

A brain hemorrhage is a type of stroke that occurs in or around the brain. It's caused by an artery in the brain bursting and causing localized bleeding in the surrounding tissues. It is frequently uncontrolled bleeding in the brain. This bleeding kills brain cells.
Brain hemorrhage is often labeled according to precisely where it occurs in the brain. In general, bleeding anywhere inside of the skull is called an intracranial hemorrhage. Bleeding within the brain tissues or ventricles itself is known as an intracerebral hemorrhage (ICH) or cerebral bleed. Bleeding can also occur between the covering of the brain and the brain tissue itself, referred to as a subarachnoid hemorrhage. If a blood clot occurs between the skull and the brain, it is known as either a subdural or epidural hematoma depending on whether it is below or above the tough covering (dura) of the brain. Subdural and epidural hematomas are more likely to occur as a result of trauma or after a fall and will not be addressed in detail here.
Bleeding can occur inside the brain, between the brain and the membranes that cover it, between the layers of the brain's covering or between the skull and the covering of the brain. It can occur from an injury or as a result of a leaky or burst blood vessel. This can happen when a blood vessel gets weakened enough that its wall can no longer withstand the pressure of the blood flowing through it.
The brain has many blood vessels running through it and around it. If a blood vessel inside the brain bursts, blood can get into the brain tissue and cause inflammation and swelling. If one of the blood vessels on the surface of the brain breaks, blood can collect between the brain and the membranes that surround it (subarachnoid hematoma). This causes pressure on the brain. Both inflammation and pressure can damage the brain.
High blood pressure, atherosclerosis (buildup of plaque in artery walls), and amyloid angiopathy (protein deposits in artery walls) can weaken blood vessel walls. Aneurysms, which are bulges in weakened areas, can form when blood vessels are damaged or they can be present at birth. Arteriovenous malformations, which are abnormal connections between arteries and veins that may be present at birth, are another vascular abnormality that can be a site of cerebral hemorrhage.
When blood from trauma irritates brain tissues, it causes swelling. This is known as cerebral edema. The pooled blood collects into a mass called a hematoma. These conditions increase pressure on nearby brain tissue, and that reduces vital blood flow and kills brain cells.
Include head / brain trauma, aneurysms, arteriovenous malformations (blood vessel abnormalities), and brain tumors. Blood or bleeding disorders, such as hemophilia and sickle cell anemia can contribute due to decreased levels of blood platelets. The largest risk factors for spontaneous bleeding are high blood pressure and amyloidosis (abnormality of blood vessel walls). Other risk factors include alcoholism, low cholesterol, blood thinners, and cocaine. Diagnosis is typically by CT scan. Other conditions that may present similarly include ischemic stroke.
Fifty-percent of patients admitted with brain hemorrhage while on anticoagulation deteriorate in the first 24 to 48 hours due to additional bleeding, with a high mortality rate of 64% by 6 months. Although blood pressure elevation is suspected as a contributing cause of the enlargement, this remains unproven.
The risk of death from an intraparenchymal bleed in traumatic brain injury is especially high when the injury occurs in the brain stem. Intraparenchymal bleeds within the medulla oblongata are almost always fatal, because they cause damage to cranial nerve X, the vagus nerve, which plays an important role in blood circulation and breathing. This kind of hemorrhage can also occur in the cortex or subcortical areas, usually in the frontal or temporal lobes when due to head injury, and sometimes in the cerebellum.
For spontaneous ICH seen on CT scan, the death rate (mortality) is 34–50% by 30 days after the insult, and half of the deaths occur in the first 2 days. Even though the majority of deaths occurs in the first days after ICH, survivors have a long term excess mortality of 27% compared to the general population.
The inflammatory response triggered by stroke has been viewed as harmful in the early stage, focusing on blood-borne leukocytes, neutrophils and macrophages, and resident microglia and astrocytes. A human postmortem study shows that inflammation occurs early and persists for several days after ICH. New area of interest are the Mast Cells.
Cerebral bleeding affects about 2.5 per 10,000 people each year. It occurs more often in males and older people. About 44% of those affected die within a month. A good outcome occurs in about 20% of those affected. Strokes were first divided into their two major types, bleeding and insufficient blood flow, in 1823. It accounts for 20% of all cases of cerebrovascular disease in the United States, behind cerebral thrombosis (40%) and cerebral embolism (30%).
Intracerebral hemorrhage represents approximately 10% to 15% (10-30/100,000 population) of all strokes. About 2 million of the 15 million strokes worldwide are intracerebral hemorrhages.
Each year, approximately 37,000 to 52,400 people suffer from an intracerebral hemorrhage. The number of intracerebral hemorrhages is expected to increase substantially over the next few decades as the population ages. Major underlying causes for the increase in incidence include more frequent use of anticoagulant medication and age related changes in the brain itself.
Men are more likely to suffer an intracerebral hemorrhage than women. It is two or more times more common in black than white people. There is racial variation in the incidence of bleeding into the brain substance; Asians, Latin American, Mexican American, Native American and African American patients have a greater risk according to epidemiological data. The variation relates to differences in genetics, rates of elevated blood pressure, diabetes, low cholesterol and disease of the small arteries in the brain.
In a recent review, 34% of patients died from their intracerebral bleed 3 months after the event. Another study documented death rates after an intercerebral bleed of 31% at 7 days, 59% at one year, 82% at 10 years and more than 90% at 16 years. Clearly this is a serious and frequently fatal condition.
Recurrent hemorrhages after the first event remain a problem especially when risk factors, especially elevated blood pressure and anticoagulant use, are inadequately addressed; there is a 4% recurrence rate for rebleeding.
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