Fiche de révision : Congenital Heart Defects and Neonatal Management

📋 Course Outline

1. Cyanotic and acyanotic congenital heart defects
2. Acyanotic defects with left to right shunt
3. Obstructive acyanotic defects and aortic stenosis
4. Coarctation of the aorta and pulmonary stenosis
5. Cyanotic defects with right to left shunt
6. Tetralogy of Fallot and hypercyanotic attacks
7. Transposition of the great vessels and mixing
8. Immunisation contraindications and vaccine deferral
9. Feeding requirements and breastfeeding benefits
10. Heart failure and congestive cardiac failure
11. Malnutrition, PEM classification and management

📖 1. Cyanotic and acyanotic congenital heart defects

🔑 Key Concepts & Definitions

• Cyanotic congenital heart defects : Cyanotic congenital heart defects : congenital lesions causing right-to-left shunting that leads to systemic desaturation and cyanosis.
• Acyanotic congenital heart defects : Acyanotic congenital heart defects : congenital lesions that do not cause primary systemic desaturation, often with normal or increased pulmonary blood flow.
• Pulmonary blood flow : Pulmonary blood flow : the amount of blood reaching the lungs, which helps classify defects as ↑ or ↓ and predicts clinical patterns.
• Right-to-left shunt : Right-to-left shunt : blood flows from the systemic side to the pulmonary side, bypassing lung oxygenation and producing cyanosis.
• Left-to-right shunt : Left-to-right shunt : blood flows from the systemic circulation to the pulmonary circulation, increasing pulmonary blood flow and causing heart failure signs if large.

📝 Essential Points

• Cyanotic defects are typically associated with ↓ pulmonary blood flow and right-to-left shunting.
• Cyanotic infants are often cyanosed yet comfortable, with no respiratory distress and no cardiac failure signs or chest wall deformities.
• Acyanotic defects are grouped by ↑ pulmonary blood flow (left-to-right shunt) versus normal pulmonary blood flow (obstructive lesions).
• Large left-to-right shunts can cause cardiac failure features, recurrent LRTIs, and chest deformities.
• Obstructive acyanotic lesions cause chamber hypertrophy and may be found incidentally rather than presenting with cyanosis.

💡 Memory Hook

Think “Cyanotic = ↓ lungs + right-to-left = blue but calm”; “Acyanotic = ↑ or normal lungs = murmur/heart failure patterns, not blue.”

📖 2. Acyanotic defects with left to right shunt

🔑 Key Concepts & Definitions

• Coarctation of the aorta : Acyanotic aortic narrowing that causes reduced femoral pulses and a large proximal aorta with bounding upper limb pulses.
• Brachialis bounding : A clinical sign where the brachial pulse feels unusually strong, reflecting increased upper-limb arterial pressure.
• Aortic stenosis : A cyanosis-free valve narrowing that produces a small-volume ejection murmur and may cause LVH if severe.
• Pulmonary stenosis : A cyanosis-free right ventricular outflow obstruction that gives an ejection systolic murmur with a possible systolic click and thrill.
• Patent ductus arteriosus : A persistent duct connection that creates a left-to-right shunt, leading to pulmonary plethora and cardiomegaly.

📝 Essential Points

• Coarctation: absent femoral pulses with brachialis bounding and a large proximal aorta on imaging.
• Coarctation: ejection murmur findings are described as normal ejection with a mid/left-sided pattern and cardiomegaly with pulmonary plethora.
• Aortic stenosis: ejection murmur is small volume with normal pulmonary blood flow and a large proximal aorta.
• Aortic stenosis: axis is normal unless severe, where LVH is expected.
• Pulmonary stenosis: ejection systolic murmur is heard at the 2nd ICS on the left with a systolic click and thrill when severe.
• Pulmonary stenosis: pulmonary blood flow is normal and lung vascularity is normal, with RV enlargement and right axis deviation.

💡 Memory Hook

Coarctation = upper pulses strong, femorals absent; Aortic stenosis = small ejection + LVH if severe; Pulmonary stenosis = left 2nd ICS + RVH/right axis.

📖 3. Obstructive acyanotic defects and aortic stenosis

🔑 Key Concepts & Definitions

• Obstructive acyanotic defects : Obstructive acyanotic defects are heart lesions that block blood flow while usually not causing cyanosis.
• Aortic stenosis : Aortic stenosis is narrowing of the aortic valve that obstructs left ventricular outflow.
• Deep tendon reflexes : Deep tendon reflexes are stretch reflexes tested clinically to assess the integrity of the reflex arc and nervous system pathways.
• Babinski sign : Babinski sign is an abnormal plantar response indicating corticospinal tract dysfunction.

