Nocturnal enuresis — branching viva

Station opening

Examiner: "Define nocturnal enuresis and classify it for me." [1]

Strong candidate (must-hit)

• Defines nocturnal enuresis as intermittent involuntary voiding during sleep in a child aged five years or older, per the International Children's Continence Society, and splits it first into monosymptomatic (no daytime lower urinary tract symptoms) versus non-monosymptomatic (daytime symptoms present), then into primary (never dry for six months) versus secondary (relapse after at least six months of dryness); explains that the daytime history is the first branch because it decides whether the child flows to alarm or desmopressin or to daytime evaluation first. [1]

Weak candidate

• "It is when a child wets the bed; I would just call it bedwetting and treat it." [1]

Branch A — The 7-year-old with monosymptomatic bedwetting and a family history

Examiner: "A 7-year-old wets the bed most nights, is dry by day, and his father was enuretic until 11. How do you assess and treat him?" [4] [5]

Strong

• Confirms monosymptomatic primary enuresis on the daytime history; assesses with a voiding and fluid diary and urinalysis rather than routine imaging; explains that the family pattern is autosomal dominant with about a 44 per cent risk if one parent was enuretic; offers first-line therapy with the alarm for a motivated family wanting durable dryness (about two-thirds become dry) or desmopressin where nocturnal polyuria is the driver or a rapid result is needed; and frames the choice around family preference, the urine-volume phenotype and the need for speed. [4] [5]

Weak

• "Reassure the family it is just a phase and review in a year." [1]

Branch B — The 9-year-old needing dryness for a school camp

Examiner: "A 9-year-old needs to be dry for a school camp in three weeks. How do you achieve rapid control?" [4]

Strong

• Chooses desmopressin for rapid and predictable control, because the alarm takes weeks and demands sustained commitment; states the oral dose of 200 micrograms titrated to 400 micrograms or the sublingual dose of 120 to 360 micrograms at bedtime; teaches the fluid-restriction rule (restrict fluids from one hour before the dose until eight hours after, and withhold during illness) to prevent hyponatraemia; notes that the intranasal spray is not recommended for enuresis because of a higher hyponatraemia risk; and plans a structured overlap with the alarm afterwards for durable dryness rather than an abrupt stop. [4]

Weak

• "Start the alarm the week before camp; it should work by then." [5]

Branch C — The 6-year-old with daytime urgency and holding

Examiner: "A 6-year-old wets the bed but also has daytime urgency, leg-crossing and occasional daytime wetting. What changes about your plan?" [1] [3]

Strong

• Reclassifies the child as non-monosymptomatic nocturnal enuresis on the daytime symptoms; explains that the correct first step is to assess and treat the daytime lower urinary tract symptoms and any constipation, usually with urotherapy and, where appropriate, an anticholinergic such as oxybutynin, before addressing the night; and warns that treating him as monosymptomatic with an alarm or desmopressin alone is the common error that delays dryness, because the daytime bladder dysfunction is the rate-limiting step. [1] [3]

Weak

• "Start desmopressin at bedtime and see if the bedwetting settles." [3]

Branch D — The 8-year-old with new polyuria, polydipsia and weight loss

Examiner: "An 8-year-old who has been dry for two years develops new bedwetting with excessive drinking, nocturnal thirst and weight loss. What is your concern?" [3]

Strong

• Recognises diabetes mellitus until proven otherwise, with the bedwetting secondary to osmotic diuresis; checks the urine for glucose and ketones and a capillary blood glucose immediately; explains that hyperglycaemia with ketonuria is diabetic ketoacidosis pending and is managed along the diabetic emergency pathway, not the continence pathway; and notes that secondary enuresis always prompts a search for a trigger such as infection, constipation, sleep-disordered breathing and psychosocial stress once diabetes is excluded. [3]

Weak

• "It is secondary enuresis; start an alarm and review in a few months." [3]

Close

Examiner: "Summarise your approach to the child who wets the bed in one sentence." [1] [4]

Strong

• "I confirm the child is five or older, separate monosymptomatic from non-monosymptomatic disease on the daytime history, exclude red flags with a focused examination and urinalysis, and then offer first-line therapy with the alarm for durable dryness in a motivated family or desmopressin at 200 to 400 micrograms orally or 120 to 360 micrograms sublingually with strict evening fluid restriction for nocturnal polyuria and rapid short-term control, combining them for the partial responder and reserving imipramine as a third-line option because it is cardiotoxic in overdose." [1] [4]