Pulmonary Circulation

The pulmonary artery bifurcates into left and right main pulmonary arteries after it leaves the right side of the heart. The pulmonary circulation is a low-pressure system, but pulmonary artery pressures may rise to approach systemic pressures in pulmonary parenchymal and pulmonary vascular diseases. Nevertheless, pulmonary hypertension alone rarely causes hemoptysis.

Prospective angiographic studies for hemoptysis in which both pulmonary and bronchial circulations have been imaged do not exist. Bleeding from the pulmonary arterial circulation accounts for less than 10% of massive hemoptysis cases and has been noted in a variety of destructive pulmonary lesions including tuberculosis, lung abscess, and aspergillosis.2,8 Aneurysms of the pulmonary artery, arteriovenous malformations (AVMs), and pulmonary artery rupture have also been reported.

Bronchial Circulation

Bleeding from the higher pressure bronchial circulation has been estimated to cause 88% of the cases of massive and submassive hemoptysis.⁹ The bronchial arteries arise from the descending aorta with considerable anatomic variation. The one or two bronchial arteries that supply each lung in the majority of individuals¹⁰ arise from the area near the first and second intercostal arteries. Particularly on the right side, the bronchial arteries may arise directly from the proximal first intercostal artery. The arteries course along the trachea, major bronchi, and bronchioles and have terminal communications with the pulmonary capillaries or pulmonary venules. The small-vessel bronchial supply to the trachea and major bronchi drains into the azygos vein with direct communication to the superior vena cava. Aneurysmal dilation of bronchial arteries (Dieulafoy’s vascular malformation) has been noted in some patients with hemoptysis, and it can occasionally be visualized endobronchially and noted on bronchial arteriography.¹¹

A direct anastomotic communication between the bronchial and pulmonary arterioles has been sought to explain the preservation of lung parenchyma after injuries to the pulmonary vascular supply. Anatomic studies have found that intermeshing of pulmonary and bronchial capillary networks is the most common anastomotic arrangement that prevents pressurization of the pulmonary arterioles with systemic pressures.¹² However, in chronic inflammatory diseases of the airways, anatomic anastomoses have been found that allow direct pressurization of the pulmonary artery with systemic pressures.¹³ The extent to which these vascular communications are related to hemoptysis remains unknown.

Bronchial arteries vasodilate in the presence of cholinergic, β₂-adrenergic, and some nonadrenergic, noncholinergic agonists. Although the effect of β₂-agonists on the course of hemoptysis remains unstudied, the balance between improved mucociliary clearance of blood affected by β₂-agonists and detrimental bronchial artery dilation should be considered.¹⁴ Other physiochemical maneuvers can influence bronchial blood flow—cold air causes blanching of the human airway,¹⁵ humidified air decreases bronchial blood flow compared with dry gas,¹⁶ and increased alveolar pressure decreases bronchial blood flow by applied pressure at the capillaries.¹²

Nonbronchial Systemic Collateral Circulation

In diseases of the lung associated with inflammation, neovascularization of the lung parenchyma can occur. Although proliferation of the bronchial circulation is the most common mechanism to extend the vascular supply, an extensive network of systemic arteries may neovascularize the lung after crossing the pleural space. This most commonly occurs in diseases that produce pleural scarring, such as in aspergillomas and cystic fibrosis (CF). Anatomically these collateral vessels commonly arise from the intercostal, subclavian, axillary, and phrenic arteries. However, nonbronchial collaterals have also been described from the internal mammary, thyrocervical, carotid, and even the coronary arteries. Suspicion that these vessels may be involved is heightened by recurrence of hemoptysis after bronchial artery embolization (BAE), the presence of pleural disease, and the absence of bronchial arteries supplying an area of lung parenchyma on initial bronchial arteriography.

Pulmonary Venous Abnormalities

Bleeding from the pulmonary veins is most likely in cardiac disease such as mitral stenosis or mitral regurgitation. Focal varices of the pulmonary veins that are occasionally visualized on chest radiography, but are best identified on the venous phase of pulmonary arteriography, have been described.17,18

Bronchiectasis

Bronchiectasis is characterized by abnormal dilation of the bronchi with altered mucociliary clearance, persistent bacterial colonization, chronic inflammation of the bronchial mucosa, and submucosal neovascularization that predisposes to hemoptysis. Hemoptysis in bronchiectasis can present as a single life-threatening episode but is more commonly heralded by intermittent blood streaks intermixed with purulent sputum. In patients without a previous diagnosis, the evaluation can be difficult because chest radiography can be normal or alveolar filling with blood can obscure abnormalities. Diagnosis can usually be confirmed with high-resolution chest CT. Suspicion of the diagnosis warrants broad-spectrum antibiotics to cover the multiple organisms causing infection in addition to management of the hemoptysis.

