Master Paediatrics
for PLAB 1

What the PLAB 1 Tests in Paediatrics

PLAB 1 Paediatrics tests the initial assessment, recognition of serious illness, and evidence-based management of common paediatric presentations from birth to adolescence. Candidates must demonstrate knowledge of neonatal resuscitation (APGAR, NICE guidelines), paediatric basic life support (PBLS), growth and development milestones (e.g., Denver II), immunisation schedules (UK routine schedule), and management of acute conditions like bronchiolitis (RSV), croup (dexamethasone dose), asthma (BTS/SIGN stepwise), febrile seizures, meningitis (NICE sepsis pathway), and dehydration (oral rehydration salts). Also tested: safeguarding (non-accidental injury, FII), congenital heart disease (VSD, PDA), and common infections (UTI, tonsillitis, otitis media).

High-Yield Concepts

• Bronchiolitis Management (NICE NG184): Diagnose in infants <1 year with coryza, cough, and wheeze/crackles. Supportive care: nasal suction, oxygen if SpO2 <90%, NG fluids if unable to feed. No routine bronchodilators or steroids. Indications for admission: SpO2 <92%, poor feeding, respiratory rate >60/min, apnoeas.
• Febrile Seizure Criteria and Management: Simple febrile seizure: generalised tonic-clonic <15 minutes, single in 24h, age 6 months–5 years. No routine investigations if well; treat fever with paracetamol/ibuprofen. Complex: focal, prolonged >15 min, or multiple in 24h – consider lumbar puncture and EEG. No long-term anticonvulsants for simple.
• Paediatric Basic Life Support (PBLS): Resuscitation Council UK: 5 rescue breaths initially, then 15:2 compressions-ventilation ratio (single rescuer). Use 2 fingers for infant, 1 hand for child. Depth: 4cm infant, 5cm child. Attach AED if available. Continue until signs of life or advanced help arrives.
• Meningitis and Meningococcal Sepsis (NICE NG51): Give IV/IM benzylpenicillin (or cefotaxime) immediately if suspected. In hospital: IV ceftriaxone 80mg/kg (max 4g) for <3 months or if resistant suspected. Dexamethasone 0.15mg/kg IV (max 10mg) given before or with first antibiotic for bacterial meningitis. Monitor for petechial rash, shock, and raised ICP.
• Dehydration Classification and Rehydration (NICE CG84): Clinical dehydration: no signs (mild), sunken eyes, reduced skin turgor, dry mucous membranes (moderate), shock, oliguria, lethargy (severe). Mild-moderate: oral rehydration salts (ORS) 50ml/kg over 4h. Severe: IV 0.9% saline bolus 20ml/kg. Reassess and repeat if needed. Use NG if oral fails.
• Asthma Acute Management (BTS/SIGN 2023): Acute severe: SpO2 <92%, PEF 33-50% predicted, unable to complete sentences. Give salbutamol 2.5mg (nebulised) every 20-30 min, plus ipratropium 0.25mg. Add oral prednisolone 20mg (<5yr) or 40mg (≥5yr). Life-threatening: silent chest, cyanosis, exhaustion – add IV magnesium sulfate 40mg/kg (max 2g) and consider IV salbutamol.
• Neonatal Jaundice Management (NICE NG98): Plot bilirubin on treatment threshold graph. Phototherapy for significant jaundice; exchange transfusion if phototherapy fails or bilirubin > threshold for exchange. Check conjugated bilirubin if >20% direct. Consider ABO/Rh incompatibility, G6PD deficiency. Kernicterus risk: lethargy, poor feeding, high-pitched cry.
• Safeguarding: Non-Accidental Injury (NAI) Red Flags: Bruises in non-mobile infant, torn frenulum, burns with clear lines (immersion), spiral fractures, metaphyseal fractures, subdural haematoma (shaken baby). Skeletal survey and CT head in <2 years with suspected NAI. Always document, involve safeguarding team, and follow local policy.

Common Traps in Paediatrics Questions

• Applying adult BLS ratios (30:2) to children – PBLS uses 15:2 for single rescuer.
• Giving ibuprofen in suspected chickenpox – increases risk of necrotising fasciitis; use paracetamol.
• Using oral antibiotics for first-line UTI in <3 months – must have IV antibiotics (e.g., cefotaxime) due to risk of urosepsis.
• Forgetting to check capillary refill time (<2 seconds) as part of shock assessment in paediatric sepsis.
• Assuming all wheeze in infants is asthma – bronchiolitis is far more common in <1 year and does not respond to bronchodilators.
• Omitting dexamethasone in croup management – single dose 0.15mg/kg oral/IV reduces intubation risk.

How to Revise Paediatrics for the PLAB 1

Focus on acute presentations: breathless child, fever with rash, fitting child, and dehydrated infant. Questions often present a clinical scenario with vital signs and ask for the next step in management or diagnosis. Prioritise NICE guidelines for bronchiolitis, asthma, and meningitis. Memorise key drug doses (e.g., benzylpenicillin 60mg/kg IV, ceftriaxone 80mg/kg). Practise interpreting growth charts and bilirubin nomograms. Be alert to safeguarding cues in trauma or burn cases. Review UK immunisation schedule (2,3,4 months, 1 year, preschool, adolescent). Expect questions on differentials (e.g., Kawasaki vs scarlet fever) and red flags (e.g., fever >5 days, conjunctivitis, strawberry tongue).

Practise it: MedLumen has 50 Paediatrics questions for the PLAB 1, each with a full explanation and references.