The 15-Year-Old Who Won't Eat
A 15-year-old girl is brought by her parents to an outpatient clinic. She has lost 9 kg over 5 months and now weighs 38 kg at a height of 165 cm (BMI approximately 14.0). Her mother reports she has become 'obsessed' with 'clean eating,' refuses family meals, and exercises for 90 minutes each morning before school. She has not had a menstrual period for 4 months; her previous cycles were regular. On examination she is bradycardic at 48 bpm, hypotensive at 88/54, and has cold extremities and fine lanugo hair. She is polite, denies being thin, and says she 'just wants to be healthy.' She insists she is 'fine' and refuses to consider any change. The parents are tearful and ask whether she can be treated as an outpatient.
1. Using the clinical data, justify whether this patient meets criteria for inpatient admission, and identify the specific findings that drive your decision.
Read the worked answer
This patient has severe anorexia nervosa with medical instability and meets criteria for inpatient (medically monitored) admission. The drivers are objective, not merely the low weight:
- BMI ~14.0 - severe malnutrition; many services use BMI <15 or rapid weight loss as an admission threshold.
- Bradycardia 48 bpm - significant; resting bradycardia <50 in an adolescent with malnutrition signals risk of arrhythmia and is a recognized admission criterion.
- Hypotension 88/54 - orthostatic instability risk; check lying/standing BP and pulse.
- Amenorrhea 4 months - hypothalamic suppression consistent with low energy availability.
- Lanugo, cold extremities - signs of significant starvation physiology.
- Rapid weight loss (9 kg in 5 months) and excessive compulsive exercise - high risk of refeeding syndrome and cardiac events.
- Lack of insight and refusal - she cannot safely be managed with outpatient meal support alone at this point.
The decision is not based on weight alone; it is the combination of low BMI, hemodynamic instability, and poor insight that makes outpatient management unsafe. She needs cardiac monitoring, electrolyte monitoring, and a structured refeeding protocol with a multidisciplinary team.
2. The family asks about refeeding. Explain the main risk, how you would prevent it, and why starting 'gently' matters.
Read the worked answer
The main risk is refeeding syndrome: reintroduction of carbohydrate drives insulin release, which shifts phosphate, potassium, and magnesium intracellularly, causing hypophosphatemia, hypokalemia, and hypomagnesemia. This can precipitate arrhythmias, heart failure, seizures, rhabdomyolysis, and sudden death.
Prevention:
- Start low and go slow - begin at a modest caloric intake (e.g., around 10–15 kcal/kg/day in a severely malnourished patient, individualized) and advance gradually over days.
- Check electrolytes (especially phosphate, potassium, magnesium) before starting and daily during early refeeding.
- Prophylactic or early phosphate replacement per protocol, plus potassium and magnesium repletion.
- Thiamine supplementation before or with feeding.
- Continuous cardiac monitoring in the first days, given her bradycardia.
- Monitor for edema, tachycardia, and fluid overload.
Why 'gently' matters: the malnourished body has depleted intracellular stores and cannot buffer a rapid influx of glucose and electrolytes. Aggressive refeeding can kill a patient who appears to be improving, so the pace is a safety parameter, not a matter of preference.
3. The parents ask about 'just getting her to eat at home.' How do you frame the rationale for family-based treatment versus individual therapy at this stage?
Read the worked answer
At this stage, the priority is nutritional rehabilitation and medical stabilization, and the evidence-based first-line psychological treatment for adolescents with anorexia nervosa is family-based treatment (FBT, the 'Maudsley approach'), delivered once the patient is medically safe.
Rationale to give the parents:
- Anorexia nervosa in adolescents is ego-syntonic - the patient does not experience the behavior as a problem, so individual insight-oriented therapy alone is often ineffective early on.
- FBT empowers parents to take charge of refeeding in a structured, non-blaming way, which matches the developmental stage and the family's motivation.
- 'Just getting her to eat at home' is not a plan - it lacks structure, monitoring, and a protocol for the compulsive exercise and the distorted beliefs, and it risks a dangerous rate of refeeding without medical oversight.
- Individual therapy is not excluded; it may be added later, but it is not a substitute for nutritional rehabilitation and family involvement in an adolescent with severe malnutrition.
Frame it as: 'We are not taking over your role as parents - we are giving you a structured, evidence-based framework to do what you are already trying to do, safely.'