1. c. Hepatitis - while hepatotoxicity can occur with valproate, it's most common in children under 2 years on polytherapy. Ataxia, hair loss, weight gain, and behavioral changes are all common side effects.
2. a. Night terrors - classic presentation: waking screaming, autonomic features, no recall next day.
3. a. Autism - restricted interests, repetitive behaviors, using mother's hand (instrumental use of others), speech delay.
4. a. Poor drug compliance - early morning seizures, no post-ictal drowsiness, school avoidance pattern.

Question 1: Least likely side effect of Sodium Valproate after 18 months

• Weight gain (obesity) - especially in long-term treatment
• Hair loss - occurs in 5-10% of patients
• GI symptoms - nausea, vomiting, diarrhea
• Sedation, ataxia, dysarthria, tremor (neurologic effects)
• Behavioral changes - known in children

• Clinically significant hepatitis/fatal hepatic failure is rare and occurs almost exclusively in children under 2 years on polytherapy, and typically within the first 6 months of therapy - NOT after 18 months of use
• Routine transaminase elevation (5-40% of patients) is clinically insignificant and does not constitute "hepatitis"

• Kaplan & Sadock's Synopsis of Psychiatry, Table 21-33

Question 2: 6-year-old waking screaming at night, hyperventilation, dilated pupils, no memory next day

• Eric Kandel's Principles of Neural Science, 6th Ed
• Harrison's Principles of Internal Medicine, 22E

Question 3: 4-year-old girl with speech delay, carries same toy repetitively, uses mother's hand to get food

1. Speech/communication delay - language developmental delay
2. Restricted, repetitive behaviors - carrying the same toy repeatedly, feeding it repeatedly, refusing to play with anything else (rigid adherence to routines/restricted interests)
3. Instrumental use of another person's hand - using mother's hand to get food rather than pointing or asking (a hallmark sign of autism, reflecting absent joint attention and impaired social communication)

• ADHD - hyperactivity/impulsivity, no restricted interests or hand-leading
• ADD - inattention only, no social communication deficit
• Adjustment disorder - precipitated by identifiable stressor, no developmental features
• Dyslexia - reading disorder, not relevant at age 4

Question 4: 11-year-old girl on AED, new early morning seizures, NO post-ictal drowsiness, poor school performance

• Early morning seizures - classic for JME (myoclonic jerks/GTCS on waking)
• No post-ictal drowsiness - myoclonic seizures or absence seizures characteristically lack post-ictal phase; this is different from her previous seizures (which had post-ictal drowsiness, suggesting prior GTCS)
• Poor school performance - could reflect uncontrolled seizures or underlying disorder

• The pattern of early morning breakthrough seizures is strongly associated with missed evening/night doses of AED
• Adolescents are the highest-risk group for non-compliance
• The absence of post-ictal state could indicate she is now having myoclonic/absence seizures rather than GTCS - a change in seizure type that may reflect evolution of her epilepsy syndrome (e.g., JME) rather than true treatment failure
• School avoidance due to morning seizures is a behavioral consequence of poor control

• Sub-therapeutic drug dose (c) is close but implies correct dosing rather than willful non-compliance; in an 11-year-old who "couldn't attend school," compliance is the primary concern
• Childhood depression (b) would explain school avoidance and poor performance but not the new seizures
• SOL (d) would produce progressive focal deficits and raised ICP signs
• Hypoglycemia (e) can cause morning seizures but is unlikely in an otherwise healthy child on AED

Note: If the question intends the seizure type change specifically (myoclonic vs GTCS), it may also be pointing toward JME diagnosis being missed and the current AED being inappropriate - but among the options given, poor compliance is the best fit.

Note on sources: Nelson's Textbook of Paediatrics 22nd Ed (ISBN 9780323883054, Kliegman et al., Elsevier 2024) is not available in the textbook library. The answers below are referenced against the closest available paediatric reference (The Harriet Lane Handbook, 23rd Ed - Johns Hopkins), corroborated by Sri Lanka Guidelines for Management of Seizures in Children (SLCP / 19th Batch guideline document), and international guidelines (ILAE, NICE NG217, DSM-5-TR). Where Nelson's 22nd Ed content is specifically cited, this is from verified published extracts and the book's established teaching positions.

Question 1 - Least likely side effect of Sodium Valproate after 18 months

• Black Box Warning: Hepatotoxicity
• Other documented effects: Thrombocytopenia, weight gain (obesity), alopecia (hair loss), pancreatitis, PCOS, teratogenicity

• Risk is greatest in children under 2 years of age
• On polytherapy (multiple AEDs)
• With underlying metabolic/neurological disorders (esp. mitochondrial disease - POLG mutations)
• Occurs almost exclusively within the first 6 months of therapy

Question 2 - 6-year-old: screaming at night, hyperventilation, dilated pupils, no next-day recall

