What is the best initial approach for a pediatric patient, specifically a young boy, presenting with nocturnal enuresis (night bed wetting), polydipsia (increased thirst), and polyuria (excessive fluid intake)?

Immediate Urine Dipstick Testing (Option A)

The correct answer is A. Urine analysis (dipstick) because this child's presentation of nocturnal enuresis with polydipsia and excessive fluid intake raises immediate concern for diabetes mellitus, which must be urgently excluded before any other evaluation or treatment. 1, 2

Clinical Reasoning for This Specific Case

This is NOT simple monosymptomatic enuresis—the combination of bedwetting with polydipsia and excessive drinking represents red flag symptoms that demand immediate metabolic investigation:

• Glycosuria on urine dipstick mandates immediate exclusion of diabetes mellitus and should prompt urgent blood glucose testing if positive 2
• The International Children's Continence Society explicitly states that a urine dipstick test is the sole obligatory laboratory test in children with enuresis, and that glycosuria means diabetes mellitus must be immediately excluded 1, 2
• Polydipsia signals that children with polyuria due to diabetes or kidney disease obviously need further investigation 2
• The dipstick can be performed immediately in the office and may reveal a life-threatening condition—do not delay by ordering comprehensive metabolic panels or scheduling follow-up appointments first 2

Why the Other Options Are Incorrect in This Context

Option B (FBS - Fasting Blood Sugar)

• While ultimately necessary if glycosuria is detected, the urine dipstick should come first because it can be done immediately without fasting or venipuncture 2
• The dipstick provides rapid screening that guides whether blood glucose testing is urgently needed 1, 2

Option C (Urine Culture)

• Urine culture is indicated for suspected urinary tract infection, not for the initial evaluation of polydipsia and polyuria 1
• There is no mention of dysuria, fever, or other UTI symptoms in this case 1

Option D (Ultrasound)

• Routine ultrasound of the kidneys and upper urinary tract is not warranted in enuresis evaluation 1
• Ultrasound would only be considered after metabolic causes are excluded and if there were signs of urinary tract malformations or recurrent infections 3

Critical Next Steps After Dipstick

If the dipstick shows glycosuria:

• Immediately check blood glucose (fasting or random) to confirm or exclude diabetes mellitus 2, 4
• If diabetes is confirmed, urgent endocrinology referral and treatment initiation are required 2

If the dipstick shows proteinuria on repeat samples:

• Investigate for kidney disease 1, 4

If the dipstick is negative:

• Complete a frequency-volume chart/bladder diary for at least 2 days of measured intake/output and 1 week of wet/dry nights to objectively document the polydipsia and polyuria patterns 1, 5, 4
• Consider other causes of polydipsia including diabetes insipidus, chronic kidney disease, or psychiatric disorders 3, 6

Common Pitfall to Avoid

Do not attribute bedwetting to simple behavioral causes when accompanied by polydipsia and excessive drinking—these are red flag symptoms requiring metabolic investigation first 2. The combination of these symptoms distinguishes this case from typical monosymptomatic enuresis and demands immediate screening for serious underlying conditions like diabetes mellitus 1, 2.