A 43-year-old Vietnamese-American woman was referred for evaluation of dyspnea. Six months prior to presentation, left-sided chest pain radiating to her shoulder had developed, and she also noted nonproductive cough and decreased exercise tolerance. These symptoms resolved spontaneously after 10 days, and she returned to her usual state of good health. Within a few weeks began the insidious onset of progressive exertion-related dyspnea. She denied fevers, night sweats, weight loss, cough, sputum production, hemoptysis, wheezing, or recurrent chest pain. She was seen by her primary care physician who started her on loratadine, 10 mg/d, and albuterol by metered-dose inhaler. When her symptoms failed to improve, she was referred to our institution.
Her medical history was significant for hypertension, hyperlipidemia, and polycystic kidney disease. Her medications at the time of presentation to our center included hydrochlorothiazide, simvastatin, lansoprazole, and loratadine. She was a lifetime nonsmoker, denied recent travel, and had no risk factors for tuberculosis. There was no known family history of polycystic kidney or parenchymal lung disease.
On physical examination, vital signs were normal and pulse-derived oxygen saturation was 98% on room air. Lung auscultation revealed diminished breath sounds bilaterally, but without crackles, wheeze, or rhonchi. She was not clubbed, nor did she have peripheral edema, rash, or skin lesions. Neurologic examination was unremarkable.
Results for CBC count, chemistry panel, liver tests, and coagulation studies were normal. Room air, resting blood gas showed pH 7.45, PaCO2 of 33 mm Hg, and PaO2 of 71 mm Hg. Urinalysis was normal. Spot urine protein/creatinine ratio was 0.1. Spirometry showed the following: FVC, 3.67 L (86% of predicted); FEV1, 2.92 L (85% of predicted); and FEV1/FVC, 0.80. Lung volumes measured by body plethysmograph revealed total gas volume of 4.01 L (123% of predicted), residual volume of 3.25 L (171% of predicted), and total lung capacity of 6.82 L (118% of predicted). Diffusion capacity of the lung for carbon monoxide unadjusted for hemoglobin was 90% of predicted. High-resolution CT of the chest and unenhanced CT scans of the abdomen and pelvis were performed (Fig 1, 2).