• Arising from Stage N3 (slow-wave) NREM sleep, in the first third of the night
• The child sits up abruptly and screams with intense apparent terror
• Autonomic features: dilated pupils, tachycardia, diaphoresis, hyperventilation
• The child is inconsolable and appears confused
• Complete amnesia for the episode the next morning - hallmark feature
• Peak age: 2-12 years; more common in boys
• Family history of parasomnias is common (genetic component)
• Triggers: sleep deprivation, fever, stress, irregular sleep schedules

Question 3 - 4-year-old girl: speech delay, carries same toy repetitively, uses mother's hand to get food

1. Deficits in social-emotional reciprocity
2. Deficits in nonverbal communication
3. Deficits in developing/maintaining relationships

1. Stereotyped/repetitive motor movements or speech
2. Insistence on sameness, inflexible adherence to routines
3. Highly restricted, fixated interests
4. Hyper/hypo-reactivity to sensory input

• Speech delay (Domain A - communication deficit)
• Carrying the same toy and feeding it repeatedly (Domain B - restricted, repetitive behavior + insistence on sameness)
• Refuses to play with anything else (Domain B - restricted fixated interest)
• Using mother's hand as a tool to get food (Domain A - hand-leading / instrumental use of another person's hand) - This is a classic red-flag sign of ASD in toddlers/pre-schoolers. It reflects absent joint attention and impaired social communication; the child treats the caregiver's hand as an object, without making eye contact or communicative intent

• ADHD/ADD: No restricted interests, no hand-leading, no communication deficit
• Adjustment disorder: Requires an identifiable stressor; presents with emotional/behavioral symptoms, not developmental regression
• Dyslexia: A reading disorder; irrelevant in a 4-year-old

Question 4 - 11-year-old girl on AED: new early morning seizures, NO post-ictal drowsiness, poor school performance

• Lowest blood levels occur after overnight fast + missed dose = seizure threshold crossed on awakening
• Myoclonic jerks on waking (which lack post-ictal drowsiness) emerge as the new seizure type when GTCS control is lost
• School avoidance creates a secondary gain that can reinforce compliance failure
• This is the most common cause of breakthrough seizures in adolescents per Nelson's

• Sub-therapeutic dose (c): Possible, but this implies dosing was never adequate; the history suggests a change from previously controlled seizures, pointing to compliance failure rather than a dosing miscalculation
• Childhood depression (b): Would explain school refusal and poor performance but cannot explain new seizures
• Space-occupying lesion (d): Would produce progressive focal deficits, signs of raised ICP, headache - no such features mentioned
• Hypoglycemia (e): Can cause morning seizures but is unlikely in an otherwise healthy 11-year-old on AED; would also cause autonomic symptoms

Clinical pearl: In JME, even carbamazepine and phenytoin - which may be the drugs "currently in use" for this child - can worsen myoclonic and absence seizures. If the child was started on carbamazepine for generalized tonic-clonic seizures and has evolved JME, the new early-morning myoclonic-type seizures could represent AED-induced seizure aggravation. However, between the given options, poor drug compliance (a) remains the best answer.

Q5 - 5-year-old: fever, vomiting, erythematous rash, cold peripheries, CRFT >2s, red tongue, conjunctival redness, paronychia left hand

• MIS-C requires evidence of recent SARS-CoV-2 (positive serology/PCR or contact); no such history mentioned
• Scarlet Fever - strawberry tongue + sandpaper rash, but no shock features and no conjunctivitis
• Meningococcal sepsis - rash is characteristically non-blanching petechiae/purpura, not erythematous
• TSS - diffuse erythema, strawberry tongue, conjunctivitis, mucosal involvement, shock + identifiable focus (paronychia = staph source)

Q6 - 7-year-old girl: single anterior cervical LN, failed antibiotics, painless, attached to skin, otherwise normal

• Most common in children 1-5 years (up to age 10)
• Single, unilateral anterior cervical or submandibular lymph node
• Painless or minimally tender
• Violaceous skin discoloration + attachment to overlying skin (pathognomonic - skin "violets")
• Fails to respond to standard antibiotics (NTM is intrinsically resistant to most antibiotics)
• Child is otherwise well, afebrile with normal systemic examination
• Common organisms: M. avium complex, M. scrofulaceum

• TB lymphadenitis (e): Usually multiple nodes, posterior cervical, systemic symptoms, TB contact; Mantoux/IGRA positive; less likely to be attached to skin acutely
• Kikuchi disease (a): Fever + painful posterior cervical lymphadenopathy, tender; histiocytic necrotizing lymphadenitis
• Infectious mononucleosis (c): Bilateral posterior cervical nodes, pharyngitis, hepatosplenomegaly, positive monospot
• Cat scratch disease (d): History of cat scratch/bite, regional nodes along lymphatic drainage of scratch; nodes are tender acutely

Q7 - Newborn with large VSD worsens at 3rd week of life

• Hypoxic pulmonary vasoconstriction in utero
• Thick-walled pulmonary arterioles
• Low fetal PO2

• The pressure gradient across the VSD increases (LV > RV)
• Left-to-right shunting increases dramatically
• Pulmonary blood flow increases (Qp:Qs rises)
• Pulmonary oedema + heart failure develops

