Spontaneous thoracic spinal subdural hematoma associated with fibromuscular dysplasia.

Spontaneous spinal subdural hematoma (SDH) is an uncommon cause of acute spinal cord compression. When it does occur, however, it may have disastrous results and a poor prognosis. The nontraumatic acute spinal SDH usually results from a defect in a hemostatic mechanism (such as coagulopathy or the use of anticoagulant therapy) or from iatrogenic causes (such as spinal puncture). Fibromuscular dysplasia (FMD) is a nonatherosclerotic systemic arteriopathy of unknown cause that typically affects the small and medium arteries in young to middle-aged women. The authors report on their experience with a patient with an acute spontaneous spinal SDH that occurred in conjunction with FMD.