CVS DISORDERS.
Kawasaki Disease (KD)
Definition:
Kawasaki disease is an acute, self-limiting vasculitis of unknown origin, primarily affecting medium-sized arteries, including the coronary arteries, in children <5 years.
Causes & Risk Factors:
- Genetic predisposition (Asian children at higher risk)
- Infectious trigger (viral/bacterial superantigens suspected)
Signs & Symptoms (CRASH & Burn Mnemonic):
- Conjunctivitis (bilateral, non-purulent)
- Rash (polymorphous, non-vesicular)
- Adenopathy (cervical, unilateral >1.5 cm)
- Strawberry tongue and red lips
- Hands and feet swelling, erythema, desquamation
- Burn – Prolonged fever >5 days
Complications:
- Coronary artery aneurysm (most serious)
- Myocarditis, pericarditis
- Thrombosis and myocardial infarction
Diagnosis:
- Echocardiography – Detects coronary artery abnormalities
- Elevated inflammatory markers (CRP, ESR)
- Increased platelet count in subacute phase
Management:
- IV Immunoglobulin (IVIG) – First-line treatment
- High-dose Aspirin (Acute phase), then low-dose for thromboprophylaxis
- Echocardiographic follow-up for coronary involvement
Rheumatic Fever (RF)
Definition:
Rheumatic fever is a post-streptococcal autoimmune disease affecting the heart, joints, skin, and CNS, primarily occurring 2-4 weeks after a Streptococcus pyogenes infection.
Causes & Risk Factors:
- Untreated or inadequately treated Group A Streptococcal (GAS) pharyngitis
- Low socioeconomic conditions, overcrowding
Signs & Symptoms (Jones Criteria – Major & Minor):
Major Criteria (JONES Mnemonic):
- Joint involvement (Migratory polyarthritis)
- O = ♥ (Carditis – Pancarditis, valvulitis, myocarditis, pericarditis)
- Nodules (Subcutaneous, firm, painless)
- Erythema marginatum (Reddish, non-itchy, annular rash)
- Sydenham chorea (Uncontrolled jerky movements)
Minor Criteria:
- Fever >38.5°C
- Elevated ESR/CRP
- Prolonged PR interval on ECG
Complications:
- Rheumatic heart disease (RHD) – Permanent valvular damage (Mitral > Aortic valve)
- Heart failure (due to valvular dysfunction)
Diagnosis:
- ASO (Anti-streptolysin O) titer – Confirms recent streptococcal infection
- Echocardiography – Detects valvular lesions
Management:
- Penicillin (Benzathine Penicillin G IM every 3-4 weeks for prophylaxis)
- Aspirin (For arthritis and fever)
- Corticosteroids (For severe carditis)
Infective Endocarditis (IE)
Definition:
Infective endocarditis is an infection of the endocardial surface of the heart, usually affecting damaged or prosthetic heart valves.
Causes & Risk Factors:
- Bacterial infection (Streptococcus viridans, Staphylococcus aureus, Enterococcus)
- History of rheumatic heart disease (RHD)
- Congenital heart defects (if previously repaired or surgically treated)
- Indwelling central lines, catheters
Signs & Symptoms (FROM JANE Mnemonic):
- Fever
- Roth spots (Retinal hemorrhages)
- Osler nodes (Painful red nodules on fingers/toes)
- Murmur (New or changing heart murmur)
- Janeway lesions (Non-tender hemorrhagic macules on palms/soles)
- Anemia
- Nail hemorrhages (Splinter hemorrhages)
- Emboli (Septic emboli → Stroke, PE, limb ischemia)
Complications:
- Valvular destruction leading to heart failure
- Septic embolism (Stroke, splenic infarct, renal infarct, pulmonary embolism)
Diagnosis:
- Blood cultures (Multiple positive cultures needed to confirm bacterial etiology)
- Echocardiography (Vegetations seen on valves – Transesophageal Echo is best)
Management:
- Empirical IV antibiotics (Vancomycin + Gentamicin initially, then targeted therapy based on culture)
- Valve surgery (if severe valvular destruction or uncontrolled infection)
Myocarditis
Definition:
Myocarditis is inflammation of the heart muscle, leading to cardiac dysfunction and arrhythmias.
Causes:
- Viral infections (Most common) – Coxsackievirus, Adenovirus, Parvovirus B19
- Bacterial causes – Diphtheria, Lyme disease (Borrelia burgdorferi)
- Autoimmune diseases (SLE, Kawasaki disease)
Signs & Symptoms:
- Fever, malaise, and fatigue
- Tachycardia disproportionate to fever
- Chest pain (Mimicking myocardial infarction in older children)
- Signs of heart failure (Edema, hepatomegaly, dyspnea, cardiomegaly on CXR)
Complications:
- Dilated Cardiomyopathy (DCM)
- Arrhythmias (Ventricular tachycardia, heart block)
- Cardiogenic shock
Diagnosis:
- ECG – ST-T wave changes, arrhythmias
- Echocardiography – Global hypokinesia, dilated LV
- Cardiac MRI – Detects myocardial inflammation
Management:
- Supportive therapy (Oxygen, diuretics, inotropes if heart failure is present)
- IV immunoglobulin (IVIG) in suspected viral myocarditis
- Heart transplant (If refractory heart failure develops)
Key Points for Competitive Exams
✔️ Most common cause of acquired pediatric heart disease worldwide? – Rheumatic Fever
✔️ Most common cause of myocarditis in children? – Viral infections (Coxsackievirus, Adenovirus)
✔️ Most serious complication of Kawasaki disease? – Coronary artery aneurysm
✔️ Best initial test for Infective Endocarditis? – Blood cultures
✔️ Most common valve affected in Rheumatic Heart Disease? – Mitral Valve
✔️ Drug of choice for acute rheumatic fever prophylaxis? – Benzathine Penicillin G
✔️ Classic feature of myocarditis on ECG? – ST-T wave changes without coronary artery disease
✔️ Best imaging modality for coronary artery aneurysms in Kawasaki disease? – Echocardiography