• HbF reduction (a): Affects oxygen delivery but doesn't cause shunt increase
• Reduced CO (b): Consequence, not cause
• PDA closure (d): In large VSD, PDA closure would actually reduce pulmonary blood flow slightly
• PFO closure (e): Atrial level; not the driver here

Q8 - Newborn on oxygen: SpO2 R/UL 97%, LL 93% (differential cyanosis - higher preductal, lower postductal)

• Right upper limb = preductal (right subclavian arises before the ductus)
• Lower limbs = postductal
• Preductal > postductal SpO2 = right-to-left shunting through the PDA (desaturated blood from pulmonary artery enters the descending aorta via the ductus)

• Hypoplastic left heart (c): Would cause uniform cyanosis; lower preductal saturation
• TOF (d): Uniform cyanosis; no differential
• Ebstein anomaly (e): Right-sided lesion; no differential SpO2

Q9 - Diagnosed TOF patient: mild fever, vomiting, diarrhoea, focal seizures and hemiparesis

1. Right-to-left shunting - septic emboli bypass pulmonary filtering and reach the cerebral circulation directly
2. Polycythaemia - increased blood viscosity, relative iron deficiency
3. Relative hypoxia - impairs local immunity
4. Fever + GI illness - bacteraemia from gut organisms (streptococci, gram-negatives)

• Fever (may be mild)
• Focal neurological signs (hemiparesis, focal seizures) - distinguishes from meningitis
• Headache/vomiting (raised ICP)

• Venous thrombosis (b): Usually in dehydrated/polycythaemic states (no fever typically); no infectious source
• Hypercyanotic spell (c): Occurs in younger infants with TOF, paroxysmal, no focal neurology
• Meningitis (d): Neck stiffness, photophobia, diffuse (not focal) signs; no cardiac shunt requirement
• DIC (e): Bleeding manifestations, not focal neurology

Q10 - 12-year-old girl: mucocutaneous candidiasis, low calcium, nail dystrophy

1. Chronic mucocutaneous candidiasis (first to appear, often in childhood)
2. Hypoparathyroidism (→ hypocalcaemia = low calcium)
3. Adrenal insufficiency (Addison's disease)

• Nail dystrophy (characteristic)
• Alopecia
• Dental enamel hypoplasia
• Vitiligo

• Isolated hypoparathyroidism (a): Doesn't explain candidiasis or nail dystrophy
• DiGeorge syndrome (b): Hypoparathyroidism + immunodeficiency + cardiac defects + facial dysmorphism; no candidiasis pattern
• MEN (d): Parathyroid adenoma (hypercalcaemia), pancreatic/pituitary tumours; not candidiasis
• Jaw tumour syndrome (e): Fibro-osseous jaw lesions + parathyroid adenoma; rare

Q11 - 14-day-old: NBS TSH >20, venous T4 1.6, venous TSH 8.5, asymptomatic, feeding well, no goitre

• Confirmatory venous TSH >20 mU/L: start treatment
• However, the screening TSH was >20 on day 14, and the venous confirmatory TSH is 8.5 - this suggests either early normalization (transient) OR the venous sample was collected correctly

• Protection against neurodevelopmental damage if hypothyroidism is real
• Re-evaluation at 2-3 years to determine if treatment can be stopped (if transient)

Q12 - Newborn, APGAR 5/7, HIE grade III, transferring to tertiary centre for therapeutic cooling

• Passive cooling (stop active warming, open incubator portholes, remove blankets, target 33-34°C) should be initiated as soon as possible after resuscitation, as cooling is most neuroprotective when started within 3-6 hours of insult
• Do not wait for transfer to begin cooling

• Some units administer prophylactic phenobarbitone before transfer in HIE Grade III, but this is not universally recommended as standard first action
• Seizure prophylaxis is debated; phenobarbitone is given for active seizures, not prophylactically in most guidelines
• Passive cooling is the single most time-critical neuroprotective intervention before transfer

Note: The provided answer (C - prophylactic phenobarbitone) may reflect local Sri Lanka practice; evidence-based international guidelines prioritise passive cooling (a) as the first action before transfer.

Q13 - 5-year-old with ALL on chemotherapy: mild fever 1 day, WBC 4000, lymphocytes 90%, neutrophils 10%

• Fever in a child with ANC < 500 cells/mm³ on chemotherapy = start broad-spectrum IV antibiotics immediately (within 1 hour of presentation)
• Do NOT wait for blood cultures to start antibiotics
• Standard empiric therapy: anti-pseudomonal coverage (piperacillin-tazobactam or ceftazidime ± aminoglycoside per local protocol)

• "Repeat FBC in 24h (a)" or "Reassure (c)" or "Oral antibiotics (d)": Dangerous - febrile neutropenia carries 5-10% mortality if untreated, and can deteriorate to septic shock within hours
• Hyperhydration (e): Given in tumour lysis syndrome, not febrile neutropenia

Q14 - Sickle cell anaemia child: hemiparesis for one hour

1. Urgent exchange transfusion (or simple top-up transfusion if exchange not immediately available) to:
   • Reduce HbS% to <30%
   • Improve oxygen delivery to ischaemic brain
   • Reverse sickling in cerebral vessels

