A common condition found with traumatic brain injury is a collection of blood between the layers of the protective covering of the brain. This collection of blood is known as a subdural hematoma. The blood builds up beneath the tough outer layer of the brain’s protective cover, called the dura mater, or dura for short. A subdural hematoma is most often caused by torn, bleeding veins on the inside of the dura caused by a blow to the head.
A slight impact on the head or even a fall to the ground without hitting the head may be enough to cause bleeding inside the skull, often without fracturing the skull. In some cases, a subdural hematoma can exist without any visible signs.
Subdural hematomas may cause no symptoms at all or can be life threatening. Small subdural hematomas may not be very serious, and the blood can be slowly absorbed over several weeks. In other cases, small or medium subdural hematomas may slowly grow in size over weeks to months. This growth can compress the brain, possibly leading to death if the blood is not drained. Larger hematomas may require immediate surgery to reduce pressure on the brain.
Symptoms can show up right after an injury, or they may take several weeks to appear. A subdural hematoma with symptoms appearing in less than 48 hours may be caused by the tearing of one of the large veins in the brain, called venous sinuses. This kind of subdural hematoma can be very serious, and if not treated, can cause death.
Based on when the symptoms appear, subdural hematomas can be divided into acute or chronic. Acute subdural hematomas are those with symptoms that appear quickly after the injury. If weeks pass before symptoms appear, the hematoma is called a chronic subdural hematoma, and is often the result of a slower bleeding, smaller tear. Children and the elderly are most likely to experience a chronic subdural hematoma. This chronic form is less risky, because it happens slowly and the brain is often able to adjust to the bleeding. However, if the bleeding continues and the hematoma is not treated, the condition can become very serious.
If any symptoms occur, it is important to seek medical attention as soon as possible to reduce the chances of permanent damage to the brain.