Headache is among the most common complaints evaluated by primary care physicians and neurologists. Although all neurological diagnoses are ultimately established through a carefully taken history, this is true for no condition more than headache. A thorough review of the following factors usually helps to establish the diagnosis.
Patient age, gender, and medical history may suggest specific headache etiologies in some instances. While the description of the actual events is more important than any single epidemiological factor, the following associations between patient population and headache etiology are clinically useful:
• Patients older than 55 are at risk for temporal arteritis.
• Young women are the population that is most likely to have migraines.
• Middle-aged men are susceptible to cluster headaches.
• Obese young and middle-aged women are the patients most likely to have pseudotumor cerebri.
• Puerperal women and those with hypercoagulable states are at greatest risk for cerebral venous sinus thrombosis.
Because most headaches are frontal or holocranial, location may not be particularly helpful in establishing headache etiology. Temporal and parietal headaches are also fairly nonspecific. Occipital or nuchal headaches are most commonly tension headaches or occipital neuralgia. Common causes of unilateral retro-orbital headaches include migraine, cluster headaches, and indomethacin-responsive headaches.
Headache character is frequently the most helpful factor in classifying it. Dullness and squeezing are typical features of tension headaches, but are also common in many other headache types, including those caused by dangerous conditions such as brain tumors, temporal arteritis, and pseudotumor cerebri. Throbbing and pulsation are the typical qualities of migraines and other vascular headaches. Sharp, stabbing pain is most typical of cluster headaches and indomethacin-responsive headaches.
Rapidity of onset
Most headaches develop over minutes to hours. Sudden-onset, severe headaches require immediate attention, as they often represent life-threatening neurological emergencies such as subarachnoid hemorrhage, carotid artery dissection, and pituitary apoplexy.
Headache duration often has limited value in establishing a diagnosis, as most headaches can last for half an hour at a time or for days on end. Important exceptions to this rule include cluster headaches and indomethacin-responsive headaches, which are very brief, usually lasting from just a few seconds to several minutes at a time. Occipital neuralgia may last for only seconds at a time. Although it may not help to classify the type of headache, duration is often important to establish headache severity and to determine the need for treatment.
Most headaches, including tension headaches and migraines, develop in the late morning or early afternoon. Exceptions include cluster headaches and headaches caused by increased intracranial pressure, which are usually worse at night and may awaken a patient from sleep.
Symptoms that accompany headaches are often the ones that help to clinch the diagnosis. This is perhaps most true for migraines, in which the headache itself may be somewhat nonspecific, and the diagnosis rests on the presence of an aura or other accompanying features. An aura is a neurological symptom that begins several minutes prior to migraine onset and most commonly takes the form of visual hallucinations of flashing lights, lightning strikes, starburst patterns, or distortions in size such as micropsia and macropsia. Auras are not restricted to vision, and may have sensorimotor manifestations including tingling, weakness, and numbness. Aura symptoms characteristically spread over 15–20 minutes, which distinguishes them from stroke (sudden-onset symptoms) and seizure (symptoms that develop over seconds).
Other neurological symptoms
Sudden unilateral or sequential visual loss is a worrisome symptom that suggests temporal arteritis. Seizures or other rapidly developing, fixed neurological signs point to serious pathologies including intracranial hemorrhage, mass lesions, venous sinus thrombosis, encephalitis, or hypertensive encephalopathy.
Nausea, vomiting, photophobia, and phonophobia frequently accompany migraine. Conjunctival injection, lacrimation, and rhinorrhea are features of both cluster and indomethacin-responsive headaches. Visual loss, scalp tenderness, jaw claudication (pain with chewing), low-grade fever, and proximal muscle tenderness are all well-known systemic symptoms of temporal arteritis.
High stress levels worsen almost all headaches. Actions that strain the neck including excessive head turning, staring at a computer screen for prolonged periods, and even sleeping in the wrong position tend to precipitate tension headaches. Not eating, poor sleep, excessive caffeine or caffeine withdrawal, the menstrual period, chocolate, cheese, and red wine all exacerbate migraine headaches. Lying flat and sleeping worsen headaches due to increased intracranial pressure, while standing precipitates or worsens low-pressure headaches secondary to spontaneous intracranial hypotension or lumbar puncture.
Other than medications, patients describe a variety of different factors that help to alleviate their headaches. Rest in a quiet, dark room improves migraines. Loosening a tight necktie, massage, or applying heat often helps tension headaches. Lying down improves low-pressure headaches, while standing up improves headaches due to increased intracranial pressure.
With the exception of cluster headache in which multiple episodes of headache occur within a span of a few weeks or months, headache frequency is not very helpful in establishing a specific diagnosis. It may, however, be important in determining which patients require only symptomatic treatment and which will need prophylactic treatment. If there is any doubt about the actual headache frequency, instruct the patient to keep a headache diary.