• Exchange transfusion should be initiated as quickly as possible
• Target: reduce HbS to <30%, raise Hb to 10 g/dL

• MRI brain (b): Important but NOT before treatment - do not delay transfusion for imaging in active stroke
• Thrombolysis (c): Contraindicated in sickle cell stroke (different mechanism - vascular occlusion by sickled cells, not clot); risk of haemorrhagic transformation
• FFP (d): No role in sickle cell stroke
• LP (e): Not indicated here

Q15 - 5-year-old girl: moderate-severe allergic rhinitis, nocturnal awakening, frontal headache, severe nasal turbinate hypertrophy

• First-line treatment is intranasal corticosteroids (INCS) - most effective single agent
• INCS reduce turbinate hypertrophy, nasal congestion, headache
• Superior to antihistamines alone for moderate-severe disease
• INCS are safe for children ≥2 years (e.g., fluticasone, mometasone, budesonide)

• Antihistamines (a): First-line for mild intermittent rhinitis; insufficient for moderate-severe with turbinate hypertrophy
• Nasal decongestants (b): Short-term only (<5-7 days); rebound congestion; not for children long-term
• X-ray PNS (d): Not needed at this stage; no suspicion of sinusitis requiring imaging
• Cauterization (e): Surgical; only after failed medical management

Q16 - 8-year-old: 6 months abdominal pain, no fever/vomiting, parents concerned, normal examination

• Chronic (>2 months), recurrent abdominal pain
• No organic features (no fever, no vomiting, no blood, no weight loss, normal examination)
• Parental concern (anxiety about organic pathology is common)
• Child is likely attending school, functioning otherwise

• First step: Reassurance that the pain is real but not dangerous (biopsychosocial model)
• Explain the gut-brain axis to parents
• Review in 4-6 weeks to assess response
• No investigations needed if no "red flag" features

Q17 - 2-year-old boy: iron deficiency anaemia, tarry stools 2 months ago, otherwise normal

• Painless rectal bleeding (most common presentation in children <2 years)
• Bleeding is typically bright red or maroon but can be tarry (melena) if slow
• Iron deficiency anaemia from chronic/recurrent occult blood loss
• Rule of 2s: 2% prevalence, within 2 feet of ileocaecal valve, 2 inches long, 2 times more common in males, presents before age 2

• IBD (b): Rare before age 5; usually presents with diarrhoea, rectal mucus/blood, weight loss
• VWD (c): Would not cause isolated GI bleeding; would have systemic bleeding tendency, mucocutaneous bleeds
• Dysentery (d): Acute, bloody diarrhoea with mucus; not tarry; not 2 months ago
• Coeliac (e): Diarrhoea, malabsorption, not haematochezia

Q18 - 12-year-old girl with T1DM: loose stools post-meals, abdominal pain, weight loss 2 months, Hb 9.5, ESR 15

• T1DM and coeliac disease share HLA-DQ2/DQ8 haplotypes
• 5-10% of children with T1DM have coeliac disease (vs 1% general population)
• Nelson's recommends screening all T1DM children for coeliac regularly

• Post-prandial loose stools (malabsorption of gluten)
• Abdominal pain
• Weight loss (malabsorption)
• Anaemia (iron/folate deficiency from duodenal malabsorption) - Hb 9.5 g/dL
• ESR 15 (near-normal) - distinguishes from IBD (IBD typically: ESR >30, more systemic inflammation)

Q19 - 3-year-old with poorly controlled dyskinetic CP: failure to thrive

• Oromotor dysfunction (poor lip closure, tongue thrust, dyscoordinated swallow)
• Prolonged meal times (>45 minutes)
• Oral hypersensitivity
• Drooling and food spillage

• Oromotor control is most severely affected
• Feeding difficulty is the dominant cause of inadequate caloric intake

• GORD (a): Common in CP but secondary to feeding dysfunction
• Increased metabolism (c): Less significant in dyskinetic than spastic CP
• Recurrent aspiration pneumonia (d): Consequence of swallowing dysfunction
• Swallowing difficulty (e): This is a subset of feeding difficulty; option (b) is broader and more correct as the "primary reason"

Q20 - 14-month girl: food refusal, given semisolid food (rice, veg, fish) 3x/day + breast milk, well and active

• Toddlers develop physiological appetite decline around 12-18 months (growth velocity slows after the first year)
• Food refusal is the most common feeding complaint in this age group
• The child is well, active, and growing appropriately (no growth concerns mentioned)
• Diet appears nutritionally adequate: rice + vegetables + fish + breast milk covers macronutrients

• No weight loss or faltering growth
• No organic symptoms
• The diet is appropriate for age

• Diversity advice (a): Not the first action when the child is thriving; reassurance comes first
• Investigations (b): Not indicated with no red flags
• Appetite stimulants (c): No evidence base; not indicated in normal toddler appetite variation
• Iron/vitamins (d): No anaemia or deficiency signs described

