C63-11 When Bleeding Turns Deadly: Hemothorax as an Atypical Presentation of Hereditary Hemorrhagic Telangiectasia

Abstract Hereditary hemorrhagic telangiectasia (HHT), or Osler-Weber-Rendu syndrome, is a rare autosomal dominant vascular disorder classically presenting with epistaxis, telangiectasias, and positive family history. Rarely, it can manifest with life-threatening bleeding, posing both diagnostic and management challenges. We report the case of a 49-year-old male in whom HHT was diagnosed following presentation with hemothorax, an uncommon manifestation HHT. A 49-year-old male with no significant past medical history presented with a one-day history of left-sided pleuritic chest pain. He reported hemoptysis over the past year, progressing from small clots to palm-sized clots, and recent exertional fatigue. He noted chronic epistaxis since childhood, with a father who also experienced frequent nosebleeds but had no hematologic diagnosis. Recent exposure to insecticides and methamphetamine use were reported. Computed tomography pulmonary angiography (CTPE) revealed a moderate left pleural effusion with atelectasis, possible pulmonary sequestration or hemothorax, and a pulmonary arteriovenous malformation (AVM) in the left upper lobe with a partial filling defect. He was admitted to general medicine with pulmonary consultation for thoracentesis. Ultrasound-guided thoracentesis removed 57 cc of bloody fluid, with post-procedure imaging showing increased effusion and compression atelectasis. CBC revealed a 2 g/dL drop in hemoglobin. Fluid analysis indicated an exudative effusion with elevated protein, lactate dehydrogenase, and abundant red blood cells. Physical exam revealed mucocutaneous telangiectasias on the inner lower lip and right lower extremity. A chest tube was placed and interventional radiology performed a pulmonary angiography, identifying a left lower lobe AVM with a single arterial feeder and two venous outflows, which was successfully embolized with coils. The chest tube was removed after three days with a total output of 2,125cc of bloody fluid and no complications. On admission day 4, the patient developed sudden increased oxygen requirements. Due to inability to provide DVT prophylaxis in setting of recent bleed and immobility, duplex ultrasound revealed a non-occluding proximal superficial femoral vein thrombosis and bilateral peroneal vein occlusions. Repeat CTPE demonstrated new bilateral distal pulmonary emboli involving segmental and sub-segmental arteries. After risk-benefit discussion, the patient was started on intravenous heparin, later transitioned to oral apixaban, with no further bleeding. The patient was discharged with recommendations for pulmonary follow-up and genetic evaluation, confirming a new diagnosis of hereditary hemorrhagic telangiectasia (HHT). This case highlights the complex relationship of AVM-related hemothorax, thromboembolic risk, and management challenges in HHT, emphasizing the importance of early recognition and multidisciplinary care in patients with recurrent epistaxis and vascular malformations. This abstract is funded by: none