Severity and disability level
While severity and disability level do not help to classify headaches accurately, they are important to determine appropriate treatment. Although grading headache severity on a scale of 1 to 10 is often used in practice, this rating system is frequently unhelpful, as each patient has their own pain “nocistat” that reflects numerous psychosocial factors. One rule of thumb is that a patient who reports that they have a high pain tolerance almost never does. While I do not want to dismiss numeric rating scales completely, the best way to establish pain severity is to ask the patient whether they ever miss work or school because of their headaches. Frequent interference with daily commitments essentially mandates treatment.
Prior evaluation and treatment
Many patients undergo neuroimaging or other laboratory studies prior to neurological consultation, and it is obviously necessary to review these studies before determining the need for additional ones. Patients usually try to treat their headaches with over-the-counter medications such as acetaminophen, ibuprofen, and naproxen. Primary care physicians often prescribe triptans for migraine patients before obtaining a neurologist’s assistance, and some even feel comfortable prescribing a prophylactic agent such as propranolol, amitryptiline, or topiramate. Because many patients who seek neurological attention for headache management have refractory headaches, it is important to keep an updated log containing a patient’s response to and tolerance of all medications.
Although most headaches are benign and may be managed safely in the outpatient setting, some headaches reflect dangerous and sometimes life-threatening conditions. Headache red flags include sudden onset, fixed neurological symptoms, seizures, and change in headache character. Headaches in patients with known cancer or immunosuppression are also worrisome. Patients older than 55 with new-onset headache are at risk for temporal arteritis. Dangerous headaches may be divided into sudden-onset or “thunderclap” headaches and chronic headaches.
Sudden-onset dangerous headache syndromes
Subarachnoid hemorrhage (SAH) due to aneurysmal rupture is among the most serious of neurological emergencies. The concept that “the worst headache of my life” and SAH headache are synonymous is widely known but slightly misleading. Every person will eventually have the worst headache of their life, and SAH will be the cause in only a small fraction.1 While SAH headaches are usually extremely severe, it is their rapid onset rather than their intensity that defines them. Subarachnoid hemorrhage headache builds to a climax in just a few seconds, and is sufficiently jarring to stop the patient in their tracks. Vomiting and stiff neck often accompany the headache, and in many cases, seizure and loss of consciousness occur at onset. Some patients may have a sentinel headache due to leakage of a small amount of blood from the responsible aneurysm and preceding the SAH by up to 2 weeks. The exact incidence of sentinel headache is unknown, but may be as high as 40%.2
Urgent and thorough evaluation is necessary for all patients with suspected SAH. Noncontrast head CT, the first diagnostic test in evaluating potential SAH, is extremely powerful in detecting acute subarachnoid blood (Figure 19.1), but the likelihood of finding subarachnoid blood after SAH decreases with time3,4:
• 95% between 0 and 1 days after rupture
• 90% between 1 and 2 days after rupture
Figure 19.1 Noncontrast head CT demonstrating subarachnoid hemorrhage (arrows).
• 85% at 5 days after rupture
• 50% at 1 week after rupture
• 30% at 2 weeks after rupture
• almost zero at any time after 3 weeks
Although the sensitivity of a CT scan is very high in the first few hours after SAH, the penalty for missing the diagnosis is extreme. Thus, all patients with suspected SAH and negative CT scans should undergo lumbar puncture to look for subarachnoid blood. Visual inspection of the CSF may be sufficient to diagnose SAH, but in some cases, it may be difficult to differentiate between blood due to a traumatic lumbar puncture and SAH. The best way to distinguish between SAH and a traumatic tap is by using spectrophotometry to find bilirubin reflective of hemolysis within the CSF.5
Any patient with evidence of aneurysmal SAH should undergo conventional angiography, as both magnetic resonance angiography (MRA) and computed tomography angiography (CTA) have limited sensitivities to detect aneurysms smaller than 5 mm.6 Patients with confirmed subarachnoid hemorrhage should be evaluated by a neurosurgeon for possible surgical clipping or endovascular coiling of the responsible aneurysm. Because aneurysmal SAH is principally a neurosurgical disease, it will not be discussed further here. The interested reader is referred to the American Heart Association’s article on Guidelines for the management of aneurysmal subarachnoid hemorrhage.6
Box 19.1 Unruptured intracranial aneurysms
Intracranial aneurysms most commonly come to clinical attention when they rupture, resulting in SAH. Unruptured aneurysms are almost always asymptomatic and are noted when neuroimaging is performed to evaluate headache, memory loss, or another vague neurological complaint. The first step to determine the best course of action is to understand the chance of aneurysmal rupture. The two main factors that determine this probability are the size and location of the aneurysm. Data on the 5-year risk for aneurysmal rupture from the International Study of Unruptured Intracranial Aneurysms (ISUIA) are shown below.7
This risk for aneurysmal rupture must be weighed against the risk for surgical or endovascular interventions. Based again on data from the ISUIA, the 1-year risk for death or poor neurological outcome is approximately 13% in patients undergoing open surgical clipping and 9% in patients undergoing endovascular coiling.7 As might be predicted, older age, larger aneurysm size, and posterior circulation location are all associated with a greater likelihood of poor outcome. Ultimately the decision to intervene on an unruptured intracranial aneurysm must be made on an individual basis after careful discussion with the patient and neurosurgeon. The patients with the most obvious benefit from intervention are younger patients with aneurysms between 7 and 24 mm in diameter. Patients with aneurysms smaller than 7 mm in diameter or asymptomatic intracavernous aneurysms should not undergo intervention.