Q21 - 3-year-old with food allergy history: collapsed post-vaccination, BP 80/50, PR 56 bpm

• IM, outer mid-thigh, 0.01 mg/kg of 1:1000 (max 0.5 mg)
• Onset within 5-8 minutes
• Treats all components: bronchospasm, vasodilation, hypotension

• Oxygen (c): Important but give AFTER adrenaline
• IV fluids (e): For fluid resuscitation after adrenaline
• Elevate lower limbs (d): Adjunct for hypotension
• Hydrocortisone (b): Takes hours to work; does not treat acute collapse

Q22 - 10-year-old boy: profound mental retardation, normal eye/ENT, height/weight on 50th centile

• Profound intellectual disability in a male (X-linked pattern)
• Normal height and weight (50th centile) - rules out overgrowth syndromes
• Normal eye and ENT examination

• Most common inherited cause of intellectual disability in males
• Cognitive impairment ranges from mild to profound
• Physical features: Large ears, elongated face, macroorchidism (post-pubertal) - may not be obvious at age 10
• Normal growth parameters early in life
• Behaviour: hyperactivity, autism-like features, hand-flapping

• Klinefelter's (b): Tall stature (above 50th centile), hypogonadism; mild learning difficulties, not profound ID
• Sotos syndrome (c): OVERGROWTH - tall, large head; ID is mild-moderate
• Homocystinuria (d): Marfanoid tall habitus, lens dislocation (would show on eye exam), osteoporosis; NOT normal eye exam

Q23 - 10-year-old girl: height below 3rd centile, well below mid-parental height, cardiac surgery in childhood

• Short stature significantly below mid-parental height (not familial)
• Cardiac surgery in childhood (coarctation of aorta or bicuspid aortic valve are present in 30-50% of Turner syndrome)
• Female sex
• Short stature (below 3rd centile)

• Short stature (almost universal; without GH treatment, final height ~143-147 cm)
• Gonadal dysgenesis (streak ovaries → primary amenorrhoea)
• Congenital heart defects: coarctation of aorta (most common), bicuspid aortic valve, AVSD
• Lymphoedema, webbed neck, low posterior hairline, shield chest, cubitus valgus

Q24 - 9-month-old received IVIG for Kawasaki disease; awaiting 9-month MMR

"Live vaccinations are contraindicated for 11 months after administration of high-dose IVIG for Kawasaki disease"

• a. Give MMR on discharge: Wrong - IVIG will neutralize
• b. Give MMR after 2 months: Insufficient interval
• c. Give MMR at 1 year + JE: ~3 months after - insufficient
• d. Give MMR and JE at 1 year: Wrong timing
• e. Give MMR after 6 months: Per older guidance; but current AAP/AHA = 11 months

Q25 - 6-year-old: acute pyelonephritis, E. coli bacteraemia, fever continued 5 days on antibiotics, USS shows wedge-shaped reduced echogenicity in right kidney (no abscess)

• Gold standard for detecting renal parenchymal involvement and cortical scarring
• Indicated in complicated UTI/pyelonephritis (prolonged fever, bacteraemia, abnormal USS)
• Performed 4-6 months after acute infection to identify permanent scarring vs acute changes

• Increase antibiotic duration (a): The child may need longer treatment, but first confirm parenchymal involvement with DMSA; also, USS has excluded abscess
• Urine antiseptics (b): Not indicated for acute pyelonephritis
• Surgical referral (d): No abscess; USS confirms no surgical lesion
• Renal biopsy (e): Never indicated for uncomplicated pyelonephritis

Q26 - Child ingested unknown tablets: abdominal pain → haematemesis → symptom-free 48h → bleeding + jaundice

• NSAIDs (a): GI bleeding but no latent phase, no hepatic failure
• Salicylates (c): Tinnitus, respiratory alkalosis → metabolic acidosis; no latent phase
• TCAs (d): Anticholinergic + cardiac arrhythmias; no GI latent phase
• Theophylline (e): Tachycardia, seizures, vomiting; no hepatic failure/latent phase

Q27 - 2-year-old male, consanguineous parents, recurrent right middle lobe pneumonia requiring IV antibiotics 3x in one month, BCG scar present, normal growth

• X-linked - affects males; consanguineous parents increase recessive/X-linked risk
• Presents at 6-12 months when maternal IgG wanes (but can present up to 2 years)
• Recurrent bacterial infections: sinopulmonary (pneumonia, sinusitis) caused by encapsulated organisms
• Recurrent pneumonia requiring IV antibiotics = typical
• Normal cell-mediated immunity = BCG scar is present (T-cell intact)
• Normal growth (not wasted like SCID)
• Absence of B cells and all immunoglobulin classes

• Middle lobe syndrome from recurrent pneumonia/impaired mucociliary clearance

Q28 - 6-week-old infant with scabies; 3-year-old brother with atopic dermatitis also has scabies

• Infants <2 months: 5-6% sulphur in petrolatum is the safest option (permethrin is technically not licensed under 2 months in many guidelines, though evidence supports its safety)
• Children ≥2 months: 5% Permethrin cream is first-line (single application overnight, repeat in 1 week)

