<s>[INST] context: These x-rays show a marked degree of hyperinflation depicted radiographically by increased lung volume with flattened diaphragm and widened interspaces. Attenuation of the pulmonary vasculature in the peripheral lung zones, especially in the lower zones, is seen.These x-ray are consistent with severe emphysema. The lower lobe accentuation of hyperinflation is consistent with a1 antitrypsin deficiency causing panacinar emphysema. The physical signs and CXR suggest emphysema. This is confirmed by an obstructive ventilatory impairment with hyperinflation, air trapping, and reduced diffusion. In bronchial asthma, there would typically be marked bronchodilator response, and the patient with chronic bronchitis would present with chronic sputum production. Tuberous sclerosis presents radiographically as hyperinflation and lower zone infiltrates, but clinically is a systemic disease with a clinical triad of mental retardation, seizure disorder, and dermal angiofibromas called adenoma sebaceum. Pulmonary disease is rare (it is seen in less than 1% of cases) and presents with pneumothoraces and hemoptysis. Pulmonary emphysema is a chronic condition characterized by irreversible enlargement of airspaces distal to the terminal bronchioles with destruction of the alveolar walls and intraalveolar septa. It results in a loss of lung elastic recoil causing airflow obstruction, air trapping, and hyperinflation. Pulmonary function tests reveal an obstructive pattern with elevated total lung capacity, increased residual volume, and decreased diffusion capacity. Chest x-ray reveals all signs of hyperinflation as illustrated above. CT scan is the most sensitive imaging modality to reliably detect emphysema. Although pulmonary aery enlargement and mild pulmonary aerial hypeension are common in advanced emphysema, radiographic evaluation of pulmonary aery size is a poor indicator of PA pressures. Other concomitant pulmonary disease processes such as pneumonia or pulmonary edema may present in an atypical fashion in a patient with emphysema. Forms of emphysema include the following: 1. Centrilobular emphysema is the most common form, found predominantly in cigarette smokers. The destructive process begins with involvement of the center of the secondary lobule and extends into the lung parenchyma. The upper lobes are more frequently involved. 2. Panacinar emphysema begins with the involvement of the entire secondary lobule with diffuse, widespread lung destruction. It is seen in a1 antitrypsin deficiency and has lower zone predominance. 3. Paraseptal emphysema refers to peripheral lung destruction adjacent to the visceral pleura and interlobular septa. Progressive dyspnea associated with increasing paraseptal emphysema forming bullae refers to the "vanishing lung syndrome" 4. Congenital emphysema is seen in the first few months of life and refers to a large hyperlucent lobe associated with compressive and mass effect on the adjacent structures. 5. Compensatory emphysema refers to hyperlucent and hyperinflated airspaces adjacent to areas of deformity, atelectasis, or resection of lung and represents overexpansion without actual lung destruction. 6. Scar emphysema is associated with conditions of fibrosis and scarring and associated honeycombing as in stage 4 sarcoidosis or chronic inflammatory conditions. [/INST] question: A 50-year-old male smoker is evaluated for chronic shoness of breath. On physical examination his vital signs are: pulse 110 bpm; temperature normal; respirations 30/min with use of accessory muscles and pursed-lip breathing; blood pressure 110/78 mm Hg. Other peinent findings are: hea exam: apex beat (impulse) is medial to the midclavicular line with generalized decreased breath sounds on lung exam; ABGs (FiO2 0.21): pH 7.38; PCO2 47 mm Hg; PO2 67 mm Hg. PFTs/spirometry: FVC 2.80 L (67% of predicted); FEV1 1.56 (50% of predicted); FEV1/FVC% 56%; TLC 134% of predicted; RV 170% of predicted; DLCO 43% of predicted. There is no reversibility with bronchodilators. Chest radiograph are shown below.What is the most likely diagnosis? | options: A: Bronchial asthma with status asthmaticus B: Emphysema C: Chronic bronchitis D: Tuberous sclerosis | answer: B </s>