Carotid artery dissection
Dissection of the cervical carotid artery may produce a sudden-onset, severe headache. Trauma, especially that caused by vigorous exercise, yoga, or chiropractic manipulation, is commonly identified as the precipitant. The headache of carotid dissection is typically unilateral, throbbing, and retrobulbar, and may therefore be misdiagnosed as migraine. When accompanied by ipsilateral Horner’s syndrome (due to involvement of the oculosympathetic fibers, which ascend into the skull with the internal carotid artery), it may be misdiagnosed as cluster headache. The diagnosis is confirmed with CTA or MRA of the neck. The most important problem posed by carotid artery dissection is obviously not the headache, but rather the possibility of embolic stroke: thrombus at the dissection site is fertile ground for small clots, which are thrown distally into the anterior circulation. Treatment therefore must focus on preventing such emboli. Although there is no clear difference in stroke prevention between anticoagulation or antiplatelet therapy (meta-analysis of multiple nonrandomized studies showed an approximate embolic stroke risk with either therapy of 2%), most stroke specialists choose short-term anticoagulation to prevent distal embolization.8
Pituitary apoplexy occurs most often when a rapidly growing pituitary adenoma outstrips its vascular supply, leading to infarction of the pituitary gland. The headache of pituitary apoplexy is sudden in onset and resembles that of SAH. Neurological signs that accompany pituitary apoplexy include bitemporal hemianopsia due to compression of the optic chiasm and ophthalmoplegia due to involvement of the ocular motor nerves in the adjacent cavernous sinus. The most urgent problem facing a patient with pituitary apoplexy, however, is hypotension, which results from the acute loss of adrenocorticotropic hormone. Treat patients with suspected pituitary apoplexy with dexamethasone (4 mg IV) to prevent adrenal insufficiency, and intravenous fluid boluses to maintain adequate blood pressure. Definitive management of pituitary apoplexy requires the assistance of an endocrinologist and possibly a neurosurgeon.
Of the sudden-onset, severe headaches that bring patients to the emergency room, at most 25% are actually secondary to subarachnoid hemorrhage.9 Although migraine likely accounts for the majority of sudden-onset, severe headaches, it should be considered a diagnosis of exclusion.
Subacute and chronic dangerous headache syndromes
The headache of temporal arteritis may have fairly nonspecific features, and therefore masquerade as a more benign disorder such as migraine or tension headache. Temporal arteritis is exclusively a disease of patients older than 55. Despite its name, the headaches do not occur exclusively in a temporal distribution. Clues to the diagnosis include monocular visual loss, jaw claudication, scalp tenderness, and fever. Polymyalgia rheumatica, characterized by pain in the shoulders and hips, frequently accompanies temporal arteritis. Firmness, tenderness, and induration of the superficial temporal arteries are classical but not universal physical examination findings. Because visual loss is the principal danger of temporal arteritis, it is discussed further in Chapter 5.
Cerebral venous sinus thrombosis
Cerebral venous sinus thrombosis (CVST) produces a variety of signs and symptoms including headache, seizures, encephalopathy, and venous strokes. The condition often takes several weeks to develop, and in its earliest stages, a nonspecific headache that resembles migraine or tension headache may be the only problem. Women in the puerperium and those who use oral contraceptives are at increased risk for cerebral venous sinus thrombosis. Sepsis, malignancy, dehydration and hypercoagulable states are other important risk factors. Neurological examination may be entirely normal, may show an encephalopathy, or may show focal signs that reflect a venous stroke. Contralateral leg weakness due to superior sagittal sinus thrombosis is particularly suggestive of stroke due to CVST. Neuroimaging of CVST shows a wide variety of abnormalities. The best known (although often absent) of these is the positive delta sign on contrast-enhanced CT scan, which indicates collateral channels surrounding a torcular thrombus. A CT scan may also show hemorrhagic infarction or cerebral edema. In milder cases, the diagnosis is made only with the aid of magnetic resonance venography (MRV). Although the quality of the evidence guiding CVST treatment is limited, anticoagulation likely reduces morbidity and mortality.10 My preference is to treat patients with heparin to achieve a goal partial thromboplastin time (PTT) of 60–80 seconds in the acute setting, and transition to warfarin with a goal international normalized ratio (INR) of 2–3 for 3–6 months after diagnosis. Serious neurological problems that may result from CVST include increased intracranial pressure (Chapter 2), seizure (Chapter 20), and stroke (Chapter 21).