Bronchiectasis is the usual cause of massive hemoptysis in patients with CF and occurs in approximately 4.1% of patients during their lifetime.¹⁹ Massive hemoptysis is more common in patients over the age of 18 years and has been associated with pancreatic insufficiency, Staphylococcus aureus colonization, reduced lung function, and diabetes.¹⁹ Although Pseudomonas aeruginosa remains the predominant pathogen associated with decline in lung function, its presence does not translate into an increased incidence of hemoptysis. Origin of the bleeding is most often upper lobe bronchial or systemic arteries. These patients are difficult to treat because of minimal pulmonary reserve in the majority of patients at the time of hemoptysis. Guidelines for treatment of massive hemoptysis in CF patients recommend empiric antibiotic coverage to include S. aureus, discontinuation of nonsteroidal anti-inflammatory drugs, discontinuation of airway clearance therapies, discontinuation of aerosolized hypertonic saline, and use of BAE to control bleeding.²⁰ Although inhaled tobramycin and dornase alfa use were associated with a lower hemoptysis incidence,¹⁹ consensus was not reached on whether to discontinue these therapies in massive hemoptysis.²⁰

Tuberculosis

The resurgence of tuberculosis in many parts of the world and the prevalence of global travel mandate consideration of the disease whenever hemoptysis occurs. Hemoptysis can occur with active cavitary disease or as late sequelae of lung destruction causing bronchiectasis. Hemoptysis has also been reported in miliary tuberculosis, although the mechanism is unknown. The pathologic lesion that causes hemoptysis in tuberculosis is often Rasmussen’s aneurysm, a small aneurysm of the pulmonary circulation positioned within a cavity wall. Bleeding from the bronchial circulation can also complicate bronchial erosions in active tuberculosis, and study of both circulations is occasionally necessary when resection for local disease is not possible. Although all patients suspected of having hemoptysis secondary to tuberculosis should be placed in respiratory isolation, active pulmonary tuberculosis is found in only a third of such cases. Post-tuberculous bronchiectasis requires antibacterial therapy.

Lung Malignancy

Lung cancer is associated with hemoptysis in 20% to 30% of cases and may be the presenting manifestation.²¹ Although the clinical course of hemoptysis is often that of chronic blood-streaked sputum, massive hemoptysis may occur as a terminal event. Massive hemoptysis is most commonly associated with squamous cell type²²; cavitation within the carcinoma²³; and central endobronchial position, occasionally with invasion into the pulmonary arteries. The blood supply to most lung carcinomas is derived from diffuse neovascularization from the bronchial circulation, making BAE effective in some cases.

Other less common cancers can bleed when found in the lung. Kaposi sarcoma has a high incidence of bloody pleural effusions and hemoptysis. Angiosarcomas are vascular tumors that may bleed continuously from small tumor sites.²⁴ Choriocarcinomas may bleed profusely, particularly after initiation of chemotherapy. Metastatic disease including renal, ovarian, and breast cancer have rarely been associated with hemoptysis.

Massive hemoptysis may also result from interventions that treat lung malignancies. Endobronchial brachytherapy has resulted in massive, fatal hemoptysis and was found to be associated with direct contact of the brachytherapy applicator and tracheobronchial walls near great vessels.²⁵ Radiofrequency ablation of lung neoplasms has been associated with massive bleeding due to intraparenchymal hemorrhage and pulmonary artery pseudoaneurysm.^26,27

Lung Abscess

Lung abscesses are commonly found in parenchymal areas prone to aspiration. The indolent course of these infections allows time for hypertrophy of the bronchial circulation within the walls of the abscess cavity. Additionally, these cavities may enlarge and erode into major pulmonary arteries and other thoracic vessels, including the aorta.²⁸ With either of these abnormalities, bleeding can be massive and recurrent. Although the abscesses are focal and amenable to surgery, the patient who chronically aspirates because of alcoholism or dementia may have other contraindications for surgery.

Chronic Bronchitis

Chronic bronchitis rarely causes massive hemoptysis, but it is a frequent cause of mild hemoptysis. The pathologic lesions responsible for bleeding are likely dilated bronchial arteries that are eroded during active inflammation of the airways.²⁹ A comprehensive management approach is required to treat hemoptysis and ensure that other lesions such as lung cancer are not present.

