Subdural Hematoma: Causes, Symptoms, and When Surgery Is Needed

A head injury—even a seemingly minor one—can sometimes hide a serious underlying condition. One of the most critical complications to watch for is a Subdural Hematoma (SDH).

Often described as a "silent" threat because symptoms can take days or even weeks to appear, understanding this condition is vital for anyone who has experienced head trauma.

What is a Subdural Hematoma?

A subdural hematoma occurs when a blood vessel (usually a vein) ruptures between the surface of the brain and its outermost protective covering, the dura mater. This leaked blood forms a clot (hematoma) that creates pressure on the brain tissue.

Medical professionals generally categorize SDH into three types based on how quickly symptoms develop:

• Acute: The most dangerous type, usually caused by severe trauma. Symptoms appear within minutes or hours.
• Subacute: Symptoms develop over several days to a couple of weeks.
• Chronic: Common in older adults; symptoms may not appear for weeks or months after a very minor head injury.

Common Causes

The primary cause of a subdural hematoma is head trauma, but the severity of the impact required varies depending on the individual.

• High-Impact Accidents: Car crashes, serious falls, or physical assaults are the leading causes of acute SDH.
• Minor Falls: In older adults, the brain shrinks slightly (atrophy), stretching the small "bridging" veins. This makes them much easier to tear, even from a slight bump to the head.
• Blood Thinners: Medications like aspirin, warfarin, or newer anticoagulants increase the risk of bleeding after any head injury.
• Alcohol Use Disorder: Long-term alcohol use can lead to brain shrinkage and liver issues that affect blood clotting.

Red Flags: Symptoms to Watch For

The signs of a subdural hematoma can be subtle at first and often mimic other conditions like a stroke or even dementia.

Immediate Symptoms (Acute)

• Severe, worsening headache
• Confusion or drowsiness
• Nausea and vomiting
• Slurred speech or difficulty speaking

Delayed Symptoms (Chronic)

• Persistent "dull" headache
• Gradual changes in personality or mood
• Balance issues or frequent falls
• Weakness on one side of the body
• Seizures

Important: If someone loses consciousness—even briefly—following a head injury, they should be evaluated by a doctor immediately.

When Is Surgery Necessary?

Not every subdural hematoma requires a trip to the operating room. If the bleed is small and the patient is stable, doctors may choose "watchful waiting," using repeated CT scans to ensure the blood is being reabsorbed by the body.

However, surgery becomes necessary when the hematoma is large or causing significant pressure on the brain (mass effect). The two primary surgical options are:

1. Burr Hole Trephination

For chronic hematomas where the blood has become more liquid, a surgeon drills small holes in the skull to drain the fluid and relieve pressure.

2. Craniotomy

For acute cases with solid blood clots, a larger section of the skull is temporarily removed to allow the surgeon to remove the hematoma and stop any active bleeding.

Don't Leave Your Recovery to Chance

The road to recovery from a hematoma is often a race against time. Whether you are dealing with a chronic case requiring drainage or an acute injury needing intensive therapy, the quality of your neurosurgical team matters. At IGEA Brain, Spine, Pain & Orthopedics, our board-certified neurosurgeons use state-of-the-art CT and MRI imaging to catch damage before it becomes permanent.

Protect your brain health with the specialists who lead the field.