Bacterial and viral meningitis are potentially serious neurological emergencies characterized by fever and sometimes by headache and stiff neck. Headache may be the most prominent or a solitary symptom in immunocompromised patients. Further evaluation and treatment of meningitis is discussed in Chapter 1.
Headache secondary to mass lesions
Headaches from intracranial masses are classically worse while recumbent, may awaken the patient in the middle of the night, and may be associated with focal neurological signs or seizures. In clinical practice, however, these features are actually uncommon, as most patients with brain tumors (and other mass lesions) have headaches that resemble tension headaches.11 Evaluation of intracranial mass lesions is discussed further in Chapter 23.
Pseudotumor cerebri (idiopathic intracranial hypertension)
Pseudotumor cerebri is a syndrome of uncertain etiology characterized by headache and visual loss. Because it is widely known that young, obese women are the most commonly affected population, the diagnosis is often missed in other groups. Precipitants of pseudotumor other than obesity include excess vitamin A, lithium, tetracyclines, and both steroid administration and withdrawal. The headaches of pseudotumor cerebri are fairly nonspecific and often resemble tension headaches. In the earliest stages of disease, visual symptoms may be limited to occasional blurriness or transient orthostatic visual loss. As pseudotumor cerebri progresses, visual symptoms become more constant, and blindness may occur if increased intracranial pressure goes untreated. Four diagnostic studies help to confirm the presence of pseudotumor cerebri:
1. CT scan or MRI of the brain to exclude the possibility of true tumor or another cause of increased intracranial pressure.
2. Lumbar puncture showing an opening pressure of at least 20 cmH2O.
3. Dilated funduscopic examination to look for papilledema.
4. Formal perimetry to determine the exact extent of visual field loss.
Obviously, the first step in treating pseudotumor cerebri is to discontinue any potentially responsible medications. Although weight loss may help reverse many of the symptoms of pseudotumor, most patients are not able to lose the weight necessary to result in a meaningful improvement. The mainstay of medical treatment is acetazolamide, administered at doses ranging from 250 mg bid to 1000 mg bid. Perioral and acral paresthesias may be dose-limiting side effects of this medication. If acetazolamide is not effective, the next line of treatment is serial lumbar punctures, which are obviously impractical for doctor and patient alike. If serial lumbar punctures provide consistent relief, then consider ventriculoperitoneal shunting as a more permanent method to remove CSF and lower intracranial pressure. Patients with rapidly progressive visual loss may need optic nerve sheath defenestration to prevent complete blindness.
Despite popular belief, essential hypertension does not lead to headaches. Hypertensive encephalopathy (a cause of posterior reversible encephalopathy syndrome or PRES, Chapter 1), however, occurs in patients with either very high blood pressure or rapid increases in blood pressure. In addition to headaches, patients with hypertensive encephalopathy may be confused, seize, lose their vision, or have essentially any focal neurological finding. Hypertensive encephalopathy is frequently accompanied by other problems related to malignant hypertension including angina, pulmonary edema, and renal failure. It is imperative to rapidly lower the blood pressure in patients with hypertensive encephalopathy in order to prevent irreversible neurological and systemic damage.
Many patients describe any severe headache as a migraine, even if they actually have tension or cluster headaches. It is, therefore, essential to ask the patient what they mean by migraine and ensure that their self-diagnosis is correct. In its most typical form, migraine is characterized by a throbbing, unilateral headache associated with nausea, vomiting, photophobia, and phonophobia. It is common but not universal for migraineurs to describe a variety of aura symptoms including visual loss, scintillating scotoma, tingling in the extremities, and even weakness resembling stroke. Most patients with migraine experience their first attacks during their teens or early 20s. The disorder is three times as common in women as it is in men. Migraines do not usually begin in patients over the age of 50, and other causes of headache should be excluded in this patient population before attributing their headaches to migraines. The diagnosis is ultimately made on clinical grounds, with neuroimaging studies being used mainly to exclude other more serious conditions.