📝 Essential Points

• The provided material does not include specific clinical features, investigations, or management details for obstructive acyanotic defects or aortic stenosis.
• The source text mainly lists neurologic findings (reflexes, Babinski sign, tone) and pediatric milestones, not lesion-specific facts for aortic stenosis.
• Deep tendon reflexes can be absent or depressed in central injury patterns described in the source.
• Babinski sign is listed as absent in the peripheral/LMN pattern described in the source.
• No comparison between obstructive acyanotic defects and other cyanotic/non-obstructive lesions is provided in the excerpt.

💡 Memory Hook

No natural mnemonic for aortic stenosis appears in the excerpt; the section content is largely unrelated to the lesion.

📖 4. Coarctation of the aorta and pulmonary stenosis

🔑 Key Concepts & Definitions

• Coarctation of the aorta : A congenital narrowing of the aorta that reduces systemic blood flow and can lead to heart failure in infants.
• Pulmonary stenosis : A congenital narrowing at the pulmonary valve that obstructs right ventricular outflow and increases pulmonary blood flow demands.
• Duct-dependent circulation : A circulation that relies on the ductus arteriosus to maintain adequate blood flow when a major vessel is narrowed.
• Heart failure in infants : A clinical syndrome where the heart cannot meet the body’s metabolic needs, producing poor perfusion and fluid overload signs.

📝 Essential Points

• Heart failure presentation commonly includes tachypnoea, poor colour, sweating, inability to complete feeds, and failure to thrive.
• Early oedema signs include puffy eyes, while dependent oedema is a late sign; hepatomegaly can appear earlier than oedema.
• Inspiratory crackles at the lung bases suggest pulmonary congestion in infant heart failure.
• Treatment is given regardless of diagnosis: nurse at 60°, give oxygen, start inotropes (digoxin), and use diuretics to reduce preload.
• Vasodilators (e.g., captopril) reduce LV afterload, and furosemide plus spironolactone are used together to manage fluid overload.

💡 Memory Hook

Coarctation/Pulmonary stenosis → think “duct-dependent + heart failure”: feeds fail, tachypnoea, puffy eyes early, hepatomegaly early, treat with oxygen + digoxin + diuretics.

📖 5. Cyanotic defects with right to left shunt

🔑 Key Concepts & Definitions

• Right-to-left shunt : A circulation pattern where blood moves from the right side of the heart to the left, bypassing normal oxygenation.
• Cyanotic defect : A congenital heart abnormality that causes persistent low oxygen levels leading to cyanosis.
• Cyanosis : A clinical sign of reduced arterial oxygen saturation causing bluish discoloration of skin and mucous membranes.

📖 6. Tetralogy of Fallot and hypercyanotic attacks

🔑 Key Concepts & Definitions

• Hypercyanotic attacks : A cyanotic crisis in which a baby with Tetralogy of Fallot develops sudden worsening cyanosis from acute right-to-left shunting.
• Tetralogy of Fallot : A congenital heart defect that predisposes to right-to-left shunting and can trigger hypoxia-related complications during hypercyanotic attacks.
• Hypoxic ischaemic encephalopathy : A brain injury caused by significant fetal or newborn hypoxia leading to impaired cerebral perfusion and subsequent tissue damage.
• SIADH hyponatraemia : A syndrome where excess ADH causes water retention, producing hyponatraemia during systemic stress such as hypoxia.

📝 Essential Points

• Initial hypoxia increases breathing effort, leading to fatigue, then primary apnoea before respiration restarts and may end in a secondary apnoea with a last gasp pattern.
• Hypoxia and acidaemia can progress to tissue injury affecting CNS (hypoxic ischaemic encephalopathy, IVH, cerebral oedema, seizures) and CVS (myocardial ischaemia, hypotension, poor contractility).
• Systemic complications listed include metabolic problems (SIADH → hyponatraemia, hypoglycaemia, hypocalcaemia, myoglobinuria) and haemostatic failure (DIC).
• Respiratory complications include respiratory distress syndrome and persistent foetal circulation.
• Comparison: Primary apnoea vs secondary apnoea—primary occurs after fatigue from increased breathing effort, while secondary occurs after respiration restarts and culminates in a last gasp.

💡 Memory Hook

Breathing → fatigue → primary apnoea → restart → last gasp → secondary apnoea (hypoxia spiral).