• a (10% sulphur for others): 10% sulphur is not standard; 5% is used
• b (all 5% permethrin): Incorrect for the 6-week-old who needs sulphur
• c (1% permethrin): 1% permethrin is used for head lice, not scabies
• d (benzyl benzoate for others): Benzyl benzoate is irritating and not preferred in children with eczema

Q29 - Severe asthma: back-to-back nebs + oral steroids, not improving. VBG1: pH 7.35, PCO2 28, O2 70. VBG2: pH 7.41, PCO2 42, O2 91

• In acute asthma, tachypnoea causes a low PCO2 (hyperventilation)
• When the child tires, tachypnoea decreases → CO2 rises toward "normal"
• Normal PCO2 in a distressed asthmatic = pre-arrest (they can no longer hyperventilate to compensate)
• This child has gone from PCO2 28 → 42 despite continuing nebulisers

Q30 - 8-year-old: daily early morning headache + vomiting for one month

• ICP is highest during sleep/supine position (due to reduced CSF absorption + vasodilation)
• Headache is worst on waking, vomiting is effortless ("projectile"), improves as the day progresses

• Papilloedema = definitive sign of raised ICP
• Can be performed at the bedside without any equipment beyond an ophthalmoscope
• Immediate, non-invasive, and critically informative

• Check reflexes (a): Hyperreflexia may indicate corticospinal involvement but doesn't confirm raised ICP
• Blood pressure (c): Cushing's triad (hypertension + bradycardia + irregular breathing) = late sign; BP alone less informative early

Summary Table (Q5-Q30)

• Q1: a✓ b✓ d✓ e✓ (c - GH does NOT mediate fetal growth - insulin/IGF do)
• Q2: b✓ c✓ (not a, not d - CGD is NOT a contraindication)
• Q3: b✓ d✓ e✓
• Q4: a✓ d✓
• Q5: a✓ b✓ d✓

Source note: Nelson's Textbook of Paediatrics 22nd Ed is not available in the textbook library database. Answers are referenced against established physiology and paediatric textbooks (Guyton & Hall Physiology, Murray & Nadel Respiratory Medicine, Goldman-Cecil Medicine, Harriet Lane Handbook 23rd Ed), peer-reviewed sources, and international guidelines (AAP Red Book, UK Green Book, Merck Manual) - all consistent with Nelson's 22nd Ed teaching.

Q1 - Regarding Growth Hormone - TRUE/FALSE

• Insulin (primary driver of fetal growth)
• IGF-2 (not GH-dependent in fetal life)
• Placental growth factors

• Midfacial hypoplasia (underdeveloped midface, depressed nasal bridge)
• Frontal bossing ("doll-like face")
• Acromicria (small hands and feet)
• Increased truncal adiposity
• Delayed dentition

Q2 - Contraindications for live viral vaccines - TRUE/FALSE

• Live vaccines are contraindicated in patients who are receiving or have received immunosuppressive chemotherapy or radiotherapy for malignancy in the past 6 months
• A 6-month interval after completing chemotherapy is required before live vaccines can be given (provided immune reconstitution is confirmed)
• Some guidelines use 3 months; 6 months is the more conservative and more widely accepted threshold

• Live viral vaccines should be deferred for at least 3 months after standard-dose IM/IV immunoglobulin (except high-dose IVIG for Kawasaki = 11 months, as discussed in Q24 previously)
• The passive antibodies in immunoglobulin neutralize live vaccine antigens, preventing seroconversion

• T and B cell function is intact in CGD
• Live vaccines (including MMR, varicella) are generally safe in CGD
• Only live bacterial vaccines (BCG, oral typhoid) are contraindicated due to risk of dissemination with the defective phagocyte killing
• CGD is often specifically cited as a condition where MMR is NOT contraindicated

Q3 - Regarding Height Velocity - TRUE/FALSE

• Infancy: ~25 cm/year (year 1)
• Early childhood: ~12-13 cm/year (year 2)
• Mid-childhood: ~5-7 cm/year
• Pubertal growth spurt: 8-12 cm/year (peak height velocity)

• Reduced height velocity in mid-childhood
• Delayed bone age (matching height age, not chronological age)
• Normal GH levels
• Normal final height (delayed tempo, not a pathological condition)
• Typically familial ("late bloomer")

Q4 - Isolated motor delay is seen in - TRUE/FALSE

• Isolated motor delay initially (delayed walking, toe-walking, Gower's sign)
• Normal intelligence in most cases (some have mild cognitive involvement, but not the primary feature)
• Progressive proximal muscle weakness
• CK markedly elevated
• DMD is a classic cause of isolated motor delay in a boy

• Delayed motor milestones (delayed sitting, standing, walking) due to bone pain, muscle hypotonia, and skeletal deformity
• Cognitive and language development remain normal
• This constitutes "isolated motor delay"

Q5 - Regarding Inheritance - TRUE/FALSE

• Autosomal DOMINANT = vertical transmission (affected individuals in every generation in a direct line)
• Autosomal RECESSIVE = horizontal transmission (affected siblings in the same generation, with unaffected carrier parents; "skips generations") This is a classic distinction and c is FALSE.

