Spontaneous rapid reduction of a large acute subdural hematoma.

The majority of acute post-traumatic subdural hematomas (ASDH) require urgent surgical evacuation. Spontaneous resolution of ASDH has been reported in some cases. We report here on a case of a patient with a large amount of ASDH that was rapidly reduced. A 61-yr-old man was found unconscious following a high speed motor vehicle accident. On initial examination, his Glasgow Coma Score scale was 4/15. His pupils were fully dilated and non-reactive to bright light. Brain computed tomography (CT) showed a massive right-sided ASDH. The decision was made to treat him conservatively because of his poor clinical condition. Another brain CT approximately 14 hr after the initial scan demonstrated a remarkable reduction of the previous ASDH and there was the new appearance of high density in the subdural space adjacent to the falx and the tentorium. Thirty days after his admission, brain CT revealed chronic SDH and the patient underwent surgery. The patient is currently able to obey simple commands. In conclusion, spontaneous rapid resolution/reduction of ASDH may occur in some patients. The mechanisms are most likely the result of dilution by cerebrospinal fluid and the redistribution of hematoma especially in patients with brain atrophy.