The first step in treating migraines is lifestyle modification. Ask the patient about migraine precipitants such as sleep deprivation, stress, not eating, menstruation, and foods such as chocolate, cheese, caffeine, and red wine. A headache diary is often helpful to keep track of these exposures and the consequent migraine frequency. Lifestyle modifications may reduce headache frequency considerably or even cure the headaches in a very small minority. Most patients with migraines respond to an over-the-counter abortive medication such as acetaminophen, ibuprofen, or naproxen, and never come to the attention of a neurologist. The usual first-line agent in patients who do not respond to one of these medications is a triptan (serotonin 1B/1D agonist). These agents are effective in aborting migraines if given early enough in the course of an attack: ideally, a patient should take the triptan within 30 minutes of developing a headache, but they may still benefit up to 3 hours after headache onset. The main side effects of triptans include chest pain, flushing, nausea, and grogginess. These medications should be avoided in patients with cardiovascular or cerebrovascular disease and in those who are taking monoamine oxidase inhibitors. Table 19.1 gives a brief summary of the triptans. There is no convincing evidence that one triptan is superior to another. Sumatriptan (20 mg) and zolmitriptan (5 mg) are both available in inhaled formats, which makes them particularly useful for patients with disabling nausea. Sumatriptan is also available in an injectable (6 mg) formulation. It is important to monitor triptan use, as excessive intake may precipitate chronic daily headaches.
Some patients will have migraines of such frequency and severity that they will require prophylactic medication. In general, consider prophylactic medications for patients with more than three migraines a month or for
Table 19.2 Migraine prophylactic agents
Table 19.1 Triptans
patients with attacks that interfere with the patient’s ability to work or to attend school. Table 19.2 contains a summary of some of the commonly used migraine prophylactic agents.
Tension headaches are the most common type of headache. They are characterized by bifrontal, holocranial, nuchal, or occipital squeezing or tightness. Severe tension headaches may be accompanied by nausea and vomiting, symptoms that are more typical of migraines. Precipitants include neck strain, sitting still for a prolonged time, and sleeping in an awkward position. While most tension headaches respond to treatment with mild analgesics such as acetaminophen or ibuprofen, those that are severe enough to cause a patient to seek neurological attention are usually refractory to these medications. Heat application and stretching exercises may help. Muscle relaxants such as diazepam (2–5 mg tid), metaxalone (400–800 mg bid), baclofen (10–40 mg bid), or cyclobenzaprine (5–10 mg tid) are also often helpful. For patients with refractory tension headaches, trigger point injections in the cervical paraspinal muscles, occipital muscles, and trapezii may relieve pain.
The typical cluster headache patient is a middle-aged man who is awakened from sleep by a severe, retrobulbar headache. The headache lasts for seconds to minutes at a time and is associated with conjunctival injection, tearing, and rhinorrhea. Ipsilateral Horner’s syndrome is a frequent finding. Cluster headaches derive their name from the fact that they occur in clusters that occur night after night for several weeks. The differential diagnosis of cluster headaches includes carotid artery dissection, chronic paroxysmal hemicrania, and sometimes subarachnoid or intraparenchymal hemorrhage. In most cases, the diagnosis may be made by the clinical features alone. Acute treatment options for cluster headaches include inhaled 100% oxygen, triptans (see above), or intranasal lidocaine (1 ml 4% solution). The two main prophylactic agents are verapamil (120–240 mg qd) and lithium (300 mg bid, titrated to 600 mg bid with a goal plasma level between 0.6 and 1.2 mmol/l). Be cautious when prescribing lithium, as it produces a number of side effects including tremor, ataxia, hyperthyroidism and renal failure.
Chronic paroxysmal hemicrania
Chronic paroxysmal hemicrania (CPH) is characterized by brief, episodic unilateral headaches, which are accompanied by conjunctival injection, tearing, and rhinorrhea. It is most frequent in young women, and is sometimes confused with migraine or cluster headaches. It is distinguished from other forms of headache by its exquisite sensitivity to indomethacin at doses of 25–100 mg bid–tid.
Visual strain headaches
Most headaches due to disease of the eye and its supporting structures come to the attention of ophthalmologists rather than neurologists. Visual strain headaches are mentioned here because they are exceedingly common and may be confused with primary headache disorders. Following excessive reading, television watching, or computer work, patients note an aching or burning pain behind the eyes accompanied by ocular fatigue and sometimes by conjunctival injection. The pain often radiates into the forehead or temples. Correction of refractive errors often helps to reduce the frequency and severity of these headaches.
Headache is listed as a side effect in the product inserts of almost every medication. Common offenders include beta-blockers, cyclosporine, dipyridamole, isotretinoin, and vasodilators such as nitroglycerin. It is often difficult to distinguish between headaches caused by medication and those that are caused by a primary headache disorder. A brief trial of withdrawing the presumed precipitant may be warranted.
