Overview
Definition:
Neurogenic bladder in spina bifida refers to bladder dysfunction resulting from a congenital defect in the neural tube, leading to impaired innervation of the bladder and sphincter muscles
This results in a range of voiding dysfunctions, including detrusor-sphincter dyssynergia, detrusor overactivity, and poor bladder compliance.
Epidemiology:
Spina bifida affects approximately 1 in 3000 live births
The majority of individuals with spina bifida (over 80-90%) will develop some form of neurogenic bladder dysfunction, requiring lifelong management.
Clinical Significance:
Untreated neurogenic bladder can lead to severe complications, including recurrent urinary tract infections (UTIs), hydronephrosis, vesicoureteral reflux (VUR), renal scarring, and ultimately, end-stage renal disease
Effective management is crucial for renal preservation, continence, and improving quality of life.
Clinical Presentation
Symptoms:
Difficulty initiating voiding
Incomplete bladder emptying
Urinary incontinence (daytime and/or nighttime)
Recurrent urinary tract infections with fever, dysuria, and flank pain
Constipation or fecal incontinence
Poor growth
Abdominal distension.
Signs:
Palpable bladder on abdominal examination
Poor anal sphincter tone
Ascending infection signs
Hypertension due to autonomic dysreflexia (less common in pediatric population but important to recognize)
Signs of renal damage on imaging.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on the history of spina bifida and signs of voiding dysfunction
Urodynamic studies are essential to characterize the type and severity of bladder dysfunction, guiding management
Renal ultrasound is used to assess upper tract status.
Diagnostic Approach
History Taking:
Detailed birth history and type of spina bifida
Previous surgical interventions
History of UTIs, fever, or flank pain
Voiding patterns: frequency, urgency, hesitancy, straining, incomplete emptying
Bowel habits: constipation is common and impacts bladder function
Family history of neurological or urological issues.
Physical Examination:
General assessment for associated anomalies
Neurological examination, focusing on lower extremity motor and sensory function, and sacral reflexes
Abdominal examination for palpable bladder or masses
Genitourinary examination, including assessment of external genitalia and anal sphincter tone
Back examination for skin integrity over the defect.
Investigations:
Urinalysis and urine culture: to diagnose and manage UTIs
Renal and bladder ultrasound: to assess kidney size, structure, hydronephrosis, and bladder wall thickness
Urodynamic studies: including cystometry to assess bladder filling and storage function (e.g., detrusor overactivity, low compliance), and pressure-flow studies to evaluate detrusor-sphincter coordination
Voiding cystourethrogram (VCUG): to assess for VUR and bladder shape
Renal nuclear scans: to evaluate differential renal function and identify scarring.
Differential Diagnosis:
Other causes of urinary incontinence in children: functional incontinence, congenital anomalies of the urethra or bladder, spinal cord lesions not related to spina bifida, behavioral voiding disorders
However, in a child with known spina bifida, neurogenic bladder is the most likely cause.
Management
Initial Management:
Establish a management goal: renal protection and continence
Educate parents/caregivers on the condition and treatment plan
Implement a bladder diary to monitor fluid intake, voiding episodes, and incontinence
Start Clean Intermittent Catheterization (CIC) if the child is unable to empty their bladder effectively.
Medical Management:
Anticholinergic medications: These are used to reduce bladder contractions and increase bladder capacity
Common agents include oxybutynin (0.4-1 mg/kg/day divided TID-QID, max 15 mg/day), tolterodine (0.5-1 mg/kg/day divided BID, max 4 mg/day), and solifenacin (0.25-0.5 mg/kg/day once daily, max 5 mg/day)
Dosing should be individualized and titrated
Monitor for side effects such as dry mouth, constipation, blurred vision, and heat intolerance
Bladder instillations of anticholinergics are also an option in some cases.
Surgical Management:
Indications for surgery include failure of medical management, severe detrusor sphincter dyssynergia, intractable incontinence, or significant bladder augmentation needs
Surgical options include: bladder augmentation (e.g., augmentation cystoplasty using intestinal segments), creation of Mitrofanoff channels for easier CIC, and sphincter augmentation procedures
These are typically considered for older children and adolescents with well-selected indications.
Supportive Care:
Bowel management program: A regular bowel regimen is crucial as constipation significantly impacts bladder function and increases intra-abdominal pressure
Adequate fluid intake to ensure good hydration
Monitor for UTIs and manage promptly
Regular follow-up with a multidisciplinary team including urology, neurology, and nephrology
Psychological support for the child and family.
Complications
Early Complications:
Urinary tract infections
Catheter-related injuries or bleeding
Autonomic dysreflexia (rare in children, but a consideration with severe lesions).
Late Complications:
Upper urinary tract deterioration (hydronephrosis, renal scarring, renal failure)
Chronic UTIs
Bladder stones
Urethral strictures from repeated catheterization
Osteoporosis (due to immobility and possibly medication effects).
Prevention Strategies:
Adherence to regular CIC schedule
Optimal hydration
Prompt diagnosis and treatment of UTIs
Regular urodynamic and renal function monitoring
Effective bowel management
Prophylactic antibiotics are generally not recommended unless specific indications exist.
Prognosis
Factors Affecting Prognosis:
The level of the spinal lesion (higher lesions generally have more severe bladder dysfunction)
Adherence to management regimen
Early and aggressive management to protect the upper urinary tract
Presence of associated anomalies.
Outcomes:
With consistent and appropriate management including CIC and anticholinergics, the prognosis for renal preservation is good, and continence can often be achieved
Long-term complications can be minimized, allowing for a better quality of life.
Follow Up:
Lifelong follow-up is typically required
This includes regular clinical assessments, renal and bladder ultrasounds, and periodic urodynamic studies to monitor bladder function and upper tract status
Adjustments to medication and CIC protocols may be needed as the child grows.
Key Points
Exam Focus:
Understand the primary goal of neurogenic bladder management in spina bifida: renal preservation
Differentiate between detrusor overactivity, detrusor-sphincter dyssynergia, and poor compliance on urodynamics
Recognize the critical role of CIC and anticholinergics.
Clinical Pearls:
Always consider bowel management alongside bladder management
they are intrinsically linked
Educate caregivers thoroughly on CIC technique
Start anticholinergics at the lowest effective dose and titrate slowly to minimize side effects
Monitor renal function vigilantly throughout treatment.
Common Mistakes:
Underestimating the importance of regular CIC leading to bladder overdistension
Inadequate bowel management contributing to bladder dysfunction
Delaying initiation of anticholinergic therapy or failing to titrate effectively
Neglecting regular renal ultrasound surveillance for hydronephrosis.