of edema seen in acute obstructive hydrocephalus is interstitial edema, as the CSF is forced by hydrostatic pressure to move from the ventricular spaces to the interstitium of the parenchyma. Transependymal edema is another term used for this type of edema.

The patient depicted in question 2 has a brain tumor with surrounding vasogenic edema. Vasogenic edema is an extracellular accumulation of fluid that is usually associated with a disruption in the blood-brain barrier, leading to the extravasation of fluid out of the intravascular space. Multiple factors play a role in extravasation of fluid, including hydrostatic forces, inflammatory mediators, and endothelial permeability, leading to the opening of the endothelial tight junctions and subsequent formation of the edema. Vasogenic edema is usually seen surrounding neoplastic lesions.

In cytotoxic edema there is intracellular accumulation of fluid. This type of edema is most commonly seen in hypoxic-ischemic insult, in which there is a lack of energy to the cells, leading to depletion of adenosine triphosphate (ATP) and subsequent failure of the Na-K ATPase, causing an alteration in the selective permeability of cellular membranes. Cytotoxic edema may also be seen with alterations in the systemic osmolality, leading to intracellular edema.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 3. c

There is evidence to support the use of hypothermic therapy in cardiac arrest from ventricular fibrillation, but not in pulseless electrical activity or in asystole.

Patients with out-of-hospital cardiac arrest have a very high mortality rate, and those who survive have a significant risk of cerebral and cognitive dysfunction caused by damage from the absence of blood flow.

Based on recent studies, management recommendations for unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest when the initial rhythm is ventricular fibrillation have been proposed. These patients should be treated with hypothermia targeting a temperature of 32°C to 34°C for 12 to 24 hours. This therapy may also be beneficial for patients with other types of cardiac arrest, such as pulseless electrical activity or asystole; however, as of 2011 there is not strong evidence to support its use in these latter cases.

Mild hypothermia with temperatures between 32°C and 34°C has been used safely. However, lower temperatures may not provide extra benefit and may be harmful.

 Sanders A. Therapeutic hypothermia after cardiac arrest. Curr Opin Crit Care. 2006; 12:213–217.

 4. a

Uncal herniation produces mass effect and pressure over the ipsilateral midbrain, affecting the ipsilateral cranial nerve III nucleus, and the corticospinal fibers. The mass effect compresses parasympathetic fibers that mediate miosis, resulting in mydriasis. Since the corticospinal tract has not decussated at the level of the midbrain, patients have a contralateral hemiparesis. Occasionally, the uncal herniation will lead to displacement of the midbrain against the contralateral Kernohan’s notch, resulting in a contralateral compression of the corticospinal tract, and therefore an ipsilateral hemiparesis.

The other types of herniation syndromes do not include an ipsilateral dilated pupil with contralateral hemiparesis.

 Posner JB, Saper CB, Schiff ND, Plum F. Plum and Postern’s Diagnosis of Stupor and Coma, 4th ed. New York, NY: Oxford University Press; 2007.

 5. b

Hypernatremia is not a cause of cerebral edema.

There are different types of cerebral edema—Vasogenic edema, in which there is accumulation of fluid in the extracellular space, and cytotoxic edema, in which the fluid accumulates in the intracellular space.

In hyponatremia, there is a decrease in the osmolarity of the extracellular fluid, leading to the entry of water into the cells, especially when hyponatremia develops rapidly. On the other hand, in hypernatremia water moves from the intracellular space to the extracellular space; therefore, there is no cerebral edema. To that end, hypertonic saline and other hyperosmolar agents are used for the treatment of cerebral edema.

Prolonged cardiac arrest leading to hypoxic-ischemic encephalopathy is associated with diffuse cytotoxic edema, likely caused by the lack of energy supply and failure of the Na-K ATPase pumps in cellular membranes.

Rapid ascent into high altitude, lead intoxication, and liver failure are other conditions associated with cytotoxic cerebral edema.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 6. d

An intraventricular catheter should be placed. The CT scan depicts hydrocephalus with intraventricular blood. To measure the ICP, a surgically placed device is required. In general, an ICP-measuring device may be used in patients with a Glasgow Coma Scale score of 7 or less, and should be placed if the following conditions are met:

–  The patient has a condition leading to ICP elevation amenable to treatment.

–  The ICP measurement will have an impact on the decisions made for the treatment of the patient.

–  The benefits of the device outweigh the risks.

If there is a need for ventricular CSF drainage, an intraventricular device is preferred. This patient has hydrocephalus with intraventricular blood and needs an intraventricular catheter. This device is inserted through a burr hole into the ventricular system, providing the capability to transduce the ICP and allowing the possibility of CSF drainage, which can help decrease ICP. Intraventricular catheters have a 1% to 6% risk of hemorrhage and a 2% to 22% risk of infection.

Parenchymal devices are inserted into the brain parenchyma and provide pressure measurements. However, these do not allow CSF drainage and may be susceptible to pressure gradients across the parenchyma.

Epidural devices are placed between the dura and the calvarium and have lower rates of hemorrhage and infection, but their accuracy is low. Subarachnoid bolts are placed in continuity with subarachnoid space. The accuracy is not optimal, but their placement is relatively technically simple and the risks of infection and hemorrhage are not as high as with intraventricular devices.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 7. b

Hyperventilation is a short-lived therapy, and a rebound increase in the ICP may occur.

This patient has increased ICP, which normally ranges between 5 and 15 mm Hg. Intracranial hypertension is deleterious since it produces a decrease in the cerebral perfusion pressure and therefore cerebral blood flow, resulting in cerebral ischemia. The care of the patient with increased ICP includes general measures and more specific therapy. The general measures are used in every patient and include head position (the head should be elevated above 30 degrees), maintenance of normothermia, glucose control, blood pressure control, adequate nutrition, and prevention of complications.

Specific interventions to reduce ICP include hyperventilation, use of osmotic agents, use of hypertonic solutions, use of corticosteroids in select cases, CSF drainage, surgical decompression in select cases, and barbiturate coma, pharmacologic paralysis, and hypothermia in refractory cases. Some of these therapies are controversial.

Hyperventilation has a rapid effect; however, it lasts for 10 to 20 hours and subsequently a rebound phase with increased ICP may be seen. Hyperventilation produces a reduction in partial pressure of CO2 (pCO2), and this hypocapnia leads to cerebral vasoconstriction, reducing cerebral blood volume and therefore reducing ICP. This therapy should be used to target a reduction of 10 mm Hg of the pCO2, and/or to a target of approximately 30 mm Hg of pCO2, and should be reversed slowly. Hyperventilation does not act by changing the CSF osmolarity.

