Lumbar MRI is the Next Investigation
In a 6-year-old with continuous day-and-night enuresis combined with a sacral dimple, lumbar spine MRI must be performed immediately to rule out tethered cord or occult spinal dysraphism—this combination represents a neurological red flag that supersedes routine urological workup. 1
Why Lumbar MRI Takes Priority
The presence of a sacral dimple with both diurnal and nocturnal enuresis mandates immediate neurological investigation rather than starting with urinalysis. 1 This clinical presentation suggests possible tethered cord, lipoma, or other occult spinal dysraphism that requires urgent identification. 2, 1
Key distinguishing features in this case:
- Continuous wetting (all day and night) at age 6 indicates non-monosymptomatic enuresis requiring aggressive investigation 1, 3
- Sacral dimple is a cutaneous marker of potential spinal dysraphism 2
- The combination of these findings creates high suspicion for underlying neurological pathology 1
The Diagnostic Sequence
Immediate action: Obtain lumbar spine MRI to evaluate for tethered cord, lipoma, or spinal dysraphism. 1
Concurrent testing: Urinalysis and culture can be performed at the same time but should not delay imaging. 1 While urinalysis is mandatory for all enuretic children 2, 3, the presence of a sacral dimple with continuous incontinence shifts the diagnostic priority to neurological evaluation.
Critical Pitfalls to Avoid
Do not attribute continuous day-and-night wetting to behavioral causes when a sacral dimple is present—this combination mandates neurological investigation first. 1
Do not delay imaging with prolonged behavioral interventions or empiric medications when red flags exist. 1 The standard approach of starting with urinalysis alone applies to simple nocturnal enuresis, not to this presentation with anatomical warning signs. 2
Do not assume the sacral dimple is benign based on the child being otherwise healthy. While research shows most isolated sacral dimples in asymptomatic neonates are benign (only 0.13% requiring surgery) 4, 5, this child is symptomatic with severe continuous incontinence, fundamentally changing the risk assessment.
Expected Next Steps
If MRI reveals tethered cord or lipoma: Immediate neurosurgical consultation is mandatory. 1 Untethering procedures can improve urinary symptoms, as demonstrated in case reports of tethered cord with bladder dysfunction. 6, 7
If MRI is normal: This severity of symptoms still requires pediatric urology referral, not primary care management alone. 1 The continuous nature of wetting at age 6 suggests significant pathology even without structural spinal abnormalities.
Why Not Start with Urinalysis
While urinalysis is the standard first test for simple enuresis 2, 3, the physical examination finding of a sacral dimple combined with continuous incontinence changes the diagnostic algorithm. 1 The guidelines specifically state that examination of the back for sacral dimple or other signs of vertebral/spinal cord anomaly should direct subsequent imaging decisions. 2, 3
The risk-benefit calculation favors MRI first because missing a tethered cord can lead to progressive neurological deterioration, while a brief delay in treating a urinary tract infection (if present) poses minimal risk when managed appropriately once identified.