Walking for 6 minutes causes mild dyspnea, and oxygen saturation drops to 88%. Chest x-ray shows no infiltrates. Pulmonary function testing reveals FEV1 at 95% of predicted and a FEV1/FVC ratio of 84%. Pulmonary artery systolic pressure estimated by Doppler echocardiography is 65 mm Hg at rest (normal 15-30 mm Hg).
Lung biopsy will most likely demonstrate which of the following?

Question

Walking for 6 minutes causes mild dyspnea, and oxygen saturation drops to 88%.  Chest x-ray shows no infiltrates.  Pulmonary function testing reveals FEV1 at 95% of predicted and a FEV1/FVC ratio of 84%.  Pulmonary artery systolic pressure estimated by Doppler echocardiography is 65 mm Hg at rest (normal 15-30 mm Hg). 
Lung biopsy will most likely demonstrate which of the following?

Quizplus · Accepted Answer

Right heart catheterization is the most accurate method of measuring pulmonary arterial pressure (PAP); however, echocardiography can noninvasively provide a reliable estimate of PAP and confirms pulmonary hypertension in this patient (resting pulmonary arterial systolic pressure >30 mm Hg). In systemic sclerosis (SS), a common mechanism of pulmonary hypertension is hyperplasia of the intimal smooth muscle layer of the pulmonary arteries leading to increased pulmonary vascular resistance. This condition is referred to as pulmonary arterial hypertension (PAH). The lung parenchyma is generally unaffected in PAH, which is evidenced by the absence of infiltrates on chest x-ray and normal FEV1 and FEV1/FVC ratio on pulmonary function testing (PFT). (Choice A) Alveolar spaces filled with fibroblasts are consistent with interstitial lung disease (ILD), which is a common cause of secondary pulmonary hypertension in patients with SS. However, in pulmonary hypertension due to ILD, PFT should demonstrate a restrictive pattern with FEV1 <80% of predicted (as well as low FVC and normal or high FEV1/FVC ratio). In addition, reticular opacities should be present on chest x-ray. (Choice C) Bronchial wall thickening with mucus plugs occurs in bronchiectasis, which like ILD may cause secondary pulmonary hypertension due to chronic hypoxia. Autoimmune diseases such as SS do have a rare association with bronchiectasis; however, pulmonary function testing should reveal an obstructive pattern with an FEV1/FVC ratio <70% of predicted. (Choice D) Chronic inflammation with noncaseating granulomas is consistent with sarcoidosis. Pulmonary hypertension is a potential complication of sarcoidosis; however, PFT typically shows a restrictive pattern and chest x-ray should reveal hilar adenopathy possibly in combination with interstitial infiltrates. (Choice E) Septal widening with hemosiderin-loaded macrophages is characteristic of pulmonary edema due to left-sided heart failure, which can cause secondary pulmonary hypertension. Pleural effusion and evidence of pulmonary edema (eg, Kerley B lines, bilateral infiltrates) would be expected on chest x-ray. Educational objective: Pulmonary arterial hypertension (PAH) is a common manifestation of systemic sclerosis that results from intimal hyperplasia of the pulmonary arteries. Absence of alveolar airspace disease and normal FEV1 and FEV1/FVC ratio help differentiate PAH from pulmonary hypertension due to lung disease or left-sided heart failure. References: Pulmonary hypertension in rheumatic diseases: epidemiology and pathogenesis. (http://www.ncbi.nlm.nih.gov/pubmed/23334373)

Walking for 6 Minutes Causes Mild Dyspnea, and Oxygen Saturation