📖 7. Transposition of the great vessels and mixing

🔑 Key Concepts & Definitions

• Transposition of the great vessels : A congenital heart defect where the aorta and pulmonary artery are connected to the wrong ventricles, separating oxygenated and deoxygenated blood circuits.
• Mixing : The process that allows oxygenated and deoxygenated blood to combine in transposition, usually via shunts, to sustain systemic oxygen delivery.
• Placental circulation : The fetal blood flow through the placenta that controls fetal gas exchange and oxygen delivery before birth.
• Pulmonary level circulation : The newborn’s oxygenation pathway that depends on effective lung function after birth to replace placental oxygen delivery.

📝 Essential Points

• Transposition-related physiology depends on adequate mixing to prevent severe hypoxia and organ injury.
• Failure of oxygen exchange at the placental level in the fetus causes fetal hypoxia due to placental ischaemia.
• Failure of oxygen exchange at the pulmonary level in the newborn causes hypoxia after birth.
• Systemic hypoxia triggers maintenance of cerebral blood flow, with reduced perfusion to other organs leading to lower CO, lower BP, and vital-organ damage.
• Organ injury pattern includes myocardial ischaemia with poor contractility, GI ischaemia with risk of perforation, renal failure with ↑K+, ↓Na+, and ↓HCO3-, and acute liver failure with marked AST/ALT rise.

💡 Memory Hook

Mixing is the “oxygen blender”: without it, hypoxia → brain protected first, other organs suffer.

📖 8. Immunisation contraindications and vaccine deferral

📖 9. Feeding requirements and breastfeeding benefits

🔑 Key Concepts & Definitions

• Breastfeeding benefits : Breastfeeding benefits refer to health advantages for the infant that support feeding choices in early life.
• Feeding requirements : Feeding requirements are the specific nutritional needs that must be met to support growth, hydration, and recovery in infants and children.
• Hypoxic/ischaemic injury : Hypoxic/ischaemic injury is brain damage caused by reduced oxygen or blood flow, which can contribute to neurological problems.
• Infection-related encephalopathy : Infection-related encephalopathy is altered brain function caused by infections such as meningitis or encephalitis.

📝 Essential Points

• The source material provided does not include specific breastfeeding benefits or infant feeding requirements.
• No feeding volumes, schedules, contraindications, or breastfeeding technique guidance are stated in the provided text.
• No exam-relevant breastfeeding or feeding rule (e.g., when to stop, when to supplement) appears in the provided section.
• Neurological content in the source focuses on causes of seizures and encephalopathy rather than feeding practices.
• Because the section source is missing the feeding/breastfeeding content, no faithful feeding-specific facts can be extracted.

📖 10. Heart failure and congestive cardiac failure

🔑 Key Concepts & Definitions

• Congestive cardiac failure : Congestive cardiac failure is a heart failure state where blood backs up, causing congestion and impaired oxygenation.
• Cardiac failure wheeze : Cardiac failure wheeze is wheezing caused by pulmonary congestion from heart failure rather than primary airway disease.
• Large airway wheeze causes : Large airway wheeze causes are conditions that narrow or obstruct the trachea or large bronchi, producing wheeze.
• Small airway wheeze causes : Small airway wheeze causes are conditions affecting bronchioles, leading to wheeze from distal airway narrowing or inflammation.

📝 Essential Points

• Cardiac failure is listed as a cause of wheezing in the small-airway category.
• Large-airway wheeze causes include foreign body, TB gland obstruction, congenital anomalies, anomalous artery, bronchogenic cyst, and tracheomalacia.
• Small-airway wheeze causes include acute viral bronchiolitis, asthma, pneumonia with eosinophilia, aspiration pneumonia, cystic fibrosis, and bronchiectasis.
• Wheezing from cardiac failure should be considered when the clinical picture suggests pulmonary congestion rather than infection alone.

💡 Memory Hook

Think “heart → congestion → wheeze”: cardiac failure can mimic airway disease by causing small-airway wheeze.

📖 11. Malnutrition, PEM classification and management

🔑 Key Concepts & Definitions

• Protein-energy malnutrition : Protein-energy malnutrition is a condition caused by insufficient energy and/or protein intake leading to impaired growth and body function.
• PEM classification : PEM classification is the system that groups malnutrition severity based on clinical signs such as weight loss, wasting, and oedema.
• Oedema : Oedema is abnormal fluid accumulation in tissues that can signal severe malnutrition when present with other PEM features.
• Wasting : Wasting is loss of body mass from muscle and fat, reflecting acute or severe protein-energy deficiency.
• Marasmus : Marasmus is severe PEM dominated by marked wasting without oedema.

