View Abstract

A5322 - Fat Chance: An Unusual Case of Diffuse Alveolar Hemorrhage
Author Block: A. Puravath1, P. Vijhani2, N. Sood2; 1Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX, United States, 2Pulmonary, Critical Care, and Sleep Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX, United States.
INTRODUCTION: Fat embolism frequently complicates the course of long bone injury and typically presents as petechia, tachycardia, fever, hypoxemia, and central nervous system depression. We present a case of fat embolism causing an uncommon presentation of diffuse alveolar hemorrhage and profound hypoxic respiratory failure. DESCRIPTION: A 30 year old previously healthy man on no medications presented to the emergency department after injuring his left leg while playing soccer. Radiography showed a comminuted fracture of the proximal left tibia and fibula. He underwent intramedullary nail closed reduction of the tibia and internal fixation of the fibula. The following day, the patient became short of breath, febrile, tachycardic, hypotensive, and developed progressive hypoxic respiratory failure requiring mechanical ventilation. A computed tomography pulmonary angiogram was negative for pulmonary embolism but demonstrated diffuse bilateral airspace infiltrates. He was also noted to have an acute drop in hemoglobin as well as renal insufficiency. He had no evidence of overt bleeding or hemolysis. A transthoracic echocardiogram demonstrated normal left ventricular function with increased right ventricular strain. His arterial blood gas showed a pH of 7.28, partial pressure of carbon dioxide of 56, partial pressure of oxygen of 35, and an oxygen saturation of 58% on room air. He required high levels of ventilator support and was placed on assist-control at a rate of 24, tidal volume of 325 mL, fraction of inspired oxygen of 100%, and a positive end expiratory pressure of 20 cm of water. He underwent a bronchoscopy and was found to have normal airways with a bronchoalveolar lavage consistent with alveolar hemorrhage. All infectious workup and cultures, including viral, were negative. Serum serology was also negative for HIV, hepatitis, ANA, ANCA, and anti-GBM. Over the next 48 hours, his hemoglobin stabilized and he was weaned off of his ventilation, underwent rehabilitation and discharged home. DISCUSSION: Fat embolism is most commonly associated with skeletal fracture in the setting of trauma. In the post-traumatic setting, it typically presents with petechia, tachycardia, fever, hypoxemia, and central nervous system depression. Diffuse alveolar hemorrhage is an exceptionally rare presentation of fat embolism. It is postulated to be an inflammatory response caused by lipoprotein lipase activated by stress-induced catecholamine surge. The clinical course for this patient required the exclusion of all infectious and autoimmune etiologies before the diagnosis of diffuse alveolar hemorrhage due to fat embolism could be made.