Obstructive Atelectasis Caused by an Endobronchial Blood Clot Following Negative-Pressure Airway Injury in Non-Fatal Drowning: A Case Report

Abstract

Background: Atelectasis is most commonly obstructive in origin. An endobronchial blood clot is an uncommon but fully reversible cause that is easily overlooked, especially when the preceding hemoptysis is limited to a single episode and has resolved by presentation. Drowning has not previously been described as a precipitant. Case presentation: A 26-year-old previously healthy woman choked on water while swimming at night and experienced a single episode of hemoptysis the following day. She subsequently developed progressive dyspnoea and presented with an oxygen saturation of 85–90% on a non-rebreathing mask at 10 L/min. Chest radiography demonstrated right upper-zone opacification accompanied by ipsilateral tracheal deviation and elevation of the right hemidiaphragm — findings that indicate volume loss rather than alveolar filling. High-flow nasal cannula oxygen and chest physiotherapy did not improve the patient, and saturation fell to 81%. Serial radiographs over the following days showed progression to near-complete opacification of the right hemithorax with worsening mediastinal shift. Bronchoscopy with bronchoalveolar lavage revealed and retrieved an organized endobronchial blood clot. Oxygen saturation rose to 100% immediately after the procedure, arterial blood gases normalized, and the radiograph showed full re-expansion with return of the trachea and hemidiaphragm to the midline. Conclusions: Forceful inspiratory effort against a closed or obstructed glottis during drowning can disrupt tracheobronchial vessels and produce airway bleeding — negative-pressure airway injury — a mechanism that is distinct from negative-pressure pulmonary edema and that has different radiographic and therapeutic implications. The resulting clot may obstruct a lobar bronchus and cause resorptive atelectasis that is refractory to supplemental oxygen and physiotherapy. Radiographic volume loss is the key sign distinguishing this entity from swimming-induced and negative-pressure pulmonary edema, in which lung volume is preserved or increased. Early bronchoscopy is both diagnostic and definitive.