What causes neurogenic bladder?

Causes of Neurogenic Bladder

Neurogenic bladder is caused by neurological disorders or injuries that disrupt normal communication between the nervous system and the bladder, leading to abnormal function of the bladder, bladder neck, and/or sphincters. 1

Primary Neurological Causes

Central Nervous System Disorders

• Spinal cord injury/trauma - most common cause of neurogenic bladder with high risk of upper urinary tract damage
• Myelomeningocele/spina bifida - congenital defect affecting approximately 26% of patients who develop renal failure 1
• Multiple sclerosis - progressive demyelinating disease causing variable bladder dysfunction
• Stroke/cerebrovascular accident - disrupts brain control of micturition
• Parkinson's disease - affects autonomic control of bladder function
• Brain tumors - can compress areas controlling bladder function
• Degenerative disorders - including multiple system atrophy 1

Peripheral Nervous System Disorders

• Diabetes mellitus - causes peripheral neuropathy affecting bladder sensation and control
• Peripheral neuropathies - various causes including:
  • Chronic alcohol use
  • AIDS-related neuropathy
  • Guillain-Barré syndrome
  • Vitamin deficiencies
• Pelvic nerve damage - from surgery, trauma, or radiation

Autonomic Nervous System Disorders

• Autonomic neuropathy - affects bladder sensation and contractility
• Shy-Drager syndrome - progressive autonomic failure

Secondary Causes and Risk Factors

Surgical/Iatrogenic Causes

• Radical pelvic surgery - particularly radical prostatectomy
• Abdominoperineal resection - for colorectal cancer
• Pelvic radiation therapy - causes progressive fibrosis and neuropathy
• Urethral procedures - including urethroplasty 1

Systemic Conditions

• Chronic renal failure - affects neural control of bladder
• Chronic liver failure - metabolic encephalopathy affecting bladder control 1

Pathophysiological Classification

Based on the location of neurological lesion, neurogenic bladder can be categorized as:

1. Suprapontine lesions - cerebrovascular disease, Parkinson's, dementia, brain tumors

   • Typically causes detrusor overactivity with coordinated sphincter function

2. Suprasacral spinal cord lesions - trauma, multiple sclerosis, transverse myelitis

   • Often results in detrusor overactivity with detrusor-sphincter dyssynergia

3. Sacral spinal cord/cauda equina lesions - trauma, disc herniation, spina bifida

   • Typically causes detrusor areflexia with sphincter denervation

4. Peripheral lesions - diabetes, alcoholism, vitamin deficiencies

   • Often results in impaired bladder sensation and contractility

Urodynamic Findings in Neurogenic Bladder

The American Urological Association identifies the following common urodynamic findings 1, 2:

• Detrusor overactivity - most common finding (~48% of cases)
• Impaired detrusor contractility - (~30% of cases)
• Poor bladder compliance - (~15% of cases)
• Detrusor-sphincter dyssynergia - uncoordinated contraction of bladder and sphincter
• Increased post-void residual - indicating incomplete emptying

Complications of Untreated Neurogenic Bladder

If left untreated, neurogenic bladder can lead to serious complications 2:

• Recurrent urinary tract infections
• Upper urinary tract deterioration
• Renal failure
• Bladder stones
• Autonomic dysreflexia (in patients with spinal cord injury)

Evaluation Approach

The American Urological Association recommends risk stratification of patients with neurogenic bladder as either low-risk or unknown risk (requiring further evaluation) 1. Initial evaluation should include:

1. Detailed history and physical examination
2. Urinalysis
3. Post-void residual measurement (if patient voids spontaneously)
4. Urodynamic studies to determine the specific type of dysfunction

Early diagnosis and appropriate management are essential to prevent complications and preserve renal function in patients with neurogenic bladder.