Blood in Cough - Symptoms, Types, Causes & Diagnosis

The expulsion of blood from the lower respiratory system is known as hemoptysis. The majority of the time, it is a self-limiting event, but in less than 5% of instances, it may be massive, signifying a condition that is...

What is blood in cough/Hemoptysis

The goal of this paper is to provide a thorough review of the literature on hemoptysis, including an analysis of its pathophysiologic mechanisms, causes, and anatomy of the systemic bronchial and non-bronchial arteries that cause hemoptysis.

In order to determine the cause of hemoptysis and guide therapy, the strengths and limitations of chest radiography, bronchoscopy, multi-detector computed tomography (MDCT), MDCT angiography, and digital subtraction angiography were described, with a special focus on MDCT angiography. It was noted that bronchial artery embolisation played the primary role in the treatment choices for recurrent or severe hemoptysis.

Most of the time, hemoptysis is a self-limiting event, but in less than 5% of instances, it may be severe or massive, signifying a condition that is life-threatening and requires immediate attention.

Death is typically caused by asphyxia, which floods the airways rather than exsanguination, and is frequently followed by cardiovascular collapse. Untreated massive hemoptysis has a mortality risk of more than 50%.

Thus, early detection of severe hemoptysis and the determination of its causes are essential to starting an effective course of therapy and preventing fatal complications. Imaging is important in the treatment of this clinical disease.

With a focus on the pathophysiologic mechanisms, the anatomy of the systemic and pulmonary arteries responsible for hemoptysis, and the role of imaging modalities in diagnosing causes and assisting with treatment, this article aims to provide a thorough review on massive and nonmassive hemoptysis. A management plan for hemoptysis based on the most recent medical literature will be suggested after the strengths and weaknesses of the various diagnostic modalities are examined.

Causes and Pathophysiology

There are numerous reasons for hemoptysis, which are typically grouped under parenchymal diseases, airway diseases, and vascular diseases.

Blood can leak from either tiny or large lung vessels. A focal or diffuse alveolar haemorrhage is frequently caused by bleeding from the small arteries and is primarily brought on by immunologic, vasculitic, cardiovascular, and coagulatory factors.
Vascular, infectious, cardiovascular, congenital, neoplastic, and vascular illnesses are among the conditions that can cause bleeding from large arteries. However, bronchiectasis, TB, fungus infections, and cancer are the most frequently occurring illnesses that result in hemoptysis.

Causes of Big Vessel Hemoptysis

The bronchial arteries and the pulmonary arteries are the two arterial vascular networks that supply blood to the lungs. The pulmonary arteries play a role in gas diffusion and supply 99% of the arterial blood to the lungs. Without taking part in gas exchange, the bronchial arteries feed the extra- and intrapulmonary airways as well as the pulmonary arteries (vasa vasorum). The bronchial arteries also supply blood to the mediastinal lymph nodes and nerves, visceral pleura, pharynx, vasa vasorum of the aorta, and pulmonary veins.
The pulmonary arteries and the systemic lung arteries have intricate capillary anastomoses.
The pulmonary arteries and the systemic lung arteries have intricate capillary anastomoses. The bronchial supply gradually increases when pulmonary circulation is compromised (for example, in thromboembolic disease, vasculitic disorders, or in hypoxic vasoconstriction), causing a hyperflow in the anastomotic vessels. These vessels then become hypertrophic with thin walls and have a propensity to break into the alveoli and bronchi, leading to hemoptysis.
Likewise, the release of angiogenic growth factors promotes neovascularization and pulmonary vessel remodelling with involvement of collateral systemic vessels in neoplastic diseases as well as chronic inflammatory disorders like bronchiectasis, chronic bronchitis, tuberculosis, mycotic lung diseases, and lung abscess. These collateral and new blood vessels are weak and prone to burst into the lungs.
90% and 5%, respectively, of cases of severe hemoptysis needing treatment have bronchial and pulmonary arteries as the cause of bleeding. Hemoptysis may result from non-bronchial systemic arteries in the residual 5% of cases. Very rarely, hemoptysis from capillaries and pulmonary and bronchial veins has been described According to a new study by No et al. , bronchial artery bleeding can coexist with non-bronchial and pulmonary artery bleeding in the same patient.
Hemoptysis may also result from non-bronchial systemic arteries that penetrate the lung parenchyma via pulmonary ligaments or transpleural adhesions brought on by long-lasting inflammatory processes (tuberculosis, mycosis) . These arteries then anastomose with the pulmonary arterial circulation.. The inferior phrenic, musculophrenic, pericardiodiaphragmatic, posterior intercostal, thyrocervical, internal mammary, and subclavian arteries are the most frequent sources of non-bronchial vessels.
Typically, two or three bronchial artery branches travel parallel to the major bronchi and anastomose to form a peribronchial plexus. A parallel plexus is formed in the bronchial submucosa by arterioles from this plexus that penetrate the muscle layer. The diameter of bronchial arteries is less than 1.5 mm at the origin and less than 0.5 mm more distally under typical circumstances. When larger than 2 mm at the origin, they are typically regarded as hypertrophic and a possible source of hemoptysis.
Hemoptysis may have pulmonary arterial aetiology. Even after effective systemic artery embolization, persistent hemoptysis points to a pulmonary arterial cause of bleeding. Activated tuberculosis, pulmonary abscesses, aspergillosis, and necrotic lung carcinoma were all examined as potential causes of pulmonary arterial hemoptysis by Khalil et al. (24), as well as vasculitis (Behçet disease or Hughes-Stovin syndrome), trauma from a Swan-Gang catheter, and pulmonary arteriovenous malformation. (PAVM).

Diagnosis Modalities

Chest radiography (CXR), bronchoscopy, Multidetector CT and other diagnostic procedures are available to investigate hemoptysis.

