[Spontaneous resolution of an acute subdural hematoma]

Acute postraumatic subdural hematoma is known to have bad prognosis. Traditionally, its treatment consisted in urgent surgical evacuation. Rapid spontaneous resolution of the hematoma has been infrequently observed. We report a case of a patient with an acute traumatic subdural hematoma which disappeared without surgery. CT-scan showed a left-sided subdural hematoma with marked mass effect. A low density layer, which implied involvement of CSF in the subdural space, was observed between the hematoma and the inner wall of the skull. We think that the spontaneous resolution of the hematoma was due to the dilution and washing-out by the CSF through an arachnoid tear. Another suggested mechanism in the literature is blood redistribution in the subdural space. Selected patients with an acute subdural hematoma can be managed with conservative treatment.