A 60-year-old Caucasian woman presented to our care with shortness of breath with exertion, which was relieved by rest for 2 weeks. She initially went to her primary care physician, who noted that the patient was hypoxic with oxygen saturations at 73%. She was therefore sent to the emergency department for further evaluation. Other complaints included intermittent substernal chest pain of moderate intensity with radiation to the back of the neck and a productive cough with white phlegm, but no blood was noted. She denied any fever, chills, nausea, vomiting, headaches, dizziness, abdominal pain, or diarrhea. Her comorbidities included hypertension and hypothyroidism. Home medications were levothyroxine 112 mcg tab daily and hydrochlorothiazide 12.5mg tab daily. She quit smoking tobacco about 3 years ago but previously had smoked 1/2 pack per day for 10 years.
Initial vital signs were significant for hypertension (blood pressure: 155/81) and hypoxia (oxygen saturation was 70% on room air). She was then placed on 3 liters of oxygen through nasal cannula; oxygenation then increased to 94%. The only significant physical examination findings were bilateral diffuse wheezing upon auscultation of the lungs. The initial laboratory workup (Table 1) was only significant for elevated liver enzymes. A chest radiograph (Figure 1) showed mild cardiomegaly with increased parahilar vascularity suggestive of pulmonary edema. Computed tomography (CT) angiogram (Figure 2) of the chest was ordered to rule out pulmonary embolism. It revealed a diffuse bilateral ground glass density in the lung parenchyma with intervening normal appearing lung parenchyma having a mosaic attenuation pattern. Diffuse micronodules throughout both lungs were also noted. 2D echocardiogram showed a borderline left atrial enlargement and left ventricle ejection fraction of 70+-5%.
Our differential diagnosis after our initial assessment and imaging studies was hypersensitivity pneumonitis, sarcoidosis, miliary tuberculosis, bacterial pneumonia, and lung malignancy. We suspected hypersensitivity pneumonitis as the most likely diagnosis but were unsure of the cause. On further questioning, the patient explained that she worked as a server at a restaurant located on a ranch approximately 35 miles east of El Paso, Texas. This ranch has several different species of farm animals, including birds (ducks and geese), cattle, and horses. She explained that she did not have actual close exposure to the animals or the birds. However, she had been collecting the feathers of the ducks and geese nearby the restaurant for the past 6 months and placed them in a vase on her kitchen table at home. She did not have any pet birds or birds living outside the house. No other possible environmental exposures were noted.
On the 3rd hospital day, a bronchoscopy was done that showed anatomically normal airways with diffusely erythematous mucosa and clear secretions. Bronchoalveolar lavage (BAL) of the right middle lobe was negative for malignancy, pneumocystic carinii, fungi, or granulomas. The BAL fluid was hazy and red, the cell analysis included a red blood cell count of 5000 cells per mm3 and white blood cell count was 1968 cells per mm3 with neutrophils accounting for 90%, lymphocytes of 6% and monocytes 4%. Cultures of BAL were negative for any microorganism growth, acid fast bacilli or fungi. The pulmonary function tests (PFTs) showed a proportional decrease in both FEV1 and FVC, leading to a decreased FEV1/FVC ratio. The carbon monoxide diffusing capacity (DLCO) was also decreased, suggesting a restrictive lung disease process. The human immunodeficiency virus (HIV) test result was negative. The absolute CD4 was 1272 cells/mcL (490-1740 cells/mcL), absolute CD8 count was 652 cells/mcL (180-1170 cells/mcL), and the CD4/CD8 ratio was 1.95 (0.86-5.0). Transbronchial lung biopsy revealed non-caseating granulomas, aggregates of epithelioid macrophages, and patchy mononuclear cell infiltration with lymphocytes and fibrotic tissue.
The patient clinically improved and was discharged home on the 6th hospital day with prednisone 20 mg daily. At her 1-month follow-up with the pulmonologist after discharge, she still worked at the restaurant on the ranch, but had minimal exposure to the birds and no longer collected bird feathers. The chest CT (Figure 3) findings were unchanged from previous imaging evaluation. The chest CT findings were diffuse bilateral geographic mosaic attenuation and bilateral centrilobular/peribronchial pulmonary nodules, likely representing granulomas, measuring up to 7 mm and scattered throughout both lungs. There was also subcentimeter bilateral upper/lower paratracheal, and subcarinal and hilar lymph node enlargement. She was on home oxygen and prednisone 20 mg daily. She explained that she no longer had any shortness of breath, but on physical examination mild diffuse wheezing was present bilaterally. The PFTs still had a proportional decrease in both FEV1 and FVC with a decreased FEV1/FVC ratio, but improved from the last PFTs and the DLCO was also improved. Since the patient was doing well, we initiated a prednisone taper over the course of 1 month. Additional chest CT and PFTs were performed at the 6-month follow-up visit, without any interval improvement. At this time she was no longer using the home oxygen and was tapered off the prednisone. She was asymptomatic and no wheezing was noted on auscultation of the lungs.
Chest CT: diffuse bilateral ground glass density in the lung parenchyma with intervening normal appearing lung parenchyma having a mosaic attenuation pattern.