Mannitol is an osmotic agent and acts by raising the serum osmolarity and producing an osmotic gradient driving the flow of water from the interstitium to the intravascular compartment. It is usually given in boluses of 0.5 to 1 g/kg and not as a continuous infusion. While on this medication, serum osmolarity should be checked at regular intervals targeting a level closer to 320 mOsm/L. Mannitol as an osmotic agent will also produce diuresis and may produce hypotension and hypovolemia. It is associated with depletion of potassium, magnesium, and phosphorus. If there is damage to the blood-brain barrier, mannitol can leak into the interstitium, worsening vasogenic edema.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 8. a

Barbiturates decrease the ICP by reducing cerebral metabolic activity and thereby reducing cerebral blood flow and blood volume.

Propofol is a commonly used sedative agent in the neurocritical care unit since it has a short half-life permitting prompt neurologic examinations soon after it is discontinued. It produces sedation within a few minutes, it has a drug effect that lasts between 5 and 10 minutes, and awakening may occur 10 to 15 minutes after discontinuation (depending on the baseline neurologic function). Propofol also has been shown to reduce the ICP in patients with normal intracranial dynamics and preserved cerebral perfusion pressure, which makes this attractive in the care of patients with increased ICP. Unfortunately, Propofol is not free of side effects, and a prominent hypotensive effect is frequently encountered. Other complications include hypertriglyceridemia and infections. Propofol infusion syndrome is a lethal complication seen rarely, mainly in patients on high doses for long periods of time, and manifests with hypotension, bradycardia, lactic acidosis, hyperlipidemia, and rhabdomyolysis.

Hypertonic saline reduces the ICP by drawing water out from brain cells via an osmotic gradient. It can be used as a continuous infusion targeting a serum sodium concentration of 150 mmol/L. Serum sodium concentration should be monitored closely during administration of hypertonic saline, and changes should occur very gradually.

Barbiturates may be used when the ICP is elevated and refractory to other measures. These agents reduce the ICP by lowering cerebral metabolic activity, leading to a decrease in cerebral blood flow and blood volume. Patients on barbiturate coma should have continuous EEG monitoring to titrate to burst-suppression. Continuous β activity is seen with benzodiazepines and is not a treatment goal. Pentobarbital is the barbiturate of choice and is usually started with a bolus followed by a continuous infusion. Its discontinuation should be gradual. Unfortunately, barbiturate coma has multiple complications, including hypotension, myocardial depression, predisposition to infections, and hypothermia.

 Marino PL. The ICU Book, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 9. b

This patient is stuporous. The following are the definitions for these terms:

Stupor: state of pathologically reduced consciousness from which the patient can be aroused to purposeful response only with external stimulation.
Coma: state of unresponsiveness, in which the patient cannot be aroused even with vigorous stimulation. There may be a grimace response or stereotyped withdrawal movement of the limbs to noxious stimulation, but the patient does not localize to the stimulus.
Locked-in state: occurs in brainstem lesions, in which the patient is awake and conscious, but quadriplegic, with paralysis of the lower cranial nerves, and with horizontal gaze palsy. The patient can typically blink and move his eyes vertically (because of sparing of the vertical gaze centers) and may be able to communicate with vertical eye movements and blinking.
Persistent vegetative state (PVS): a vegetative state that last for more than 30 days. Vegetative state is characterized by return of sleep-wake cycles in an unresponsive patient (usually previously comatose), with apparent lack of cognitive function.
Delirium: a disturbance of consciousness, with poor attention and reduced ability to focus. This state develops over a short period of time and tends to fluctuate.
Obtundation: this term is not defined in neurology and should not be used.

 Bradley WG, Daroff RB, Fenichel GM, Jankovic J. Neurology in Clinical Practice, 5th ed. Philadelphia, PA: Elsevier; 2008.

 Posner JB, Saper CB, Schiff ND, Plum F. Plum and Postern’s Diagnosis of Stupor and Coma, 4th ed. New York, NY: Oxford University Press; 2007.

10. c

This patient has a large right MCA infarct that affects almost the entire MCA vascular territory, with evidence of cerebral edema and midline shift. Reperfusion therapy in acute ischemic stroke either with intravenous tissue plasminogen activator (tPA) or intraarterial therapies is used within the first few hours since the onset of symptoms, and when there is brain tissue at risk for ischemia. In this patient, a large portion of the brain tissue in the affected vascular territory has already infarcted, since the CT scan shows hypodensity, and there is very little, if any, salvageable tissue in this vascular distribution. Therefore, reperfusion therapy should not be contemplated.

Cerebral edema in ischemic stroke develops within hours of stroke onset, with a peak of maximal swelling at days 2 to 5 poststroke. Malignant cerebral edema, which occurs in complete MCA infarctions, is associated with up to 80% mortality with conservative therapy. It is most commonly seen in strokes with occlusions at the ICA terminus and most proximal (M1) segment of the MCA. Other predictors of malignant cerebral edema include high National Institute of Health Stroke Scale (NIHSS) score (greater than 15), hypertension, early hypodensity of more than 50% of the MCA territory on CT, and younger age. The initial management of these patients is based on supportive care, along with tight control of blood glucose, blood pressure, and temperature. General measures for the treatment of increased ICP, such as hyperventilation, hypertonic saline, and mannitol, are also used. In the appropriate patient (see discussion in question 42), the plan for early hemicraniectomy (<48 h from symptom onset) should be discussed soon with the family, since this intervention improves survival.

Anticoagulation should not be used and may increase the risk of hemorrhage.

An intraventricular catheter is not indicated, since there is no hydrocephalus or intraventricular blood on CT, and there are no clear indications for ICP measurement in this case (see question 6). Steroids play no role in the treatment of cerebral edema in the setting of ischemic stroke.

 Bershad EM, Humphreis WE, Suarez JI. Intracranial hypertension. Semin Neurol. 2008; 28:690–702.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

 Subramaniam S, Hill MD. Decompressive hemicraniectomy for malignant middle cerebral artery infarction: An update. Neurologist. 2009; 15:178–184.

11. e, 12. c

This patient has posterior reversible encephalopathy syndrome (PRES), also known as reversible posterior leukoencephalopathy syndrome (RPLS), and this condition is not associated with hyperlipidemia.

