Avoidant restrictive food intake disorder — branching viva

Stem

The examiner will test whether you can hold the ARFID versus anorexia nervosa boundary under pressure, keep the child medically safe, choose pattern-matched evidence-based therapy, and refuse both coercion and dismissal. [3] [2]

Branch 1 — First presentation and the boundary

Examiner: A 15-year-old has restricted her intake for four months, lost 7 kg, and her BMI is now just above the 0.4th centile. Her periods have stopped. What do you do first, and what is the most important diagnosis to exclude? [1]

Strong answer: See her alone, state conditional confidentiality with its lawful limits, and take a focused eating and psychosocial history. The most important diagnosis to exclude is anorexia nervosa, because the service pathway differs. Screen explicitly for drive for thinness, fear of weight gain, body-image disturbance, purging and compulsive exercise. If those are absent and the restriction is driven by sensory sensitivity, an aversive event, or low appetite with associated harm, the diagnosis is ARFID — but because some patients cross over, I screen for weight and shape overvaluation at every future contact. The amenorrhoea and low BMI raise the stakes regardless of which restrictive eating disorder this is; she needs medical safety assessment now. [2] [3]

Branch 2 — Medical safety and refeeding

Examiner: Her BMI is falling, her heart rate is 45, and she is clinically malnourished. What is your immediate management? [7]

Strong answer: This is a medical emergency. Admit for stabilisation and refeeding surveillance. Refeeding syndrome is the preventable killer — restore nutrition gradually under phosphate, magnesium and potassium surveillance with supplementation per local refeeding protocol, because the shift from catabolism to anabolism drives electrolytes intracellularly. An electrocardiogram is indicated for the bradycardia to assess cardiac risk. I pause any graded-exposure work until she is medically stable — you cannot desensitise a child who needs refeeding. Whether this turns out to be ARFID or anorexia nervosa, the medical stabilisation is identical at this stage, and the diagnostic pathway runs in parallel. [7]

Branch 3 — Evidence-based therapy

Examiner: Once she is stable, how do you treat the ARFID? [4]

Strong answer: The leading evidence-based therapy is cognitive-behavioural therapy for ARFID, CBT-AR — a manualised treatment built around psychoeducation, regular eating, and graded exposure matched to the driver mechanism. Thomas and colleagues established its feasibility and preliminary effects, and Burton-Murray made it practicable. For a fear subtype I use systematic desensitisation; for sensory selectivity, sensory-based exposure; for low interest, interoceptive exposure and scheduled eating. For a younger child I would consider an FBT adaptation empowering the parents to lead non-coercive exposure at home. I protect nutrition with dietetics throughout, treat comorbid anxiety in parallel, and set shared functional goals rather than a perfect-plate target. The Canadian practice guidelines support a family-involved, evidence-informed approach. [4] [5] [6]

Branch 4 — Coercion and autism

Examiner: Now an 8-year-old with autism, six accepted brand-specific foods, weight crossing two centiles down, and ninety-minute force-feeding battles. What do you say to the mother? [3]

Strong answer: First I validate her — she has been trying to protect his growth, and that care is real. Then I explain that force-feeding amplifies the avoidance loop: when every meal is a battle, the child learns that food equals threat and loss of control, intake collapses, and the restriction worsens. Stopping coercion is treatment, not giving up. The first prescription tonight is to stop force-feeding and restore a calm meal structure of three meals and two to three snacks with no pressure. Then we build the plan: dietetics to close energy and micronutrient gaps within his accepted foods, CBT-AR or an FBT adaptation with sensory-based exposure changing one variable at a time, neurodiversity-affirming goals rather than a demand for a neurotypical plate, and surveillance for micronutrient emergencies such as scurvy that are documented in autistic ARFID. Growth, swallow and swallow-safety still need checking even when the pattern is clearly sensory. [3]

Branch 5 — Crossover challenge

Examiner: Six months later the adolescent says she has started wanting to be thinner and is exercising to burn off the supplements. [8]

Strong answer: This is diagnostic crossover toward anorexia nervosa — the emergence of weight and shape overvaluation and compensatory exercise. I reroute her to the specialist eating-disorder pathway immediately, because the therapy, the medical-risk profile, and the service differ. I reassess medical safety — bradycardia, electrolytes, refeeding risk — because anorexia nervosa carries its own acute risks. I do not abandon the ARFID work if sensory or aversive features persist, but the primary frame and pathway have changed. I document the reassessment and reasoning, and tell her and her family what has changed and why. [8]

Branch 6 — Tube exit plan

Examiner: A child with severe low-weight ARFID has been on nasogastric feeds for three months. The team wants to keep going. What is your view? [7]

Strong answer: A feeding tube is a bridge with an exit plan, never an endpoint. Bryson and Lange show that low-weight ARFID carries persistent morbidity, so I want a defined re-intake goal, a weaning schedule, and a review date, with structured psychological therapy running throughout so the child is building oral intake while the tube is reduced. Prolonged tube dependence without a plan creates iatrogenic dependence and family disempowerment. If outpatient care has failed, this is an indication for an intensive day-program or inpatient rehabilitation pathway that combines medical, nutritional and psychological care to get the tube out safely. [7]

Examiner extras

• Hold the boundary with anorexia nervosa early and at every contact — it is the single highest-yield move. [2]
• Refeeding syndrome kills — restore gradually under electrolyte surveillance. [7]
• CBT-AR is pattern-matched; name the mechanism and the exposure type. [4]
• Stopping coercion is treatment, not permissiveness. [3]
• A tube without an exit plan is iatrogenic dependence. [7]
• Never let the ARFID label stop you thinking when a new red flag appears. [8]