Neurogenic bladder

Overview

Pediatric neurogenic bladder is a bladder malfunction in children caused by central nervous system injury.

The muscles and nerves of the urinary system work together to deliver information from the brain to the bladder in most children and adults. However, these connections can be disrupted by a developmental malformation, a physical injury to the nervous system, or another defect; when this occurs, a child may have incomplete bladder emptying or incontinence caused by neurogenic bladder. Other possible complications include kidney or bladder stones.

Neurogenic bladder can be caused by any disease that disrupts bladder and bladder outlet afferent and efferent signals. The central nervous system (e.g., spinal injury, meningomyelocele) and peripheral nerves (e.g., vitamin B12 deficient neuropathies; herniated disks; pelvic surgical damage) may be involved in the causes. Bladder outlet obstruction (e.g., fecal impaction or urethral strictures) frequently coexists and can aggravate symptoms.

Symptoms might include overflow incontinence, frequency, urgency, urge incontinence, and retention. Risk of serious complications (eg, recurrent infection, vesicoureteral reflux, autonomic dysreflexia) is high. Imaging and cystoscopy or urodynamic tests are used to make a diagnosis. Catheterization or urination-inducing methods are used in treatment.

Anatomy and physiology of urinary system

Normal micturition necessitates the proper function of both the bladder and the urethra. To sustain good urine continence, the detrusor muscle and physiologically competent internal and external urethral sphincters must work normally. The central nervous system regulates the micturition process by coordinating sympathetic and parasympathetic nervous system activity with the somatic nervous system in order to preserve urine continence.

Bladder dysfunctions can be better understood if the basic neuroanatomy and neurophysiology of the upper and lower urinary tract systems are understood. The process of voluntary micturition consists of bladder filling, storage, and emptying. The kidneys excrete roughly 1L of fluid every day as urine. It passes through the ureter and into the bladder, where it stays for a while unless it exceeds the bladder storage capacity, which is 400 to 500cc.

Anatomically, the bladder divides into two parts: the dome and the base. The dome of the bladder is made up of smooth muscle, and the base consists of a trigone and neck that are closely connected to the pelvic floor. There are two urethral sphincters at the bladder outlet that are necessary for normal voluntary micturition. The internal urethral sphincter is in the bladder neck and proximal urethra, while the external sphincter is present at the membranous part of the urethra. Any disturbance to the normal functionality of the structures mentioned above as a result of trauma or disease can cause bladder dysfunction.

Classifications of Neurogenic bladder in children

1. Uninhibited:

Uninhibited bladder is generally caused by brain injury from a stroke or a brain tumor. This can result in a decreased sensation of bladder fullness, a low bladder capacity, and urinary incontinence. Unlike other forms of neurogenic bladder, it does not lead to high bladder pressures that can cause kidney damage.

2. Spastic:

The bladder muscle (detrusor) and urethral sphincter do not work together and are frequently strongly contracted at the same time in spastic neurogenic bladder (also known as upper motor neuron or hyper-reflexive bladder). This condition is also known as detrusor external sphincter dyssynergia (DESD). This causes urine retention and high pressures in the bladder, which can harm the kidneys. Because of increased muscular tone in the bladder, the bladder capacity is generally less than normal. Spastic neurogenic bladder is often caused by spinal cord injury above the 10th thoracic vertebrae.

3. Flaccid:

The muscles of the bladder lose their capacity to contract regularly in flaccid bladder (also known as lower motor neuron or hypotonic bladder). This can result in an inability to evacuate urine even when the bladder is full, as well as a large bladder capacity. Although the internal sphincter can contract correctly, urine incontinence is widespread. Damage to the peripheral nerves that flow from the spinal cord to the bladder causes this form of neurogenic bladder.

4. Mixed:

A combination of the above problems can be caused by a mixed form of neurogenic bladder. The bladder muscle is flaccid in mixed type A, while the sphincter is hyperactive. This results in a large, low-pressure bladder and difficulty to urinate, but it does not provide the same risk of kidney damage as a spastic bladder. Mixed type B is distinguished by a flaccid external sphincter and a spastic bladder, which causes incontinence.

Epidemiology and causes of Neurogenic bladder in children

Congenital defects of the neural tube (CDNT) are frequent anomalies in children that result in a neurogenic bladder. Their occurrence varies between continents and within continents, ranging from 1 in 10,000 births in Alaska to 34.4 in 10,000 births in northern China. This prevalence might reach 19.6 per 10,000 births in South America. When there is a sibling with spinal dysraphism, the probabilities rise by 20 to 50 times, and by 40 times if the mother has it. The prevalence of CDNT has decreased over the last two decades, owing mostly to the use of early prenatal diagnosis, the consequent discontinuation of pregnancy, and the introduction of folates into the diet.

MMC is the most prevalent kind of CDNT and occurs at the lumbosacral level (30-50%), followed by the lumbar and thoraco-lumbar levels (20-30%, respectively), with less frequency at the cervical and thoracic levels (0-5 percent and 5-10 % , respectively). The frequency of concealed spinal dysraphism is unclear, owing to underdiagnosis; nevertheless, it is known that roughly 40% of patients will have urological symptoms at the time of diagnosis.