The diagnosis of PRES is usually based on neuroimaging demonstrating a characteristic pattern of vasogenic edema predominantly in the posterior cerebral region, especially in the occipital and parietal lobes (though more anterior areas can also be involved in PRES). Risk factors and causative factors associated with PRES include hypertension, renal failure, organ transplantation, autoimmune diseases, immunosuppressive drugs (particularly cyclosporine), cancer chemotherapy, preeclampsia, and eclampsia. Hyperlipidemia is not associated with PRES. Clinical manifestations include headache, nausea, visual changes, focal neurologic symptoms, altered mental status, coma, and seizures. Most patients present with severe hypertension, and some theories suggest that PRES is a manifestation in the spectrum of hypertensive encephalopathy. The pathophysiology is not well understood, but it is thought to be related to a disruption in autoregulation of the posterior circulation, which associated with hypertension and hyperperfusion results in alteration of the blood-brain barrier and vasogenic edema. Endothelial injury and dysfunction also play a role.

The treatment of this condition consists of aggressive blood pressure control. Supportive care is part of the treatment, and many times these patients need intensive care observation. Treating the underlying condition and/or withdrawing the offending etiologic factor is a central part of the treatment.

 Bartynski WS. Posterior reversible encephalopathy syndrome, part 1: Fundamental imaging and clinical features. Am J Neuroradiol. 2008; 28:1036–1042.

13. c

Sodium nitroprusside is a vasodilator that produces arterial and venous dilation and reduces blood pressure rapidly. It is used in a continuous infusion; while it is not the first line of treatment for hypertension, it may be indicated in severe hypertension. When sodium nitroprusside enters the circulation, nitric oxide and cyanide are produced. Nitrous oxide then acts through the guanylate cyclase pathway, increasing cyclic guanosine monophosphate (GMP) and producing vasodilation. The vasodilation occurs in both cerebral and systemic vessels, causing an increase in cerebral blood flow and volume, and increasing the ICP, which along with a decrease in the mean arterial pressures can compromise cerebral perfusion pressure. Therefore, sodium nitroprusside should be used cautiously in patients with increased ICP. With continuous and prolonged infusion of sodium nitroprusside, cyanide and thiocyanate toxicity can occur. Cyanide originates from the nitroprusside molecule and can be cleared by binding to methemoglobin, or when thiosulfate donates a sulfur group, transforming the cyanide into thiocyanate. Cyanide intoxication manifests by behavioral changes, obtundation, coma, seizures, and lactic acidosis. The accumulation of cyanide can be treated with sodium thiosulfate, which provides sulfur groups favoring the conversion to thiocyanate, which can be cleared by the kidneys. However, thiocyanate can also produce toxicity, and the risk of this intoxication is increased in patients with renal disease; therefore, sodium nitroprusside should not be used in this patient population. Manifestations of thiocyanate toxicity include anxiety, confusion, pupillary constriction, tinnitus, hallucinations, and seizures. This intoxication can be treated with dialysis.

 Marino PL. The ICU Book, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

14. e

Corticosteroids are used for the treatment of intracranial hypertension associated with primary brain tumors and metastasis to the brain. Corticosteroids are beneficial in vasogenic cerebral edema as is seen with intracranial tumors, either primary or metastatic. However, the exact mechanism of action of steroids in vasogenic edema is not well understood. Available evidence suggests that corticosteroids are not useful in the management of other conditions commonly associated with cerebral edema such as traumatic brain injury, intracerebral hemorrhage, or ischemic stroke. This is explained in part by the difference in the type of edema seen in the latter conditions (see questions 1 and 2). Acute obstructive hydrocephalus requires a neurosurgical intervention.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

15. a

The CT scan in Figure 3.6 shows a subdural hematoma, in which blood accumulates in the subdural space adopting a crescentic or concave shape over the cerebral convexity. The most common cause is trauma, by producing an acceleration force, thereby tearing and causing rupture of the cerebral surface bridging veins that drain into the dural venous sinuses. Patients usually present with headache, change in mental status, and focal neurologic deficits. Surgical evacuation is indicated if the subdural hematoma is more than 1 cm or if there is midline shift. If the subdural hematoma is small it may be observed without the need for surgical evacuation.

Rupture of the middle meningeal artery (usually associated with skull fracture) causes an epidural hematoma, in which the CT scan shows a lenticular-shaped biconvex hyperdensity. Lipohyalinosis and Charcot-Bouchard aneurysms are seen in chronic hypertension and may be associated with intraparenchymal hemorrhage. Subdural hematomas are not caused by aneurysmal rupture; therefore, coiling or clipping of an aneurysm is not indicated in this case.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

16. d

The cause of the new symptoms in the patient depicted in question 16 is likely vasospasm. Vasospasm causing ischemia and delayed infarcts is the leading case of morbidity and mortality in patients who survive initial SAH. Vasospasm can occur between 3 and 15 days from the onset of the bleeding, with a peak between days 6 and 8. The pathophysiology is not understood, but there is evidence of an inflammatory basis. Symptoms of vasospasm include headache, nausea, vomiting, altered mental status, and focal neurologic deficits. Transcranial doppler ultrasonography provides information by detecting the velocity of the flow in the intracranial vessels and should be performed daily to follow up the trends of these velocities. CT angiograms and conventional angiograms are helpful in the diagnosis of vasospasm.

Acute hydrocephalus, rebleeding, and vasospasm are complications of SAH. If a hematoma forms, it can produce mass effect and lead to uncal herniation. Acute hydrocephalus occurs from obstruction of the cerebral aqueduct associated with intraventricular extension of blood. Clinical manifestations include worsening headache, change in mental status, and coma. Treatment is placement of an intraventricular catheter. Rebleeding usually occurs early on, when the aneurysm has not been secured.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

17. e

Epidural hematoma is most commonly caused by head trauma, leading to rupture of the middle meningeal artery, which passes through the foramen spinosum. Rupture of this artery results in accumulation of blood in the epidural space. The appearance on CT is lenticular shaped or biconvex. Clinically, patients may present with a brief loss of consciousness followed by a lucid interval and subsequent deterioration over hours.

The jugular vein passes through the jugular foramen; however, injury to it is not the cause of epidural hematomas. The carotid artery passes through the carotid canal and runs in the foramen lacerum; however, injury to this structure is not the cause of epidural hematomas.

 Blumenfeld H. Neuroanatomy Through Clinical Cases, 1st ed. Sunderland, MA: Sinauer; 2002.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

18. d

Diffuse axonal injury occurs from disruption of intracerebral axons and is caused by the effect of angular accelerations and shear injury, and not from direct contusion. Patients with diffuse axonal injury typically have loss of consciousness and amnesia that lasts for longer than 6 hours. Coma with long-term disability may occur, but in general, patients with isolated diffuse axonal injury have good outcomes at 3 months in 15% to 65% of cases. Neuropathologically, there is evidence of destruction of axonal cytoskeletons, with the presence of retraction bulbs, typically at the gray-white junction or along white matter fiber tracts.