Chest Radiography

Even in the newest studies, CXR is regarded as the primary imaging modality for assessing a patient with hemoptysis.
It can be found easily, quickly, and cheaply. Involvement of the lung may be localised or widespread, and CXR can help to lateralise bleeding. The use of a CXR can identify underlying parenchymal and pleural anomalies, including masses, pneumonia, chronic lung disease, atelectasis, cavitary lesions, and alveolar opacities brought on by alveolar haemorrhage.
More effectively than a diffuse or bilateral lung involvement, a localised discovery may help direct further analysis.
CXR is not particularly sensitive in this situation, though. Only 50% of CXR tests were positive according to Hirschberg study.

Bronchoscopy

For a long time, bronchoscopy was thought to be the only reliable way to detect and locate hemoptysis, particularly if it was massive. (31).
In individuals with severe hemoptysis, bronchoscopy using a rigid or flexible endoscope is useful for spotting ongoing bleeding and for inspecting the airways.
Flexible fiberoptic bronchoscopy is more frequently used because it has the advantage of being performed at the patient's bedside without anaesthesia and in the intensive care unit, whereas rigid bronchoscopy may play a role in massive hemoptysis due to its capacity to maintain airway potency.
Depending on the rate and extent of the haemorrhage, bronchoscopy may be able to localise the bleeding location with varying degrees of success.
However, significant haemorrhage can make it difficult to see the airways, particularly at the level of the distal bronchi. Another drawback of bronchoscopy is that lavage or endoscope use itself can irritate the bronchial epithelium and lead to repeated bleeding.
In identifying the underlying causes of bleeding, bronchoscopy is less sensitive than MDCT generally. In a study by Revel et al., 77% of the patients underwent MDCT, and 8% of the patients had bronchoscopies to determine the source of their bleeding. However, bronchoscopy provides more details on endobronchial lesions and enables for the collection of tissue samples for microbial cultures.
Additionally, if a bleeding source is found during bronchoscopy, cold saline solution can be directly injected into the airways at that location, and haemorrhage can be controlled using balloon inflation or laser coagulation, though the effectiveness of these techniques is not proven and largely depends on the practitioner's skill.

Multi-Detector CT

In the clinical setting of hemoptysis, MDCT is a noninvasive and extremely helpful imaging technique that enables thorough assessment of the lung parenchyma, airways, and thoracic vessels by using contrast agent.
In 63% to 100% of patients with hemoptysis, MDCT may locate the bleeding location . It is also better than bronchoscopy at identifying underlying causes of bleeding, such as bronchiectasis, pulmonary infections, lung cancer, etc. Additionally, MDCT has the benefit of demonstrating distant airways above the bronchoscope's level , and it has a sensitivity of more than 90% for detecting endobronchial lesions
However, there are some drawbacks to diagnosing lesions, including the inability to distinguish between endobronchial blood clots and tumours and to see an endobronchial process when there is acute bleeding flooding the bronchial lumen. In these situations, bronchoscopy continues to be a crucial supplemental diagnostic instrument. It has been determined that the greatest accuracy in evaluating patients with hemoptysis comes from combining the use of MDCT and bronchoscopy. . All patients with hemoptysis should undergo MDCT before undergoing bronchoscopy, according to numerous writers.
When there is hemoptysis, both bronchial and non-bronchial arteries as well as the pulmonary arterial circulation should be considered in the vessel study. The number and origin of bronchial arteries can be carefully assessed during an MDCTA of the chest done prior to treatment, and the presence of a second non-bronchial arterial supply can be readily depicted to determine the best angiographic approach Before beginning endovascular therapy for patients with massive hemoptysis, it will be easier to select ectopic vessels that can be successfully embolised and avoid subsequent episodes of hemoptysis from occurring. ). The time required for the procedure and any possible iatrogenic risks associated with looking for abnormal vessels are decreased by having access to this information prior to the patient entering the angiographic suite.

Treatment

Up until twenty years ago, once the bleeding location was localised, surgery was thought to be the best option for treating hemoptysis. The associated mortality rate for surgery during an acute episode of haemorrhage, however, is significant, varying from 7% to 18%, and it can reach 40% in emergency situations. Additionally, some patients—such as those with pre-existing respiratory and cardiovascular comorbidities—are not prospects for surgery.
Aside from the immediate control of bleeding, recently demonstrated that in patients with massive hemoptysis due to tuberculosis and post-tuberculous sequelae, the effectiveness of BAE tends to decrease over years, being 51% in the first year and 39% in the second year after treatment. Nevertheless, repeated BAE in patients with early recurrence improves the outcome.
Also, non-bronchial systemic arteries and pulmonary arteries may be subjected to endovascular treatment, if they are the source of the hemorrhage.

Management

According to the rate and type of bleeding (massive or nonmassive), as well as the patient's clinical state, hemoptysis patients should be managed. Prior to conducting any other diagnostic tests, resuscitation is required in cases of significant bleeding in unstable patients.

Summary/Conclusion

It is crucial to manage hemoptysis properly in various clinical settings, particularly when it involves massive bleeding, which is a condition that can be fatal.
By providing a thorough and accurate evaluation of the lung parenchyma, airways, and thoracic vessels, imaging, particularly MDCTA, plays a significant role in this context by allowing identification of a potential cause for the bleeding and guiding eventual treatment.

On MDCTA, systemic bronchial and non-bronchial arteries can be seen and are important in large-scale haemorrhage. For the planning of endovascular embolization, a comprehensive understanding of the typical and variant anatomy of these arteries is essential. Pre-embolization MDCTA can decrease bleeding recurrences and shorten the procedural time, and arterial embolisation is currently the most efficient and least invasive method for treating massive and recurrent hemoptysis.