📝 Essential Points

• PEM severity can be assessed clinically using features like wasting and oedema rather than relying on symptoms alone.
• Oedema in PEM is a marker of more severe disease than wasting alone.
• Marasmus is characterized by severe wasting without oedema.
• PEM classification guides management intensity and monitoring frequency.
• Management decisions depend on severity and presence of complications such as dehydration or infection.

💡 Memory Hook

Wasting = “dry” (marasmus); Oedema = “wet” (more severe PEM).

📊 Synthesis Tables

Cyanotic vs acyanotic congenital heart defects (classification by pulmonary blood flow)

⚠️ Common Pitfalls & Confusions

1. Mixing up shunt direction: right-to-left shunts cause cyanosis and bypass lung oxygenation, while left-to-right shunts increase pulmonary blood flow and can lead to cardiac failure.
2. Assuming cyanosis always means cyanotic CHD: obstructive acyanotic lesions can cause hypertrophy and be incidental with normal pulmonary blood flow.
3. Confusing early vs late heart failure oedema: puffy eyes are early, while dependent oedema is a late sign.
4. For Tetralogy of Fallot hypercyanotic attacks, forgetting the sequence of breathing changes (fatigue → primary apnoea → restart → last gasp → secondary apnoea).
5. For transposition of the great vessels, forgetting that survival depends on mixing via PDA/VSD/ASD; without mixing, severe hypoxia occurs.
6. For coarctation, mixing up pulses: arms have present/strong pulses while femoral pulses are absent or decreased, with a systolic murmur at the back between the left scapula and spine.
7. For PEM, mixing marasmus and kwashiorkor: marasmus is severe wasting without oedema, while kwashiorkor includes oedema and dermatosis after weaning.

✅ Exam Checklist

1. Classify congenital heart defects by pulmonary blood flow (↑, ↓, normal) and link each to the shunt direction (left-to-right vs right-to-left) and cyanosis pattern.
2. For cyanotic CHD with ↓ pulmonary blood flow, state the key clinical pattern: cyanosed but comfortable, no respiratory distress, no cardiac failure signs, and usually no chest wall deformities or cardiomegaly.
3. For acyanotic CHD with ↑ pulmonary blood flow (left-to-right shunt), list the expected clinical consequences: cardiac failure signs if significant, recurrent LRTIs, and chest deformities.
4. For VSD, recall timing (present between 2–6 weeks), typical murmur location/character (loud pansystolic over left sternal border 4th ICS), and the large-shunt addition (mid diastolic murmur at apex).
5. For ASD, recall that it is usually normally asymptomatic, the murmur pattern (ejection systolic at 2nd ICS on left; fixed splitting of S2; tricuspid diastolic at lower left sternal edge), and ECG axis differences (ostium
6. For PDA, recall the left-to-right shunt physiology and the typical auscultation pattern (continuous machinery murmur) plus the expected CXR/plethora and cardiomegaly pattern.
7. For obstructive acyanotic lesions with normal pulmonary blood flow, state the mechanism (LV outflow obstruction → LVH/LVF → ↓CO and pulmonary congestion) and the key murmur/pulse findings for aortic stenosis (harsh systo
8. For pulmonary stenosis, state the murmur location (2nd ICS on left), the presence of click/thrill in severe cases, and the severe-case cyanosis mechanism (right-to-left shunt via patent foramen ovale when RAP > LAP).
9. For coarctation of the aorta, state the pulse pattern (arms present, femorals absent/decreased), the murmur location (back between left scapula and spine), and the imaging clue (proximal aorta enlargement/figure 3 sign).
10. For Tetralogy of Fallot hypercyanotic attacks, reproduce the breathing sequence (fatigue → primary apnoea → respiration restarts → last gasp → secondary apnoea) and the emergency treatment steps listed (knee-chest/squatt
11. For transposition of the great vessels, state the physiology of separated circuits and the survival requirement for mixing via PDA/VSD/ASD.
12. For heart failure/CCF, list the core clinical features (tachypnoea, poor colour, sweating, inability to complete feeds, FTT, puffy eyes early, hepatomegaly earlier than oedema, inspiratory crackles) and the treatment set
13. For PEM, distinguish marasmus vs kwashiorkor using the defining features (marasmus: severe wasting without oedema; kwashiorkor: oedema with dermatosis) and recall the Waterlow classification approach (weight-for-height/w
14. For immunisation contraindications and deferral, recall the specific contraindication rules stated: egg allergy for certain vaccines, immunosuppression deferring BCG/measles/MMR/TOPV for at least 3 months after cessation