Clinical characteristics of non-traumatic intramuscular hematomas in patients with spinal cord injury

CONTEXT/OBJECTIVE: Intramuscular hematomas are an uncommon but potentially serious complication in patients with spinal cord injury. They are often overlooked due to sensory impairment and atypical presentations. We aimed to elucidate the clinical characteristics, diagnostic indicators, and management strategies of non-traumatic intramuscular hematomas in such patients, including cases without anticoagulant or antiplatelet therapy. DESIGN: Retrospective observational study. SETTING: An inpatient rehabilitation hospital in Japan. PARTICIPANTS: Fifteen patients (after exclusions) with spinal cord injury who developed non-traumatic intramuscular hematomas during a 13-year period. INTERVENTIONS: None. OUTCOME MEASURES: Patient demographics, clinical characteristics, laboratory findings, imaging findings, and management strategies. RESULTS: Patients were predominantly men (14/15) with a median age of 46 years, and most had thoracolumbar spinal cord injury and complete motor paralysis. Six patients were not receiving anticoagulant or antiplatelet therapy. Hematomas developed a median of 113 days after injury and 60 days after admission. Local findings were present in eight patients, while systemic findings prompted diagnosis in seven patients. All hematomas occurred within paralyzed regions, mainly the buttocks and thighs. Computed tomography was the primary imaging modality (13/15 cases). One patient required blood transfusion, but no surgical interventions were necessary. CONCLUSION: In our cohort, non-traumatic intramuscular hematomas tended to occur in relatively young men with thoracolumbar spinal cord injuries and complete motor paralysis. They could also occur in patients who were not receiving anticoagulant therapy or who lacked local symptoms. This complication should be considered when unexplained fever, anemia, or abnormal laboratory results occur, and paralyzed regions should be promptly evaluated with imaging.