Subdural Hematoma

What is subdural hematoma?

A subdural hematoma is a collection of blood that forms between the brain and the tough outer covering that protects it. The brain is wrapped in three layers of tissue called the meninges. The outermost and thickest layer is the dura mater. When bleeding occurs in the space just beneath the dura — the subdural space — the pooled blood is called a subdural hematoma. Because the skull is a rigid box, this trapped blood can press on the brain, and that pressure is what makes the condition potentially serious.

Understanding what is subdural hematoma starts with understanding where the blood comes from. In most cases, the bleeding begins when small veins that cross the subdural space, known as bridging veins, tear. This often happens after a blow to the head, but in some people — especially older adults — it can follow a very minor bump or even occur without any remembered injury.

Doctors usually describe subdural hematomas by how quickly they develop:

• Acute subdural hematoma: symptoms appear within hours to a few days of a head injury, often a significant one. This is the most dangerous form and is frequently a medical emergency.
• Subacute subdural hematoma: symptoms develop over several days to a few weeks after an injury.
• Chronic subdural hematoma: blood collects slowly over weeks or months, often after a minor injury the person may not even recall. This form is most common in older adults.

A subdural hematoma can affect anyone, but certain groups face higher risk: older adults, people who take blood-thinning medications, people with long-term heavy alcohol use, infants, and anyone who experiences significant head trauma, such as from falls, traffic accidents, or contact sports. In hospital settings, this condition is generally evaluated and managed by neurology and neurosurgery teams.

Symptoms of subdural hematoma

Subdural hematoma symptoms depend largely on how quickly the blood collects, how large the hematoma becomes, and how much pressure it places on the brain. Symptoms can appear immediately after an injury, or they can emerge gradually over weeks — which is one reason chronic subdural hematomas are sometimes mistaken for other conditions, such as dementia or stroke.

Common subdural hematoma symptoms include:

• Headache that may be persistent or gradually worsening
• Confusion or difficulty thinking clearly
• Drowsiness or excessive sleepiness
• Nausea and vomiting
• Weakness or numbness, often on one side of the body
• Slurred speech or trouble finding words
• Vision changes, such as blurred or double vision
• Balance problems, dizziness, or unsteady walking
• Seizures (sudden episodes of abnormal electrical activity in the brain)
• Changes in personality, mood, or behavior
• Loss of consciousness, ranging from brief fainting to coma in severe cases

With an acute subdural hematoma, symptoms often develop rapidly after a head injury. A person may lose consciousness at the scene, or they may seem fine at first and then deteriorate over the following hours. Rapidly worsening headache, repeated vomiting, one pupil becoming larger than the other, and declining alertness are warning signs of dangerous pressure on the brain.

With a chronic subdural hematoma, symptoms tend to be subtler and slower. Family members may notice gradual memory problems, apathy, increasing falls, or personality changes before the person themselves recognizes anything is wrong. In older adults, these gradual changes are sometimes attributed to normal aging, which can delay diagnosis.

In infants, subdural hematoma symptoms can look different: a bulging soft spot on the head, irritability, poor feeding, vomiting, unusual sleepiness, or seizures. Any of these signs in a baby needs urgent medical attention.

Causes and risk factors

The most common subdural hematoma causes involve head trauma. When the head moves suddenly — from a fall, a car crash, an assault, or a sports collision — the brain can shift slightly inside the skull. This movement can stretch and tear the bridging veins that run between the surface of the brain and the dura, allowing blood to leak into the subdural space.

Not all subdural hematomas follow a major injury. In some people, especially older adults, the brain shrinks slightly with age. This shrinkage stretches the bridging veins and makes them more fragile, so even a minor bump on the head — or, occasionally, no remembered injury at all — can cause slow bleeding that builds up over weeks.

Recognized risk factors include:

• Older age: age-related brain shrinkage makes bridging veins more vulnerable to tearing.
• Blood-thinning medications: anticoagulants (medicines that slow blood clotting, such as warfarin or newer oral anticoagulants) and antiplatelet drugs (such as aspirin or clopidogrel) make it easier for bleeding to start and harder for it to stop.
• Long-term heavy alcohol use: alcohol can contribute to brain shrinkage, impair blood clotting, and increase the risk of falls.
• Repeated falls: people with balance problems, frailty, or conditions that cause fainting are at higher risk of head injuries.
• Bleeding disorders: conditions that impair the blood’s ability to clot, such as hemophilia or a low platelet count.
• Previous head injuries or prior subdural hematoma: earlier bleeds can increase the chance of another.
• Contact sports and high-impact activities: boxing, football, cycling without a helmet, and similar activities carry a higher risk of head trauma.
• Very young age: infants have delicate blood vessels, and subdural hematomas in babies can result from birth-related trauma, accidents, or, in some cases, abusive head trauma. Any unexplained head injury in an infant requires careful medical evaluation.
• Conditions with very low pressure of the fluid around the brain: in rare cases, low cerebrospinal fluid pressure (the fluid that cushions the brain and spinal cord) can contribute to subdural bleeding.

