Subdural hematoma occurs when blood collects outside the brain, specifically between the tissue layers surrounding the brain called the dura and arachnoid. The dura is the outermost layer surrounding the brain. Next to it is the arachnoid. The space between those layers is known as the subdural space. Both the increased pressure on the brain and excessive bleeding can put your life at risk. While some types of this condition resolve by its own, others need to be drained surgically. It's important to note that the collection of blood happens under the skull and not in the brain itself. But even so, when the blood accumulates, there becomes an increased pressure on the brain. If the pressure becomes too high, the condition can result in unconsciousness and even death.
Causes of Subdural Hematoma
The most common cause of subdural hematoma is injury to the head from a fall, assault or car accident. When a sudden blow hits the head, the blood vessels running along the brain's surface get torn. This is called acute subdural hematoma. Bleeding disorders as well as blood thinning medications also put people at greater risk of subdural hematoma. Even a minor head injury can immediately lead to this condition if a person has a bleeding tendency. There's a type of subdural hematoma that's chronic. In this condition, the small veins in the dura may tear and wear out. This leads to bleeding in the subdural space.
Symptoms of Subdural Hematoma
For the first days to a few weeks, symptoms may not yet appear. The onset depends primarily on the rate of bleeding. For sudden and severe bleeding, a person may immediately lose conscious and fall into coma. For minor head injuries, a person may not feel anything days after the head injury. But gradually, he/she may become confused and be unconscious later on. In very-slow growing subdural hematoma, symptoms only become noticeable after several weeks when the bleeding starts. Symptoms include headache, confusion, change in behavior, dizziness, nausea, vomiting, lethargy, excessive drowsiness, weakness, apathy and seizures.
Diagnosis of Subdural Hematoma
Right after a head injury, people usually go to the doctor for physical examination. The doctor will perform imaging tests such as the computed tomography (CT) scan or the magnetic resonance imaging (MRI) scan. These imaging tests provide clear picture of the skull's interior, enabling the doctor to detect the presence of subdural hematoma. While CT scan is faster and more readily available, MRI gives a clearer picture of the skull and is more efficient in detecting subdural hematoma.
Treatment of Subdural Hematoma
The doctor will formulate a treatment depending on the condition's severity. For those with mild symptoms, watchful waiting is done. Regular imaging tests on the head are done to find out if the condition is improving. For those who have severe or life-threatening subdural hematomas, surgery is required to remove the pressure on the brain. Surgical procedures include burr hole trephination, craniotomy and craniectomy.