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Excerpt from Intracranial HemorrhageSynonyms, Key Words, and Related Terms: intracranial hemorrhage, intracerebral hemorrhage, intraparenchymal hemorrhage, intracranial hematoma, intracerebral hematoma, intraparenchymal hematoma, epidural hematoma, subdural hematoma, subarachnoid hemorrhage, intraventricular hemorrhage Please click here to view the full topic text: Intracranial HemorrhageBackground: Intracranial hemorrhage (ie, the pathological accumulation of blood within the cranial vault) may occur within brain parenchyma or the surrounding meningeal spaces. Hemorrhage within the meninges or the associated potential spaces, including epidural hematoma, subdural hematoma, and subarachnoid hemorrhage, is covered in detail in other articles. Intracerebral hemorrhage (ICH) and extension of parenchymal bleeding into the ventricles (ie, intraventricular hemorrhage [IVH]) are detailed here. ICH accounts for 8-13% of all strokes and results from a wide spectrum of disorders. ICH is more likely to result in death or major disability than ischemic stroke or subarachnoid hemorrhage. ICH and accompanying edema may disrupt or compress adjacent brain tissue, leading to neurological dysfunction. Substantial displacement of brain parenchyma may cause elevation of intracranial pressure (ICP) and potentially fatal herniation syndromes.Pathophysiology: Nontraumatic ICH most commonly results from hypertensive damage to blood vessel walls (eg, hypertension, eclampsia, drug abuse), but it also may be due to autoregulatory dysfunction with excessive cerebral blood flow (eg, reperfusion injury, hemorrhagic transformation, cold exposure), rupture of an aneurysm or arteriovenous malformation (AVM), arteriopathy (eg, cerebral amyloid angiopathy, moyamoya), altered hemostasis (eg, thrombolysis, anticoagulation, bleeding diathesis), hemorrhagic necrosis (eg, tumor, infection), or venous outflow obstruction (eg, cerebral venous thrombosis). Nonpenetrating and penetrating cranial trauma are also common causes of ICH. Chronic hypertension produces a small vessel vasculopathy characterized by lipohyalinosis, fibrinoid necrosis, and development of Charcot-Bouchard aneurysms, affecting penetrating arteries throughout the brain including lenticulostriates, thalamoperforators, paramedian branches of the basilar artery, superior cerebellar arteries, and anterior inferior cerebellar arteries. Predilection sites for ICH include the basal ganglia (40-50%), lobar regions (20-50%), thalamus (10-15%), pons (5-12%), cerebellum (5-10%), and other brainstem sites (1-5%). IVH occurs in one third of ICH cases from extension of thalamic ganglionic bleeding into the ventricular space. Isolated IVH frequently arise from subependymal structures including the germinal matrix, AVMs, and cavernous angiomas. Frequency:
Mortality/Morbidity:
Race: ICH has a higher incidence among populations with a higher frequency of hypertension, including African Americans. A higher incidence of ICH has been noted in Chinese, Japanese, and other Asian populations, possibly due to environmental factors (eg, a diet rich in fish oils) and/or genetic factors. Sex: ICH has a slight male predominance, though study results have been conflicting.
Age: Incidence of ICH increases in individuals older than 55 years and doubles with each decade until age 80 years.
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