Newborn bloodspot screening for inherited metabolic disease and follow-up — formative SAQs

SAQ 1 — Critical TSH in a well neonate (20 marks, ~15 minutes)

A 6-day-old term infant is at home and feeding well. The bloodspot laboratory reports a critical elevated TSH. Parents are anxious and ask whether review can wait until next week because “he looks perfect.” [3]

Questions

1. Define screening versus diagnosis in this setting and state the result-state urgency. (4 marks) [14]
2. Outline your same-day management steps, including confirmatory testing and treatment principles for congenital hypothyroidism. (6 marks) [3]
3. Explain the pathophysiology that makes well appearance an unsafe reassurance. (5 marks) [3]
4. Write the safety-net and handover content you would document. (5 marks) [17]

Model answer (must-hit)

1. Screen positive/presumptive positive is not a final diagnosis; it requires confirmatory free T4/TSH and a defined pathway. Critical markers need same-day contact, not routine delay. [3] [14]
2. Phone family; arrange urgent clinical review and confirmatory thyroid function tests; start levothyroxine on the current protocolised pathway with endocrine follow-up; do not wait for developmental signs. State you use local dosing protocol rather than inventing figures. [3]
3. After birth, maternal/placental thyroid support falls. Low thyroxine injures the developing brain while growth and feeding may still look acceptable. [3]
4. Document result state, tests done, treatment started or timed, who owns follow-up, contact numbers, and advice for poor feeding, lethargy or jaundice concerns. [17]

SAQ 2 — Incomplete card and possible galactosaemia (20 marks, ~15 minutes)

A 48-hour-old neonate is prepared for rural discharge. The bloodspot card is marked unsatisfactory. A second programme message later the same day raises possible classic galactosaemia while the infant is on milk feeds and still looks well. [10] [17]

Questions

1. What does an unsatisfactory card mean operationally? (4 marks) [17]
2. What immediate feed and clinical actions are required for possible classic galactosaemia? (6 marks) [10]
3. How do early discharge and rural distance change logistics without changing principles? (5 marks) [17]
4. How would you counsel parents using screen-versus-diagnosis language? (5 marks) [14]

Model answer (must-hit)

1. Unsatisfactory = incomplete screen until a valid repeat is collected and processed; not a clear result. Name an owner. [17]
2. Stop lactose/galactose-containing feeds; use suitable non-galactose formula; arrange confirmatory testing; assess for jaundice, liver dysfunction, coagulopathy and sepsis; escalate if unwell. [10]
3. Prefer complete critical actions before travel; if transfer needed, plan destination and transport; do not rely on vague “see GP sometime.” [17]
4. Explain this is a screening alert needing confirmation; explain why feeds change now; avoid saying the baby definitely has lifelong disease before confirmation; invite teach-back. [10] [14]