Along the same spectrum of diffuse axonal injury is brain concussion, in which there is alteration of consciousness with confusion and amnesia in the setting of brain trauma, but with no evidence of contusion, and the prognosis is good.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

19. d

A waves last between 5 to 20 minutes and are more sustained than B and C waves.

ICP can be reliably assessed using invasive ICP monitors that will display several waveforms. Lundberg A waves or “plateau waves” are pathologic and associated with decreased intracranial compliance and intracranial hypertension, with the risk of cerebral ischemia. These waves are sustained with duration between 5 and 20 minutes. Their amplitude is high, in the range of 50 100 mm Hg. B waves are normal, with duration of 1 to 2 minutes and amplitudes in the range of 20 to 50 mm Hg. C waves are also normal and last for 4 to 5 minutes with less than 20 mm Hg of amplitude.

Along with the above-mentioned waves, the cardiac cycle and respirations also influence ICP monitor tracings.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

20. b

Signs of skull fracture include periorbital ecchymoses or hematoma (raccoon eyes), postauricular ecchymosis (Battle’s sign), CSF rhinorrhea, and otorrhea.

Patients with head trauma may have a broad variety of injuries, including scalp injury, cervical injury, linear or depressed skull fractures, basal skull fractures, epidural hemorrhage, subdural hemorrhage, intraparenchymal hemorrhages, cerebral contusions, and SAH. All these can be potentially present in the patient depicted in this case; however, given the clinical findings, skull fracture is most likely to be present.

Patients with head trauma should be initially stabilized at the scene, with subsequent ICU care to prevent secondary injuries from hypoxia, increased ICP, and brain edema. ICU care includes not only management of increased ICP but also blood glucose control, blood pressure control, temperature control, prevention of deep venous thrombosis and infections, nutrition, and ventilatory and hemodynamic support. Surgery may be needed in some cases. In the case of basal skull fracture, nasogastric tubes should be avoided, and antibiotics should be used prophylactically since there may be an external access to the CSF.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

21. a

This patient has had fat embolism, which results from fat droplets entering the circulation usually in the setting of surgery or trauma, and most frequently after fractures of long bones such as the femur. Fat microparticles from the bone marrow travel in the venous system to the lungs and spread systemically. Patients will present with agitation, delirium, coma, respiratory distress, anemia, thrombocytopenia, and generalized petechial rash, often concentrated in the axilla, subconjunctival area, and palate. Multiple petechial hemorrhages can be seen in the gray and white matter of the brain on autopsy.

The clinical presentation and finding of petechial hemorrhages after multiple fractures is not consistent with the other options.

 Posner JB, Saper CB, Schiff ND, Plum F. Plum and Postern’s Diagnosis of Stupor and Coma, 4th ed. New York, NY: Oxford University Press; 2007.

22. c

Hypercapnia on arterial blood gas is not a sensitive indicator of the need for intubation in this setting.

This patient has a progressive ascending paralysis after a diarrheal illness and albumino-cytologic dissociation evidence from CSF analysis, which is consistent with Guillain Barré syndrome (GBS), an acute inflammatory demyelinating polyneuropathy. Patients with this disorder should be hospitalized and may need intensive unit care, since they may develop respiratory failure, inability to protect the airway, and autonomic dysfunction, with labile blood pressure and cardiac arrhythmias. Therefore, these patients should have close cardiac and ventilatory monitoring with frequent evaluations of negative inspiratory force and vital capacity. Arterial blood gases are not accurate predictors of the need for intubation and mechanical ventilation, since hypoxia and hypercapnia occur late in the course of respiratory failure, once the patient is decompensating.

The care of these patients include general supportive care, prevention of complications, rehabilitation, and specific therapies for the inflammatory process, which include plasmapheresis and intravenous immunoglobulin. Steroids play no role in the treatment of GBS.

 Hughes RA, Wijdicks EF, Barohn R, et al. Practice parameter: Immunotherapy for Guillain-Barre syndrome: Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2003; 61:736–740.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

23. d

This patient suffered head trauma with coup and contrecoup injury. Figure 3.7 shows a left frontal lobe hematoma from direct contusion (coup) as well as a right occipito-temporal hematoma (contrecoup injury). The scalp laceration in this patient indicates that the initial impact was in the left frontal region. As deceleration occurs, the frontal lobe strikes the frontal bone and the falx, leading to formation of a hematoma. The countrecoup also seen in this patient is the result of injury that occurs distant from the site of initial impact and is usually seen in the frontal or temporal lobes, as these are in close relationship with the frontal bone and the sphenoid ridge, respectively.

With cerebral contusions there may be loss of consciousness and focal deficits, and subsequent rapid deterioration from mass effect. Multiple contusions can predispose to the rapid development of cerebral edema and elevated ICP.

The CT scan findings do not correlate with SAH from aneurysmal rupture, subdural hematoma, fat embolization, or diffuse axonal injury.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

24. b, 25. c

This patient has SAH, most likely caused by aneurysmal rupture. This patient’s SAH is graded as Hunt Hess of 3. This patient has a clinical presentation and CT scan findings of a SAH, which seems to be denser in the left Sylvian fissure, likely associated with rupture of a left MCA aneurysm, as seen in Figure 3.8.

Overall, the most common cause of SAH is trauma, and aneurysmal rupture is the most common nontraumatic cause. Hypertension and smoking are the most important risk factors for aneurysmal SAH. Family history, heavy alcohol use, atherosclerosis, and oral contraceptives are other risk factors for this condition.

TABLE 3.1 SAH grading scales

The diagnosis of SAH can be suspected based on a clinical presentation of sudden onset severe headache (thunderclap headache, the “worst headache of my life”), sometimes accompanied by nausea, vomiting, photophobia, and neck stiffness. Altered mental status, coma, and focal neurologic findings are also common.

Whenever a SAH is suspected, a brain CT should be performed, demonstrating the hemorrhage in more than 95% of the cases when the scan is performed within 48 hours. If the CT scan is negative, a lumbar puncture should be performed in order to detect blood in the subarachnoid space, evidenced by elevated RBC count and xanthochromia. A negative CT scan does not rule out SAH.

Clinical and radiologic grading systems have been developed for SAH and include the Hunt and Hess Grading Scale, World Federation of Neurological Surgeons Grading Scale, and the Fisher Scale (Table 3.1).

 Drake CG, Hun WE, Sano K, et al. Report of World Federation of Neurological Surgeons Committee on a universal subarachnoid hemorrhage grading scale. J Neurosurg. 1988; 68:985–986.

 Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning. Neurosurgery. 1980; 6:1–9.

 Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968; 28:14–20.

