Intracranial Space Occupying Lesions – Subdural Hematoma
This is collection of blood between the dura and the arachnoid. This may follow injuries which may be apparently trivial or even unnoticed. The development of the hematoma may be acute (within 3 days), subacute (within two weeks) or chronic (within months). Chronic subdural hematomas are more common in alcoholics, epileptics, patients receiving anticoagulants therapy and in dehydrated children. Sudden reduction of ICT following shunt surgery for hydrocephalus or even lumbar puncture may give rise to subdural hematoma.
Common cuase of subdural hematoma is bleeding from super-ficial veins or venous sinuses but is may also develop as a complication of cerebral hemorrhage or cortical tumors. The usual sites are the frontal, anterior temporal, and parietal regions. The lesion is bilateral in 10% cases. The hematoma may consist of fluid or clotted blood or blood mixed with CSF (subdural hygroma).
The hematoma consists of fluid blood covered on the inner and outer aspects by layers of fibrin. The blood is defribrinated on account of the constant pulsation of the brain. The high protein content of the fluid from the surroundings and enlarges, thereby increasing the ICT. Subdural hematoma may be the only lesion in many patients. In hematoma or intracerebral hemorrhage. Acute and subacute subdural hematomas are often associated with cerebral contusion, laceration or edema.
Clinical features: The symptoms, in general are similar to those of extradural hematoma but less dramatic and often typical. Chronic subdural hematoma differs in symptomatology from the acute and subacute varieties. It presents as dementia, altered behavior, psychiatric manifestations, or focal neurological deficits. The level of consciousness fluctuates. History of trauma may be doubtful or may be absent in many cases. In the middle aged and elderly, headache, contralateral hemiplegia and papilledema are the prominent features. Children present with vomiting, restlessness, irritability, refusal to feed, anemia, seizures and failure to thrive.
Diagnosis: In the acute and subacute forms, diagnosis may be easy. Around 60% of cases of fracture of the skull show accompanying subdural hematoma. A high degree of clinical suspicion is necessary for the diagnosis of chronic subdural hematoma in the elderly and children, especially so if history of trauma is not forthcoming. CT scanning shows up the hematoma clearly in almost all cases. In its absence angiography is the investigation of choice. The hematoma appears as a clear avascular zone between the compressed brain below and the skull above.
Course and prognosis: Acute subdural hematoma which is often associated with underlying injury to the brain is associated with a mortality of 40-60%. Sudacute and chronic subdural hematomas act as progressive space occupying lesions and end fatally. If left untreated. If treated in time, recovery is complete and prognosis is excellent.
Treatment: Surgical evacuation should be undertaken without delay, after locating the hematoma, Medical therapy consists of measures to lower intracranial tension and anticonvulsants.