9.2 Congenital Heart Disease (Cyanotic & Acyanotic) & Rheumatic Fever
Key Takeaways
- Ventricular Septal Defect (VSD) is the most common congenital heart defect, presenting with a harsh holosystolic murmur at the left lower sternal border; small defects often close spontaneously.
- Tetralogy of Fallot is the most common cyanotic heart defect, defined by PROVe (Pulmonary stenosis, RVH, Overriding aorta, VSD); "Tet spells" are managed with knee-chest positioning and oxygen.
- Transposition of the Great Arteries (TGA) presents with severe cyanosis in the neonatal period and requires maintenance of the ductus arteriosus with Prostaglandin E1 (alprostadil) for survival until surgical correction.
- Acute Rheumatic Fever follows Group A Streptococcal pharyngitis; diagnosis relies on the Jones criteria (e.g., migratory polyarthritis, carditis, Sydenham chorea, erythema marginatum, subcutaneous nodules).
- Kawasaki disease requires a high index of suspicion in young children with prolonged fever (≥5 days) and mucosal changes; treatment with IVIG and aspirin prevents coronary artery aneurysms.
Pediatric Cardiology: Congenital and Acquired Conditions
Understanding pediatric cardiology requires distinguishing between acyanotic and cyanotic congenital heart defects (CHDs) and recognizing critical acquired inflammatory conditions. The clinical presentation often depends on the direction of blood shunting and the degree of pulmonary or systemic outflow tract obstruction. Early detection through newborn pulse oximetry screening has improved outcomes for critical congenital heart disease.
Acyanotic Congenital Heart Disease (Left-to-Right Shunts)
These defects involve blood shunting from the higher-pressure left side of the heart to the lower-pressure right side. They typically do not cause cyanosis early in life but can lead to pulmonary hypertension and heart failure if left untreated.
1. Ventricular Septal Defect (VSD): VSD is the most common congenital heart defect overall.
- Presentation: A small VSD is often asymptomatic and presents with a loud, harsh holosystolic murmur at the left lower sternal border. Large VSDs can present with failure to thrive, diaphoresis with feeding, and signs of heart failure by 2-3 months of age as pulmonary vascular resistance drops.
- Management: Small VSDs often close spontaneously during childhood. Large symptomatic defects require medical management (diuretics, ACE inhibitors, high-calorie feeds) followed by surgical closure to prevent Eisenmenger syndrome (irreversible pulmonary hypertension leading to shunt reversal).
2. Atrial Septal Defect (ASD):
- Presentation: Often asymptomatic in childhood. The classic physical finding is a widely split and fixed S2 (due to delayed pulmonic valve closure from increased right-sided volume) and a systolic ejection murmur at the left upper sternal border.
- Management: Small ASDs may close spontaneously. Larger defects are closed transcatheter or surgically in early childhood to prevent right ventricular enlargement and atrial arrhythmias later in life.
3. Patent Ductus Arteriosus (PDA):
- Presentation: Failure of the fetal ductus arteriosus to close. It is very common in premature infants and those with congenital rubella syndrome. The classic finding is a continuous, "machine-like" murmur at the left infraclavicular area.
- Management: In premature infants, cyclooxygenase inhibitors (indomethacin or ibuprofen) are used to close the PDA. If pharmacological closure fails or in older children, percutaneous device closure or surgical ligation is required.
Cyanotic Congenital Heart Disease (Right-to-Left Shunts)
These defects involve shunting of deoxygenated blood into the systemic circulation, leading to cyanosis. Remember the "5 Ts" of cyanotic heart disease: Truncus arteriosus, Transposition of the great arteries, Tricuspid atresia, Tetralogy of Fallot, and Total anomalous pulmonary venous return.
1. Tetralogy of Fallot (ToF): The most common cyanotic CHD presenting beyond infancy.
- Components (PROVe): Pulmonary infundibular stenosis, Right ventricular hypertrophy, Overriding aorta, and Ventricular septal defect.
- Presentation: The degree of cyanosis depends on the severity of right ventricular outflow tract (RVOT) obstruction. A harsh systolic ejection murmur is heard. "Tet spells" are hypercyanotic episodes triggered by crying or feeding (increased right-to-left shunting).
- Management of Tet Spells: Knee-chest position (increases systemic vascular resistance, decreasing the right-to-left shunt), supplemental oxygen, morphine, and sometimes beta-blockers or phenylephrine.
