Case 327: Exogenous Lipoid Pneumonia

A 58-year-old male patient with an active smoking status was admitted twice to the intensive care unit (ICU) of a tertiary referral thoracic center for severe hypercapnic acute respiratory failure and persistent bilateral chest radiograph opacities that were unchanged over the course of the two ICU admissions within a 3-month period. The patient had obesity (body mass index, 36), stage 3 vascular chronic renal insufficiency, and hebephrenic schizophrenia treated with haloperidol, carbamazepine, and cyamemazine. He reported chronic dyspnea on exertion, which worsened for 6 months. At the second ICU admission, the patient was afebrile, with a blood pressure of 160/72 mm Hg and pulse oximetry of 93% on 6 L/min oxygen therapy through a nonrebreathing mask. Physical examination showed signs of respiratory failure with wheezing and active abdominal expiration, and bilateral pulmonary crackles without chest pain, hemoptysis, clubbing, or signs of cardiac failure. The patient had no peripheral lymphadenopathy and no enlarged spleen. Blood gases (on 6 L/min oxygen) showed respiratory acidosis (pH, 7.15 [normal range, 7.38-7.42]; PaO₂ level, 67 mm Hg [normal range, 80-100 mm Hg]; PaCO₂ level, 102 mm Hg [normal range, 38-42 mm Hg]; bicarbonate [HCO_3-], 29 mmol/L [normal range, 22-27 mmol/L]). Noninvasive ventilation was initiated. Imaging performed during the second ICU hospitalization included CT and MRI of the chest without contrast enhancement, and fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT.