<prompt> A 20 year old male presents with acute respiratory distress and tachypoea. His B.P. is 9060. Loud P2 is nt. True about his conditionD-dimer assay should be doneS wave in lead 1 and Q wave in lead 3 of ECG is seenStreptokinase hold be givenAll  <response>: The patient is presenting with dyspnea and tachpnea;dyspnoea with hypotensionBP:9060 mmHg indicates a massive pulmonary embolism.He is also presenting with a classic sign of PE,i.e.,an accentuated pulmonic component of the second hea sound.The most sensitive test for PE is D-dimer ELISA assay which rises due to the breakdown of fibrin by plasmin.The most frequently cited abnormality in ECG,in addition to sinus tachycardia ,is the S1Q3T3 sign-an S wave in lead I,a Q wave in lead III,and an inveed T wave in lead III.This finding is relatively specific.The gold standard test for PE is CT pulmonary angiography.On confirming the diagnosis ,primary therapy consisting of clot dissolution with thrombolytics like tPAstreptokinase or removal of PE by embolectomy is done.Anticoagulation with heparin and warfarin or placement of an inferior vena caval filter constitutes secondary prevention. Reference:Harrisons medicine-18th edition,page no:2172-2177. 