By far the best resource for hemoptysis is Ep 188 Hemoptysis – ED Approach and Management.*
*Helman, A. Weingart, S. Tillmann, B. Hemoptysis – ED Approach and Management. Emergency Medicine Cases. November, 2023. https://emergencymedicinecases.com/hemoptysis. Accessed November 16, 2023
Today, I reviewed, link to, and excerpt from Radiographics‘ CT for Evaluation of Hemoptysis [PubMed Abstract] [Full-Text HTML] [Full-Text PDF]. Published Online: May 3, 2021. https://doi.org/10.1148/rg.2021200150
All that follows is from the above resource.
Hemoptysis, which is defined as expectoration of blood from the alveoli or airways of the lower respiratory tract, is an alarming clinical symptom with an extensive differential diagnosis. CT has emerged as an important noninvasive tool in the evaluation of patients with hemoptysis, and the authors present a systematic but flexible approach to CT interpretation. The first step in this approach involves identifying findings of parenchymal and airway hemorrhage. The second step is aimed at determining the mechanism of hemoptysis and whether a specific vascular supply can be implicated. Hemoptysis can have primary vascular and secondary vascular causes. Primary vascular mechanisms include chronic systemic vascular hypertrophy, focally damaged vessels, a dysplastic lung parenchyma with systemic arterial supply, arteriovenous malformations and fistulas, and bleeding at the capillary level. Evaluating vascular mechanisms of hemoptysis at CT also entails determining if a specific vascular source can be implicated. Although the bronchial arteries are responsible for most cases of hemoptysis, nonbronchial systemic arteries and the pulmonary arteries are important potential sources of hemoptysis that must be recognized. Secondary vascular mechanisms of hemoptysis include processes that directly destroy the lung parenchyma and processes that directly invade the airway. Understanding and employing this approach allow the diagnostic radiologist to interpret CT examinations accurately in patients with hemoptysis and provide information that is best suited to directing subsequent treatment. ©RSNA, 2021.
Hemoptysis is defined as expectoration of blood from the alveoli or airways of the lower respiratory tract. Clinically, hemoptysis must be distinguished from hematemesis and aspirated blood related to nasopharyngeal injury. . . . Asphyxiation rather than exsanguination is the main cause of death in patients with hemoptysis. As little as 250 mL of blood, or less than the volume of a 12-oz soft drink, fills the entire tracheobronchial tree (1,2). In cases of life-threatening hemoptysis, the initial priority is
given to maintaining the airway, optimizing oxygenation, and ensuring hemodynamic stability. After these initial goals are met, attention is then turned to determining the underlying cause and best available treatment options.
In this article, we discuss a systematic yet flexible approach to evaluation of patients with hemoptysis that includes consideration of the clinical scenario and relevant clinical history, focusing on the CT findings and pathophysiologic mechanisms.
In this article, we have provided an overview of
the major mechanisms that can cause hemoptysis
and their associated CT findings. These mechanisms and specific diseases that can cause them are summarized in Table 2.
To use this information in real clinical practice, a structured yet flexible approach to CT interpretation is required. Our suggested approach is presented in Table 3 and is based on the identification of indirect and direct signs.
Indirect pulmonary signs are the CT manifestations of hemorrhage and include both findings of parenchymal bleeding and aspirated blood.
Indirect vascular signs are indicative of increased vascular supply.
Direct signs are more specific and implicate a focally abnormal causative culprit vessel or lesion. Examples include an
infectious pseudoaneurysm (ie, a culprit vessel) or a tumor (ie, a culprit lesion).
The use of indirect and direct signs at CT interpretation has two important functions.
First, indirect and direct signs can be used to support an
underlying mechanism as the cause of hemoptysis. Some mechanisms, such as systemic vascular hypertrophy, will be described with indirect signs only, because patients present with pulmonary findings indicative of parenchymal bleeding as well as findings of increased vascular supply.
Other mechanisms are combinations of indirect and direct signs. For example, a bleeding focally damaged vessel may demonstrate the direct sign of formation of a pseudoaneurysm and an indirect sign of adjacent parenchymal hemorrhage or distally aspirated blood.
Perhaps more relevant, however, is the use of indirect and direct signs identified at CT to help direct patient treatment.
Indirect pulmonary signs can be used to localize treatment to
a particular portion of the lung, or conversely, when diffuse hemorrhage is present, to indicate that no localizable site of hemorrhage is identifiable.
Indirect vascular signs are valuable when endovascular therapies are pursued because they can implicate a specific vascular source. Thisis particularly important when the source lies outside orthotopic bronchial arteries because the interventional radiologist is directed to vascular sources that may not otherwise have been interrogated.
Direct signs identified at CT affect patient treatment by defining a focal targetable cause of hemoptysis. For example, identification of a broncholith (ie, a culprit lesion) drives treatment away from endovascular therapies and toward
surgical or bronchoscopic treatment. Recognition of a pulmonary artery pseudoaneurysm, (ie, a culprit vessel) necessitates either surgical treatment or endovascular treatment with a systemic venous approach.
In conclusion, CT has emerged as an important noninvasive tool in the evaluation of patients with hemoptysis. To best interpret these examinations, diagnostic radiologists must understand the potential mechanisms of hemoptysis and their imaging features. This will allow accurate diagnosis and the identification of CT findings that can be used to direct treatment.