Other Pulmonary Infections

Although hemoptysis can complicate any bacterial or fungal pneumonia, massive hemoptysis is rare unless tissue necrosis is present. Tissue necrosis is a hallmark of anaerobic, staphylococcal, and actinomycotic³⁰ pneumonias but can occur with many different bacterial causes. Septic pulmonary emboli, particularly from staphylococcal species, have a high incidence of concomitant lung cavitation.³¹ Mycotic pulmonary artery aneurysms may also be hidden within pneumonias and can be diagnosed by pulmonary arteriography or multidetector CT angiography.³²

Hemoptysis is particularly common in fungal pneumonias that invade the vasculature. Invasive Aspergillus can be found in nonimmunosuppressed patients with chronic obstructive pulmonary disease (COPD)³³ but is more commonly found in the persistently neutropenic patient. A characteristic radiographic pattern of cavitation and hemoptysis follows the recovery of neutrophils and should be anticipated in at-risk patients.^34,35 The use of prophylactic surgery to resect areas of infarcted lung tissue has been advocated^36,37 because of the high mortality rate associated with medical management of the hemoptysis. However, such surgery remains high risk, and controlled trials have not been performed. Although more rare, invasive pulmonary mucormycosis³⁸ may produce similar findings. Hemoptysis complicates primary coccidioidal infections in 15% of cases and may approach a 50% incidence in patients with chronic coccidioidal cavities. Histoplasmosis, cryptococcosis, and blastomycosis can also cause hemoptysis. Frequent and sometimes massive hemoptysis can occur with the parasitic diseases paragonimiasis,³⁹ echinococcosis,⁴⁰ strongyloidiasis, and ancylostomiasis.

Pulmonary Embolism

Hemoptysis occurs in approximately 30% of patients with thrombotic pulmonary emboli. Characteristically, hemoptysis is mild and requires no specific therapy. Hemoptysis usually implies some degree of pulmonary infarction with potential disruption of either vascular supply. The suspicion for pulmonary emboli is increased in the presence of risk factors for thrombosis, multicentric bleeding, and pleuritic chest pain. Paradoxically, this cause of hemoptysis must be treated with anticoagulants to prevent propagation of venous thromboemboli. The incidence of worsening hemoptysis after heparin or thrombolytics has not been documented. Nonthrombotic emboli have also been associated with hemoptysis. Septic emboli usually respond to antibiotics alone.

Aspergillus Fungus Balls

Hemoptysis occurs in more than half of patients with pulmonary Aspergillus fungus balls.⁴¹ The cavity walls are richly vascularized by branches of the bronchial circulation, and enlargement of these cavities may also extend into large branches of the pulmonary artery. The mechanism of hemoptysis is likely multifactorial from secondary bacterial invasion of the fungal cavity, microinvasion of the cavity wall by Aspergillus (semi-invasive aspergillosis), or less commonly by truly invasive disease. Therapy of hemoptysis depends on the underlying cause for the cavitary lung disease.

Systemic antifungal therapy remains controversial because there is not a well-defined means to diagnose semi-invasive disease.42,43 Intracavitary amphotericin B, however, instilled via a transthoracic catheter has proved successful at dissolution and sclerosis of the cavity with control of hemoptysis and is a viable option in patients who are poor surgical candidates.^44,45 Alternatively, antifungal therapy with ketoconazole,⁴⁶ miconazole,⁴⁷ or amphotericin B⁴⁸ has been given endobronchially for fungus ball dissolution and hemoptysis control, but these techniques are effective in less than half of patients.⁴⁹ External beam radiotherapy of 3.5 Gy given once per week has been used as an adjunctive measure in nonoperable patients.⁵⁰

Surgery remains the therapy of choice in patients with adequate pulmonary reserve due to the recurrent nature of hemoptysis. Simple aspergilloma (no abnormality in surrounding lung) has an excellent response to surgical resection, most commonly a lobectomy. Complex aspergilloma with surrounding pleural and parenchymal involvement usually requires pneumonectomy and is associated with variable success.⁵¹ Fungus balls complicating sarcoidosis usually occur in patients with bilateral upper lobe cavitary disease (stage IV), in which underlying lung function prohibits resection.

Cardiovascular Causes

Mitral stenosis is one of the most common cardiac abnormalities that can present with hemoptysis.⁵² The risk of hemoptysis is likely related to the elevation of pulmonary venous pressure and the rapidity with which the stenosis developed. Clinical examination may reveal an opening snap or diastolic murmur. An echocardiogram should be obtained for definitive diagnosis.

