Cardiovascular Infections

Infective Endocarditis - Valve Vandals

• Etiology: S. aureus (acute, IVDU), Viridans streptococci (subacute, dental), Enterococci, HACEK, Fungi.
• Risk Factors: Prosthetic valves, IVDU, RHD, indwelling lines.
• Pathogenesis: Endothelial injury → Non-Bacterial Thrombotic Endocarditis (NBTE) → Bacteremia → Vegetation.
• Clinical: 📌 FROM JANE: Fever, Roth spots, Osler nodes, Murmur (new), Janeway lesions, Anemia, Nail-bed hemorrhages, Emboli.
• Diagnosis: Duke Criteria
  • Major: +ve Blood Culture (typical organism); Echo (vegetation, abscess, new regurgitation).
  • Minor: Predisposition; Fever ≥38°C; Vascular (emboli, Janeway); Immunologic (Osler, Roth, Glomerulonephritis); +ve microbiology not meeting major criteria.
  • Definite IE: 2 Major OR 1 Major + 3 Minor OR 5 Minor.

⭐ Culture-negative endocarditis: often due to prior antibiotics; also consider Coxiella burnetii, Bartonella spp.

• Management:
  • Empiric antibiotics (e.g., Vancomycin + Gentamicin).
  • Specific therapy (culture-guided) for 4-6 weeks.
  • Surgery: valve dysfunction, persistent sepsis, large vegetations (>10mm) + emboli risk.

Rheumatic Fever/RHD - Strep's Sad Encore

• Immune-mediated sequel (2-4 weeks) to untreated Group A Strep (GAS) pharyngitis.
• Pathogenesis: Molecular mimicry (Strep M protein vs. host tissues like heart, joints, CNS, skin).
• 📌 JONES Criteria (Evidence of prior GAS infection + 2 Major OR 1 Major & 2 Minor):
  • Major: Carditis (pancarditis), Polyarthritis (migratory, large joints), Chorea (Sydenham's), Erythema Marginatum, Subcutaneous Nodules.
  • Minor: Fever (≥38.5°C), Arthralgia, ↑ESR (≥60) / CRP (≥3), Prolonged PR.
• Carditis: Most severe. Aschoff bodies (pathognomonic myocardial granulomas); MacCallum patch (LA endocardium).
• RHD: Chronic valvular disease from ARF. Mitral valve most affected (stenosis > regurg.), then aortic. "Fish-mouth"/"button-hole" deformity.
• Prevention: Primary (treat GAS pharyngitis), Secondary (long-term Penicillin prophylaxis post-ARF).

⭐ Mitral valve: most frequently and severely affected in chronic RHD, classically causing stenosis.

Myo/Pericarditis - Heart's Inflamed Hug

• Etiology:
  • Viral (Coxsackie B, Adenovirus, Parvovirus B19) common for both.
  • Myocarditis: Also autoimmune (SLE, sarcoidosis), drugs (clozapine), toxins, Chagas disease, giant cell myocarditis.
  • Pericarditis: Also bacterial (TB), fungal, uremia, post-MI (Dressler's syndrome), autoimmune, malignancy, trauma, radiation.
• Clinical Features:
  • Myocarditis: Chest pain (often vague), dyspnea, fatigue, palpitations, arrhythmias, signs of heart failure (HF). Can be fulminant.
  • Pericarditis: Sharp, pleuritic chest pain (relieved by sitting up/leaning forward, worsened by lying supine/inspiration), pericardial friction rub (triphasic, often transient). Fever common.
• Investigations:
  • ECG:
    • Myo: Sinus tachycardia, ST-T changes (non-specific), AV block, ventricular arrhythmias.
    • Peri: Diffuse concave ST elevation & PR depression (Stage 1); T-wave inversions (Stage 3).
  • Biomarkers: ↑ Troponin (more significant in Myo), ↑ CK-MB, ↑ ESR/CRP.
  • ECHO: Myo (LV systolic dysfunction, regional wall motion abnormalities), Peri (pericardial effusion, signs of tamponade e.g., diastolic RV collapse).
  • CXR: Myo (cardiomegaly, pulmonary edema), Peri (normal or "water-bottle" heart with large effusion).
• Management:
  • Supportive: Rest, O2. Treat HF (ACEi, ARBs, beta-blockers, diuretics), arrhythmias.
  • Myocarditis: Specific Rx if cause identified (e.g., immunosuppression for giant cell/sarcoidosis).
  • Pericarditis: NSAIDs (e.g., Ibuprofen 600-800 mg TID) + Colchicine (0.5-0.6 mg OD or BID for 3 months to prevent recurrence). Steroids for refractory cases or if NSAIDs contraindicated.
  • Pericardiocentesis for tamponade or large symptomatic effusion.
• Complications:
  • Myo: Dilated cardiomyopathy (DCM), arrhythmias, sudden cardiac death (SCD).
  • Peri: Cardiac tamponade, constrictive pericarditis, recurrent pericarditis.

⭐ In acute pericarditis, PR segment depression is highly specific, especially when present with diffuse ST elevation.

High‑Yield Points - ⚡ Biggest Takeaways

• Infective Endocarditis (IE): Diagnosis via Duke Criteria. Staph. aureus (IVDU, tricuspid), Viridans streptococci (post-dental).
• Culture-negative IE: Consider Coxiella, Bartonella, HACEK. Stigmata: Janeway lesions, Osler's nodes.
• Acute Rheumatic Fever: Post-Group A Strep; Jones Criteria. Mitral valve most affected.
• Myocarditis & Pericarditis: Often viral (Coxsackie B). Pericarditis pain improves leaning forward.
• TB pericarditis prevalent in India. Early Prosthetic Valve Endocarditis: Staph. epidermidis.
• IE Prophylaxis: For high-risk patients during specific dental/respiratory procedures.