A 62-year-old man is brought to the emergency department by a friend due to severe shortness of breath. He is agitated and gasping for air and is unable to provide history. His friend says the patient has a history of chronic alcohol use and attends Alcoholics Anonymous meetings. He is unaware of any other medical history. Temperature is 36.7 C (98 F), blood pressure is 110/70 mm Hg, pulse is 104/min, and respirations are 32/min. Due to worsening respiratory distress, immediate endotracheal intubation is performed and mechanical ventilation is begun. The patient is admitted to the intensive care unit and, despite appropriate therapy, dies several hours later. Autopsy examination is performed, and histopathology of the lungs reveals engorged pulmonary capillaries and abundant intraalveolar, acellular, pink material that is more prominent at the bases. This patient most likely had which of the following conditions?
This patient's histopathologic findings of engorged alveolar capillaries (reflecting increased pulmonary venous pressure) and pink, acellular material within the alveoli (transuded plasma across the alveolar-capillary membrane) are most consistent with acute pulmonary edema. Given the patient's history of chronic alcohol use, he likely had underlying dilated cardiomyopathy. Subsequent decompensation then led to increased alveolar capillary hydrostatic pressure, causing pulmonary congestion and acute respiratory failure.
(Choice A) Aspiration pneumonia may be chemical (eg, aspiration of gastric contents) or bacterial (eg, aspiration of oral flora). Histopathology of acute pneumonia shows neutrophil-rich, inflammatory exudates within the bronchioles and alveolar spaces.
(Choice B) Centriacinar emphysema most commonly results from heavy smoking. Enlarged airspaces with macrophage-predominant infiltrates are expected.
(Choice C) Hypersensitivity pneumonitis results from exposure to an environmental irritant (eg, mold). Histopathology shows lymphocyte-predominant, interstitial inflammation, often accompanied by non-necrotizing granulomas.
(Choice D) Histopathology in pulmonary arterial hypertension typically shows hypertrophy of the pulmonary vascular smooth muscle.
(Choice F) Pulmonary infarction yields hemorrhagic, ischemic necrosis of the lung parenchyma. Histopathology shows a well-demarcated area of alveolar and vascular wall necrosis with cells that lack nuclei, and the alveolar spaces may contain red blood cells.
Educational objective:
Acute cardiogenic pulmonary edema results from increased pulmonary venous pressure. The alveolar capillaries become engorged with blood and there is a transudation of fluid plasma across the alveolar-capillary membrane, appearing as pink, acellular material within the alveoli.