Massive Hemoptysis

Chapter 79


Massive Hemoptysis



Massive hemoptysis (approximately 5% of all hemoptysis cases) is variably defined as the expectoration of blood greater than 100 to 500 mL over a 24-hour period. It is a medical emergency and often a sign of a serious underlying medical condition. With a mortality rate as high as 75%, death is due to acute airway obstruction and hypoxemic respiratory failure, not exsanguination. With total airway dead space measuring only 150 mL, conducting airways can become obstructed with minimal bleeding if a patient cannot clear blood from his or her tracheobronchial tree.



Anatomy


The lungs have a dual blood supply: the pulmonary arterial circulation participates in gas exchange, while the bronchial arterial circulation supplies the pulmonary parenchyma. The pulmonary arteries branch into lobar arteries and eventually form the fine alveolar capillary interface for gas exchange. The pulmonary arterial circulation is a low-pressure, low-resistance system with capacity to accommodate significant increases in blood flow without a marked pressure increase. The pulmonary parenchyma nutrient supply is provided by the bronchial arteries, which arise from either the aorta or intercostal arteries. In contrast to the pulmonary arterial circulation, the bronchial artery circulation is a high-pressure system with frequent anastomoses that surround the airway and lie in the peribronchial space, and small penetrating arteries that supply the bronchial mucosa via a submucosal plexus. Because of the pressure difference between these two systems, massive hemoptysis is more likely to originate from the bronchial than the pulmonary arterial circulation. Furthermore, in many of the inflammatory and infectious conditions mentioned later, parasitized intercostal arteries can form and become the bleeding source.



Differential Diagnosis of Massive Hemoptysis


Historically, tuberculosis (TB), bronchiectasis, and lung abscess were the most common causes of massive hemoptysis and accounted for approximately 90% of cases. However, the etiologic spectrum has evolved with widespread antibiotic use significantly reducing the infectious disease prevalence causing massive hemoptysis. When a patient presents with massive hemoptysis, recall the phrase “These things INCITE bleeding” as a mnemonic for the differential diagnosis: I – Infection, N – Neoplasm, C – Cardiovascular, I – Iatrogenic, T – Trauma, E – Everything else.



Infections


Prior to antituberculous medical therapy, TB and its sequelae were the most common cause of massive hemoptysis through various mechanisms: (1) active cavitary disease eroding into adjacent vessels, (2) Rasmussen’s (pulmonary artery) aneurysm eroding into an adjacent cavity, (3) residual bronchiectasis from a prior infection, (4) erosion of a broncholith through a vessel into an airway, and (5) mycetoma formation in a prior cavity.


Bronchiectasis is characterized by abnormal bronchial wall thickening with luminal dilatation that manifests clinically as daily cough with sputum production and airflow obstruction (see Box 79.1 for list of causes). Repeated bacterial infections, particularly with Staphylococcus aureus and Pseudomonas aeruginosa, and chronic airway inflammation are bronchiectasis hallmarks that can lead to enlarged and tortuous bronchial arteries, systemic-pulmonary vascular anastomoses, or parasitized intercostal arteries. Rupture of these vessels can cause rapidly fatal massive hemoptysis.



Fungal infections have become an increasingly common source of massive hemoptysis, particularly in two patient populations: those with preexisting cavitary lung disease and profoundly immunocompromised patients (e.g., hematopoietic stem cell transplantation). Patients with cavitary lung disease can develop intracavitary fungal colonization and mycetoma formation (e.g., aspergilloma). The bronchial and intercostal artery dilation and hypertrophy surrounding these cavities can be dramatic. From 50% to 90% of these patients can have hemoptysis at some course during their disease. Interestingly, massive hemoptysis tends to be uncommon in cases of immunocompromised invasive fungal infections until neutrophil count recovery begins after a prolonged neutropenic period.


Other pulmonary infections can cause massive hemoptysis. Lung abscesses caused by polymicrobial and anaerobic bacteria or necrotizing pneumonias caused by Staphylococcus species, Klebsiella pneumoniae, or Legionella pneumoniae can cause massive hemoptysis. Community-acquired methicillin-resistant S. aureus has been a source of massive hemoptysis resulting from its tendency to cause both parenchymal cavitation and necrosis.



Neoplasms


Any type of bronchogenic carcinoma can cause hemoptysis, which can occur either at presentation (7% to 10 % of cases) or subsequently during the malignancy course (20% of cases). In a large retrospective analysis of more than 800 cases of lung cancer, squamous cell histology was the most frequent cell type associated with massive hemoptysis, followed by adenocarcinoma, small cell carcinoma, and large cell carcinoma. Endobronchial location or cavitation was associated with a higher hemoptysis incidence. New targeted, chemotherapeutic agents (e.g., bevacizumab) with dramatic cavitary responses can predispose to massive hemoptysis.


Any endobronchial or intraparenchymal metastatic tumor to the lung can cause massive hemoptysis. Melanoma, lung, colon, breast, or prostate cancer tends to form endobronchial metastases, whereas renal cell carcinoma, thyroid cancer, and sarcomas tend to form parenchymal metastases that are prone to cause massive hemoptysis.



Cardiovascular Disease


Among the primary cardiac hemoptysis sources (see Box 79.1), elevated pulmonary venous pressure leads to venous dilation and varix formation, which may rupture and bleed during sudden pulmonary venous pressure increases (e.g., systolic or diastolic failure, cough, Valsalva). Such hemoptysis is generally self-limited but can be severe and life threatening on occasion.

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Jul 7, 2016 | Posted by in CRITICAL CARE | Comments Off on Massive Hemoptysis

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