Spontaneous haemarthrosis causing anterior shoulder dislocation.

Nontraumatic haemarthrosis secondary to anticoagulant therapy is a recognized clinical problem. The involved joints are usually large weight-bearing joints, particularly the knee. We describe a case of spontaneous haemarthrosis in a 53-year-old female patient, who had been started on anticoagulant drugs after a pulmonary embolism in the past (international normalized ratio on admission: 2.4). The patient presented with acute onset of severe shoulder pain with no history of trauma. Her shoulder showed radiological signs of anterior dislocation. Attempts to relocate her shoulder under intravenous sedation with midazolam were unsuccessful. The patient subsequently underwent aspiration of the shoulder joint and made full recovery after a course of physiotherapy. The case is unusual because it occurred in a previously healthy shoulder joint and because the bleeding caused the shoulder to appear clinically and radiologically anteriorly dislocated. No history of trauma was reported before presentation; the apparent dislocation was caused solely by spontaneous haemarthrosis. This case emphasizes that it is important to consider spontaneous haemarthrosis as a possible diagnosis in patients with no history of trauma, particularly in those on anticoagulant drugs, who present with what appears to be an anterior shoulder dislocation.