Postlumbar puncture headaches
Severe headaches affect approximately 20–30% of patients following lumbar puncture, and are caused by persistent leakage of CSF through the puncture site. The headaches characteristically develop between 1 and 2 days after the lumbar puncture is performed, involve the frontal or occipital regions bilaterally, appear within seconds of assuming an upright position, and are relieved (often completely) by lying flat. The first step in treating these headaches is to instruct the patient to lie flat for 24 hours and drink caffeinated, carbonated beverages. If symptoms do not resolve, try the combination of caffeine/butalbital/acetaminophen for no more than 72 hours, as chronic use of this medication may actually worsen headaches. For patients who do not respond to conservative therapy, an epidural blood patch, which promotes sealing of the dural tear, is almost always effective.
Spontaneous intracranial hypotension
Spontaneous intracranial hypotension (SIH) is caused, in most cases, by a traumatic dural tear with resulting spinal fluid leakage.12 The characteristic holocranial or occipital headache develops suddenly and occurs when the patient is upright, and improves or resolves
Figure 19.2 Axial fluid attenuation inversion recovery (FLAIR) MRI showing diffuse meningeal enhancement in a patient with spontaneous intracranial hypotension (arrows).
completely when they lie flat. The patient may report vertigo and diplopia, and some patients develop sixth-nerve palsies. Neuroimaging findings include sagging of the cerebellar tonsils and diffuse pachymeningeal enhancement (Figure 19.2). Treatment of SIH includes aggressive hydration, caffeine, and epidural blood patches. In some cases, multiple epidural blood patches are needed. Patients with refractory symptoms should undergo CT myelography for the purpose of localizing the leak and planning surgical closure.
Occipital neuralgia is an uncommon disorder characterized by brief, intermittent, stabbing pains that radiate from the nuchal region into the occipital region. Attacks are generally unilateral, may occur many times per day, and may be quite disabling. Physical examination is usually normal, and the diagnosis rests on the clinical history. Occipital nerve blocks may be used for both diagnostic and therapeutic purposes.13 Medications used for trigeminal neuralgia (see below) may help in some cases. MRI of the upper cervical spine (sensory fibers over the occiput are derived from the C2 and C3 nerve roots) and brain is indicated for patients who do not improve with nerve blocks, who have continuous rather than intermittent symptoms, and who have fixed sensory loss.
Headache in pregnancy
Pregnant women may develop headaches that range in severity from entirely benign to malignant and life-threatening. Uncommon but dangerous causes of headache that may develop during pregnancy include cerebral venous sinus thrombosis (see above), eclampsia (Chapter 20), and pituitary apoplexy (see above). As a rule of thumb, any woman without a prior history of headaches should undergo MRI of the brain, especially if the headaches are associated with neurological findings. The two most common headache types in pregnancy are migraines (which tend to improve in frequency and severity during pregnancy) and tension headaches (which often worsen during pregnancy). In general, it is best to avoid medications as much as possible during pregnancy. Acetaminophen (650–1000 mg) or local ice pack application are the most benign treatments, and should be tried first. For women who do not respond to these conservative approaches, use low doses of codeine (30–60 mg) or short courses of NSAIDs. Avoid NSAIDs in the late part of the third trimester, as they may lead to premature closure of the ductus arteriosus. Stronger opioids should be used sparingly, as they pose a risk for neonatal withdrawal. Avoid triptans and dihydroergotamine altogether, as these medications may cause placental vasoconstriction. Consider propranolol or nortryptiline for women who require migraine prophylaxis.
Status migrainosus is defined as migraine that lasts continuously for >72 hours.14 It seldom occurs as the first manifestation of migraine, and it usually does not affect patients with mild, infrequent headaches. Precipitants include noncompliance with prophylactic medications, stress, poor sleep, and head trauma. Treating status migrainosus is often a difficult task, and it is important to be patient when approaching this problem. Depending on the severity of symptoms, some or all of the following interventions may be necessary:
1. Basic supportive care. Place the patient in a dark, quiet room and obtain intravenous access to administer medications and replace fluids. Because patients with status migrainosus are usually bed bound, provide prophylaxis against deep venous thrombosis as needed.
2. Antiemetic agents. It is important to control the severe nausea and vomiting that often accompany status migrainosus. Commonly prescribed antiemetics include:
• Promethazine 25–50 mg IV q6h
• Prochlorperazine 5–10 mg IV q6h or 25 mg PR q6h
• Ondansetron 4–8 mg IV q6h
3. Acute pain control.
• Ketorolac (15–30 mg IV q6–8h) is a powerful nonsteroidal anti-inflammatory drug (NSAID) that is often effective in patients with status migrainosus. It may be used safely for only 48–72 hours because prolonged use frequently leads to gastrointestinal ulceration.