Other causes of increased pulmonary venous pressure, such as mitral regurgitation or severe congestive cardiomyopathy, may also produce hemoptysis that usually presents with radiographic pulmonary edema and a prodrome of pink frothy sputum. Fibrosing mediastinitis,⁵³ pulmonary veno-occlusive disease,⁵⁴ and congenital pulmonary venous stenosis⁵⁵ are less common causes of pulmonary venous congestion.

Rarely, hemoptysis will occur from systemic venous hypertension in severe biventricular heart failure by azygous vein hypertension and dilation. Because the azygous vein drains the trachea and major bronchi, the submucosal dilated venous plexus of the trachea can be friable and produce major hemoptysis.

Interstitial Lung Disease

Only a few interstitial lung diseases are prone to hemoptysis. Lymphangioleiomyomatosis (LAM) is a disease of smooth muscle proliferation around pulmonary lymphatics, airways, and vasculature. Any of the triad of hemoptysis, pneumothorax, and chylothorax should suggest the diagnosis in a woman of childbearing age.⁵⁶ The airway granulomas of sarcoidosis have also been associated with hemoptysis, although the presence of traction bronchiectasis may be a more common cause. Additionally, the erosion of calcified hilar lymph nodes into the vasculature can produce hemoptysis. Other interstitial lung diseases that cause hemoptysis usually have diffuse alveolar hemorrhage.

Broncholithiasis

Broncholithiasis is an infrequent cause of hemoptysis. The typical patient usually has an established diagnosis of mediastinal calcification from granulomatous disease. Previous infections of histoplasmosis, sarcoidosis, or tuberculosis are most common. Broncholithiasis is diagnosed by bronchoscopy when any degree of lymph node calcification is visualized in the bronchial lumen. Symptoms of cough, chest pain, airway obstruction, and hemoptysis can be seen. Lithoptysis, coughing out a broncholith, can also confirm the diagnosis.

Therapy of hemoptysis involves broncholith removal. Broncholith removal by rigid or flexible bronchoscopy is usually successful when the broncholith is free. When broncholiths are partially embedded in the airway wall, removal is best facilitated by rigid bronchoscopy⁵⁷ or by thoracic surgery. Surgical options include lymph node resection with or without bronchoplasty or lobectomy. One surgical series had a 34% complication rate and a 15% rate of recurrent or persistent disease.⁵⁸

Diffuse Alveolar Hemorrhage

Diffuse alveolar hemorrhage (DAH) most commonly presents abruptly and may or may not be associated with frank hemoptysis. The early manifestations are often confused with other alveolar filling processes such as pulmonary edema, bacterial pneumonia, or the acute respiratory distress syndrome (ARDS). Consideration of DAH is prompted by the presence of diffuse infiltrates on chest radiograph, the presence of systemic manifestations of vasculitis, the association of hemoptysis, hypoxemic respiratory failure, and the common finding of anemia.⁵⁹ Unfortunately, the many causes of DAH are often differentiated on the basis of laboratory tests that may not be routine in many hospitals. Furthermore, specific therapy is often not initiated until a definitive diagnosis has been established by biopsy.

The differential diagnosis of DAH is listed in Box 46.2. Although some of these diseases have no specific therapy, establishing a diagnosis and instituting supportive care help to avoid unnecessary diagnostic and therapeutic maneuvers. Many of the vasculitides are stabilized only with aggressive immunosuppressive therapy, which would not be appropriate for infectious diseases that can present with the same features in a chest radiograph.

Bronchoscopy with transbronchial biopsy and bronchoalveolar lavage (BAL) are usually performed in a patient with unknown pulmonary infiltrates in the intensive care unit (ICU) if respiratory compromise is not severe. Although often not sufficient to establish a specific diagnosis, finding a bloody lavage, hemosiderin-laden macrophages, and the lack of specific pathogens can presumptively yield a diagnosis of DAH. The diagnosis of DAH is best made by quantitation of hemosiderin in alveolar macrophages obtained by BAL. A Prussian blue stain is graded by the methods of Kahn and colleagues⁶⁰; hemosiderin scores above 100 are virtually diagnostic of alveolar hemorrhage. Hemosiderin-laden macrophages may not appear in BAL fluid until 48 to 72 hours after acute hemorrhage, resulting in a low sensitivity for hemosiderin scores in this setting.⁶¹