Pica and rumination disorder OSCE — harm gate, discriminator and behavioural plan

Station objectives

1. Run the harm gate before assigning a behavioural label — lead poisoning, bezoar, helminth infection, malnutrition and weight loss come first. [2] [12]
2. Distinguish pica from normal developmental mouthing and rumination from reflux, cyclic vomiting and purging using the effortless, post-prandial, non-nauseated quality. [9]
3. Treat reversible drivers — iron and zinc deficiency, the lead source, infection — and re-assess the behaviour as they resolve. [1]
4. Co-build a behavioural replacement plan — supervision, response prevention and enrichment for pica; diaphragmatic breathing and habit reversal for rumination — and refuse punitive restraint. [6]

Candidate brief

You are the paediatric doctor in a general paediatric clinic. You have 10 minutes for Station A (three-year-old, paint-chip eating, pre-1970 housing, behavioural regression) and 12 minutes for Station B (fourteen-year-old, effortless post-prandial regurgitation, re-chewing, weight loss, normal endoscopy). Examiners score harm-gating, discriminator framing, evidence-based behavioural planning, and partnership language with worried families. [1] [2]

Station A — Toddler with paint-chip eating and behavioural regression

Setup: A three-year-old living in housing built before 1970 has been eating paint chips for four months. Over recent weeks the child has become irritable and has stopped using several words they previously had. The parent wonders if it is just a phase. Growth is stable. [2] [12]

Expected actions:

• Recognise irritability and loss of words as red flags for lead toxicity and run the harm gate before reassuring. [12]
• Define pica aloud: non-food, non-nutritive ingestion for at least one month that is not developmentally or culturally appropriate. [1]
• Order targeted tests — venous blood lead, full blood count, iron studies, zinc — and identify the lead source with public health involvement. [2] [12]
• Plan environmental source removal plus behavioural therapy: supervision, response prevention, redirection, environmental enrichment, positive reinforcement — not punitive restraint. [1]
• Give an explicit safety-net: return for abdominal pain, regression, neuro signs or rising lead; admit for encephalopathy or chelation. [12]

Station B — Adolescent with effortless regurgitation and weight loss

Setup: A fourteen-year-old describes food coming back up within minutes of meals for three months. There is no nausea and no retching; she re-chews and re-swallows or spits it out. Oesophagogastroduodenoscopy was normal. She has lost weight and is missing school. [6] [9]

Expected actions:

• Give the one-sentence problem representation and justify rumination over reflux, cyclic vomiting, gastroparesis and purging using the effortless, post-prandial, non-nauseated quality. [9]
• Confirm growth failure, exclude structural obstruction, and avoid repeating a normal endoscopy; use high-resolution impedance, pH or manometry where available to show the post-prandial non-acidic pattern. [8] [9]
• Explain the somato-visceral reflex mechanism in family-friendly language — an involuntary abdominal-wall contraction raises intragastric pressure — and frame it as a disorder of gut–brain interaction. [9]
• Start diaphragmatic breathing with a trained therapist as first-line, augmented by habit reversal and cognitive-behavioural therapy where needed, often within an intensive outpatient protocol. [6] [7]
• Screen for psychosocial stressors and safeguarding without dismissing the gut; coordinate dietetics, psychology and school liaison. [7]

Marking anchors

Clear pass: runs the harm gate before the label; defines pica and rumination aloud and separates each from its mimics using the effortless, non-nauseated discriminator; orders targeted tests matched to the substance and the behaviour; names diaphragmatic breathing as first-line for rumination and supervision plus response prevention for pica; refuses punitive restraint and forced re-feeding; gives a concrete safety-net and a coordinated multidisciplinary plan. [2] [6] [9] Borderline: frames the behaviour correctly but defers the harm gate, offers vague therapy, or avoids the safety-net conversation. Fail: reassures on a phase when growth or neurology is regressing; misses iron or lead; confuses rumination with reflux or purging; prescribes punitive restraint or forced re-feeding; orders endless repeat endoscopies; ignores safeguarding when stress precedes the behaviour. [1] [6]

Debrief pearls

• The question that guards the harm gate: is there a complication driving this — lead, bezoar, helminth, malnutrition, weight loss? [2] [12]
• The discriminator you can say aloud: effortless, post-prandial, no nausea, no retching. [9]
• Treat the driver and re-assess: deficiency-driven pica often settles as iron or zinc stores recover. [1]
• Replace the behaviour, never restrain it — diaphragmatic breathing for rumination, supervision and enrichment for pica. [6] [15]