Abstract 345: Occult Antiphospholipid Syndrome Presenting as Subdural Hematoma: A Rare Manifestation of Arterial Hypercoagulability

Objective To describe a case of antiphospholipid syndrome (APS) which presented with subdural hemorrhage, a rarely described manifestation of a commonly hypercoagulable disorder. Background APS is a common arterial and venous hypercoagulable state—though rare in the general population with an incidence of 5 per 100,000 individuals. It most commonly presents with systemic ischemic insults, commonly to the brain in the form of ischemic stroke. This case highlights a known rare manifestation of APS: intracranial hemorrhage. Design/Methods: N/A Results Patient is a 49 year old female with history of end‐stage renal disease who initially presented with altered mentation and hypertension. Her GCS was 7 upon arrival prompting intubation. CT head at that time revealed acute left parietal subdural hematoma. There was no clear history of trauma per the patient's family, and the patient was unable to provide any additional history of their own at that time. The etiology of her hemorrhage, in the acute setting, was not clearly discerned. She was managed in the ICU for several days, however she remained somnolent and unable to participate in examination despite removal of sedating agents. A repeat CT scan of the head was done at that time which revealed multifocal hypodensities consistent with late acute‐early subacute ischemic stroke. Subsequent CT angiography of the head and neck was negative for large vessel occlusive disease, extracranial atherosclerotic disease, vasospasm or other clear cerebrovascular constriction. Other embolic stroke workup including transthoracic and transesophageal echocardiogram was negative. At this point, a broader workup for embolic stroke of unclear source was launched. These studies included hypercoagulablity labs were sent and ultimately returned positive with elevated anticardiolipin and beta‐2 microglobulin consistent with an antiphospholipid antibody syndrome, prompting the initiation of anticoagulation. The patient has since improved clinically and is no longer mechanically ventilated, though does still require significant assistance with activities of daily living. Conclusions While rare, patients with otherwise unexplained hemorrhage should be investigated for possible immune‐mediated mechanisms for stroke—both ischemic and hemorrhagic.