FCPS Paediatrics TOACS · Interactive Station

✅ Candidate's answer:
• Diagnosis: Transient tachypnea of the newborn (TTN) – also known as "retained fetal lung fluid" or "wet lung syndrome".
• Key clinical features supporting TTN:
1️⃣ Term infant (38 weeks).
2️⃣ Elective Cesarean section without labor – major risk factor (no thoracic squeeze to expel lung fluid).
3️⃣ Early onset of tachypnea (within 2 hours of birth).
4️⃣ Mild respiratory distress (grunting, nasal flaring, tachypnea 80-90/min).
5️⃣ No cyanosis; pink on room air; SpO2 92-94% (only mild desaturation).
6️⃣ Chest X-ray shows perihilar interstitial markings, fluid in horizontal fissure – classic for TTN.
7️⃣ The infant is otherwise well-appearing (no signs of sepsis, no fever, good perfusion).
8️⃣ Usually resolves spontaneously within 24-72 hours.

✅ Candidate's answer:
• In utero, fetal lungs are filled with fluid (approximately 30 mL/kg).
• During vaginal delivery, passage through the birth canal provides a "thoracic squeeze" that helps expel about 1/3 of the lung fluid. The remaining fluid is absorbed by pulmonary lymphatics and capillaries after birth, facilitated by the infant's first breaths.
• In Cesarean section without labor, there is no thoracic squeeze, and catecholamine surge (which promotes fluid absorption) is reduced. The infant is born with excess lung fluid that mechanically impedes gas exchange → decreased lung compliance, increased work of breathing, and tachypnea.
• The retained fluid also activates pulmonary stretch receptors → rapid shallow breathing (tachypnea).
• Risk is even higher if C-section is performed <39 weeks (late preterm/early term) because lung fluid clearance mechanisms are less mature.
• The condition resolves as the fluid is gradually absorbed over 24-72 hours.

✅ Candidate's answer:
• Elective Cesarean section (especially without labor) – the most important risk factor.
• Late preterm (34-36 weeks) or early term (37-38 weeks) – delayed lung fluid clearance.
• Maternal diabetes (gestational or pregestational) – increased risk even without C-section.
• Maternal asthma.
• Precipitous delivery (rapid labor) – reduced time for fluid clearance.
• Maternal hypertension/pre-eclampsia.
• Macrosomia (large for gestational age).
• Male sex.
• Perinatal asphyxia/depression – reduces initial respiratory effort.
• Multiple gestation (twins, especially second twin).
• Maternal sedatives/anesthesia (may depress neonatal breathing).

✅ Candidate's answer:
• TTN chest X-ray findings:
- Prominent perihilar interstitial markings (streaky densities radiating from hila).
- Fluid in the horizontal fissure (right-sided) – a classic sign (sometimes also on the left).
- Mild hyperinflation (flattened diaphragms).
- Normal or increased lung volumes (not decreased).
- Clear lung fields peripherally (no diffuse granularity).
- Small pleural effusions may be present.
• RDS (Hyaline Membrane Disease) findings:
- Low lung volumes (atelectasis).
- Diffuse reticulogranular pattern ("ground-glass" appearance).
- Air bronchograms (air-filled bronchi against opaque lung).
- No fluid in fissure.
- No hyperinflation.
• TTN resolves radiologically within 24-72 hours; RDS resolves over 3-7 days.

✅ Candidate's answer:
• Respiratory distress syndrome (RDS): Usually preterm; chest X-ray shows reticulogranular pattern, low lung volumes, air bronchograms; requires oxygen, often CPAP/ventilation; surfactant deficiency.
• Sepsis/Pneumonia (especially GBS): Presents with respiratory distress + temperature instability, lethargy, poor feeding, hypotension; chest X-ray may show focal infiltrates or appear like RDS; elevated CRP, positive blood culture. May require antibiotics.
• Meconium aspiration syndrome (MAS): History of meconium-stained amniotic fluid; chest X-ray shows coarse infiltrates, hyperinflation, pneumothorax; severe hypoxemia.
• Pneumothorax: Sudden deterioration, asymmetric breath sounds, hyperresonance; chest X-ray shows air in pleural space.
• Congenital heart disease (cyanotic CHD): Cyanosis, murmur, preductal-postductal gradient, cardiomegaly on X-ray; echocardiography differentiates.
• Polycythemia: Ruddy appearance, may cause tachypnea; hematocrit >65%.
• Hypoglycemia, hypocalcemia, or cold stress – may cause tachypnea without primary lung disease.