A spinal cord lesion or damage can potentially induce neurogenic bladder dysfunction in children. This etiology accounts for between 3% and 5% of all spinal cord injuries. Its prevalence rises with age, with around 30% of patients between the ages of 17 and 23 suffering from it, and 53% suffering from it between the ages of 16 and 30. Males have a higher incidence after the age of three (4:1).

Of all the causes of neurogenic bladder, spinal dysraphism accounts for up to 93 % (open myelodysplasia accounts for 85 %, closed/occult dysraphism accounts for 8%), sacral agenesis, imperforate anus, and spinal cord lesion account for 1% each, and cerebral palsy accounts for 3%. Cerebral/spinal tumors and pelvic surgery are two less common causes.

Up to 98 % with myelomeningocele have neurogenic bladder. The prevalence of detrusor muscle areflexia ranges between 13 and 49.5 %, while hyperreflexia ranges between 25 and 76 %. In a group of 112 children with myelomeningocele who underwent urodynamic evaluation in 2015, only 4 children (3.6%) had normal bladder function, 49.1 % had overactivity of the detrusor, 14% had detrusor-sphincter dyssynergia, 14.3% had areflexia of the bladder, and 22% had deficient bladder compliance.

What are the symptoms of Neurogenic bladder?

Because the symptoms can range from mild to severe, determining if a kid has a neurogenic bladder can be challenging. Children with this condition may need to urinate often (overactive bladder) or may not urinate frequently enough (an underactive bladder).

Here are some of the most prevalent symptoms of pediatric neurogenic bladder with overactive bladder:

• Urinating frequently in small amounts.
• Problems emptying all the urine from the bladder.
• Loss of bladder control.
• Urgency.

Here are some common symptoms of pediatric neurogenic bladder associated with underactive bladder:

• Leaking urine.
• Inability to tell when the bladder is full.
• Problems starting to urinate or emptying all the urine from the bladder.
• Urinary retention.
• Urinary tract infections.

Consult a pediatric urologist if your kid is having continence problems and has a medical condition that might cause neurogenic bladder. Treatment is determined by the child's age, general health, medical history, bladder symptoms, and the origin of the nerve injury or neurologic disorder.

How are children with Neurogenic bladder evaluated?

Even if there are no neuro-orthopedic abnormalities, all patients with MMC should have an initial urologic assessment. The first assessment should offer information on the state of the detrusor-sphincter and determine the kind of dysfunction. 1B Strong recommendation: moderate-quality evidence. Damage to the renal parenchyma in a child with MMC acquired postnatally is avoidable with proper assessment, follow-up, and proactive management.

1. Renal and urinary tract ultrasound: They should be done as soon as possible after birth. It aids in the detection of hydronephrosis or other upper urinary tract abnormalities.1C Strong recommendation: evidence of low or very low quality. Increased detrusor wall thickness does not predict urodynamic results. Except for bladder trabeculation, there are no significant changes in bladder wall thickness evaluated at each maximal cystometric capacity in terms of adverse videourodynamic observations.
2. Voiding cystourethrography (VCUG): It offers anatomical information on the lower urinary tract and mainly on the presence or absence of VUR.
3. Urodynamic evaluation: It evaluates the bladder's filling and voiding processes. This examination is critical since therapies are dependent on a particular diagnosis of the kind of neurogenic dysfunction. When the spinal shock is predicted to be resolved, a VCUG and urodynamic examination should be conducted at least 6 weeks after the defect has closed. It is not required to wait 6 weeks if the problem was closed intrauterine. The VCUG and upper urinary tract examination should be done at regular intervals. Video-urodynamics integrates the data from urodynamic assessment and VCUG in a single study and apparatus, with the added benefit of testing simultaneity. It is advised not just at the first evaluation but also during follow-up in children with VUR.

The first examination is useful in identifying a subgroup of individuals who are more likely to have nephro-urologic impairment. Creatinine levels should be measured after the seventh day of life. Reduced bladder capacity and compliance, as well as high detrusor leak point pressure (DLLP), are urodynamic parameters that indicate renal impairment. VUR is less likely to be resolved in bladders having these features.

A higher risk of renal damage is associated with the existence of ureterohydronephrosis and VUR. During the first year of life, all patients with spina bifida should get Tc-99m DMSA renal scintigraphy.

Patients with a neurogenic bladder require urologic control for life. The degree of severity in the renal damage conditions the frequency of urologic controls by imaging and urodynamic evaluation. 

Renal and urinary tract ultrasounds are performed every 3-4 months throughout the first year of life, every 6 months until age 2, and then yearly until age 5. Urodynamic evaluations are performed on a yearly basis till puberty. 

VCUG and/or Video-urodynamic evaluation: it will be performed yearly in patients with VUR prior to urologic surgery, and as soon as feasible in patients who have stopped therapy and are no longer being followed. We propose renal and urinary tract ultrasonography management and yearly residual urine examination for individuals who are neurologic and urologically stable and have satisfactory bladder continence.