• Intravenous narcotics are another option for acute pain treatment. Battles between migraineur and doctor over narcotic selection and dosage are unfortunately frequent. Fast-acting, short-lasting agents such as morphine, oxycodone, and hydromorphone must be used sparingly in favor of longer-acting formulations. Patient-controlled anesthesia may be necessary in patients in whom oral sustained-release morphine or oxycodone prove ineffective or intolerable.
4. Migraine abortive agents. Triptans are ineffective by the time a patient meets the operational definition for status migrainosus. Dihydroergotamine (1 mg IV), however, is a vasoconstrictor and serotonin 1B/1D agonist that may help abort migraine symptoms, even after 72 hours of symptoms.
5. Sleep aids. In many cases, the best way to break an acute migraine attack is with sleep. Diazepam (5–10 mg PO or IV) is often effective as a sleep aid and in helping to resolve status migrainosus.
6. Steroids. Short courses of prednisone (60 mg PO qd) or dexamethasone (10 mg IV) are often employed for status migrainosus, although there is little evidence to suggest that they are effective.
7. Other therapies. Conventional medical treatment often fails to resolve status migrainosus completely. Additional options for this scenario include trigger point injections, lidocaine or ketamine infusions, biofeedback, acupuncture, and psychiatric evaluation.
Once an attack of status migrainosus is under control, the patient must be transitioned to a regimen that is appropriate for outpatient use. Switch to long-acting orally administered pain relievers and discontinue antiemetics, narcotics, and sleeping aids as tolerated. Prophylactic regimens must be augmented to prevent recurrence of status migrainosus.
Chronic daily headache
Chronic daily headache (CDH) is a syndrome characterized by headaches that occur at least 15 days/month and last for at least 4 hours/day.15 The headaches in patients with CDH are usually a mix of migraines and tension headaches. Medication overuse, especially of narcotics, caffeine-containing medications, barbiturates, and triptans, plays an important role in the development of CDH. Psychiatric factors including depression, personality disorders, and malingering are other important contributors. Unfortunately, treating CDH is extremely challenging, and any approach that I offer is better in theory than in practice. First, limit habit-forming analgesics as much as possible, as these only worsen symptoms over time. Use NSAIDs, or, if absolutely required, longer-acting narcotics such as methadone or fentanyl for pain relief. Periodic lidocaine or ketamine infusions may also help. Although changing migraine and tension headache prophylactic regimens is usually of limited benefit, do not discard it as a futile approach. Alternative therapies including biofeedback, acupuncture, and massage are effective for some patients. Finally, it is essential to address any important psychosocial factors such as depression, domestic abuse, and malingering. Although curing CDH is rare, a multidisciplinary approach may help to restore the patient back to a reasonable functional level.
Trigeminal neuralgia, as its name suggests, is characterized by pain in the distribution of the trigeminal nerve, most commonly in its maxillary and mandibular divisions. Patients describe sudden attacks of intense burning or electrical pain that shoot into the face and last for a few seconds at a time. In between the attacks of neuralgia, patients may note a residual aching pain in the trigeminal distribution. Almost all patients have multiple attacks per day. Patients with trigeminal neuralgia are characteristically able to trigger their pain by touching the cheek or jaw, shaving, brushing their teeth, or eating.
The presumed cause of trigeminal neuralgia is microvascular compression of the trigeminal nerve as it enters the pons. Mass lesions or demyelinating lesions of the pons produce trigeminal neuropathy, which is distinguished from simple trigeminal neuralgia by accompanying sensory loss in the trigeminal nerve distribution. Patients with facial numbness, therefore, should undergo MRI with thin cuts through the brainstem and along the course of the trigeminal nerve. It may also be worthwhile considering MRI in patients younger than 40 in order to exclude the possibility of multiple sclerosis.
Anticonvulsants and antidepressants are the mainstays of medical treatment for trigeminal neuralgia. The agent of first choice is carbamazepine, typically started at a dose of 200 mg bid and increased up to 600 mg bid as needed. Alternatives include:
• phenytoin 100 mg tid
• gabapentin 300 mg tid titrated up to 1200 mg tid
• baclofen 10 mg tid titrated up to 20 mg tid
• oxcarbazepine 300 mg bid titrated up to 900 mg bid
• pregabalin 75 mg bid titrated up to 150 mg bid
Because trigeminal neuralgia pain is intense and disabling (it may precipitate suicide attempts in rare cases), it is important to switch medications quickly if it does not appear that the first agent chosen is working. Do not hesitate to prescribe narcotics in the acute stage of trigeminal neuralgia.