 Rosen DS, Macdonald RL. Subarachnoid hemorrhage grading scales. Neurocrit Care. 2005; 2:110–118.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

26. d

The history and images are consistent with central pontine myelinolysis (CPM), which is a disorder seen after rapid and aggressive correction of hyponatremia. This condition is not limited to the pons and could affect other areas of the central nervous system.

Because of the risk of CPM, the rate of correction of hyponatremia should be no more than 12 mEq/L per day, or 0.5 mEq/L per hour. Patients may develop CPM after rapid correction of hyponatremia, and the manifestations are evident within 3 to 10 days, with progressive paraparesis or quadriparesis, pseudobulbar palsy, dysphagia, dysarthria, and altered mental status. Progressive extension of the demyelination may lead to locked-in syndrome. Most patients who survive will have clinical disabilities.

Pathologically, there is bilateral symmetric focal destruction of myelin in the ventral pons, sparing axons and neuronal cell bodies. The myelin disruption is not limited to the pons, and extrapontine myelinolysis has been observed in the cerebellum, thalamus, external and extreme capsules, basal ganglia, deep layers of the cerebral cortex and adjacent white matter, and sometimes even in the fornix, subthalamic nucleus, amygdala, optic tract, and spinal cord.

Other conditions associated with CPM are severe alcoholism, chronic liver disease and liver transplantation, and extensive burns.

 Aminoff MJ. Neurology and General Medicine, 4th ed. Philadelphia, PA: Elsevier; 2008.

27. c

This patient is in cholinergic crisis. Patients with myasthenia gravis taking excessive amounts of acetylcholinesterase inhibitors such as pyridostigmine may be at risk for a cholinergic crisis (also discussed in Chapter 10). It is sometimes difficult to differentiate this from a true myasthenic crisis; when patients start experiencing symptoms of worsening myasthenia, they may increase the frequency and dose of their pyridostigmine, putting themselves at risk for a cholinergic crisis.

The following include manifestations of a cholinergic crisis: small and even pinpoint pupils, excessive secretions, diarrhea, sweating, bradycardia, muscle weakness, and fasciculations. The symptoms will subside with cessation of the acetylcholinesterase inhibitor. The presence of pinpoint pupils and increased cholinergic activity suggest a cholinergic crisis and not a myasthenic crisis. A patient with adrenergic crisis or thyrotoxicosis may have similar manifestations but will have mydriasis and tachycardia. The clinical picture does not correlate with botulism (discussed in Chapter 17).

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

28. a

In SAH, hypertensive therapy should be avoided until the aneurysm is secure. The goals of therapy in SAH are initial stabilization, prevention of complications such as rebleeding and vasospasm, and specific aneurysmal treatment.

Patients who are comatose or cannot protect the airway should be intubated. Blood pressure should be controlled, and hypertension should be avoided in the first few hours, and until the aneurysm has been secured (either by clipping or coiling). Intravenous isotonic fluids are aggressively administered, and hypotonic fluids should be avoided. Until the aneurysm is secured, prophylactic antiepileptic agents are given, since a generalized seizure may be catastrophic in a patient with an unsecured aneurysm. Mild sedation should be generally provided, and pain control should be optimal.

Nimodipine (not Nifedipine) is a calcium channel blocker that is utilized in a dose of 60 mg every 4 hours for 21 days following aneurysmal SAH and has been shown to improve outcomes from vasospasm. Pravastatin therapy has also been shown to improve outcomes and reduce delayed ischemic deficits from vasospasm.

Specific aneurysmal treatment includes isolation of the aneurysm from the circulation, either by surgical clips or endovascular coils. Once the aneurysm is secure, blood pressure can be liberalized, and hypertensive therapy can be used in case of vasospasm. “Triple H therapy” is used for the treatment of vasospasm, and it consists of hypervolemia, hypertension, and hemodilution. This is achieved by expanding the intravascular volume using isotonic fluids, and sometimes colloids such as albumin. Vasopressors can also be utilized. The risk of triple H therapy includes rebleeding from an unsecured aneurysm, pulmonary edema, congestive heart failure, and cerebral edema. If vasospasm is refractory, endovascular therapies may play a role, including intraarterial papaverine or nicardipine, or direct angioplasty. The use of intraventricular catheters is reserved for acute hydrocephalus, or intraventricular extension of blood (Fisher grade 4).

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

29. b,

30. c

Apneustic breathing pattern is seen in patients with pontine lesions (patients with pontine lesions have pinpoint pupils). Medullary lesions are associated with ataxic breathing.

Breathing is a complex action that is integrated by circuits in the brainstem, with connections at different neural levels in the brain and upper cervical cord, and under the influence of chemical and mechanical input that enter via the vagus and the glossopharyngeal nerves. Respiratory rhythm is an intrinsic function of a group of neurons in the ventrolateral medulla, but under the control of a pontine cell group that integrates breathing with other functions, reflexes, and metabolic input.

Apneusis is a respiratory pause at full inspiration and occurs from bilateral pontine lesions. Since pinpoint pupils are seen in pontine lesions, it is most likely that this patient will have an apneustic breathing pattern, and likely decerebrate posture.

Cheyne Stokes respiration is a pattern of periodic breathing in which hyperpnea alternates with apnea and the depth of breathing increases and decreases gradually. It is seen in patients with forebrain impairment in the setting of intact brainstem respiratory reflexes, but it is also present in patients with cardiopulmonary disease.

Hyperventilation may be seen in metabolic encephalopathies such as in uremia and hepatic encephalopathy, but has also been reported in patients with midbrain lesions.

Ataxic breathing is an irregular and gasping respiration seen with lesions damaging the respiratory rhythm generator in the upper medulla.

 Posner JB, Saper CB, Schiff ND, Plum F. Plum and Posner’s Diagnosis of Stupor and Coma, 4th ed. New York, NY: Oxford University Press; 2007.

31. b

A four-vessel angiogram should be performed in all cases of SAH.

All patients with suspected SAH should have a brain CT scan, which will detect hemorrhage in 95% of the cases within 48 hours of the bleed. As days pass, the sensitivity of the CT will drop, being approximately 50% by day 7 posthemorrhage. If the CT does not show the hemorrhage, but there is high clinical suspicion, a lumbar puncture should be performed. CSF RBC count that does not decrease in subsequent tubes and xanthochromia are findings consistent with SAH. The appearance of xanthochromia requires the presence of RBCs in the CSF for some time; therefore, it may not be present in the first few hours following the hemorrhage.

A lumbar puncture is not required in all cases, and actually is rarely performed if the CT scan shows the hemorrhage. Brain MRI is less sensitive for SAH, and therefore is less helpful in the acute setting.

