Sudden onset of a cough followed by increasing dyspnea is characteristic of

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)