Case report: Spontaneous hemothorax following anticoagulation for microthrombi in severe COVID pneumonia.

Background: Anticoagulant therapy has become a hallmark of treatment for critically ill COVID patients. Gastrointestinal and intracranial hemorrhage are known major complications of anticoagulation, but spontaneous hemothorax is a rare event, particularly in the absence of pre-existing structural lung disease, vascular malformations, or genetic bleeding diatheses. Herein is a case of spontaneous hemothorax following anticoagulation for microthrombi in a patient with acute hypoxic respiratory failure due to Covid pneumonia. Case presentation: A 49 year old male with hypertension, asthma, and obesity was admitted for acute hypoxic respiratory failure due to Covid pneumonia. He was treated with dexamethasone, baricitinib, and therapeutic enoxaparin as empiric therapy for severe COVID disease. He subsequently developed a massive right hemothorax with associated hemorrhagic shock, which required initiation of massive transfusion protocol, vasopressor support and mechanical ventilation. No clear etiology for the hemothorax was determined upon investigations. The patient eventually improved and was discharged to a skilled nursing facility on chronic oxygen therapy. Conclusions: Various mechanisms have been proposed for the development of non-traumatic hemothoraces, including tearing of adhesions and rupture of vascularized bullae. Such explanations find support in radiologic and pathologic studies of pleural changes in Covid pneumonia, and likely played a role in the hemorrhage experienced by our patient.