Often, several factors combine. For example, an older adult who takes an anticoagulant for a heart condition and then has a minor fall faces a considerably higher risk than a younger person with the same fall.

Diagnosis

Subdural hematoma diagnosis relies mainly on brain imaging, combined with a careful medical history and neurological examination. Because symptoms can mimic other conditions — including stroke, dementia, infection, or medication side effects — imaging is essential to confirm that blood is present in the subdural space.

The main steps doctors typically use include:

• Medical history: your doctor will ask about recent head injuries (even minor ones), falls, medications — especially blood thinners — alcohol use, and how symptoms have developed over time. Because some patients cannot recall an injury, information from family members is often helpful.
• Neurological examination: this checks alertness, memory, speech, strength, sensation, coordination, reflexes, and how the pupils react to light. Doctors often use a standardized scoring system called the Glasgow Coma Scale to measure a person’s level of consciousness.
• CT scan (computed tomography): this is usually the first and most important test. A CT scan is a fast X-ray–based imaging study that shows bleeding inside the skull clearly. It can reveal the location and size of a subdural hematoma, whether it is pressing on or shifting the brain, and whether the blood appears fresh or older. The appearance of the blood on CT helps doctors judge whether the hematoma is acute, subacute, or chronic.
• MRI scan (magnetic resonance imaging): MRI uses magnetic fields rather than X-rays to create detailed images. It may be used when a CT scan is inconclusive, when a small or older hematoma is suspected, or when doctors need more detail about the brain tissue itself.
• Blood tests: these commonly include tests of how well the blood clots, particularly important for people taking anticoagulants, as well as a blood count and other basic studies.

In people with an acute head injury and worsening symptoms, imaging is performed urgently, because the speed of subdural hematoma diagnosis directly affects how quickly treatment can begin. For a suspected chronic subdural hematoma, imaging may be arranged when gradual symptoms — such as new confusion, headaches, or weakness in an older adult — cannot be explained by other causes.

Treatment options for subdural hematoma

Subdural hematoma treatment depends on the size of the hematoma, how much pressure it is placing on the brain, how severe the symptoms are, the person’s age and overall health, and whether the bleed is acute or chronic. Treatment ranges from careful observation to emergency surgery, and the care team — often including specialists from a neurology department working alongside neurosurgeons — tailors the approach to each patient.

Watchful waiting and observation

Small subdural hematomas that cause few or no symptoms may not need surgery. In these cases, doctors may recommend close monitoring with repeat neurological examinations and follow-up brain scans to check whether the blood is being reabsorbed by the body or is growing. Some small hematomas resolve on their own over time. During observation, patients and families are told which warning signs should prompt an immediate return to the hospital.

Medications

Medication does not remove a hematoma, but it plays several supporting roles:

• Reversing or pausing blood thinners: if a person on anticoagulant or antiplatelet medication develops a subdural hematoma, doctors often stop the drug temporarily and may give agents that help the blood clot again. Decisions about when to restart these medications are made individually, weighing bleeding risk against the reason the blood thinner was prescribed.
• Anti-seizure medication: because subdural hematomas can trigger seizures, your doctor may prescribe medication to prevent or control them, at least for a period of time.
• Medicines to reduce brain swelling: in some situations, drugs may be used in the hospital to help lower pressure inside the skull.
• Symptom relief: pain and nausea can be managed with appropriate medications, chosen carefully to avoid drugs that increase bleeding risk.

Surgical procedures

When a subdural hematoma is large, causing significant symptoms, or growing, surgery is often needed to remove the blood and relieve pressure on the brain. Common procedures include:

• Burr hole drainage: the surgeon drills one or more small holes in the skull and drains the liquid blood, sometimes leaving a soft drain in place for a short time afterward. This approach is frequently used for chronic subdural hematomas, in which the blood has liquefied.
• Craniotomy: for larger or acute hematomas containing clotted blood, the surgeon temporarily removes a section of the skull bone, removes the clot, controls the source of bleeding, and then replaces the bone. A craniotomy is often required in emergencies when the brain is under dangerous pressure.
• Craniectomy: in severe cases with major brain swelling, part of the skull may be left off temporarily to give the brain room to swell safely; it can be replaced later once swelling has subsided.

Newer, less invasive techniques for certain chronic subdural hematomas are being studied and used in selected centers, but the choice of procedure always depends on the individual situation and the surgical team’s judgment. Within the Acibadem hospital network, subdural hematoma treatment is coordinated by neurology and neurosurgery specialists together with intensive care and rehabilitation teams as needed.

Rehabilitation

After treatment — especially after a significant acute subdural hematoma — many people benefit from rehabilitation. This may include physical therapy for strength and balance, occupational therapy for daily activities, and speech and language therapy if communication or swallowing was affected. Rehabilitation needs vary widely from person to person.

Living with subdural hematoma and outlook

The outlook after a subdural hematoma varies considerably. It depends on the type of hematoma, its size, how quickly it was treated, the person’s age and general health, and whether the brain itself was injured. It is not possible to promise any particular outcome, but some general patterns are widely recognized.