To determine the presence of aneurysm, a CT angiogram or MR angiogram can be performed; however, conventional cerebral angiography is the gold standard, and a four-vessel angiogram should be performed in all cases of SAH, since about 15% of the patients will have multiple aneurysms in different territories.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

32. d

The first step in the treatment of this patient is endotracheal intubation.

This patient has a massive intracranial hemorrhage, likely originating from the basal ganglia and extending to the ventricles. As in every patient who is in a critical condition, an initial survey should be performed, addressing the “ABC” (airway, breathing, circulation). Therefore, this patient should be intubated first in order to receive ventilatory support and maintain oxygenation. Second, hemodynamic support should be addressed, and in this case, blood pressure control is paramount. Once the patient is stable from the ventilatory and hemodynamic standpoint, specific therapies to address his neurologic condition should be started, such as correction of coagulopathy if this is present, an external ventricular drain, and surgical decompression, if needed.

It is important to always address the goals of therapy, code status, and end-of-life care with the family. This should be done early to avoid nondesired treatment against the patient’s wishes and his family.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

33. e

Protamine sulfate does not correct warfarin-related coagulopathy. Protamine sulfate is utilized to reverse anticoagulation due to heparin, and it plays no role in the treatment of warfarin-related intracranial hemorrhage.

Coagulation factors II, VII, IX, and X and the anticoagulant proteins C and S require γ-carboxylation in the liver for their activation, and this process requires the reduced form of vitamin K. Warfarin is a vitamin K antagonist. Warfarin is rapidly absorbed in the gastrointestinal tract, highly bound to proteins, and metabolized in the liver. The use of this medication causes a prolongation in the prothrombin time (PT). However, to standardize the measure, the INR is used for this purpose.

Patients presenting with warfarin-related intracranial hemorrhage and a high INR need various therapies to reverse the anticoagulation and arrest the bleeding process. Administration of vitamin K is effective in reversing the effects of warfarin, and it can be used by oral, subcutaneous, or intravenous route. The intravenous route is preferred for urgent reversal of anticoagulation, with the rare risk of anaphylaxis. However, even with intravenous vitamin K, it may take between 6 hours and sometimes more than 24 hours to reverse the coagulopathy.

Fresh frozen plasma (FFP) provides the factors depleted by warfarin and is a fast way to reverse coagulopathy from warfarin. However, the use of FFP may result in delays in the process of compatibility testing and administration, and it may lead to fluid overload, allergic reactions, and transfusion-related complications. Furthermore, the reversal of anticoagulation from warfarin with FFP may be only transient. Recombinant factor VIIa (rFVIIa) is a procoagulant agent approved for bleeding complications in patients with hemophilia. It has been used in warfarin-related intracranial hemorrhage, and a study demonstrated reduction in hematoma expansion and rapid correction of the INR. A subsequent study showed no improvement in mortality or functional outcome. Recombinant FVIIa has been associated with increased incidence of thromboembolic events.

 Ansell J, Hirsh J, Hylek E, et al. Pharmacology and management of the vitamin K antagonists. Chest. 2008; 133(6 Suppl):160S–198S.

 Elijovich L, Patel PV, Hemphill JC. Intracerebral hemorrhage. Semin Neurol. 2008; 28:657–667.

 Mayer SA, Brun NC, Broderick J, et al. Safety and feasibility of recombinant factor VIIa for acute intracerebral hemorrhage. Stroke. 2005; 36:74–79.

 Mayer SA, Brun NC, Begtrup K, et al. Efficacy and safety of recombinant activated factor VII for acute intracerebral hemorrhage. N Engl J Med. 2008; 358:2127–2137.

34. b

Negative inspiratory force and vital capacity are the best methods of assessing the ventilation of patients with Guillain Barré syndrome (GBS) (discussed in Chapter 9).

Indications for intubation in GBS include the following:

–  Clinical evidence of fatigue

–  Severe oropharyngeal weakness

–  Respiratory function: vital capacity less than 15 to 20 mL/kg, or less than 1 L, or a reduction of more than 30% of the baseline and/or negative inspiratory force less than 30 cm H2O

Other parameters associated with the possible need for intubation include bulbar weakness or the presence of cranial nerve palsies, autonomic dysfunction, short period from onset to peak of symptoms, and the presence of abnormalities on chest x-ray, such as infiltrates or atelectasis.

Arterial partial pressure of oxygen (pO2) and partial pressure of carbon dioxide (pCO2) are not good predictors of need for early intubation, since abnormalities in these parameters occur when the patient is already decompensating. A subjective sensation of dyspnea and pulse oximetry are not adequate means of assessing ventilation.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

35. d

Critical illness polyneuropathy and myopathy is a neuromuscular disorder seen in patients admitted to the ICU. It is a cause of failure to wean patients from ventilatory support. There are multiple risk factors for this condition, such as sepsis, systemic inflammatory response syndrome, use of neuromuscular blocking agents, use of steroids, poor nutrition, abnormal glucose levels, and low albumin levels. The patient depicted in this question was critically ill, septic, and received sedatives, paralytics, and steroids, all of which are risk factors for critical illness polyneuropathy and myopathy.

The pathophysiology of the neuropathy is related to an inflammatory response and nerve microcirculatory dysfunction and hypoxia, leading to primary axonal degeneration and muscle tissue damage. NCS demonstrate normal latencies and conduction velocities, with reduced compound motor and SNAP. In the presence of critical illness myopathy, needle EMG will demonstrate myopathic motor unit potentials, creatine kinase levels may be elevated, and muscle biopsy demonstrates a myosin loss myopathy.

There is no evidence to support the other diagnoses provided in the options.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

36. e

Status epilepticus is a neurologic emergency. Classically, it has been defined as seizures lasting more than 30 minutes, or recurrent seizures without recovery in between. This definition is outdated and may not be useful in clinical practice, since patients presenting with ongoing seizures should be treated rapidly without waiting for a 30-minute time limit.

The goal of treatment is to stabilize the patient, abolish the seizures, and treat the underlying cause. Initial therapy should always begin with “ABC” (airway, breathing, circulation). Benzodiazepines are the first line of therapy to stop ongoing seizures, and lorazepam is the most commonly used, based on its rapid onset of action, and preferred to diazepam based on its relative longer half-life. It is usually given intravenously at a dose of 0.1 mg/kg. Following benzodiazepines, the second line of treatment is phenytoin and/or fosphenytoin, for which maximal effects peak at around 15 to 20 minutes. Fosphenytoin is preferred since it can be infused faster, with fewer infusion-related side effects and cardiovascular reactions. The usual loading dose is 20 mg/kg intravenously.