✅ Candidate's answer:
• Management is primarily supportive and expectant.
• Monitoring: Pulse oximetry, vital signs (respiratory rate, heart rate, temperature), work of breathing assessment.
• Oxygen therapy: If SpO2 <90-92%, provide low-flow oxygen by nasal cannula or head box to maintain saturations >92%. Most infants with TTN require only room air or minimal oxygen (<30%).
• Feeding: If tachypnea is mild and the infant can coordinate suck-swallow-breathing, continue breastfeeding or bottle feeding. If tachypnea is severe (RR >80-100) or the infant tires easily, withhold oral feeds and start intravenous fluids (10% dextrose, 60-80 mL/kg/day) to prevent aspiration and dehydration. Offer expressed breast milk by gavage if prolonged.
• Antibiotics: Not routinely indicated if sepsis risk is low (no maternal fever, no prolonged rupture of membranes, no signs of infection). However, if there is any suspicion of sepsis (maternal GBS colonization, prolonged rupture, maternal fever), obtain blood culture and start empirical antibiotics (ampicillin + gentamicin) while awaiting results. In this scenario, no risk factors → no antibiotics.
• NICU admission: Mild TTN can be managed in the newborn nursery or intermediate care unit with monitoring. If oxygen requirement is significant (>30-40%) or respiratory distress worsens, transfer to NICU.
• Nasal CPAP is rarely needed but may be used if hypoxia is moderate (e.g., SpO2 <90% on >40% oxygen).
• Most infants improve within 24-48 hours.

✅ Candidate's answer:
• TTN vs sepsis:
- Sepsis usually presents with systemic signs: temperature instability (fever or hypothermia), lethargy, poor feeding, irritability, hypotension, metabolic acidosis.
- TTN: Infant is well-appearing, afebrile, active, feeds well (if tachypnea mild), no signs of shock.
- Maternal risk factors: Sepsis is more likely with maternal fever, chorioamnionitis, prolonged rupture of membranes (>18 hours), or known GBS colonization without intrapartum prophylaxis.
- Chest X-ray: TTN shows fluid in fissure, perihilar streaking; GBS pneumonia may look like RDS (reticulogranular pattern).
- Labs: Sepsis may have leukocytosis/neutropenia, elevated CRP, thrombocytopenia; TTN has normal labs.
• Antibiotics decision:
- In this scenario (elective C-section, no labor, no maternal fever, well-appearing infant, classic X-ray), the risk of sepsis is extremely low. Antibiotics are NOT indicated.
- However, if there is ANY risk factor (e.g., GBS positive mother with no intrapartum prophylaxis, maternal fever, prolonged rupture), I would obtain blood culture and start ampicillin + gentamicin while awaiting results, even if the presentation resembles TTN.
- Many centers have a low threshold to start antibiotics and discontinue if cultures are negative at 48 hours.

✅ Candidate's answer:
• No, diuretics are NOT recommended for routine treatment of TTN.
• Reasons:
1️⃣ TTN is a self-limited condition that resolves with supportive care within 24-72 hours.
2️⃣ No evidence that diuretics shorten the course or reduce the need for respiratory support.
3️⃣ Diuretics can cause electrolyte disturbances (hyponatremia, hypokalemia, hypochloremia), dehydration, and ototoxicity (with loop diuretics).
4️⃣ The retained fluid is interstitial lung fluid, not intravascular volume overload. Diuretics primarily reduce intravascular volume and may worsen perfusion.
• When diuretics may be used (rare): If there is significant pulmonary edema with cardiac dysfunction (e.g., in a preterm infant with PDA). Not in isolated TTN.
• Evidence: Cochrane review found no benefit of diuretics in TTN.
• Management: supportive care only (oxygen, IV fluids if needed).

✅ Candidate's answer:
• Clinical course: Tachypnea usually peaks within 6-12 hours of birth and gradually resolves over 24-72 hours. Most infants are asymptomatic by 72 hours.
• Oxygen requirement: Most infants require <40% oxygen, often weaned rapidly. Only a small percentage require CPAP or mechanical ventilation (<5%).
• Feeding: Once respiratory rate decreases to <60-70/min and the infant demonstrates coordinated suck-swallow, oral feeds can be initiated. If severe tachypnea persists, gavage feeding or IV fluids may be needed.
• Resolution: Chest X-ray findings (fluid in fissure, interstitial markings) clear within 24-72 hours.
• Prognosis: Excellent. No long-term pulmonary sequelae. No increased risk of asthma or later respiratory disease (some studies suggest a slightly increased risk of wheezing in infancy, but this may be confounded by C-section itself, not TTN).
• Discharge: Once the infant is breathing comfortably in room air, feeding well, and maintaining temperature, discharge is safe.

