Symptoms of<unk>  are typically sudden in onset and may include one or many of the following: dyspnea (shortness of breath), tachypnea (rapid breathing), chest pain of a "pleuritic" nature (worsened by breathing), cough and hemoptysis (coughing up blood). More severe cases can include signs such as cyanosis (blue discoloration, usually of the lips and fingers), collapse, and circulatory instability because of decreased blood flow through the lungs and into the left side of the heart. About 15% of all cases of sudden death are attributable to<unk> . While<unk>  may present with syncope, less than 1% of syncope cases are due to<unk> . On physical examination, the lungs are usually normal. Occasionally, a pleural friction rub may be audible over the affected area of the lung (mostly in<unk>  with infarct). A pleural effusion is sometimes present that is exudative, detectable by decreased<unk> rcussion note, audible breath sounds, and vocal resonance. Strain on the right ventricle may be detected as a left parasternal heave, a loud<unk>  component of the second heart sound, and/or raised jugular venous pressure. A low-grade fever may be present, particularly if there is associated<unk>  hemorrhage or infarction. As smaller<unk>  emboli tend to lodge in more<unk> ripheral areas without collateral circulation, they are more likely to cause lung infarction and small effusions (both of which are painful), but not hypoxia, dyspnea, or hemodynamic instability such as tachycardia. Larger<unk> s, which tend to lodge centrally, typically cause dyspnea, hypoxia, low blood pressure, fast heart rate and fainting, but are often painless because there is no lung infarction due to collateral circulation. The classic presentation for<unk>  with pleuritic pain, dyspnea, and tachycardia is likely caused by a large fragmented<unk>  causing both large and small<unk> s. Thus, small<unk> s are often missed because they cause pleuritic pain alone without any other findings and large<unk> s are often missed because they are painless and mimic other conditions often causing ECG changes and small rises in troponin and brain natriuretic<unk> ptide levels.<unk> s are sometimes described as massive, submassive, and nonmassive depending on the clinical signs and symptoms. Although the exact definitions of these are unclear, an accepted definition of massive<unk>  is one in which there is hemodynamic instability. This is a cause of obstructive shock, which presents as sustained low blood pressure, slowed heart rate, or pulselessness.
Pulmonary embolism
Dilated cardiomyopathy
Pulmonary hemorrhage
Pneumonia
Pleural effusion
Costochondritis
Lung infarction
Myocardial stunning