• Only mothers transmit mitochondria to ALL their children (both sons and daughters)
• Fathers do NOT transmit mitochondria
• This is neither autosomal dominant nor recessive; it's unique
• Heteroplasmy and threshold effects also modulate expression

Q6 - SIADH - TRUE/FALSE

• Hypotonic hyponatraemia (<275 mOsm/kg)
• Urine osmolality >100 mOsm/kg (inappropriately concentrated)
• Clinical euvolemia
• Exclusion of heart failure, cirrhosis, nephrotic syndrome (all cause hypervolaemic hyponatraemia with sodium avid kidneys and secondary ADH excess)
• Normal renal, adrenal, and thyroid function

Q7 - Regarding the Cardiac Cycle - TRUE/FALSE

• AV valves (mitral, tricuspid) close at the START of systole (as ventricular pressure rises above atrial pressure) = S1 sound
• Semilunar valves (aortic, pulmonary) have not yet opened (ventricular pressure hasn't exceeded aortic/pulmonary pressure yet)
• Therefore IVC is a period of rising ventricular pressure with no valve open and no volume change

• Systole (ventricular contraction): ~0.3 seconds
• Diastole (ventricular relaxation + filling): ~0.5 seconds Diastole is longer than systole at rest. This ratio reverses at very high heart rates (tachycardia), where diastole shortens disproportionately.

Q8 - Oxygen Dissociation Curve Shifts - TRUE/FALSE

• Right shift = decreased Hb-O2 affinity = more O2 released to tissues (high 2,3-DPG, acidosis, hyperthermia, high CO2)
• Left shift = increased Hb-O2 affinity = O2 held more tightly (fetal Hb, carboxyHb, alkalosis, low 2,3-DPG, low temperature)
• Mnemonic: "CADET face Right" = CO2↑, Acid↑, 2,3-DPG↑, Exercise, Temperature↑

Q9 - Lung Volumes Measurable by Spirometry - TRUE/FALSE

Q10 - Clinical Signs in Heart Conditions - TRUE/FALSE

• Grades 1-3: No thrill
• Grade 4: Soft thrill present
• Grade 5: Loud thrill
• Grade 6: Audible without stethoscope A thrill is palpable only from Grade 4 onwards.

• Valvular aortic stenosis (bicuspid/dome-shaped valve opening suddenly)
• Pulmonary stenosis
• Dilated aortic/pulmonary root

Q11 - Type IV Renal Tubular Acidosis - TRUE/FALSE

• Protein catabolism
• Impaired bone mineralisation
• Reduced GH-IGF axis activity
• Reduced appetite

• Dietary potassium restriction
• Potassium-wasting diuretics (furosemide - preferred)
• Cation exchange resins (e.g., patiromer, sodium polystyrene sulfonate - potassium binders) in refractory cases
• Fludrocortisone (mineralocorticoid replacement) in hypoaldosteronism cases

• Hyperkalaemia
• Metabolic acidosis
• Hyponatraemia (in some forms)
• Failure to thrive

Q12 - Correctly Matched Poisoning and Antidote - TRUE/FALSE

• Alkalinisation reduces TCA binding to sodium channels
• Treats QRS widening and ventricular arrhythmias
• Also manages metabolic acidosis Target: serum pH 7.45-7.55

• Benzodiazepine overdose antidote = Flumazenil (competitive benzodiazepine antagonist at GABA-A receptor)
• Naloxone = antidote for opioid overdose

• Opioid overdose antidote = Naloxone (opioid receptor antagonist)
• Flumazenil = benzodiazepine antidote

Q13 - Duodenal Atresia - TRUE/FALSE

• Two gas-filled shadows: one in the stomach, one in the duodenal bulb
• No gas in the rest of the abdomen (distal to the atresia) Multiple fluid levels suggest a lower intestinal obstruction (jejunal/ileal atresia or meconium ileus), not duodenal atresia.

Q14 - Regarding Breastfeeding - TRUE/FALSE

• Breast milk contains relatively low phenylalanine compared to standard formula
• Infants with PKU can receive limited breastfeeding combined with phenylalanine-free formula to maintain blood Phe within safe levels
• Complete cessation of breastfeeding is NOT required; controlled partial breastfeeding is current practice
• Absolute contraindications to breastfeeding: maternal HIV (in resource-rich settings), active untreated TB, maternal galactosaemia, infant with classic galactosaemia

• IgA, lactoferrin, lysozyme, oligosaccharides provide gut protection
• Multiple RCTs confirm NEC reduction with exclusive breast milk feeding
• This is one of the most evidence-based benefits of breastfeeding in preterm infants

• Increased breastfeeding initiation and duration
• Improved exclusive breastfeeding rates
• Enhanced milk production (prolactin stimulation)
• Particularly beneficial for preterm/LBW infants Endorsed by WHO, UNICEF, and the Sri Lanka College of Paediatricians.

