Spontaneous spinal hematomas and low-molecular-weight heparin. Report of four cases and review of the literature.

The purpose of this article is to raise awareness of spontaneous spinal hematomas that develop after administration of low-molecular-weight heparin therapy. The authors describe four patients in whom these hematomas developed without precipitating events while receiving a treatment dose of enoxaparin (Clexane) (approximately 1 mg/kg). Spontaneous spinal hematomas (not related to trauma, surgery, or lumbar puncture) are a rare clinical entity. Several causes have been identified, including acquired and congenital clotting abnormalities and underlying vascular lesions. Aspirin, warfarin, tissue plasminogen activator, and heparin have all been implicated in causing spinal hematomas. Concerns regarding the use of low-molecular-weight heparin agents in neuraxis anesthesia have been well documented. Their possible contribution to nontraumatic spinal hematomas has been less well described. The authors believe that low-molecular-weight heparin agents present a small but significant risk of spinal hematoma. This should be considered when prescribing therapy because such a complication may be catastrophic.