Unfortunately, some patients do not respond to medical treatment. Consider radiofrequency ablation (RFA) or gamma knife radiosurgery for patients with refractory symptoms. The appropriate choice and optimal timing of referral for one of these procedures depends somewhat on personal experience, and it is not clear whether there is any real difference between them.16 My practice is to refer patients for RFA or gamma knife radiosurgery after unsuccessful trials of two first-line medications. I reserve microvascular decompression for patients with persistent symptoms after failing one of the less invasive procedures. For patients who do not respond to even microvascular decompression, peripheral neurectomy of the affected branch of the trigeminal nerve is an option of last resort, as it results in permanent facial numbness and may do little to improve symptoms.
Glossopharyngeal neuralgia is characterized by lancinating pain affecting the larynx, tonsil, tongue, and ear. Pain is often triggered by chewing, swallowing, touching the ear, or yawning. Physical examination is usually normal, although the gag reflex and palatal elevation may be reduced ipsilateral to the lesion. All patients with glossopharyngeal neuralgia should undergo MRI with thin cuts through the brainstem to look for a responsible lesion in the lower pons or medulla, a mass lesion at the jugular foramen, or compression of the nerve in its course through the neck. The medical treatment of glossopharyngeal neuralgia is similar to that employed for trigeminal neuralgia. In most cases, neurosurgical evaluation is not required, but microvascular decompression of the glossopharyngeal nerve may help patients with refractory symptoms.
Inflammation of the nasal mucosa and sinuses commonly produces a sensation of facial pressure rather than frank pain. Patients with sinusitis describe fullness or aching in the cheeks, the bridge of the nose, and the upper jaw. Nasal discharge and blockage usually accompany the pressure. Finding tenderness to percussion of the sinuses or maxilla helps to make the diagnosis, but a CT scan of the sinuses may be required in unclear cases. Be aware that radiographic evidence of sinus congestion is frequent in otherwise healthy people, and that many patients who are diagnosed with sinus headaches by their primary care physicians actually have migraines. Treat sinus headache patients with decongestants, and refer patients with refractory symptoms to an otorhinolaryngologist.
Temporomandibular joint disease
Temporomandibular joint (TMJ) disease is a relatively common myofascial pain syndrome that consists of preauricular aching, limitation of mandibular motion, and crepitus with jaw movement. The exact etiology of the syndrome is unclear, but includes both biological and psychosocial factors.17 The pain is usually unilateral and is often present with or without chewing. Jaw locking is a common symptom. Occasionally, TMJ disease presents to a neurologist as a primary headache localized to the temple, vertex, or occiput. Pain with palpation of the TMJ and crepitus with jaw movement suggest the diagnosis. Panoramic radiographs are the most useful screening study. Heat, muscle relaxants, NSAIDs, and tricyclic antidepressants may improve symptoms. Refer patients with refractory disease to a dentist with a specific interest in TMJ disease for fitting of an intra-oral occlusive orthotic device (bite plate) or possibly for surgical correction of the problem.
Herpes zoster and postherpetic neuralgia
Varicella zoster infection may lie dormant in the trigeminal sensory ganglia for years, being reactivated by stress or illness. Symptoms typically begin with paresthesias or lancinating pains, which are followed in a few days by a vesicular rash in one of the divisions of the trigeminal nerve. The rash may be painful and after it heals, the patient may continue to complain of exquisite pain in the affected dermatome (postherpetic neuralgia). Treat herpes zoster with valacyclovir (1000 mg tid for 7 days). Use gabapentin (300–1200 mg tid) for acute pain or postherpetic neuralgia. Some patients benefit from capsaicin cream, which should obviously be used cautiously in patients with herpes zoster ophthalmicus.
Atypical facial pain syndrome
Atypical facial pain is characterized by unilateral or bilateral facial pain, which usually has a dull, aching quality. Patients often undergo evaluation and treatment for years before the diagnosis is made. The etiology of atypical facial pain is unclear, but the condition often overlaps with myofascial pain syndromes and fibromyalgia. Atypical facial pain should be considered only after other sources of facial pain are excluded by careful clinical history, examination, and neuroimaging studies. The mainstays of treatment include selective serotonin reuptake inhibitors and tricyclic agents. Patients with atypical facial pain who are evaluated by neurologists frequently have refractory symptoms, and a multidisciplinary approach including alternative therapies is often required.
Primary headache disorders presenting with facial pain
Tension, migraine, and cluster headaches may present as facial pain rather than as headache. The diagnosis may be fairly straightforward when the typical headaches accompany the facial pain. However, when facial pain occurs as the sole manifestation of a primary headache disorder, the diagnosis is more challenging. A trial of empiric treatment is often the only way to establish that a primary headache disorder is the source of facial pain.
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