What is a Chronic Subdural Hematoma?

A subdural hematoma is an accumulation of blood beneath the dura mater, which is the outer covering of the brain. This condition occurs when the bridging veins, which run between the surface of the brain and the dura mater, begin to leak or bleed, often after they have been stretched or excessive force has been exerted on them. A chronic subdural hematoma indicates that the blood began to collect more than 21 days before. The other most common type of subdural hematoma is an acute subdural hematoma in which the bleeding first began less than 72 hours previous.

A patient with a chronic subdural hematoma may present with a variety of symptoms which can vary with each patient, influenced by factors such as age, life style, indications of recent trauma, and medical history. Many symptoms of chromic subdural hematomas are very similar to those in other conditions. Symptoms may include anxiety, depression, memory loss, and confusion, often mimicking signs of dementia. Seizures and persistent headaches are also common.

Many symptoms can cause additional complications. For example, someone with this condition may have difficulty swallowing, which may cause choking and aspiration. Weakness in the limbs can result in poor mobility and increase the risk of falls and further injury. Confusion and an altered mental state can result in poor judgment, increasing the risk of injury and poor decision making.

A chronic subdural hematoma requires surgical intervention and will not heal unaided, as the collection of blood has nowhere to go. The procedure to treat this condition is known as craniotomy. The procedure involves creating a small opening in the skull and draining off the accumulated blood. Both the surgery and the untreated condition carry risk of permanent brain damage, but the risk is far greater in cases where the chronic subdural hematoma is not treated.

Often caused by head trauma, chronic subdural hematoma is more likely to occur in people over 60. As part of the natural aging process, the brain may shrink or atrophy, meaning that the surface of the brain grows smaller, leaving a greater gap between the dura mater and the brain surface. The bridging veins are then stretched tight, with greater force exerted on them, posing a greater threat of leakage and hematoma formation with even minor head trauma.

People taking anti-coagulant medications are at increased risk of chronic subdural hematoma because the blood is unable to clot as effectively if bridging veins do begin to leak. In infants, subdural hematoma is often caused by trauma or abuse such as shaken baby syndrome. Other people at a higher risk of developing a chronic subdural hematoma include those with long-term alcohol and substance abuse.