Failure to thrive and faltering growth: diagnostic approach — formative SAQs

SAQ 1 (10)

A 5-month-old breastfed infant has fallen from the 50th to the 9th weight centile over 8 weeks. Length is tracking the 25th centile. The infant feeds for 45 minutes each side, has three wet nappies daily, and looks thin but interactive. Examination is otherwise normal. [1] [3]

1. Define the problem representation and explain why a single low centile is not enough. (3) [1] [6]
2. List the four mechanism buckets and state the most likely primary mechanism here. (3) [1]
3. Outline your immediate assessment steps and first-line management plan, including follow-up. (4) [1] [2] [3]

Model answer

Problem representation. Serial weights show falling velocity after prior higher tracking — faltering growth / FTT pattern, not a final organ diagnosis. Definitions vary; velocity and pattern matter more than one percentile alone. [1] [6]

Mechanisms. Inadequate intake; increased losses; increased needs; ineffective utilisation. Most likely primary mechanism: inadequate milk transfer/intake (long feeds, few wet nappies, weight falling faster than length). [1] [3]

Plan. Re-measure and re-plot; assess stability; observe a feed; lactation support; ensure adequate intake (supplementation plan if needed, intentional and reviewed); directed tests only if red flags; early weight review (days–2 weeks); safety-net fewer wet nappies, lethargy, vomiting. [1] [2]

SAQ 2 (10)

A 2-year-old presents with severe wasting, cool peripheries and reduced playfulness. Caregivers give inconsistent feeding histories and have missed multiple reviews. You plan admission. [4] [5]

1. What immediate threats do you assess before debating chart cut-offs? (3) [1]
2. Explain refeeding risk principles as nutrition restarts. (3) [4]
3. How do medical care and safeguarding run in parallel? (4) [5]

Model answer

Threats. Hydration, glucose risk, hypothermia, cardiorespiratory status, infection/sepsis concern, interaction/consciousness. Chart debate waits if unstable. [1]

Refeeding. After prolonged undernutrition, insulin-driven shifts can drop phosphate, potassium and magnesium; fluid balance can swing. Restart nutrition in a supervised, monitored way using local protocols informed by ASPEN consensus principles — not an uncontrolled calorie binge. [4]

Safeguarding parallel. Stabilise and feed under supervision; document factual inconsistencies and multi-parameter faltering; escalate per local child-protection pathways; avoid humiliating language; do not assume every FTT case is neglect, but do not ignore red flags. [5]