Fatigue and lethargy in children and adolescents — formative SAQs

SAQ 1 (10)

A 4-month-old is brought to ED. Parents say the baby is "very tired" and has fed poorly for 12 hours. Temperature is 38.6°C. The infant has reduced eye contact and a weak cry. [4]

1. Distinguish fatigue from lethargy in this age group and state your immediate priority. (3) [4]
2. List five must-not-miss causes of infant lethargy. (3) [1]
3. Outline your first 10 minutes of assessment and management principles (no invented drug doses). (4) [4] [6]

Model answer

Fatigue vs lethargy. Fatigue implies reduced energy with preserved interaction. This infant has reduced interaction — lethargy emergency language. Immediate priority is ABCDE threat assessment, not a chronic-fatigue interview. [4]

Must-not-miss examples. Sepsis; meningitis/encephalitis; hypoglycaemia; cardiac failure/myocarditis; raised intracranial pressure or trauma/non-accidental injury; severe anaemia; metabolic crisis; intoxication. (Any five high-threat items scored.) [1]

First actions. Open assessment of airway, breathing, circulation, disability with glucose, exposure; senior help; sepsis-capable pathway if infection likely; parallel history; early escalation if local capability exceeded; clear safety-net only after stabilisation and disposition decision. [4] [6]

SAQ 2 (10)

A 13-year-old has four months of fatigue, unrefreshing sleep, snoring, heavy menses and post-exertional crashes after light PE. Examination shows preserved interaction, mild pallor and large tonsils. [2] [3] [5]

1. Give a one-sentence problem representation and a prioritised differential of four items. (4) [2] [3] [5]
2. Which first-line investigations are reasonable and why? (3) [3]
3. Outline stepwise management including what you would avoid if ME/CFS features dominate after exclusion. (3) [2] [6]

Model answer

Representation. "Thirteen-year-old with months of fatigue, preserved interaction, snoring, heavy menses and post-exertional crashes — concurrent OSA risk, iron deficiency, post-viral/ME-CFS pattern and mood load until sorted." Differential: OSA; iron deficiency/anaemia; prolonged post-viral/ME-CFS pattern; mood/sleep debt; (keep malignancy red flags reviewed). [2] [3] [5]

Tests. FBC and iron studies; consider further directed tests from history; sleep/ENT pathway assessment for OSA; not a random mega-panel. [3] [5]

Management. Treat iron deficiency and menstrual contribution; refer OSA risk; energy management and school plan; safety-net; avoid forced graded exercise as default if post-exertional exacerbation dominates after directed exclusion. [2] [3] [6]