HISTORY OF PRESENT ILLNESS
A 9-year-old boy developed emesis about 5:00 p.m. one evening and thereafter went to sleep. A few hours later, the parents had a difficult time arousing him, and subsequently brought him to an emergency department. In the emergency department, the child was able to relate that he fell at school and hit his head against the wall. He did not lose consciousness at the time. He complained of a headache and had two additional episodes of emesis in the emergency department. He denied any potential ingestion.
The boy was a healthy child with no significant medical history. He did not take any medications and was not allergic to any medications. His immunizations were appropriate for age.
T 37.5°C; HR 86 bpm; RR 26/min; BP 120/70 mmHg; SpO2 97% in room air
On examination he was asleep but was easily arousable. His head was atraumatic, but he had occipital pain with forward neck flexion. His occiput was diffusely tender, but no bony defects were palpated. Pupils were 4 mm and reactive to 2 mm. His tympanic membranes were normal in appearance. A fundoscopic examination was attempted, but was unsuccessful. Kernig’s and Bruzinski’s tests were negative. The remainder of his head and neck examination was normal. His lungs, cardiac, and abdominal examinations were normal as well. His neurologic examination revealed that his cranial nerves were intact. He was able to follow commands and respond appropriately.
A complete blood count and serum electrolytes were normal. Serum and urine toxicology screens were negative.
COURSE OF ILLNESS
The patient had a 5-minute generalized tonic-clonic seizure. He received phenytoin intravenously after the seizure activity ceased. Findings on the initial noncontrast head CT prompted a CT angiogram, which revealed the diagnosis (Figure 2-4).
FIGURE 2-4. CT angiogram.
DISCUSSION CASE 2-5
This case illustrates a patient who has an intracranial hemorrhage (ICH). The most common cause of ICH in children is from trauma (both accidental and nonaccidental). These traumatic hemorrhages most commonly occur in the extradural, subdural, or subarachnoid space. However, intraparenchymal hemorrhage can occur spontaneously, resulting from an arteriovenous malformation (AVM) (50%), cavernous angioma, or aneurysm. Thrombocytopenia in a patient could also lead to ICH with minor head trauma as was reported in this patient.
The CT angiogram revealed a bilobed area of abnormal contrast accumulation in the posterior aspect of an intraparenchymal hemorrhage with concomitant intraventricular hemorrhage (Figure 2-4). This patient had a ruptured segment of an arteriovenous malformation (AVM) with subsequent compression by the hematoma. He subsequently underwent operative drainage of the hematoma and resection of the AVM.
INCIDENCE AND EPIDEMIOLOGY
Cerebral AVMs are a congenital vascular malformation. They most likely result from failed differentiation of the embryonic vessels into separate arterial and venous systems, which occurs between 3 and 12 weeks of fetal age. AVMs are arteriovenous shunts that consist of feeding arteries, a mass of coiled vessels (the nidus), and draining veins without a capillary network. Usually, there is no brain tissue between the two sides of the AVM, which allows a high-flow shunt from the arterial side to the venous side. The AVM, in essence, is stealing blood from the neighboring parts of the brain. Spontaneous thrombosis and subsequent recanalization may occur and may account for the change in size of an AVM over time. Ten percent of cerebral AVMs are in the posterior fossa, 10% in the midline, and the remainder in the cortex. They may be located superficially or deep. The incidence of cerebral AVMs is 1 per 100 000 persons. Fewer than 12% of cerebral AVMs are symptomatic. They are frequently diagnosed between the age of 20 and 40 years. About one-fifth of AVMs that become symptomatic do so before 15 years of age. Hemorrhage is the most frequent complication associated with AVMs, and it is more common in children than in adults. Besides hemorrhage of prematurity and early infancy, AVM is the most common cause of spontaneous hemorrhage in the pediatric population.
Intracranial hemorrhage is the initial manifestation in up to 80% of cases of cerebral AVMs and is associated with a 25% mortality rate in children. Seizures, which occur in about one-third of cases, may result from an acute hemorrhage, as a result of an epileptogenic focus from a previous hemorrhage, or as a result of chronic ischemia in tissue adjacent to the AVM due to poor perfusion secondary to steal phenomenon. Infants may present with congestive heart failure and hydrocephalus. Stroke and seizures are more commonly seen in older children. Intracranial hemorrhage may occur after an episode of trivial head trauma. Headache is a frequent symptom in patients with AVMs, although it is not a very specific clinical sign. Patients with untreated AVMs who have had previous hemorrhages are at a higher risk for re-bleeding. Other risks of hemorrhage include deep-seated or infratentorial AVM, deep venous drainage, female sex, and associated aneurysms. The presentation of the AVM varies with its location: superficial AVMs cause seizures more frequently, and deep AVMs tend to manifest with hemorrhage. AVMs generally continue to increase in size, increasing the risk of hemorrhage and ischemia, resulting in seizures, gliosis, and neurologic deficits. However, some AVMs may remain the same size and some may even regress.
Brain imaging. The diagnosis of an AVM can be made with CT, MRI, or cerebral angiography. CT is frequently obtained after the first hemorrhage and reveals only that a hemorrhage has occurred. If intravenous contrast is administered for the CT, the AVM nidus typically can be seen; however, the AVM is small, it may be missed on CT scanning. MRI is very helpful in diagnosing AVMs. Additionally, MRI is useful in the planning of the surgical correction of the AVM. MRI and magnetic resonance angiography (MRA) are also used to monitor patients after the AVM has been treated. Additionally, MRI is helpful in differentiating AVM from other hemorrhagic brain lesions, including malignancy and cavernous malformations. Angiography provides an excellent view of the vascular anatomy of the AVM and remains the gold standard for the diagnosis, treatment planning, and clinical follow-up.
The aim of treatment is the complete removal of the AVM, because there is a high mortality from untreated AVMs. The options for removal include microsurgical excision, embolization of the AVM, and radiotherapy obliteration utilizing the gamma knife, proton beam, or linear accelerator. The therapeutic option most appropriate for the patient depends on the location and size of the AVM. If the location of the AVM is deep within the brain or on the motor cortex, excision might not be the best option. The effect of radiotherapy takes months or years, whereas surgical excision is immediately effective. Endovascular embolization alone is curative in less than 5% of lesions, but it remains an important adjuvant to surgical excision and radiotherapy.
Although the treatment of a ruptured AVM is widely accepted, the aggressive management of unruptured AVMs is more controversial, as it is important to note that these interventions are not without considerable risk. A meta-analysis of available studies concluded that intervention for an AVM is associated with a 5.1% to 7.4% median rate of permanent neurologic complications or death. Management decisions, including surgical intervention, radiotherapy, adjuvant endovascular embolization, or medical management, must be made on an individual basis and are best decided by a multidisciplinary approach involving the surgeon, endovascular neurosurgeon, and radiation oncologist.
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