A 55-year-old woman presented to an Ontario emergency department with six months of progressive exertional dyspnea, associated with a cough productive of a scant amount of grey sputum. The dyspnea had become so severe that even hair brushing elucidated symptoms. There were no infectious or cardiac symptoms. The patient described a ten-pound weight loss but no other constitutional symptoms. There was no exposure to radiation, chemotherapy, dusts, solvents, smoke, livestock, or other causes of interstitial lung disease. There was no exposure to sick contacts or tuberculosis and no features of connective tissue disease. The patient had no allergies but was a current smoker of 25 pack-years. Her medical history included depression and a nephrectomy for donation. She took tiotropium and budesonide/formoterol at home but had no documented lung disease. The patient's other medications were doxepin and pantoprazole.
On examination, she was afebrile, with a heart rate of 92 beats per minute, a respiratory rate of 40 breaths per minute, an oxygen saturation of 86% on room-air (improving to 95% on 50% oxygen by facemask), and a blood pressure of 127/87 millimeters of mercury. Physical examination revealed coarse bibasilar crackles and digital clubbing. The remainder of the examination was noncontributory. The patient was admitted to Internal Medicine for further investigation and management.
Laboratory studies demonstrated a hemoglobin of 161 grams (g)/litre (L) (normal range 115-155 g/L), while platelets and leukocytes, including differential, were unremarkable. Her electrolytes were normal with the exception of potassium at 5.1 millimoles (mmol)/L (normal range 3.5-5 mmol/L). Initial chest radiograph demonstrated hazy airspace opacification of the lower lobes bilaterally (Figure 1). Computed Tomography (CT) of the thorax revealed diffuse bilateral ground-glass opacities with intralobular septal thickening, as well as mild mediastinal, pretracheal, and para-aortic lymphadenopathy (Figure 2). The findings were reported as a crazy paving pattern.
On postadmission day two the patient became increasingly hypoxemic and required intubation. She was transferred to the Intensive Care Unit and underwent bronchoscopy with bronchoalveolar lavage (BAL). BAL fluid from all lobes appeared thin and milky (Figure 3). Under microscopic examination, the fluid contained scattered globular Periodic Acid-Schiff positive material, with no malignant cells, fungi, or hemosiderin-laden macrophages (Figures 4 and 5). BAL cultures were negative for microorganisms and contained abundant debris. The laboratory was unable to perform a cell count on the sample. BAL findings and CT results were sufficient for diagnosis of pulmonary alveolar proteinosis (PAP); this was presumed to be autoimmune given the lack of potential secondary causes. It remains unclear what may have contributed to the clinical severity.
Three sessions of whole lung lavage (WLL) over a one-week period improved the patient's oxygenation sufficiently for extubation. A radiograph taken before discharge showed improvement in her airspace disease (Figure 6). She was discharged home six days after extubation with Respirology follow-up.