Unusual Cause of Sublingual Hematoma Compromising Upper Airway: Acquired Hemophilia A.

Sublingual hematoma is an uncommon but potentially life-threatening cause of upper airway obstruction. While most cases result from trauma, surgery, or anticoagulant use, acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by factor VIII inhibitors that may, in rare cases, present with spontaneous sublingual mucosal bleeding. We report a rare case of sublingual hematoma due to AHA that narrowed the upper airway. A 90-year-old woman without a history of spontaneous bleeding presented to the emergency department (ED) with acute sublingual swelling and dysphagia. She had no history of trauma, recent dental procedures, or anticoagulant use. Physical examination revealed hoarseness and purplish swelling of the sublingual and submandibular regions. Laboratory examinations showed isolated prolongation of activated partial thromboplastin time (aPTT). Contrast-enhanced computed tomography revealed a sublingual hematoma with airway narrowing. Given the risk of airway obstruction, we prepared for awake nasotracheal intubation. A mixing study demonstrated failure of aPTT correction, and factor VIII activity was undetectable, strongly suggesting AHA. Because the hematoma enlarged during the first 12 hours after ED admission, we initiated intravenous administration of activated prothrombin complex concentrate. The hematoma subsequently improved. A positive factor VIII inhibitor confirmed the diagnosis of AHA, and immunosuppressive therapy with glucocorticoids was started. The aPTT normalized within two weeks, and the inhibitor became undetectable after three weeks. She was discharged on day 41 without additional bleeding events. AHA should be considered in cases of spontaneous sublingual hematoma, particularly when accompanied by isolated aPTT prolongation. In such cases, because the hematoma may rapidly progress to cause upper airway obstruction, clinicians should initiate hemostatic therapy promptly when AHA is strongly suspected, even before a definitive diagnosis is established.