A patient of left hemiplegia with previous history of right deep vein thrombosis. Cause hemoptysis in this patient is?
Correct Answer: Pulmonary thromboembolism
Description: ANSWER: (A) Pulmonary thromboembolismREF: Harrisons Internal Medicine 17th edition Chapter 256. Deep Venous Thrombosis andPulmonary ThromboembolismPULMONARY THROMBOEMBOLISM:PathophysiologyWhen venous thrombi dislodge from their site of formation, they embolize to the pulmonary arterial circulation or, paradoxically, to the arterial circulation through a patent foramen ovale or atrial septal defect. About half of patients with pelvic vein thrombosis or proximal leg DVT develop PE, which is usually asymptomatic.With increased use of chronic indwelling central venous catheters for hyperalimentation and chemotherapy, as well as more frequent insertion of permanent pacemakers and internal cardiac defibrillators, upper extremity venous thrombosis is becoming a more common problem. These thrombi rarely embolize and cause PE.Pathophysiological abnormalities include:The most common gas exchange abnormalities are hypoxemia (decreased arterial P02) and an increased alveolar-arterial 02 tension gradient, which represents the inefficiency of 02 transfer across the lungsIncreased pulmonary vascular resistance due to vascular obstruction or platelet secretion of vasoconstricting neurohumoral agents such as serotonin.Impaired gas exchange due to increased alveolar dead space from vascular obstruction, hypoxemia from alveolar hypoventilation relative to perfusion in the nonobstructed lung, right-to-left shunting, and impaired carbon monoxide transfer due to loss of gas exchange surface.Alveolar hyperventilation due to reflex stimulation of irritant receptorsIncreased airway resistance due to constriction of airways distal to the bronchiDecreased pulmonary compliance due to lung edema, lung hemorrhage, or loss of surfactantSigns & SymptomsSudden-onset 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 due to decreased blood flow through the lungs and into the left side of the heart.Occasionally, a pleural friction rub may be audible over the affected area of the lung (mostly in PE with infarct)A pleural effusion is sometimes present that is transudativeA low-grade fever may be present, particularly if there is associated pulmonary hemorrhage or infarctionAbout 15% of all cases of sudden death are attributable to PERisk factorsThe most common sources of embolism are proximal leg deep venous thrombosis (DVTs) or pelvic vein thromboses.The development of thrombosis is classically due to a group of causes named Virchows triad (alterations in blood flow, factors in the vessel wall and factors affecting the properties of the blood). Often, more than one risk factor is present.Alterations in blood flow: immobilization (after surgery, injury or long-distance air travel),pregnancy (also procoagulant), obesity (also procoagulant), cancer (also procoagulant)Factors in the vessel wall: of limited direct relevance in VTEFactors affecting the properties of the blood (procoagulant state)Estrogen-containing hormonal contraceptionGenetic thrombophilia (factor V Leiden, prothrombin mutation G20210A, protein C deficiency, protein S deficiency, antithrombin deficiency, hyperhomocysteinemia and plasminogen/fibrinolysis disorders)Acquired thrombophilia (antiphospholipid syndrome, nephrotic syndrome, paroxysmal nocturnal hemoglobinuria)Cancer (due to secretion of pro-coagulants)DiagnosisD-dimer is highly sensitive but not very specific (specificity around 50%), In other words, a positive D-dimer is not synonymous with PE, but a negative D-dimer is, with a good degree of certainty, an indication of absence of a PEThe gold standard for diagnosing pulmonary embolism (PE) is pulmonary angiographyCT pulmonary angiography (CTPA) is a pulmonary angiogram obtained using computed tomography (CT) with radiocontrast rather than right heart catheterization. Its advantages are clinical equivalence, its non-invasive nature, its greater availability to patientsVentilation/perfusion scan (or V/Q scan or lung scintigraphy), which shows that some areas of the lung are being ventilated but not perfused with blood (due to obstruction by a clot). This type of examination is used less often because of the more widespread availability of CT technology, however, it may be useful in patients who have an allergy to iodinated contrast or in pregnancy due to lower radiation exposure than CT
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