Chapter 20 Hemoptysis
Hemoptysis is defined as the expectoration of blood that results from hemorrhage into the lower respiratory tract. It can be caused by a wide variety of disorders and constitutes a common reason for referral to a pulmonary specialist. The amount of blood expectorated can range from minimal streaking of the sputum to large volumes of pure blood and depends not only on the rate of bleeding but also on its location. For example, hemorrhage into the lung parenchyma or a distal airway may be accompanied by little or no hemoptysis, whereas even a relatively small amount of bleeding from a central airway may lead to a significant volume of expectorated blood.
Hemoptysis, by itself, does not usually lead to significant morbidity or death. Rather, it typically is important only as a sign of an underlying and often unrecognized disorder. Thus, hemoptysis is an extremely important symptom, and its cause must be determined by means of a thorough and orderly evaluation.
Massive hemoptysis is an uncommon but potentially life-threatening event, in that flooding of the airways and alveoli may quickly lead to respiratory failure. It requires rapid evaluation and emergent and specific therapy, so massive hemoptysis usually is considered to represent a distinct clinical entity and is discussed separately in a later section of this chapter.
A large number of disorders have been reported to cause hemoptysis, and the most important are listed in Box 20-1. Of these, bronchogenic carcinoma, bronchiectasis, bronchitis, and bacterial pneumonia are responsible for most cases. Table 20-1 shows the relative frequency of disorders causing hemoptysis in major series published since 1980. The significant variability, especially in the frequency of bronchiectasis, bronchitis, and tuberculosis, probably reflects differences in the time of publication, the patient population studied, and the diagnostic tests and criteria used. Figure 20-1 illustrates the percentage of patients with each diagnosis on the basis of pooled data from these studies.
Causes of Hemoptysis
Malignancy is one of the most common causes of hemoptysis, and bronchogenic carcinoma accounts for most of these cases. In patients with hemoptysis, the tumor typically involves a central airway (i.e., a main, lobar, or segmental bronchus) and most commonly is a squamous cell carcinoma. Much less commonly, hemoptysis is caused by a peripherally located carcinoma or by other primary pulmonary neoplasms, such as carcinoid tumor or hamartoma. Extrathoracic malignancies, especially melanoma and carcinoma of the breast, colon, and kidney, also may cause hemoptysis because of their propensity to metastasize to endobronchial locations in the tracheobronchial tree.
In studies published before the early 1960s, bronchiectasis often was the most common cause of hemoptysis and frequently accounted for 25% to 35% of cases. In the subsequent decades, this number dropped dramatically to less than 5%. Although this decline was correctly attributed to the greater availability and effectiveness of antibacterial and antituberculosis therapy, it probably was also caused by a marked decrease in the use of bronchography, the principal diagnostic modality of that era. Since the advent of high-resolution computed tomography (HRCT), bronchiectasis has been diagnosed with increasing frequency, and recent studies indicate that it remains a very important cause of hemoptysis.
Hemoptysis often is attributed to an acute infectious bronchitis on the basis of compatible clinical or bronchoscopic findings, and this is a common final diagnosis in most series. Although acute bronchitis undoubtedly may cause hemoptysis, the symptoms, signs, and bronchoscopic findings in this disorder are neither sensitive nor specific. In fact, several studies have demonstrated that the diagnosis of acute bronchitis often is made in patients with another source of bleeding. Thus, acute bronchitis must be considered to represent a diagnosis of exclusion, and great care must be taken to search for other causes of hemoptysis.
Although tuberculosis remains relatively common in certain patient populations and geographic regions, successful methods of treatment and prevention have markedly reduced both its incidence and its importance as a cause of hemoptysis. Hemoptysis most commonly results from active disease, but it also may be caused by the sequelae of infection, particularly bronchiectasis, parenchymal cavitation, and mycetoma formation.
Hemoptysis may result from virtually any type of bacterial pneumonia but most often accompanies infection with Streptococcus pneumoniae. Other commonly implicated pathogens include Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and anaerobic organisms.
In almost all reported series, the cause of hemoptysis remains unknown in a significant percentage of patients. As shown in Table 20-1, the frequency of cryptogenic hemoptysis has varied widely, and this variability presumably is due to differences in diagnostic criteria and the extent of evaluation.
When the patient reports a history of expectorating blood, the first step must be to determine whether hemoptysis has actually occurred. That is, bleeding must be localized to the lower respiratory tract, and alternative sites, such as the nose, mouth, pharynx, larynx, and gastrointestinal tract, must be excluded. Few patients have difficulty distinguishing between vomiting and expectorating blood, although specific questions may be required to elicit a report of nausea and retching. Distinguishing between an upper and a lower airway source of bleeding occasionally is more difficult, although this usually can be accomplished by a directed history and physical examination. Patients with hemoptysis almost always report that the expectoration of blood follows an episode of coughing; in those with an upper airway source, it typically is preceded by a feeling of blood pooling in the mouth or the need to “clear the throat.” A history of epistaxis also is an important indicator of upper airway hemorrhage. Routine examination of the nose, mouth, and pharynx is important to rule out an obvious site of bleeding. A thorough examination that includes rhinoscopy and laryngoscopy is indicated when an upper airway source cannot be reliably excluded.
Once hemoptysis has been confirmed, a search must be made for its cause. This process begins with an initial evaluation that consists of a complete history and physical examination and a chest radiograph.
Important symptoms, signs, and historical details that suggest one or more disorders are listed in Table 20-2. In some patients, such as those with pulmonary embolism, left ventricular failure, mitral stenosis, and traumatic or iatrogenic lung injury, the history and physical examination may provide the most important clues to the diagnosis.