Endocarditis vs. Pericarditis: Key Differences and Similarities
Endocarditis and pericarditis are distinct cardiac inflammatory conditions with different anatomical locations, etiologies, clinical presentations, and treatment approaches.
Anatomical Differences
- Endocarditis is an infection of the inner lining of the heart chambers and valves (endocardium), most commonly affecting heart valves 1
- Pericarditis is inflammation of the pericardium, the fibrous sac surrounding the heart 1
Etiology
Endocarditis
- Primarily infectious in origin, caused by bacteria (most commonly streptococcal species, Staphylococcus aureus) 1
- Often develops on abnormal valves after bacteremia from infected gums, genitourinary, or gastrointestinal tract 1
- Can affect normal valves in acute bacterial endocarditis 1
- Prosthetic valve endocarditis comprises a substantial proportion of cases 1
- Right-sided endocarditis is often related to intravenous drug abuse 1
Pericarditis
- Multiple causes including viral infections (most common in developed countries), bacterial infections, autoimmune diseases, uremia, post-myocardial infarction, and idiopathic 1
- Tuberculous pericarditis accounts for ≤4% of cases in developed countries but >90% in HIV-infected individuals in developing countries 1
- Approximately 5-15% of acute or recurrent pericarditis cases may have an underlying systemic autoimmune disease 1
Clinical Presentation
Endocarditis
- Fever, new or changing heart murmurs (present in 57% of cases) 1, 2
- Embolic phenomena (coronary arteries, brain, other organs) 1
- Congestive heart failure due to valvular dysfunction 1
- Abscess formation in valve annulus causing conduction abnormalities 1
- Rarely presents with pericarditis (only 21 cases reported in 40 years) 2
Pericarditis
- Sharp, pleuritic chest pain that improves with sitting up or leaning forward 3
- Pericardial friction rub (pathognomonic but only present in about one-third of cases) 3
- ECG changes: diffuse ST-segment elevation and PR-segment depression 3
- Pericardial effusion in approximately 60% of cases 3
- May present with myocardial involvement (myopericarditis) 1
Complications
Endocarditis
- Valvular dysfunction and regurgitation 1
- Periannular extension of infection 1
- Congestive heart failure 1
- Septic emboli to coronary arteries, brain, and other organs 1
- Conduction abnormalities due to abscess formation 1
- Rarely, cardiac tamponade due to rupture 1
Pericarditis
- Recurrent pericarditis (15-30% of cases) 1
- Cardiac tamponade 1
- Constrictive pericarditis (rare complication, especially in idiopathic cases) 1
- Effusive-constrictive pericarditis 1
Diagnostic Approach
Endocarditis
- Blood cultures (multiple sets) 1
- Echocardiography (transthoracic and transesophageal) to detect vegetations 1
- Modified Duke criteria for diagnosis 1
Pericarditis
- ECG: widespread ST elevation, PR depression 3
- Echocardiography to detect effusion 1, 3
- Cardiac MRI with gadolinium contrast in cases of suspected myopericardial involvement 3
- Pericardiocentesis in cases of significant effusion or suspected purulent/tuberculous pericarditis 1
Treatment
Endocarditis
- Prolonged intravenous antibiotics (4-6 weeks) targeted to the specific organism 1
- Surgical intervention for:
- Recurrent emboli
- Refractory heart failure
- Abscess formation
- Fungal endocarditis
- Prosthetic valve endocarditis not responding to antibiotics 1
Pericarditis
- NSAIDs as first-line therapy for idiopathic/viral pericarditis 1
- Colchicine in addition to NSAIDs to improve response and prevent recurrences 1
- Corticosteroids as second-line therapy when NSAIDs are contraindicated or fail 1
- Specific treatment for underlying cause (antibiotics for bacterial pericarditis, intensified dialysis for uremic pericarditis) 1
- Pericardiocentesis for cardiac tamponade or purulent pericarditis 1
Overlap and Connections
- Endocarditis can rarely cause pericarditis as a complication (reported in only 21 cases over 40 years) 2
- Both conditions can be part of a pancarditis involving all layers of the heart, as seen in rheumatic fever 1
- Both can be caused by similar infectious agents, particularly Staphylococcus aureus 1, 2
- Both can lead to heart failure through different mechanisms 1
Prognosis
Endocarditis
- Overall mortality approximately 25% 4
- Higher mortality in prosthetic valve endocarditis and when complicated by heart failure 1
- When complicated by pericarditis, mortality rates of 60% with antibiotics alone versus 31% with combined surgical and antibiotic treatment 2