Chronic subdural hematomas, particularly when diagnosed and drained before major brain compression develops, often have a favorable outlook, and many people recover well. However, chronic subdural hematomas can recur — the blood can collect again after drainage — so follow-up imaging and monitoring are usually part of care. Acute subdural hematomas caused by severe trauma are more serious; outcomes range from good recovery to lasting disability, and severe cases can be life-threatening despite prompt surgery.

Recovery can take weeks to months, and in some cases longer. During this period, people may notice fatigue, headaches, difficulty concentrating, memory lapses, or mood changes. These often improve gradually, but the pace differs from person to person. Practical steps that many care teams recommend include:

• Attending all follow-up appointments and scheduled scans
• Taking medications exactly as prescribed, and never restarting blood thinners without your doctor’s approval
• Avoiding alcohol, at least during recovery, as advised by your care team
• Reducing fall risks at home — good lighting, removing loose rugs, using handrails
• Avoiding contact sports and high-risk activities until your doctor says it is safe
• Asking your doctor before driving again, as rules and safety considerations vary
• Getting adequate rest and returning to work or normal activities gradually

Family members and caregivers play an important role, since they may be the first to notice returning symptoms such as new confusion, drowsiness, or weakness — signs that the hematoma may have re-accumulated and that medical review is needed.

Frequently asked questions

What is a subdural hematoma in simple terms?

A subdural hematoma is bleeding that collects between the brain and its tough outer covering, the dura mater. Because the skull cannot expand, this pooled blood can press on the brain and interfere with how it works. It usually results from torn veins after a head injury, though in older adults it can develop after only a minor bump or with no remembered injury at all.

How serious is a subdural hematoma?

Seriousness varies widely. A large acute subdural hematoma after major trauma is a medical emergency and can be life-threatening without prompt treatment. A small chronic subdural hematoma may cause mild symptoms and, in some cases, resolve without surgery. Because it is difficult to know how serious a bleed is without imaging, any suspected subdural hematoma should be evaluated by a doctor.

Can a subdural hematoma heal on its own?

Sometimes. Small subdural hematomas that are not pressing significantly on the brain can be reabsorbed by the body over time. In such cases, doctors may recommend observation with repeat scans rather than surgery. However, larger hematomas, or those causing symptoms, often require drainage or surgery. Only a medical team, guided by imaging, can determine whether watchful waiting is safe.

What are the first symptoms of a subdural hematoma?

Early subdural hematoma symptoms often include headache, confusion, drowsiness, nausea, or vomiting. With acute bleeds, symptoms tend to appear within hours of an injury and can worsen quickly. With chronic bleeds, early signs may be subtle — gradual memory problems, apathy, unsteady walking, or personality changes over weeks. In infants, irritability, poor feeding, vomiting, or a bulging soft spot can be early signs.

How long does recovery from a subdural hematoma take?

Recovery time differs greatly from person to person. Some people who have a chronic subdural hematoma drained feel substantially better within weeks, while recovery from a severe acute subdural hematoma with brain injury can take many months and may involve rehabilitation. Fatigue, headaches, and concentration difficulties are common during recovery and often improve gradually. Your care team can give guidance based on your specific situation.

Can a subdural hematoma come back after treatment?

Yes, recurrence is a recognized issue, particularly with chronic subdural hematomas, where blood can re-accumulate after drainage in a portion of patients. This is why follow-up scans and monitoring are typically part of care. If symptoms such as headache, confusion, or weakness return after treatment, it is important to seek medical attention promptly so doctors can check for re-bleeding.

Do I need to stop blood thinners if I have a subdural hematoma?

Blood-thinning medications are usually paused when a subdural hematoma is diagnosed, and doctors may give treatments to help the blood clot. However, the decision about when — or whether — to restart these medicines is individualized, because blood thinners are often prescribed for important reasons such as preventing strokes or clots. Never stop or restart a blood thinner on your own; always follow your doctor’s instructions.

When to see a doctor

Any significant head injury deserves medical evaluation, even if you feel fine at first, because a subdural hematoma can develop hours, days, or even weeks later. This is especially important for older adults, people taking blood thinners, and anyone with a bleeding disorder — in these groups, even a minor bump on the head warrants a check by a doctor.

Seek emergency medical care immediately if you or someone with you experiences any of the following after a head injury, or without an obvious cause:

• Loss of consciousness, even briefly, or difficulty staying awake
• A severe or rapidly worsening headache
• Repeated vomiting
• Confusion, disorientation, or unusual behavior that is new or worsening
• Weakness, numbness, or paralysis in the face, arm, or leg, especially on one side
• Slurred speech or difficulty understanding others
• A seizure
• One pupil larger than the other or sudden vision changes
• Loss of balance or sudden difficulty walking
• In infants: a bulging soft spot, persistent vomiting, extreme sleepiness, poor feeding, or inconsolable crying after any head injury

If you are recovering from a diagnosed subdural hematoma and notice returning or new symptoms — such as increasing headaches, drowsiness, confusion, or weakness — contact your medical team or go to the emergency department without delay. Acting quickly gives doctors the best chance to detect re-bleeding early and treat it before pressure on the brain increases.