Diagnostic Puzzlers: Shortness of breath after pneumonectomy and chemotherapy

Subsequently, she underwent chemotherapy. Six weeks later, she was admitted with a complaint of shortness of breath. She denied fever, chills, rigors, and excess sputum production. The patient was in obvious distress, with a respiration rate of 22 breaths per minute and the use of accessory muscles. She was afebrile. Her heart rate was 102 beats per minute and her blood pressure was 110/82 mm Hg. No clubbing or cyanosis was noted. Heart sounds were normal. Air entry was decreased in the fields of the left lung, with slight unilateral wheezing. The abdominal and neurologic examinations were unremarkable. The patient's white blood cell count was 10,000/μL, with 73% neutrophils, 22% lymphocytes, and 5% monocytes. Her hemoglobin level was 14.1 g/dL, and hematocrit was 36%. Other laboratory parameters were within normal ranges, with the exception of an elevated alkaline phosphatase level of 240 IU/L (normal level, 20 to 140 IU/L). The arterial blood gas levels on room air were pH, 7.42; PCO2, 31 mm Hg; and PO2, 62 mm Hg. A chest radiograph was obtained (Figure 1). What is the likely diagnosis? How would you proceed? Discussion In the normal postpneumonectomy chest, residual large spaces in the pleural cavity are filled in one of the following ways: entry of fluid, increased expansion of the remaining lung, or a shift of the mediastinum/diaphragm toward the newly created space. When fluid enters the cavity, it increases until the pneumothorax is obliterated. When fluid in the cavity decreases and is replaced by air, as in our patient, a BPF from the stump is indicated. Thus, the characteristic radiologic signs of postpneumonectomy BPF include failure of the potential pleural space to fill with liquid, inspiratory shifting of the mediastinum to the contralateral (nonoperated) side, and an abrupt decrease in the gas-liquid level of more than 2 cm (0.8 in). A BPF is a sinus tract between the bronchus and the pleural space that results from a necrotizing infection or trauma. The most common traumatic cause is failure to obtain good bronchial closure and healing after partial or complete resection of the lung (Table). Failure to heal may result from improper initial closure, inadequate blood supply, infection at the bronchial stump, or a residual malignant tumor at the bronchial stump. BPF typically presents 7 to 15 days following resection, although delayed BPFs have been reported.1With delayed BPF, a new air-fluid level appears in a previously opacified hemithorax. Cough and changes in the air-fluid pattern on the chest radiograph are critical warning signs of BPF. Other manifestations include fever with serosanguineous or purulent sputum. Acute respiratory distress may occur if a large BPF results in aspiration to the contralateral lung or if a tension pneumothorax develops. BPF can lead to empyema formation. In our patient, there was no evidence of infection at the bronchial stump or in the pleural space and there was no evidence of recurrent cancer at the bronchial stump. The incidence of BPF is about 4.5% to 20% after pneumonectomy and 0.5% after lobectomy.2,3 BPF can cause significant morbidity, prolonged hospitalization, and mortality. A multivariate analysis of the risk of BPF in patients undergoing resections for lung cancer identified right-sided resection, pneumonectomy (especially right pneumonectomy), mediastinal lymph node resection, highdose preoperative radiation therapy, and residual or recurrent carcinoma at the bronchial stump as predisposing factors.4 Nonoperative risk factors included diabetes mellitus, hypoalbuminemia, cirrhosis, and administration of corticosteroids.