If the patient continues seizing, a second dose of phenytoin or fosphenytoin can be attempted, or a second antiepileptic agent can be administered, such as phenobarbital or valproic acid. At the time of this publication, levetiracetam had not been assessed in clinical trials yet for the treatment of status epilepticus; however, given its availability as an intravenous agent, it has become widely used.

Data from clinical trials suggest that if one drug fails, successful termination of status epilepticus becomes subsequently difficult. Therefore, many advocate endotracheal intubation (if it has not already been done) and the use of propofol or midazolam drips if a loading dose of phenytoin/fosphenytoin fails to abort the seizure. If after continuous infusion of propofol or midazolam the patient continues to seize, barbiturate coma is the next step, usually with pentobarbital, with titration of the dose to burst-suppression on the EEG.

 Manno EM. New management strategies in the treatment of status epilepticus. Mayo Clin Proc. 2003; 78:508–518.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

37. a

From the options listed, bilateral absence of the N20 response on somatosensory-evoked potentials with median nerve stimulation is the best predictor of outcome after cardiac arrest.

A low percentage of patients survive after cardiac arrest, and of those who survive, a large number will have long-term cognitive and neurologic deficits. Prediction of outcome after cardiac arrest is important to guide treatment for these patients, as well as to provide useful information to the family.

In general, the circumstances surrounding the cardiac arrest and CPR do not have good predictive value and should not be used alone for this purpose. Physical examination findings are helpful, and there is good predictive value for poor outcome if there is no pupillary response at 24 to 72 hours from the cardiac arrest, or no corneal reflexes and eye movements at 72 hours after the cardiac arrest. Before these time frames, the predictive values of physical examination findings are not accurate.

Ancillary tests are useful in the prediction of outcome of patients after cardiac arrest. Brain edema on CT scan may occur, but its predictive value is poor for prognostication. EEG showing burst suppression or generalized suppression is associated with poor outcome. Somatosensory-evoked potentials with median nerve stimulation showing bilaterally absent N20 responses at days 1 to 3 accurately predict poor outcome. Certain biomarkers have been used, especially neuron-specific enolase, which, if elevated, will also help predict a poor outcome. Creatine kinase BB isoenzyme in the CSF can also be utilized; however the false-positive rate of this test limits its utility.

 Widjdicks EFM, Hijdra A, Young GB, et al. Practice parameter: Prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review). Neurology. 2006; 67:203–210.

38. a

An apnea test with no respiratory movements observed at a partial pressure of carbon dioxide (pCO2) level of 45 mm Hg with a core body temperature of 31°C is not confirmatory of a diagnosis of brain death.

Death by neurologic criteria or brain death is defined as the irreversible cessation of function of the brain, including the brainstem. This diagnosis requires the presence of a catastrophic CNS condition leading to irreversible damage, examination findings of absent brainstem reflexes, and the presence of apnea on the apnea test. To perform the apnea test, the patient should be preoxygenated for 10 minutes with a fraction of inspired oxygen (FiO2) of 100%. A baseline arterial blood gas is obtained, and pCO2 should be between 35 and 45 mm Hg. The patient is then disconnected from the ventilator but should receive oxygenation at a rate of 6 L/minute. The patient is then observed for 10 minutes for any chest or abdominal rise suggesting an inspiratory attempt. After this time, an arterial blood gas is obtained. If the patient had not demonstrated any respiratory movements and the pCO2 has risen to 60 mm Hg, then the test is positive, supporting a diagnosis of brain death.

Other criteria required for the diagnosis of brain death include the following:

–  Absence of intoxication, drug poisoning, neuromuscular blockade, or pharmacologic sedation

–  A core body temperature above 32°C

–  Systolic blood pressure of more than 90 mm Hg, or mean arterial pressure of more than 60 mm Hg

When in doubt, the following tests can be performed to confirm death by neurologic criteria:

–  Encephalography showing electrocerebral silence in a recording of at least 30 minutes

–  Transcranial doppler showing no flow signals

–  Angiography demonstrating no flow in the circle of Willis

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

39. d

Decorticate rigidity is associated with bihemispheric dysfunction resulting in disinhibition of the red nucleus, with facilitation of the rubrospinal tracts and lateral vestibulospinal tracts.

Decorticate posture is characterized by a flexion of the upper extremities at the elbows and extension of the lower extremities and is seen in extensive lesions involving the forebrain down to the level of the rostral midbrain. It usually is seen in lesions above the red nucleus. Bihemispheric dysfunction above the red nucleus will produce disinhibition of the red nucleus with facilitation of the rubrospinal tracts and lateral vestibulospinal tracts, causing the typical posture.

Pinpoint pupils are seen in pontine lesions, below the red nucleus, and therefore not associated with decorticate posture.

Lesions below the vestibular nucleus will abolish a posture response. Lesions below the level of the red nucleus, but above the vestibular nucleus, are associated with decerebrate posture. A decrease in activity of the rubrospinal tract will not be associated with decorticate posture.

 Blumenfeld H. Neuroanatomy Through Clinical Cases, 1st ed. Sunderland, MA: Sinauer; 2002.

40. b

This patient has a subdural hematoma and a subfalcine herniation, in which the cingulate gyrus herniates under the falx cerebri. In this type of herniation, the pericallosal and callosomarginal arteries may also herniate under the falx cerebri.

According to the Monro-Kellie doctrine, a new mass within an intracranial compartment will expand at the expense of an existing component, and if the space available is not sufficient, a displacement may occur.

Uncal herniation occurs from expansion of a lesion in a cerebral hemisphere, pushing the medial temporal lobe to herniate medially and downward over the tentorial edge. The medial temporal lobe will push against the midbrain and manifest with a fixed dilated pupil. Along with this finding, most patients have altered level of consciousness, and a hemiparesis, which is most often contralateral; however, it may be ipsilateral if the temporal lobe pushes the midbrain against the Kernohan’s notch on the contralateral side, therefore affecting the contralateral corticospinal tract (ipsilateral to the herniation). Uncal herniation may also produce a PCA compression and an infarct in this territory.

Central transtentorial herniation occurs from an expanding lesion in the diencephalon, leading to a downward displacement.

Tonsillar herniation occurs when the cerebellar tonsils are displaced through the foramen magnum, compressing the brainstem and occluding the fourth ventricle.

A transcalvarial herniation occurs when a patient with brain edema undergoes hemicraniectomy, and brain tissue herniates through the skull defect.

 Posner JB, Saper CB, Schiff ND, Plum F. Plum and Postern’s Diagnosis of Stupor and Coma, 4th ed. New York, NT: Oxford University Press; 2007.

41. c

The relationship between intracranial volume and ICP is not linear.

