Can pneumonia cause elevated Brain Natriuretic Peptide (BNP)?

From the Guidelines

Pneumonia can indeed cause elevated BNP levels, as indicated in the 2016 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 1. The guidelines list severe infections, including pneumonia and sepsis, as non-cardiac causes of elevated natriuretic peptides, which include BNP. Several mechanisms can lead to the elevation of BNP in pneumonia, including the inflammatory response, hypoxemia, and the systemic inflammatory response that can directly affect cardiac function and BNP release. When interpreting elevated BNP in patients with pneumonia, it is essential to consider that values between 100-500 pg/mL may reflect the acute illness rather than heart failure, while higher values (>500 pg/mL) might suggest concurrent heart failure or significant cardiac stress from the infection. Key points to consider in the context of pneumonia and BNP elevation include:

• The inflammatory response in pneumonia increases pulmonary vascular resistance and can cause right ventricular strain
• Hypoxemia from impaired gas exchange stimulates pulmonary vasoconstriction, further increasing right heart pressure
• The systemic inflammatory response in pneumonia releases cytokines that can directly affect cardiac function and BNP release
• Sepsis, which may accompany severe pneumonia, causes distributive shock and myocardial depression, contributing to BNP elevation
• Serial measurements showing decreasing BNP levels as pneumonia resolves can help distinguish between pneumonia-induced elevation and underlying cardiac disease, as recommended in the guidelines 1.

From the Research

Pneumonia and Elevated BNP

• Pneumonia can cause elevated B-type natriuretic peptide (BNP) levels, as shown in several studies 2, 3, 4, 5, 6.
• The increase in BNP levels is associated with the severity of pneumonia, with higher levels indicating more severe disease 2, 4.
• BNP levels can be used as a biomarker to evaluate the severity of community-acquired pneumonia (CAP) and predict mortality 2, 3, 4.
• The optimal cut-off point for BNP levels to distinguish high-risk patients from low-risk ones varies depending on the study, but ranges from 125.0 pg/mL to 279 pg/mL 2, 4.
• Elevated BNP levels are not exclusive to pneumonia, but can also be seen in other conditions such as sepsis and heart failure 6.
• The mechanism of BNP elevation in pneumonia is not fully understood, but may be related to cardiac stress and inflammation 2, 4.

Studies on Pneumonia and BNP

• A study published in the World Journal of Emergency Medicine in 2015 found that BNP levels increased with CAP severity and were highly accurate in predicting the severity of CAP 2.
• A prospective cohort study published in BMJ Open in 2016 found that BNP levels were associated with mortality in CAP patients and remained an independent mortality predictor in multivariable analysis 3.
• A study published in the Journal of Internal Medicine in 2008 found that BNP levels were powerful and independent predictors of death and treatment failure in CAP patients 4.
• A study published in Clinical Laboratory in 2022 found that high BNP levels were independently associated with mortality in COVID-19 patients with pneumonia 5.
• A study published in the European Journal of Internal Medicine in 2007 found that BNP levels were elevated in patients with community-acquired infections, including pneumonia, without severe sepsis or septic shock 6.