What is the most appropriate next step for a 6-year-old with nocturnal and diurnal enuresis, chronic constipation, and a sacral dimple?

Most Appropriate Next Step: MRI of Lumbar Spine

The presence of a sacral dimple in a child with both day and night enuresis plus chronic constipation mandates immediate MRI of the lumbar spine to rule out occult spinal dysraphism before any other intervention. 1

Critical Red Flags Present

This clinical presentation contains alarming features that distinguish it from simple monosymptomatic nocturnal enuresis:

• Sacral dimple: This physical finding raises concern for occult spinal cord abnormalities such as tethered cord, lipomyelomeningocele, or other vertebral/spinal cord anomalies 1
• Combined day and night enuresis: This represents non-monosymptomatic enuresis (NMNE), which requires more thorough evaluation than simple bedwetting 1
• Chronic constipation: When combined with urinary symptoms and a sacral dimple, this triad strongly suggests possible neurogenic bladder dysfunction 2

Why Imaging Takes Priority

Examination of the back is mandatory in all children with non-monosymptomatic enuresis or history of urinary tract infection, and any suggestion of vertebral or spinal cord anomaly requires immediate investigation. 1

The guidelines explicitly state that children with severe/continuous incontinence or concerning physical findings "must be sent to a specialized center without delay" 1. A sacral dimple is specifically mentioned as requiring thorough somatic examination and further workup 1.

Why Not the Other Options First

Urinalysis alone (Option A) would be insufficient because:

• While urinalysis is the sole obligatory laboratory test for monosymptomatic enuresis 1, this child has NMNE with anatomic concerns
• A normal urinalysis would not exclude the serious underlying pathology suggested by the sacral dimple 1

Treating constipation first (Option C) would be inappropriate because:

• Although constipation should be addressed in enuresis management 1, 3, and bladder/bowel function are closely interrelated 1, treating constipation before ruling out neurogenic causes could delay critical diagnosis
• Recent evidence shows that fecal disimpaction alone does not resolve nocturnal enuresis 4
• The combination of constipation with urinary symptoms and sacral dimple suggests neurogenic bowel/bladder rather than simple functional constipation 2

Clinical Reasoning Algorithm

When evaluating a 6-year-old with enuresis:

1. First, identify red flags requiring immediate specialized evaluation 1:

   • Weak urinary stream
   • Severe/continuous incontinence
   • Anatomic abnormalities (sacral dimple, spinal abnormalities)
   • Combined day and night symptoms with physical findings

2. If red flags present → Immediate imaging and specialist referral 1

3. If no red flags → Standard evaluation pathway:

   • Urinalysis 1
   • Frequency-volume chart 1
   • Treat constipation if present 1, 3
   • Behavioral interventions 3, 5

Critical Pitfall to Avoid

The most dangerous error would be treating this as simple enuresis with behavioral modifications or constipation management while missing an underlying neurogenic bladder from spinal dysraphism. 2 One case report describes a 6-year-old with day/night enuresis who progressed to constant wetness and ultimately required suprapubic tube drainage due to unrecognized neurogenic bladder, despite normal initial imaging that failed to identify the problem early 2.

The physical examination finding of a sacral dimple moves this child into the high-risk category requiring anatomic evaluation before any therapeutic intervention.