Inflammation of the tracheobronchial mucosa accounts for many cases of hemoptysis. Minor mucosal erosions can result from upper respiratory infections and bronchitis; blood-streaked sputum is often noted, especially if coughing has been vigorous and prolonged. Patients with bronchiectasis are more subject to recurrent episodes of grossly bloody sputum because necrosis of the bronchial mucosa can be quite severe. Up to 50% of patients with bronchiectasis experience hemoptysis. In the United States, hemoptysis occurring with tuberculosis is usually caused by mucosal ulceration, although potentially fatal bleeding can occur when a blood vessel adjacent to a cavitary lesion ruptures. About 10% to 15% of patients with TB report some form of hemoptysis; most of these episodes are minor and involve sputum tinged with small amounts of blood. Endobronchial inflammatory injury from granuloma formation is the mechanism of hemoptysis associated with sarcoidosis; small amounts of blood-streaked sputum are occasionally noted.

Mucosal injury can also be a consequence of bronchogenic carcinoma. Disruption of endobronchial tissue may be minor and cause little more than minimal hemoptysis from time to time; hemorrhage is rare. Between 35% and 55% of patients with proven bronchogenic carcinoma report at least one episode of hemoptysis during the course of their illness; it is the presenting symptom in about 10% of cases. The amount of bleeding can vary considerably and need not be impressive. For example, in one study, malignancy was the cause in 25% of patients with minimal hemoptysis. However, most patients have a positive smoking history and abnormal chest radiographic findings. Carcinoma metastatic to the lung rarely results in hemoptysis. Bronchial adenomas are quite vascular, and they are commonly central and endobronchial in location; as a consequence, they frequently bleed, and recurrent episodes of hemoptysis are reported in about half of cases.

Injury to the pulmonary vasculature is an important source of hemoptysis. Lung abscess may result in damage to adjacent vessels and frequently presents with bloody and purulent sputum. Necrotizing pneumonias, such as those produced by Klebsiella, can cause substantial vascular disruption; 25% to 50% of patients cough up tenacious, bloody sputum referred to as “currant jelly.” Aspergillomas are also capable of causing vascular injury; hemoptysis is the most common symptom of the condition. The patient with
an aspergilloma is typically a compromised host with prior cavitary disease from TB, bronchiectasis, or the like. Pulmonary infarction secondary to embolization is characterized by the sudden onset of pleuritic pain in conjunction with hemoptysis; embolization without infarction does not cause hemoptysis. Pulmonary contusion resulting from blunt chest trauma may present with hemoptysis following a nonpenetrating blow to the thorax.

Marked elevations in pulmonary capillary pressure can cause vascular injury and extravasation of red cells. The pink, frothy sputum of pulmonary edema is a manifestation of this process. More grossly bloody sputum sometimes occurs in severe mitral stenosis when a dilated pulmonary-bronchial venous connection ruptures. Vasculitic injury is responsible for the hemoptysis found in Wegener granulomatosis, Goodpasture syndrome, and microscopic polyangiitis. Hematuria often accompanies both conditions. Hereditary vascular malformations are subject to recurrent bleeding. Arteriovenous malformations may be accompanied by an audible bruit on auscultation of the lung. In hereditary hemorrhagic telangiectasia, a family history of bleeding problems is often present, or prior episodes of bleeding from multiple sites have been noted; telangiectasia may be visible in the buccal cavity and on the skin. Bleeding into the interstitium characterizes idiopathic pulmonary hemosiderosis. This rare disease, uncommon in adults, is manifested by diffuse interstitial infiltrates, anemia, and hemoptysis.

Hemoptysis may be the first sign of a bleeding disorder or excessive anticoagulant therapy; however, an underlying bronchopulmonary lesion is usually also present.

Acute and chronic bronchitis is the most common cause, followed by bronchogenic carcinoma, TB, pneumonia, and bronchiectasis. Most prevalence figures are obtained from chest clinics and inpatient units serving preselected populations of patients with either abnormal chest radiographic findings or unexplained hemoptysis; therefore, they cannot be readily extrapolated to the primary care setting. In everyday office practice, the nasal mucosa and oropharynx are more often the source of blood-tinged sputum than is the lower respiratory tract. The high incidence of pulmonary infections associated with HIV, the more widespread use of fiberoptic bronchoscopy, and increases in cigarette smoking and lung cancer in women also must be kept in mind when data from published clinical series that are greater than 10 years old are being interpreted. In a fiberoptic bronchoscopy study performed in a general hospital setting that included both inpatients and outpatients, bronchitis accounted for 37% of cases, bronchogenic carcinoma for 19%, TB for 7%, and bronchiectasis for only 1%. The briskness of bleeding did not help in discriminating among causes. In primary care settings, the diagnosis of lung cancer following a first presentation with hemoptysis is much lower: 7.5% in men and 4.3% in women in a large study of alarm symptoms in the United Kingdom. This study included patients with abnormal chest x-rays at the time of presentation. In a review of studies comprising a total of nearly 1,000 patients with hemoptysis and normal chest radiographic findings, lung cancer was eventually diagnosed in 5.4%. Most cancers that cause hemoptysis are endobronchial, but about 15% are parenchymal. The more common and important causes of hemoptysis are listed in Table 42-1.