The clinical course of subdural haematoma. A retrospective study of aetiological, chronological and pathological features in 212 patients and a proposed classification.

A retrospective study of 212 cases of subdural haematoma has been carried out in an attempt to find a basis for classification and to propose a useful terminology. It is argued that a subdural haematoma should be considered as traumatic when preceded by a trauma in the sense of a 'morbid condition of body produced by wound or external violence'. The present series contained 154 cases with and 50 cases without preceding trauma. The 154 traumatic cases were categorized according to the duration of their asymptomatic and symptomatic phases, that is the chronological criterion. It was found that the material represented a full spectrum of manifestations without natural boundaries. Combining the chronological criterion with the criteria 'outcome' and 'associated brain injury' did not improve perspectives for a useful classification. The 50 non-traumatic cases, on the other hand, could be subdivided into acute (8) and non-acute or chronic (42), the acute cases presenting with severe symptoms within six hours after sudden onset, and carrying a poor prognosis. Cases presenting from one day to six months after the onset of symptoms may be referred to as non-acute or chronic and have a relatively good prognosis. Comparison of outcome of traumatic and non-traumatic cases with symptomatic phases exceeding twenty-four hours suggests that these groups, despite their clinical and pathological similarities, have different aetiological backgrounds.