<prompt> Which of the following is least likely cause of hemoptysisPneumoniaEmpyemaBronchiectasisMetral stenosis  <response>: Answer is B Empyema: Empyema by itself is not a cause for hemoptysis. Pneumonia, Mitral stenosis and Bronchiectasis are established causess for hemoptysis. Differential Diagnosis of hemoptysis Tracheobronchial source Neoplasm branchogenic carcinoma, endobronchial metastatic tumor, Kaposis sarcoma, bronchial carcinoid Bronchitis acute or chronic Bronchiectasis Broncholithiasis Airway trauma Foreign body Pulmonary parenchymal source Lung abscess Pneumonia Tuberculosis Mycetoma fungus ball Goodpastures syndrome Idiopathic pulmonary hemosiderosis Wegeners granulomatosis Lupus pneumonitis Lung contusion Primary vascular source Aerivenous malformation Pulmonary embolism Elevated pulmonary venous pressure esp. mitral stenosis Pulmonary aery rupture secondary to balloon- tip pulmonary aery catheter manipulation Miscellaneousrare causes Pulmonary endometriosis catamenial hemoptysis Systemic coagulopathy or use of anticoagulants or thrombolytic agents 