The adult brain is encased in a nonexpansible bony cavity that also contains blood and CSF. The intracranial volume, pressure, and cerebral blood flow are intimately related. The Monro-Kellie doctrine dictates that the volume in the intracranial cavity is constant, and an increase in the volume of any of the components of this cavity will produce a displacement of the other two components. Initially, the system is compliant, with only small increases in the ICP as the volume increases. However, this compliance is limited, and as the volume continues to increase, the pressure will rise exponentially (not linearly).

Cerebral blood flow is determined by multiple factors, including perfusion, mean arterial and intracranial pressures, as well as cerebral autoregulation and rheologic and metabolic factors. The cerebral perfusion pressure (CPP, ideally >70 mm Hg) is obtained by subtracting the ICP (normal 5–15 mm Hg) from the mean arterial pressure (MAP) (CPP = MAP − ICP). Therefore, MAP and ICP are major determinants of perfusion pressure and the cerebral blood flow and are targets for therapies in the neurocritical care unit. Vascular autoregulation permits optimal cerebral blood flow and is effective at MAP ranges between 60 and 150 mm Hg. Pressure responses and metabolic factors govern autoregulation by producing cerebral vasodilatation or vasoconstriction. The major metabolic factor is CO2, and increases in pCO2 cause vasodilatation resulting in increased ICP. Blood rheologic factors are also important for cerebral blood flow. Lower hematocrit and lower blood viscosity are associated with increased cerebral blood flow.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

42. d

Larger and wider bone flaps and duraplasty may be required for better clinical results as compared with smaller bone flaps.

In malignant cerebral edema, intracranial volume increases in the compartment of the infarcted tissue, and the ICP rises. Usual measures to reduce the ICP are usually not enough, and herniation syndromes may occur. Decompressive hemicraniectomy involves removal of a large bone flap and opening of the dura, permitting the swollen tissue to herniate outward, thereby decreasing the ICP. A successful intervention requires a large and wide bone flap and duraplasty; otherwise compression of the swollen brain will occur at the borders of cranial vault.

Several studies have shown the benefit of this intervention in terms of survival, with some controversy in terms of the functional outcome; however, better neurologic outcomes were seen in patients treated surgically.

The age of the patient, timing of the surgery, and the hemispheric dominance are factors to take into account when making the decision to intervene. Patients older than 60 years of age have lower survival rates and poorer functional outcomes than those younger than 60 after this procedure. The optimal timing of surgery is unknown, but earlier hemicraniectomy is associated with better outcomes. Most compressive hemicraniectomies are performed for nondominant hemispheric infarctions, and it is thought that functional outcome will be worse if performed for dominant hemispheres, since language will be disrupted. However, there is still some controversy regarding this issue. All these aspects should be discussed clearly with the family, making sure that they understand that this surgery is a life-saving measure, with the potential of survival with significant disability.

 Bershad EM, Humphreis WE, Suarez JI. Intracranial hypertension. Semin Neurol. 2008; 28:690–702.

 Subramaniam S, Hill MD. Decompressive hemicraniectomy for malignant middle cerebral artery infarction: An update. Neurologist. 2009; 15:178–184.

43. a

Status epilepticus is a neurological emergency and should be treated as such. The most frequent cause of status epilepticus is antiepileptic medication noncompliance in patients with known epilepsy. Central nervous system infections, strokes, and tumors can also cause seizures and status epilepticus. Febrile seizures are not seen in adults, though fever can lower the threshold in patients with epilepsy.

 Manno EM. New management strategies in the treatment of status epilepticus. Mayo Clin Proc. 2003; 78:508–518.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.

44. e

Four principles of medical ethics include beneficence (providing patients with care that will be of benefit to them), nonmaleficence (doing no harm or malice to the patient), justice (ensuring equitable and fair distribution of resources), and autonomy, or self-determination, with patients as the ultimate decision maker. In order for a patient to practice autonomy, all available feasible options should be provided to the patient. Because any intervention could have potential harms, practicing nonmaleficence in practicality often means weighing the potential harms against the risks.

 ABIM Foundation, American Board of Internal Medicine, ACP-ASIM Foundation. American College of Physicians-American Society of Internal Medicine, European Federation of Internal Medicine. Medical professionalism in the new millennium: A physician charter. Ann Intern Med. 2002; 136(3):243–246.

 Jonsen A, Siegler M, Winslade W. Clinical Ethics: A Practical Approach to Ethical Decisions in Clinical Medicine, 6th ed. New York, NY: McGraw-Hill; 2006.

45. e

This patient has malignant hyperthermia, which is an uncommon syndrome seen during general anesthesia. It is an autosomal dominant disorder, in which there is an excessive release of calcium from the sarcoplasmic reticulum in the skeletal muscle in response to halogenated inhaled anesthetics and depolarizing muscle relaxants (more commonly succinylcholine). A mutation in the ryanodine receptor gene has been found, and patients with central core disease (a myopathy resulting from a mutation in the ryanodine receptor gene) are at increased risk of malignant hyperthermia.

Malignant hyperthermia presents with an initial rise in the end-tidal partial pressure of carbon dioxide (PCO2) during anesthesia, muscle rigidity, increased body temperature, altered consciousness, and autonomic instability. Rhabdomyolysis occurs, leading to myoglobinuric renal failure.

In patients developing malignant hyperthermia, the culprit anesthetics should be stopped and alternative anesthetics not associated with malignant hyperthermia should be used instead, ventilatory support and oxygenation should be optimized, intravenous fluids should be increased, and physical measures to reduce the temperature should be attempted. Dantrolene is a specific treatment that blocks release of calcium from the sarcoplasmic reticulum and should be administered early on.

This patient does not have a history of being on antipsychotics or serotonin reuptake inhibitors. These are related to neuroleptic malignant syndrome (NMS) and serotonin syndrome, respectively. NMS is similar to malignant hyperthermia and is characterized by increased body temperature, muscle rigidity, altered mental status, and autonomic instability. It is induced by antipsychotics, but other drugs that inhibit dopaminergic transmission may also be implicated. Management includes discontinuation of the antipsychotic and use of Dantrolene and bromocriptine. The latter plays no role in the management of malignant hyperthermia.

Serotonin syndrome starts abruptly and is characterized by mental status changes, hyperthermia, autonomic hyperactivity, hyperkinesis, hyperactive deep tendon reflexes, clonus, and muscle rigidity. The treatment is supportive, along with benzodiazepines and discontinuation of the causative drug.

 Ropper AH, Samuels MA. Adams and Victor’s Principles of Neurology. 9th ed. New York, NY: McGraw-Hill; 2009.

 Suarez JI. Critical Care Neurology and Neurosurgery, 1st ed. Totowa, NJ: Humana Press; 2004.