What is the most appropriate next step in managing a patient with 6 years of nocturnal and diurnal enuresis, chronic constipation, and a sacral dimple?

MRI of Lumbar Spine is the Most Appropriate Next Step

In a 6-year-old child presenting with both day and night enuresis, chronic constipation, and a sacral dimple, lumbosacral MRI must be performed immediately to exclude tethered cord syndrome before initiating any symptomatic treatment. 1

Why Imaging Takes Priority Over Other Options

The Sacral Dimple Changes Everything

• A sacral dimple combined with bowel and bladder dysfunction constitutes a red flag constellation requiring urgent neurological evaluation, as this triad mandates imaging regardless of other findings 1
• The American Academy of Child and Adolescent Psychiatry explicitly states that examination for sacral dimple or other vertebral/spinal cord anomaly is essential in every enuretic child, and when present with these symptoms, it cannot be assumed benign 2, 1
• Sacral dimples can indicate underlying spinal cord pathology, particularly tethered cord syndrome, which presents with bowel and bladder dysfunction 1

Why Not Treat Constipation First (Option C)

• Treating constipation before excluding tethered cord could mask progressive neurological deterioration 1
• If tethered cord is present, the constipation is a neurogenic symptom requiring surgical intervention, not medical management alone 1
• Recent research (2022) demonstrates that fecal disimpaction in children with enuresis and constipation does not alleviate nocturnal enuresis, with enuresis frequency remaining essentially unchanged (9.8 vs 9.3 nights per two weeks, p=0.43) 3
• While constipation can interfere with desmopressin efficacy 4 and should eventually be addressed 5, this is irrelevant if the underlying cause is neurogenic from tethered cord

Why Not Start with Urinalysis (Option A)

• Urinalysis is part of standard enuresis workup 2, but it does not address the structural neurological concern raised by the sacral dimple 1
• The physical examination finding of a sacral dimple with this symptom complex supersedes routine laboratory evaluation in determining the next diagnostic step 1

Clinical Algorithm for This Patient

Immediate Actions

1. Order lumbosacral MRI immediately if sacral dimple is present with bowel/bladder dysfunction, regardless of whether focal neurological signs are detected on examination 1
2. Perform thorough neurological examination looking for lower limb weakness or asymmetry, abnormal deep tendon reflexes, gait abnormalities, foot deformities, and muscle tone abnormalities 1

Why MRI and Not Ultrasound

• Spinal ultrasound is only useful in infants under 3-6 months before vertebral ossification obscures visualization 1
• For a 6-year-old child with suspected spinal dysraphism, MRI is the definitive imaging modality 1

Critical Pitfalls to Avoid

• Never assume a sacral dimple is benign in the presence of bowel and bladder dysfunction—this combination mandates imaging 1
• Do not delay imaging to first attempt conservative management, as progressive tethered cord can cause irreversible neurological damage 1
• Do not rely on normal neurological examination alone to exclude spinal dysraphism—subtle findings may be missed, and MRI is required for definitive evaluation 1
• Do not be falsely reassured by the chronicity of symptoms; tethered cord syndrome can present with slowly progressive symptoms over years 6

What Happens After MRI

• If MRI reveals tethered cord, neurosurgical intervention (untethering) is required and may improve urinary disturbance 6
• If MRI is normal, then proceed with standard enuresis evaluation including urinalysis 2 and treatment of constipation 5
• Even with normal MRI, constipation should still be addressed as it negatively affects response to desmopressin in patients with nocturnal enuresis, especially in severe cases 4