Thursday, March 5, 2009

Hemoptysis is the expectoration of blood that originates below the vocal cords. It is commonly classified as trivial, mild, or massive, the last defined as more than 200–600 mL in 24 hours. The dividing lines are arbitrary, since the amount of blood is rarely quantified with precision. Massive hemoptysis can be usefully defined as any amount that is hemodynamically significant or threatens ventilation, in which case the initial management goal is not diagnostic but therapeutic.
The lungs are supplied with a dual circulation. The pulmonary arteries arise from the right ventricle to supply the pulmonary parenchyma in a low-pressure circuit. The bronchial arteries arise from the aorta or intercostal arteries and carry blood under systemic pressure to the airways, blood vessels, hila, and visceral pleura. The bronchial arterial circulation represents only 1–2% of total pulmonary blood flow but is frequently the source of hemoptysis: It is a high-pressure circuit; it provides the blood supply to the airways and lesions within those airways; and flow can increase dramatically under conditions of chronic inflammation—eg, chronic bronchiectasis.
The causes of hemoptysis can be classified anatomically. Blood may arise from the airways in chronic bronchitis, bronchiectasis, and bronchogenic carcinoma; from the pulmonary vasculature in left ventricular failure, mitral stenosis, pulmonary emboli, and arteriovenous malformations; or from the pulmonary parenchyma in pneumonia, inhalation of crack cocaine, or autoimmune diseases such as Goodpasture's disease or Wegener's granulomatosis. Iatrogenic hemorrhage may follow transbronchial lung biopsies, anticoagulation, or pulmonary artery rupture due to distal placement of a balloon-tipped catheter.

Clinical Findings
Blood-tinged sputum in the setting of acute bronchitis in an otherwise healthy nonsmoker does not warrant an extensive diagnostic evaluation if the hemoptysis subsides with resolution of the infection. However, hemoptysis is frequently a sign of serious disease, especially in patients with a high prior probability of underlying pulmonary pathology. The goal of the history is to identify patients at risk for one of the disorders listed above. Pertinent features are tobacco use, duration of symptoms, and the presence of respiratory infection. Nonpulmonary sources of hemorrhage—from the nose or the gastrointestinal tract—should be ruled out.
Laboratory evaluation should include a chest radiograph and complete blood count, including platelet count. Renal function tests, urinalysis, and coagulation studies are appropriate in specific circumstances. Flexible bronchoscopy reveals endobronchial cancer in 3–6% of patients with hemoptysis who have a normal (nonlateralizing) chest radiograph. Nearly all of these patients are smokers over the age of 40, and most will have had symptoms for more than a week. Bronchoscopy is indicated in such patients. High-resolution CT of the chest is complementary to bronchoscopy. It can diagnose unsuspected bronchiectasis and arteriovenous malformations and will show central endobronchial lesions in many cases. It is the test of choice for suspected small peripheral malignancies.

The management of mild hemoptysis consists of identifying and treating the specific cause. Massive hemoptysis is life-threatening. The airway must be protected, ventilation ensured, and effective circulation maintained. If the location of the bleeding site is known, the patient should be placed in the decubitus position with the involved lung dependent. Uncontrollable hemorrhage warrants rigid bronchoscopy and surgical consultation. In stable patients, flexible bronchoscopy may localize the site of bleeding, and angiography can embolize the involved bronchial arteries. Embolization is effective initially in 85% of cases, though rebleeding may occur in up to 20% of patients over the following year. The anterior spinal artery arises from the bronchial artery in up to 5% of people, and paraplegia may result if it is inadvertently cannulated.


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