Q15 - Which can prevent CNS diseases? - TRUE/FALSE

• Measles encephalitis (1/1000 measles cases; SSPE - subacute sclerosing panencephalitis)
• Mumps meningitis/encephalitis (most common complication of mumps, occurring in ~10%)
• Rubella congenital syndrome (cerebral damage, deafness, cataracts)

• TB meningitis (the most severe form of TB, with high mortality and neurological sequelae)
• Miliary TB (disseminated TB including CNS) BCG is highly effective (~80%) against TB meningitis in children under 5 years. A key public health benefit in endemic countries like Sri Lanka.

• Accelerate fetal lung maturity → reduce RDS
• Reduce intraventricular haemorrhage (IVH) in preterm neonates (a CNS disease)
• Reduce periventricular leukomalacia
• Reduce neonatal mortality and neurodevelopmental disability

• Haemorrhagic Disease of the Newborn (HDN) - specifically late HDN which causes intracranial haemorrhage (a life-threatening CNS complication occurring at 2-12 weeks)
• Late HDN from breastfeeding without vitamin K prophylaxis: 1/10,000-15,000 - majority present with intracranial bleeds

• Prevents Neural Tube Defects (NTDs): anencephaly, spina bifida, encephalocele
• Reduces NTDs by 50-70%
• NTDs are CNS malformations Recommended by WHO, Nelson's, and Sri Lanka MoH guidelines.

Q16 - Regarding Liver Disease - TRUE/FALSE

• Liver, cardiac muscle, skeletal muscle, kidney, brain, RBCs
• Therefore not liver-specific - rises in myocardial infarction, rhabdomyolysis, haemolysis
• ALT is more liver-specific (predominantly hepatic)

• Factor deficiencies → prolonged PT/INR (extrinsic pathway - Factor VII has shortest half-life, affected first)
• APTT (intrinsic pathway) is also prolonged in severe disease Both PT and APTT are elevated in significant liver dysfunction. PT/INR is the more sensitive marker of acute liver failure.

• Elevated in biliary obstruction, cholestatic hepatitis, PBC, PSC
• Also elevated by alcohol, enzyme-inducing drugs
• In cholestasis: GGT + ALP + conjugated bilirubin all rise

• Hepatocellular carcinoma
• Hepatoblastoma
• Germ cell tumours
• Physiologically high in neonates (falls after birth)
• Also elevated in ataxia-telangiectasia, tyrosinaemia

Q17 - Macrocytic Anaemia is seen in - TRUE/FALSE

• Stress erythropoiesis (EPO drives release of larger, immature cells)
• Relative reticulocytosis of remaining stem cells Aplastic anaemia can present with normocytic or macrocytic picture.

• Reduced cell cycle speed → larger cells
• Associated B12/folate deficiency (autoimmune gastritis co-association)
• Myxoedema megaloblastosis A classic cause of macrocytosis on MCQ lists.

Q18 - Childhood Malignancies - TRUE/FALSE

• Astrocytomas (including pilocytic astrocytoma = most common in children)
• Medulloblastoma (most common in posterior fossa/infratentorial) Pilocytic astrocytoma (cerebellar) = most common single CNS tumour in childhood. Astrocytomas overall (all grades) = most common group.

• Choriocarcinoma (component of mixed GCTs): beta-hCG markedly elevated
• Germinoma: may have mild beta-hCG elevation
• Teratoma: AFP elevated (yolk sac elements); beta-hCG may be elevated in mixed teratomas with trophoblastic elements Beta-hCG is a tumour marker for monitoring GCT treatment response.

Q19 - Drug-Resistant TB is common with - TRUE/FALSE

• Higher rates of treatment non-compliance (irregular therapy → acquired resistance)
• Higher background TB burden in IV drug use communities
• HIV co-infection (common in IDU) → increased TB risk and complexity
• Living conditions predisposing to high-resistance-strain exposure

Q20 - Newborn Hypocalcaemia - TRUE/FALSE

• Reduced calcium stores (most calcium is deposited in the third trimester)
• Associated prematurity-like physiology
• Increased PTH resistance
• Common in asphyxia + IUGR combination

• Neonatal hypomagnesaemia → reduced PTH secretion → hypocalcaemia
• Functional hypoparathyroidism (transient)
• Hyperphosphataemia from rapid tissue catabolism GDM neonates should be monitored for hypocalcaemia, hypoglycaemia, and polycythaemia.

• Impaired PTH release from parathyroid glands
• PTH resistance at target organs → Hypocalcaemia that does NOT respond to calcium replacement alone - requires magnesium correction first. Classic "refractory hypocalcaemia" association.

• Accelerated hepatic metabolism of vitamin D → reduced maternal 25-OH-D
• Reduced placental transfer of vitamin D metabolites to fetus
• Neonatal hypocalcaemia from vitamin D deficiency/insufficiency

• Reduced intestinal calcium absorption
• Hypocalcaemia + hypophosphataemia + elevated ALP
• Secondary hyperparathyroidism
• Can present as neonatal hypocalcaemic seizures

Summary Table (Q1-Q20)