This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
Sudden onset of a cough followed by increasing dyspnea is characteristic of 
Select and explain. 
A. Pleural effusion, B. Lobar pneumonia, C. Myocardial infarct, D. Pneumothorax
D: Pneumothorax
Answer: D: Pneumothorax 
Explanation: PneumothoraxPatients most commonly present with chest pain, often sharp and pleuritic and may leads to severe respiratory embarrassment or becomes dull and persistent.Dyspnea is the 2ndMC symptom.Less common symptoms include a nonproductive cough and ohopnea.Physical findings may be normal if the Pneumothorax is less than 25%.Characteristic physical finding includes diminished chest excursion and hyper-resonance on percussion of the affected side. Breath sounds are diminished to absent.(Refer: Harrison's Principles of Internal Medicine, 18thedition, pg no: 2181, 2221, 3212)