A 32-year-old woman who weighs 125 kg (275 lb) is in the hospital for open reduction and internal fixation of a fractured ankle. She states that the only medication she is taking is an oral contraceptive. Four days after the surgery, she suddenly complains of chest pain and is noted to have difficulty breathing. Pulse oximetry reveals an arterial pO2 of 75%. She becomes unresponsive. During resuscitation, she is noted to have pulseless electrical activity. Despite aggressive efforts, she dies. An autopsy is most likely to reveal which of the following conditions?

A. Diffuse alveolar damage:Diffuse alveolar damage (DAD) presents with widespread interstitial involvement, alveolar edema, and hyaline membrane formation, typically causing diffuse infiltrates rather than discrete “coin lesions.” It does not manifest as multiple nodules on imaging.

B. Metastatic cancer:Multiple “coin lesions” on chest x-ray are characteristic of hematogenous spread of metastatic tumors to the lungs. CT-guided biopsy would likely reveal malignant cells consistent with secondary pulmonary involvement, making metastatic cancer the most probable diagnosis in a patient with multiple discrete nodules.

C. Nodular silicosis:Nodular silicosis presents with upper lobe nodules and may calcify, but it usually occurs in individuals with long-term occupational silica exposure and produces a more diffuse nodular pattern rather than well-circumscribed coin lesions.

D. Primary lung cancer:Primary lung cancer usually presents as a single mass or nodule rather than multiple discrete coin-shaped lesions. While it can metastasize, the primary presentation of multiple coin lesions is more consistent with secondary metastases.

E. Pulmonary abscess:Pulmonary abscesses are localized collections of pus that usually appear as cavitary lesions, often with air-fluid levels, rather than multiple well-circumscribed coin lesions. They are typically unilateral and associated with infection, fever, and purulent sputum.

A. Bronchial asthma:Asthma is characterized by episodic wheezing, reversible airway obstruction, and airway hyperresponsiveness. It usually presents with intermittent symptoms rather than a chronic productive cough and persistent hypoxia with CO₂ retention, making it less consistent with this patient’s history.

B. Chronic bronchitis:Chronic bronchitis, a form of chronic obstructive pulmonary disease (COPD), is defined by a productive cough lasting at least three months per year for two consecutive years. Heavy smoking is the primary risk factor. The patient’s chronic cough, sputum production, frequent infections, hypoxia, and CO₂ retention are classic features of chronic bronchitis, reflecting chronic airway inflammation and airflow obstruction.

C. Diffuse alveolar damage (ARDS):ARDS presents acutely with severe hypoxemia and bilateral pulmonary infiltrates following trauma, sepsis, or inhalation injury. It does not produce a 3-year history of chronic cough or sputum production and is not a chronic condition.

D. Goodpasture syndrome:Goodpasture syndrome is an autoimmune disorder targeting the lungs and kidneys, causing hemoptysis and rapidly progressive glomerulonephritis. It does not typically present with chronic productive cough or CO₂ retention from chronic airway disease.

E. Usual interstitial pneumonia:Usual interstitial pneumonia, seen in idiopathic pulmonary fibrosis, causes progressive dyspnea and dry cough, not productive cough. It also leads to restrictive lung disease rather than the obstructive pattern and CO₂ retention seen in chronic bronchitis.