A subdural hematoma represents a collection of blood inside the subdural space and results from bleeding that is most commonly induced by severe head injury.
Types of Subdural Hematoma
All subdural hematomas are classified into acute, subacute and chronic subdural hematomas.
Acute subdural hematomas are quite serious and demand prompt medical care and surgical decompression. These hematomas generally result from high speed acceleration and deceleration injuries. Acute bleeding is most commonly associated with damage to veins inside the skull. They are responsible for many deaths and are considered severe injuries.
Chronic subdural hematoma forms by slow bleeding into the subdural space that may last for several days or even weeks. It results from minor head trauma and may remain undiagnosed for many months after the injury. The bleeding is in this case slow, may stop on its own, but it generally progresses and eventually causes certain health problems. Chronic hematomas often affect elderly individuals who are prone to falls and whose blood vessels are easily damage even by minor trauma. They are also frequent among alcoholics.
Symptoms of Subdural Hematoma
Subdural hematomas (particularly chronic subdural hematomas) may remain asymptomatic for some time. Still, if accumulation of blood is rapid, this leads to increase in the intracranial pressure and many neurological abnormalities as well as mental changes.
Acute subdural hematoma forms soon after a head injury (within first 48 hours). The injured individual may lose consciousness and regain it again immediately after the injury. But, this type of hematoma typically produces the effects known as a 'lucid interval', a period of few hours during which the injured person appears well and normal, but soon deteriorates and loses consciousness due to rapid bleeding inside the subdural space. Patients who have not lost consciousness generally complain about severe headache, they may feel nauseated or vomit. Confusion, weakness of limbs on one side of the body, seizures and speech difficulties are several more problems associated with acute subdural hematoma.
Chronic subdural hematoma, on the other hand, does not cause any health problems until 2-3 weeks or sometimes months after the injury. Symptoms occur and increase in intensity gradually. Patients may experience loss of appetite and nausea. Headaches repeat and become more severe. It is also possible to detect steadily weakness of the limbs on one side of the body. Speech and visual disturbances occur as well. There are also personality changes such as drowsiness and confusion while certain number of patients end up with seizures.
Treatment for subdural hematoma depends on whether the problem is acute or chronic, the size of the hematoma and accompanying symptoms and signs.
Small, asymptomatic acute subdural hematoma is only monitored (repeated CT scans). Surgery is essential and must be performed immediately in case of severe acute subdural hematomas (massive bleeding, compression of vital brain structures, severe increase in intracranial pressure etc.) and large chronic subdural hematomas.