What is the diagnostic workup for a patient presenting with nocturnal enuresis (bedwetting)?

Diagnostic Workup for Bedwetting (Nocturnal Enuresis)

The essential workup for bedwetting includes an immediate urine dipstick, a detailed voiding and bowel history, and a frequency-volume chart (bladder diary) for at least 2 days of measured intake/output and 1 week of wet/dry nights to distinguish monosymptomatic from non-monosymptomatic enuresis. 1, 2

Initial History and Classification

Distinguish between primary versus secondary enuresis immediately, as secondary enuresis (dry period ≥6 months followed by recurrence) warrants prompt evaluation for underlying medical conditions, psychological stressors, or significant life events. 2

• Determine if the enuresis is monosymptomatic (bedwetting only) or non-monosymptomatic (bedwetting plus daytime symptoms like urgency, frequency, or incontinence), as less than half of bedwetting children are truly monosymptomatic. 2
• Ask specifically about daytime voiding symptoms, as many children initially assumed to have monosymptomatic enuresis are found to have non-monosymptomatic patterns after thorough evaluation. 2

Mandatory Initial Testing

Urine Dipstick (Immediate)

• Perform urinalysis immediately to exclude diabetes mellitus and kidney disease, checking for glycosuria, proteinuria, and signs of urinary tract infection. 1
• If glycosuria is present, urgent blood glucose testing is required to rule out diabetes mellitus. 1, 2

Frequency-Volume Chart (Bladder Diary)

• Complete a bladder diary for at least 2 days of measured intake/output and 1 week of wet/dry nights to objectively detect nocturnal polyuria and identify children with polydipsia. 1
• This is indispensable for distinguishing monosymptomatic from non-monosymptomatic patterns and documenting nocturnal polyuria. 2

Critical Comorbidity Assessment

Constipation Screening (Paramount)

• Assess bowel habits by asking about bowel movement frequency and stool consistency, as constipation is a paramount comorbid condition that decreases the chance of successful enuresis therapy and may directly contribute to bladder dysfunction. 2
• Treat constipation aggressively first before addressing enuresis, as resolving constipation may cure the enuresis. 1, 2
• Use polyethylene glycol as a stool softener (Grade Ia evidence). 1

Sleep Disorder Screening

• Screen for sleep disorders by asking if the child has problems sleeping aside from needing to urinate, if they gasp or stop breathing at night, or if they wake up without feeling refreshed. 3

Physical Examination Findings to Document

• Check for neurological abnormalities including lower limb weakness, abnormal gait, speech disturbances, or tremor. 4
• Assess for signs of anatomical abnormalities that would require immediate specialized referral. 2
• Evaluate for peripheral edema if considering nocturnal polyuria from fluid retention. 4

Additional Investigations When Indicated

Blood Tests (If Polyuria or Other Concerns)

• Electrolytes/renal function, thyroid function, calcium, and HbA1c if nocturnal polyuria is documented or diabetes is suspected. 4

Voiding History Details

• Document fluid intake patterns, particularly evening fluid consumption. 3
• Assess for a regular daytime voiding schedule. 3
• Determine if the child voids immediately before sleep. 3

Red Flags Requiring Urgent Specialist Referral

Refer urgently if any of the following are present:

• Weak urinary stream 1
• Continuous incontinence 1
• Recurrent urinary tract infections 1
• Abnormal neurological findings 1
• Non-monosymptomatic enuresis that doesn't respond to initial management 1
• "Suspicious" symptoms including numbness, weakness, speech disturbance, gait disturbance, memory loss/cognitive impairment, or autonomic symptoms 4
• Enuresis without chronic retention (unusual presentation) 4

Common Pitfalls to Avoid

• Do not use punitive parental responses, as bedwetting is involuntary. 1
• Do not delay treatment if psychological damage is occurring, as the impact on self-esteem and interpersonal relationships can be severe and warrants intervention even if the child hasn't reached a specific age threshold. 2
• Do not assume psychological factors are the primary cause, as most cases have biological underpinnings with psychological factors being contributory in only a minority. 2, 5
• Do not overlook constipation, as it is frequently the hidden culprit that prevents successful treatment. 2