✅ Candidate's answer:
• Yes, TTN can be reduced by avoiding elective C-section before 39 weeks of gestation.
• The risk of TTN is significantly higher when C-section is performed at 37-38 weeks compared to ≥39 weeks, because lung fluid clearance mechanisms are more mature at 39 weeks.
• ACOG guidelines recommend no elective delivery (either induction or C-section) before 39 completed weeks of gestation unless medically indicated.
• If C-section is necessary at 37-38 weeks, administration of antenatal corticosteroids (betamethasone) may reduce the risk of RDS but does NOT prevent TTN (TTN is not prevented by steroids). In fact, steroids do not reduce TTN.
• If labor occurs before C-section, the risk of TTN is lower (because labor promotes fluid clearance). Therefore, even a short period of labor before C-section is beneficial.
• Avoiding excess maternal fluids during labor (to reduce fetal lung fluid) is not proven to prevent TTN.

✅ Candidate's answer:
• This is a diagnostic challenge because late preterm infants are at risk for both TTN and RDS.
• Differentiating features:
- RDS usually presents with grunting, retractions, and worsening hypoxemia over the first 6-12 hours. Chest X-ray shows ground-glass appearance, air bronchograms, low lung volumes. Surfactant deficiency may be documented (L/S ratio low). Response to surfactant is rapid.
- TTN presents early (first 2 hours), is milder, and improves over 24-48 hours. Chest X-ray shows fluid in fissure, perihilar streaking, normal or increased lung volumes. No response to surfactant (not indicated).
• Management approach: If the infant has significant hypoxemia (FiO2 >0.4) or worsening distress, treat empirically as RDS and consider surfactant. TTN rarely requires surfactant or ventilation. Many late preterm infants with mild disease can be managed with CPAP and oxygen; if they improve rapidly, it's likely TTN; if they worsen or remain hypoxemic, suspect RDS.
• Antenatal steroids: If steroids were given, RDS risk is reduced but TTN risk is not. So TTN becomes relatively more common after steroid administration.

✅ Candidate's answer:
• Most infants with TTN do NOT require CPAP.
• Indications for nasal CPAP in TTN:
- Moderate to severe hypoxemia (SpO2 <90%) requiring >40-50% oxygen.
- Significant retractions or grunting that is not improving.
- Respiratory acidosis (PaCO2 >60 mmHg with pH <7.25).
- Apnea.
- Failure of weaning oxygen.
• How CPAP helps: CPAP provides positive end-expiratory pressure (PEEP) which helps stent open the airways, improve functional residual capacity (FRC), and reduce the work of breathing. It may also promote clearance of fluid.
• Typical settings: PEEP 5-6 cm H2O, FiO2 titrated to SpO2 90-95%.
• Duration: Usually 12-48 hours.
• If the infant fails CPAP (needs high FiO2, decompensates), consider mechanical ventilation and reevaluate diagnosis (may be RDS, pneumonia, or other condition).
• Most TTN infants can be managed with low-flow oxygen alone.

✅ Candidate's structured answer:
• “Your baby has a condition called transient tachypnea of the newborn. It's sometimes called 'wet lungs'.”
• “Before birth, a baby's lungs are filled with fluid. When a baby is born by C-section without going through labor, some of that fluid stays in the lungs for a while. That extra fluid makes it harder for the baby to exchange oxygen, so she breathes faster to make up for it.”
• “The good news is that this condition is usually mild and temporary. Over the next 1-3 days, the fluid will be absorbed naturally, and her breathing will return to normal. Most babies do not need any special treatment – we will just monitor her oxygen levels and give a little extra oxygen if needed.”
• “She does not have an infection, and there is no permanent damage to her lungs. Babies with this condition grow up to be completely healthy.”
• “We will keep her with you in the hospital. If her breathing stays fast, we may feed her through a small tube in her nose so she doesn't get tired. But we expect her to be feeding normally by tomorrow or the day after.”
• “You did not cause this – it is simply a result of the C-section, which was necessary. We will take good care of her, and she will be fine.”

✅ Candidate's answer:
• Most studies show no significant long-term pulmonary sequelae from TTN.
• However, some large cohort studies suggest that infants with TTN have a slightly increased risk of wheezing and asthma in early childhood (especially in the first 2-5 years of life).
• This increased risk may be due to the underlying predisposition (e.g., maternal asthma, C-section itself, late preterm birth) rather than TTN directly.
• By school age, the risk of asthma is similar to the general population.
• Practical advice: Parents do not need special follow-up beyond routine pediatric care. If the child develops recurrent wheezing, treat as usual for reactive airways disease.
• TTN does NOT cause chronic lung disease (bronchopulmonary dysplasia), restrictive lung disease, or pulmonary hypertension later in life.
• Reassure parents: Your child's lungs are normal and will function normally.