Endocarditis refers to an inflammation affecting the inner lining of the heart chambers and its valves. This condition arises when bacteria or other germs from another part of the body, such as the mouth, spread through the bloodstream and attach to damaged areas in the heart. If left unaddressed, this infection can lead to serious heart damage, making prompt and accurate diagnosis important.
Recognizing Early Indicators
The initial signs of endocarditis can be subtle, resembling common illnesses, and may include persistent fever, chills, and fatigue. These non-specific symptoms can make early detection challenging. As the condition progresses, more specific indicators may emerge, such as a new or changing heart murmur. Patients might also experience shortness of breath, swelling in the legs or abdomen, and unexplained weight loss. A thorough medical history, including any recent infections or dental procedures, combined with a comprehensive physical examination, helps identify these early clues and guide further diagnostic steps.
Blood Analysis
Laboratory tests are important in confirming endocarditis, particularly blood cultures. These cultures are performed by drawing blood samples over a period, multiple samples from different sites, to detect microorganisms in the bloodstream. The goal is to identify the specific type of bacteria or fungi causing the infection, such as Staphylococcus aureus, Streptococcus species, or Enterococcus species. Beyond cultures, other blood tests provide insights; a complete blood count (CBC) may reveal an elevated white blood cell count, indicating infection. Inflammatory markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are often measured, as their elevated levels can indicate systemic inflammation.
Visualizing the Heart
Visualizing the heart’s structure is central to endocarditis diagnosis, with echocardiography being the primary imaging technique. An echocardiogram uses sound waves to create detailed images of the heart’s chambers, valves, and surrounding structures, to observe their function and identify abnormalities. This imaging can reveal vegetations, growths composed of bacteria, platelets, and fibrin that form on the heart valves or inner lining.
Transthoracic Echocardiogram (TTE)
A transthoracic echocardiogram (TTE) is performed by placing the transducer on the chest wall, providing a general view of the heart.
Transesophageal Echocardiogram (TEE)
A transesophageal echocardiogram (TEE) involves inserting a thin, flexible tube with a transducer down the esophagus, positioning it closer to the heart and yielding clearer, more detailed images, particularly of the valves. TEE is the preferred method when endocarditis is highly suspected.
Other Imaging Techniques
In complex cases or when complications like abscesses or emboli are suspected, a computed tomography (CT) scan or positron emission tomography (PET) scan may provide additional anatomical or metabolic information.
Piecing Together the Diagnosis
The diagnosis of endocarditis requires integrating clinical, laboratory, and imaging data. Physicians combine the patient’s symptoms and physical examination findings with results from blood cultures and echocardiograms. This multi-faceted approach helps ensure accuracy, as no single test provides all the necessary information.
The Modified Duke Criteria
To standardize this process, the modified Duke criteria are often used. These criteria utilize “major” elements, such as positive blood cultures and evidence of vegetations on echocardiography, and “minor” elements, including predisposing heart conditions, fever, and vascular phenomena. A specific combination of these major and minor criteria is necessary to reach a definitive or possible diagnosis, guiding treatment decisions.