Weight loss in children and adolescents — formative SAQs

SAQ 1 (10)

A 15-year-old has lost 10 kg (about 12% of premorbid weight) over five months. BMI remains on the 35th percentile. Resting heart rate is 46/min with orthostatic dizziness. The young person describes fear of fatness and compulsive running. Caregivers thought the BMI chart was reassuring. [1] [2]

1. State the problem representation and explain why BMI percentile alone is insufficient. (3) [1] [2]
2. List immediate medical assessment priorities and admission-oriented risk features. (3) [2] [6]
3. Outline a stepwise management plan including refeeding awareness and multidisciplinary care. (4) [2] [4] [1]

Model answer

Problem representation. Adolescent with large percentage weight loss, bradycardia and body-image-driven restriction — medically significant restrictive eating (atypical anorexia pattern possible despite non-low BMI). BMI band does not cancel percent loss or physiology. [1] [2]

Medical priorities. ABCDE if unwell; resting HR, orthostatic vitals, temperature; electrolytes including phosphate/Mg/K; ECG as indicated; suicide/safety screen; quantify percent loss. Admission-oriented features: bradycardia, orthostasis, electrolyte abnormality, medical instability, suicidality, failed outpatient care, rapid ongoing loss. [2] [6]

Plan. Medical stabilisation pathway if unstable; supervised nutrition restart with refeeding monitoring principles (PO4/K/Mg); dietetic and family-based/mental-health pathway in parallel; clear follow-up and safety-net; avoid shaming. [2] [4] [1]

SAQ 2 (10)

A 10-year-old has lost 2.5 kg over 4 weeks with polyuria, polydipsia and new bedwetting. Another child in the same clinic has weight loss with nocturnal diarrhoea and mouth ulcers. [3] [5]

1. For the first child, what is the critical immediate test and why? (3) [3]
2. For the second child, what organic pathway ranks highly and what next steps follow? (3) [5]
3. Explain how intentional restriction and organic disease must both stay open in mixed presentations. (4) [1] [5]

Model answer

First child. Point-of-care glucose now (with DKA assessment if unwell). Polyuria–polydipsia–weight loss is new diabetes until proven otherwise; delay risks DKA progression. [3]

Second child. Inflammatory bowel disease ranks high with nocturnal stools, oral ulcers and weight loss. Next: directed history/examination, inflammatory markers/faecal tests as indicated, and gastroenterology pathway rather than endless symptomatic labels. [5]

Both open. Restriction can coexist with organic disease (pain-driven intake drop in IBD; body-image issues after illness). Keep glucose/gut/endocrine red flags active even when psychology is obvious, and keep mental-health support active even when an organic diagnosis is found. [1] [5]