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infection, but it is most commonly seen as a sequela of bacterial meningitis.
Cranial epidural abscess is rare, but most cases occur from extension of sinusitis,
otitis, orbital cellulitis, or calvarial osteomyelitis.
Neoplasms
Alterations in consciousness as a result of intracranial neoplasms (see Chapter 98
Oncologic Emergencies ) may be caused by seizure, hemorrhage, increases in
ICP caused by interruption of CSF flow, or direct invasion of the brainstem by the
malignancy. The location of the tumor determines additional symptoms: Ataxia
and vomiting result from infratentorial lesions versus seizures, hemiparesis, and
speech or intellectual difficulties resulting from supratentorial ones.
Hydrocephalus caused by tumor growth most commonly presents with headache
(especially morning headache), decreased activity or lethargy, and vomiting.
Vascular
Coma of cerebrovascular origin is caused by interruption of cerebral blood flow
(stroke) as a result of hemorrhage, thrombosis, or embolism (see Chapter 97
Neurologic Emergencies ). Hemorrhage can be nontraumatic, stemming from
abnormal congenital vascular structures such as arteriovenous malformations
(AVM), aneurysms, or cavernous hemangiomas. Rupture of an AVM is the most
common cause of spontaneous intracranial bleeding among pediatric patients. The
hemorrhage is arterial in origin and located within the parenchyma, but it can
rupture into a ventricle or the subarachnoid space. Aneurysm rupture is less
common in children and is unusual in that repetitive episodes of bleeding may
occur (“sentinel bleeds”), with rising morbidity and mortality from subsequent
bleeding events. Subarachnoid blood may be present in either case, although
more commonly with aneurysm rupture. Cavernous and venous hemangiomas are
lower-flow lesions that produce less acute symptom onset.
Stroke may also occur from thrombosis or embolism of a normal vessel.
Cerebral infarction caused by occlusion of the anterior, middle, or posterior
cerebral artery usually produces focal neurologic deficit rather than coma. Acute
occlusion of the carotid artery, however, may produce sufficient unilateral
hemispheric swelling to cause herniation and coma. Cerebral sinovenous

thrombosis is most commonly seen with hypercoagulable states or as a sequela of
infections of the ear or sinus.
Swelling or hemorrhage from infarcted brain can cause increased ICP, leading
to decreased cerebral perfusion pressure and coma. Focal symptoms vary based
on the size and location of brain with inadequate blood supply. Vascular accidents