What Is a Subdural Hematoma?
Subdural hematoma is the collection of blood between the layers of tissue covering the brain. The outermost layer is called the dura. In a subdural hematoma, bleeding occurs underneath the dura and the next layer, the arachnoid.
The bleeding in a subdural hematoma is not in the brain itself, but it is under the skull and outside the brain. However, as blood continues to collect, the pressure on the brain increases, which can causes subdural hematoma’s symptoms. However, if the pressure inside the skull rises to very high level, a subdural hematoma can lead to unconsciousness and death.
Causes of Subdural Hematoma:
|CD–10||I62.0, P10.0, S06.5|
|ICD–9||852.2 – traumatic;
432.1 – nontraumatic
Subdural hematoma is usually caused by a head trauma, such as from a fall, motor vehicle collision, or an assault. The sudden blow to the head tears blood vessels that run along the surface of the brain. This is referred to as an acute subdural hematoma.
People with a bleeding disorder and people who take blood thinners are more likely to develop a subdural hematoma. A relatively minor head injury can cause subdural hematoma in people with a bleeding tendency.
In a chronic subdural hematoma, small veins on the outer surface of the brain may tear, causing bleeding in the subdural space. Symptoms may not be apparent for several days or weeks. Elderly people are at higher risk for chronic subdural hematoma because brain shrinkage causes these tiny veins to be more stretched and more vulnerable to tearing.
Signs and Symptoms of Subdural Hematoma:
Symptoms of subdural hemorrhage have a slower onset than those of epidural hemorrhages because the lower pressure veins bleed more slowly than arteries. Therefore, signs and symptoms may show up in minutes, if not immediately but can be delayed as much as 2 weeks. If the bleeds are large enough to put pressure on the brain, signs of increased ICP or damage to part of the brain will be present.
Signs and symptoms of subdural hematoma can include any combination of the following:
- A history of recent head injury
- Loss of consciousness or fluctuating levels of consciousness
- Headache (either constant or fluctuating)
- Weakness or lethargy
- Nausea or vomiting
- Loss of appetite
- Personality changes
- Inability to speak or slurred speech
- Ataxia, or difficulty walking
- Loss of muscle control
- Altered breathing patterns
- Hearing loss or hearing ringing (tinnitus)
- Blurred Vision
- Deviated gaze, or abnormal movement of the eyes.
Diagnosis of Subdural Hematoma:
Patients who come to medical attention after a head injury often undergo head imaging, usually with computed tomography (CT scan) or magnetic resonance imaging (MRI scan). These tests create images of the interior of the skull, usually detecting any subdural hematoma present. MRI is slightly superior to CT in detecting subdural hematoma, but CT is faster and more readily available.
Rarely, angiography may be used to diagnose subdural hematoma. During angiography (angiogram), a catheter is inserted into the arteries, special dye is injected, and an X-ray screen shows blood flow through the arteries and veins.
Treatment of Subdural Hematoma:
Treatment depends on its size and rate of growth. Some small subdural hematomas can be managed by careful monitoring until the body heals itself. Other small subdural hematomas can be managed by inserting a temporary small catheter through a hole drilled through the skull and sucking out the hematoma; this procedure can be done at the bedside. Large or symptomatic hematomas require a craniotomy, the surgical opening of the skull. A surgeon then opens the dura, removes the blood clot with suction or irrigation, and identifies and controls sites of bleeding. Postoperative complications include increased intracranial pressure, brain edema, new or recurrent bleeding, infection, and seizure. The injured vessels must be repaired.
Subdural Hematoma references: