A brain hemorrhage is bleeding inside or around the brain, caused when a blood vessel ruptures and releases blood into surrounding tissue. The escaped blood forms a clot (called a hematoma) that physically compresses brain cells and triggers a cascade of toxic chemical reactions. Brain hemorrhages account for roughly 10 to 15 percent of all strokes and are among the most dangerous, with about 24 percent of patients dying within the first 30 days.
How a Brain Hemorrhage Damages the Brain
The damage happens in two waves. The first is purely mechanical: as blood pools, the growing hematoma presses against delicate brain tissue. This pressure can restrict normal blood flow to nearby areas and, in severe cases, push the brain out of its normal position, a life-threatening emergency called brain herniation.
The second wave is chemical. As the pooled blood breaks down, hemoglobin and its byproducts leak into surrounding tissue, triggering intense inflammation, swelling (called edema), and the release of iron-based molecules that generate harmful free radicals. These free radicals damage and kill neurons in the area surrounding the original bleed. This secondary injury also includes further swelling around the hematoma, rising pressure inside the skull, and in some cases a condition called hydrocephalus, where fluid builds up in the brain’s internal cavities. Even when the initial bleed is controlled, these secondary injuries can continue to worsen over hours and days.
Common Causes and Risk Factors
High blood pressure is the single biggest risk factor. Chronically elevated pressure weakens the walls of small arteries deep in the brain until one eventually gives way. Among patients who have experienced a stroke, roughly 70 percent have a history of hypertension. The risk climbs steeply at higher readings: people with a systolic pressure at or above 160 mmHg face more than double the risk compared to those in the 130 to 140 range, and a diastolic pressure at or above 100 mmHg triples the risk.
Structural abnormalities in blood vessels also play a role. An aneurysm, a balloon-like bulge in an artery wall, can burst under normal blood flow pressure. An arteriovenous malformation (AVM) is a tangle of blood vessels where arteries connect directly to veins, skipping the normal network of tiny capillaries that slow and buffer blood flow. This high-pressure shortcut stretches the vessel walls thin, making them prone to rupturing. AVMs can also develop aneurysms on their weakened walls, compounding the danger.
Other risk factors include blood-thinning medications (anticoagulants), heavy alcohol use, cocaine or amphetamine use, and clotting disorders. Age increases risk as well, since blood vessels naturally weaken over time.
Symptoms to Recognize
Most people who experience a brain hemorrhage say the first thing they notice is a sudden, severe headache, often described as the worst headache of their life. This headache comes on in seconds, not gradually.
Other symptoms depend on the size and location of the bleed, but they typically appear without warning:
- Sudden weakness or numbness on one side of the face, arm, or leg
- Slurred speech or difficulty understanding others
- Vision changes including partial or complete vision loss
- Severe nausea and vomiting
- Confusion or sudden drowsiness
- Loss of balance or coordination
- Seizures
- Stiff neck and sensitivity to light (more common when bleeding occurs on the brain’s surface)
In serious cases, people lose consciousness rapidly. A brain hemorrhage is always a medical emergency. Minutes matter because the hematoma can keep expanding, and every moment of additional bleeding means more brain tissue under pressure.
How It’s Diagnosed
A CT scan is the first test performed in the emergency room because it can detect bleeding inside the skull within minutes. To get a closer look at the blood vessels themselves, doctors often follow up with a CT angiogram, which uses contrast dye injected into a vein to highlight arteries and veins in detail.
An MRI may be used when the CT scan doesn’t provide a clear answer or when doctors need more information about the extent of damage to surrounding tissue. In some cases, a cerebral angiography is performed. This involves threading a thin catheter through an artery up to the brain and injecting dye to create highly detailed images of the blood vessels, which is especially useful for identifying aneurysms or AVMs.
If bleeding on the brain’s surface is suspected but imaging looks normal, a lumbar puncture (spinal tap) can confirm or rule out the diagnosis. A small sample of the fluid surrounding the brain and spinal cord is drawn and checked for traces of blood.
Treatment in the Hospital
The immediate priority is stopping the bleed from getting worse. Blood pressure is carefully lowered using medications, with the goal of achieving smooth, steady control rather than dramatic drops. Stable blood pressure reduces the chance of the hematoma expanding and leads to better outcomes.
For patients who were taking blood thinners at the time of the hemorrhage, the situation is especially dangerous. Doctors use specific reversal agents to restore the blood’s ability to clot as quickly as possible.
Surgery may be needed depending on the size and location of the bleed. In some cases, a portion of the skull is temporarily removed to relieve pressure (a procedure called a craniotomy), and the collected blood is drained. For bleeds caused by an aneurysm, a procedure may be done to seal off the aneurysm and prevent re-bleeding, either through open surgery or by threading a catheter through blood vessels to the site.
Recovery and Rehabilitation
Recovery from a brain hemorrhage varies enormously. Some people with small bleeds in non-critical areas recover most of their function. Others face long-term disability. According to long-term tracking data from the Tromsø Study, about 65 percent of patients survive the first year, and 47 percent survive five years.
For people with moderate to severe hemorrhages, the early recovery period often follows a recognizable pattern. In the most serious cases, patients may pass through stages of unconsciousness, then a state where they’re awake but not meaningfully responsive, and then a minimally conscious phase where they begin to recognize sounds, follow simple commands inconsistently, or show flickers of emotion. A person is considered to have emerged from the minimally conscious state when they can reliably answer basic questions or demonstrate they know how to use everyday objects.
A confusional phase typically follows, marked by difficulty paying attention, forming new memories, and managing frustration. During this stage, people are often agitated and restless. The fastest improvement generally happens in the first six months. During this window, both movement and thinking tend to recover most noticeably. But meaningful gains can still occur well beyond that point, even two or more years after the hemorrhage, as the brain gradually rewires around the damaged area.
Rehabilitation usually begins in the hospital within 24 to 48 hours for patients who are stable, starting with gentle stretching and basic functional exercises. Aggressive physical activity in the first 24 hours after a hemorrhage appears to worsen short-term outcomes, so the early approach is cautious. As patients stabilize, therapy intensifies and may include physical therapy to rebuild strength and coordination, speech therapy to address language or swallowing difficulties, and occupational therapy focused on regaining the ability to handle daily tasks like dressing, eating, and bathing.
The trajectory for any individual is difficult to predict early on. Recovery depends on the size and location of the bleed, the person’s age, how quickly they received treatment, and the severity of secondary brain injury from swelling and inflammation.