Is neurogenic bladder curable?

Early Treatment It involves starting therapy before to the appearance of any symptoms of damage, such as UTI, hydronephrosis, renal scarring, hypertension, or a reduced estimated glomerular filtration rate. This guideline is based on the idea that excessive detrusor muscle pressures (>40cm H20) and pyelonephritis impair renal function and should thus be avoided immediately after birth. The early use of CIC has a comparative benefit in terms of patient and family adherence and adaptability.

Some common treatments include:

1. Bladder training: A non-surgical program prepares patients skills and exercises to strengthen the pelvic floor muscles (such as Kegels). In order to develop a more controllable urine pattern, some children may be requested to keep a diary tracking the time of urination and the amount passed.
2. Anticholinergic drugs: According to urodynamic studies, the administration of anticholinergic drugs lowers intravesical pressure as well as involuntary bladder contractions. Although the use of oxybutynin in children under the age of five has not been licensed, there is sufficient global experience on its advantages. The mean end filling detrusor pressure was lowered from 33 to 21cm H2O in a multicenter, retrospective study of children with spinal dysraphism. More than 80% of patients had compliance greater than 70%. There were no significant side effects recorded, however constipation and facial redness were the most common. The oxybutynin dose recommended was 0.2-0.6mg/kg/day, either twice or three times each day.
3. Botulinum Toxin: Botulinum toxin (Botox) can be used through two different approaches. In order to treat spastic neurogenic bladder, the bladder muscle (detrusor) can be injected, causing it to be flaccid for 6–9 months. This prevents excessive bladder pressures and necessitates the use of intermittent catherization throughout this time. In individuals with detrusor sphincter dyssynergia, Botox can also be administered into the external sphincter to paralyze a spastic sphincter.
4. Sacral neuromodulation: Small electrodes and a stimulator are implanted near neurons associated to bladder function in this relatively recent method. The stimulator sends electrical impulses to the body that it would usually receive if the nerves were not injured.
5. Surgical Reconstruction: When medical and intravesical options fail to produce satisfactory outcomes, surgical reconstruction may be necessary to maintain low intravesical storage pressure and fulfill urine continence treatment goals. For those who are not candidates for CIC, current surgical options include incontinent diversion or individualized combinations of augmentation cystoplasty (AC), a bladder outlet procedure such as bladder neck reconstruction (BNR), sling, artificial urethral sphincter or bladder neck closure (BNC), and the creation of a catheterizable channel. Contributions to the literature in the recent year have included assessments of enterocystoplasty (EC) results, the selection of children for bladder neck restoration without concomitant bladder augmentation, and the growing importance of robots in reconstructive surgery.

What are possible complications of Neurogenic bladder in a child?

Neurogenic bladder can result in hydronephrosis (kidney enlargement caused by urine buildup), recurrent urinary tract infections, and recurrent kidney stones, all of which can impair kidney function. This is especially important in cases with spastic neurogenic bladder, which causes high bladder pressures. Kidney failure was once a primary cause of death in individuals with spinal cord injury, but it is now much less prevalent due to advances in bladder control. 

How can I help my child live with Neurogenic bladder?

It might be difficult to live with a neurogenic bladder. Urine leaks may be embarrassing. It may cause your child to have low self-esteem. It is critical that you remain supportive and patient with your child during his or her therapy and emotional development. Learning how to appropriately manage your child's condition takes effort and time. Encourage your child's achievement by ensuring that they adhere to the treatment plan. In some circumstances, a psychotherapist can assist the kid and family in adhering to the therapy plan.

When should I call my child’s healthcare provider?

Call the healthcare provider if your child has:

• Symptoms that don’t get better, or get worse.
• New symptoms.

Conclusion

Pediatric neurogenic bladder is a bladder defect induced by a central nervous system damage in children.

Neurogenic bladder dysfunction is one of the most common consequences of a defective neural tube closure in children. The frequency of spina bifida varies by area, and the most common kind is myelomeningocele, which has life-long consequences. Neurogenic bladder multidisciplinary groups use various plans to handle certain diseases, such as the neurogenic bowel subgroup.

The most common symptom of neurogenic bladder is being unable to control urination. Other symptoms include: weak or dribbling urinary stream, frequent urination (urinating eight or more times daily), urgency (a feeling or need to urinate immediately), and painful urination, which may mean there is a urinary tract infection.

The urinary tract is one of the most impacted systems, with the possible compromise of the renal parenchyma, which should be given special attention. The structure and function of the urinary system must be assessed in order to stratify the risk of the renal mass being exposed to unfavorable bladder conditions. It has been shown that clean intermittent catheterization and medication should be started as soon as feasible to minimize deterioration or injury.

If first-line medicine fails, more specific second-line medications, such as beta agonists and botulinum toxin-A, can postpone cystoplasty, improve urine incontinence scores, and maintain safe intravesical pressures. This helps to reduce the morbidity of reconstructive treatments while also improving quality of life.