What are the symptoms of infective endocarditis?

Symptoms of Infective Endocarditis

Fever is the hallmark symptom of infective endocarditis, occurring in up to 90% of patients, typically accompanied by a new or changing heart murmur (present in up to 85% of cases), and embolic phenomena (present in up to 25% at diagnosis). 1, 2

Cardinal Clinical Features

The classic triad of symptoms includes:

• Fever with systemic symptoms: Fever represents the most common presenting symptom, accompanied by chills, poor appetite, and weight loss 1, 2
• New or changing heart murmur: Occurs in up to 85% of patients, most commonly due to valvular insufficiency 1, 2
• Embolic phenomena: Present in up to 25% of patients at diagnosis, with septic pulmonary infarcts and abscesses occurring particularly in right-sided endocarditis 1

Peripheral Manifestations (Vascular and Immunological Phenomena)

These classic signs help distinguish IE from other febrile illnesses:

• Splinter hemorrhages: Linear hemorrhages under the nails 2
• Roth spots: Retinal hemorrhages with pale centers that serve as a significant diagnostic clue 1
• Janeway lesions: Painless hemorrhagic macules on palms and soles (implied from vascular phenomena) 2
• Osler nodes: Painful nodules on finger/toe pads (implied from immunological phenomena) 2

Organ-Specific Complications

Cardiac Manifestations

• Congestive heart failure: One of the most common complications requiring urgent surgical intervention 3
• Cardiac conduction abnormalities: Including heart block, which may indicate valve ring abscess 3
• Valvular regurgitation: The predominant functional abnormality seen 3

Neurological Manifestations

• Embolic stroke or transient ischemic attack: From septic emboli 3, 1
• Intracranial hemorrhage: From bleeding mycotic aneurysms 3, 1
• Neurological deficits: May result from systemic emboli or ruptured mycotic aneurysms 1

Renal Manifestations

• Glomerulonephritis: Occurs as an immunological phenomenon 1, 2

Pulmonary Manifestations (Right-Sided IE)

• Septic pulmonary infarcts and abscesses: Particularly in right-sided endocarditis, common in intravenous drug users 1

Critical Diagnostic Caveats

Important pitfalls to avoid:

• Fever may be absent in elderly patients, after antibiotic pre-treatment, in immunocompromised patients, or in IE involving less virulent organisms 2
• Persistent fever despite appropriate antibiotics should raise concern for complications such as valve ring abscess, mycotic aneurysm, or treatment failure 3
• Nonspecific symptoms can make diagnosis challenging, as IE can manifest with various presentations mimicking other febrile illnesses 4, 5

When to Suspect IE

Maintain high clinical suspicion in these scenarios:

• High-risk patients with unexplained fever: Those with prosthetic valves, intracardiac devices, pre-existing valvular disease, or congenital heart disease 2
• Intravenous drug users with fever and pulmonary symptoms: Suggesting right-sided endocarditis 3
• New heart murmur in a febrile patient: Particularly with embolic phenomena 1, 2
• Persistent bacteremia: Especially with typical IE organisms like Staphylococcus aureus or viridans streptococci 3