- Imaging: "Boot-shaped heart" on chest X-ray due to RVH and an upturned cardiac apex.
2. Transposition of the Great Arteries (TGA): The most common cyanotic CHD presenting in the neonatal period.
- Pathophysiology: Aorta arises from the right ventricle, and pulmonary artery from the left ventricle, creating two parallel, unmixed circulations. Survival depends on mixing via a PDA, ASD, or VSD.
- Presentation: Severe cyanosis immediately after birth that does not improve significantly with supplemental oxygen.
- Management: Continuous infusion of Prostaglandin E1 (alprostadil) is life-saving to keep the ductus arteriosus patent. Balloon atrial septostomy may be needed urgently to create an ASD for mixing, followed by definitive surgical arterial switch operation within the first weeks of life.
- Imaging: "Egg on a string" appearance on chest X-ray (narrow mediastinum due to anteroposterior relationship of great vessels).
Acquired Heart Diseases
Acute Rheumatic Fever (ARF): A delayed, nonsuppurative immune complication of Group A Streptococcus (GAS) pharyngitis, typically occurring 2-4 weeks post-infection.
- Diagnosis (Jones Criteria): Requires evidence of preceding GAS infection (positive throat culture, rapid antigen test, or elevated ASO/anti-DNase B titers) plus 2 major OR 1 major + 2 minor criteria.
- Major Criteria (JONES): Joints (migratory polyarthritis), O (Heart/Carditis, often mitral regurgitation), Nodules (subcutaneous), Erythema marginatum, Sydenham chorea.
- Minor Criteria: Fever, arthralgia, elevated acute phase reactants (ESR, CRP), prolonged PR interval on ECG.
- Management: Penicillin (to eradicate carriage), NSAIDs for arthritis, and corticosteroids for severe carditis. Secondary prophylaxis with intramuscular benzathine penicillin G every 3-4 weeks is essential to prevent recurrent attacks and progressive valvular damage (Rheumatic Heart Disease).
Kawasaki Disease: An acute, self-limiting systemic medium-sized vessel vasculitis that predominantly affects children under 5 years of age. It is a leading cause of acquired heart disease in children in developed nations.
- Diagnosis: Fever for $\ge$ 5 days plus 4 of 5 "CRASH" criteria:
- Conjunctivitis (bilateral, non-exudative, limbic sparing)
- Rash (polymorphous, often involving perineum)
- Adenopathy (cervical, usually unilateral >1.5 cm)
- Strawberry tongue (and other mucosal changes like cracked red lips)
- Hands and feet changes (erythema, edema, followed by periungual desquamation)
- Complication: Coronary artery aneurysms (up to 25% of untreated cases). Echocardiography is mandatory at diagnosis and follow-up.
- Management: Intravenous Immunoglobulin (IVIG) as a single high dose, plus high-dose aspirin (anti-inflammatory) until fever resolves, then low-dose aspirin (antiplatelet) for 6-8 weeks.
Cyanotic vs. Acyanotic Heart Defects Summary
| Defect Type | Examples | Key Clinical Finding | Primary Intervention |
|---|---|---|---|
| Acyanotic (L $\to$ R) | VSD, ASD, PDA | Heart failure, characteristic murmurs | Watchful waiting, surgical/device closure |
| Cyanotic (R $\to$ L) | ToF, TGA, Truncus Arteriosus | Hypoxemia, Cyanosis | Prostaglandin E1 (for ductal dependent), Surgery |
Understanding the pathophysiology of these lesions is vital for recognizing the appropriate acute stabilization measures in a pediatric patient.
A 4-month-old infant is brought to the clinic for poor weight gain and sweating during feeding. On physical examination, a loud, harsh holosystolic murmur is heard best at the left lower sternal border, accompanied by a palpable thrill. Which of the following is the most likely diagnosis?
A 2-day-old neonate becomes deeply cyanotic. Supplemental oxygen is administered but fails to improve the oxygen saturation. Echocardiography reveals the aorta arising from the right ventricle and the pulmonary artery arising from the left ventricle. Which of the following medications should be administered immediately to preserve life until surgical intervention?
A 3-year-old boy presents with a 6-day history of high fever that has not responded to antipyretics. Examination reveals bilateral non-exudative conjunctival injection, cracked erythematous lips, a "strawberry" tongue, and a generalized polymorphous rash, prominently involving the perineum. There is tender cervical lymphadenopathy. Which of the following complications is most specifically associated with this condition if left untreated?