Neurogenic bladder, renal calculi, and urinary incontinence

Neurogenic bladder

The central nervous system, nerves that supply the bladder, and muscles work together for bladder control. Damage or disorders that impact the bladder nerves or the central nervous system can cause a neurogenic bladder. A person with a neurogenic bladder lacks bladder control, causing it to be overactive (the bladder muscles contract uncontrollably) or underactive (the person does not have the urge to go even though the bladder is full).

The central nervous system disorders that can cause neurogenic bladder include birth defects, cerebral palsy, Alzheimer disease, brain or spinal cord tumors, multiple sclerosis (MS), Parkinson disease, stroke, and spinal cord injury. Damage and disorders of the bladder nerves can be caused by diabetes, syphilis, heavy alcohol use, neuropathy, nerve damage from pelvic surgery, herniated disk, or spinal canal stenosis. With an overactive bladder, urgency and frequency to urinate are common. With an underactive bladder, the bladder fills but the person does not have the urge to go, and incontinence (urine leakage) can occur. Problems with starting to urinate or completely emptying the bladder can also be experienced.

After a physical exam, additional procedures may be ordered, including a postvoid residual volume, blood tests to check kidney functioning (e.g., serum creatinine), renal ultrasonography, and cystoscopy. Treatment is aimed at managing the symptoms of neurogenic bladder. Possible treatments include the following:

• Medications: Antimuscarinic, anticholinergic, botulinum toxin, gamma-aminobutyric acid (GABA) supplements, and antiepileptics
• Surgical procedures: Artificial urinary sphincter, an implanted electronic device to stimulate bladder nerves, and urinary stoma (or urostomy)
• Additional procedures: Kegel exercises and a urinary catheter

Renal calculi

Renal calculi, or kidney stones, are mineral pebbles that form in the kidney. Symptoms can occur if the calculi grow larger or move into the ureters or renal pelvis. If a stone blocks the flow of urine, infection can develop from the backflow of urine. This blockage also can result in hydronephrosis.

Renal calculi can occur when high levels of certain minerals, such as calcium, oxalate, and uric acid, collect in the kidney. Calculi can also form if fluid intake is low and the filtrate becomes highly concentrated. The tendency to develop kidney stones runs in families. With small stones, the person may not experience symptoms. With larger stones or stones that cause blockages, symptoms will be experienced. Signs and symptoms of kidney stones include dysuria, nausea, vomiting, fever, chills, and severe, constant pain on either side of the lower back. The person may have cloudy, foul-smelling, or bloody urine.

After the physical exam is concluded, a urinalysis, blood tests, and imaging tests (e.g., CT scan and abdominal x-ray) are used to diagnose renal calculi. Treatment depends on the size, type, and location of the stones. Small stones may pass on their own. Analgesics may be encouraged for the pain and discomfort. Extra fluids are encouraged to flush the stone out. Typically, patients are asked to strain their urine. Kidney stone strainers should be supplied. If the patient finds a stone, it should be placed in a specimen container and brought to the lab to be analyzed. Additional procedures include the following:

• Extracorporeal shock wave lithotripsy (ESWL): Shock waves are used to break up the stones, so they pass without a problem
• Ureteroscopy: The ureteroscope is threaded up through the bladder and ureter. If the provider sees a stone, it can be removed during the procedure. Sometimes ESWL and ureteroscopy are both done. The stone is broken up before it is removed.
• Nephrolithotomy: A surgical incision is made, and the stones are removed by the tube. With percutaneous nephrolithotripsy (PNL), the stones are crushed and removed using suction.

Example: Choosing between ureteroscopy and percutaneous nephrolithotripsy

A patient has a large stone (over 2 cm) sitting in the kidney itself, not in the ureter. Would the provider most likely use ureteroscopy or percutaneous nephrolithotripsy (PNL) to remove it?

Answer: PNL. Ureteroscopy reaches stones by passing a scope up through the urethra, bladder, and ureter, so it works best for stones already in the ureter or bladder. A large stone sitting in the kidney instead calls for a percutaneous approach: a small incision in the back gives direct access so the stone can be crushed and suctioned out.

Urinary incontinence

Urinary incontinence (UI) is the loss of bladder control, causing an accidental loss of urine. There are several types of urinary incontinence:

• Stress incontinence: Leakage of urine from stress on the bladder; caused by obesity, pregnancy, laughing, running, sneezing, coughing, or lifting heavy objects.
• Urge incontinence: Also called overactive bladder; strong, sudden urge (urgency) before the accidental loss of urine.
• Overflow incontinence: Most often affects males; the person has difficulty emptying the bladder.
• Functional incontinence: Caused by a mental or physical disease; leakage occurs before the person can reach the toilet.
• Mixed incontinence: Typically affects females; leakage of urine due to overactive bladder and stress incontinence.
• Total incontinence: Severest type; constant urine leakage.
• Enuresis: Also known as “bed wetting.” This condition is usually seen in children; the bladder fills during the night, and the child does not get up to urinate.

Exam tip: stress, urge, and overflow incontinence are easy to mix up on a question stem:

• Stress incontinence leaks in response to physical pressure on the bladder (a cough, a sneeze, lifting something heavy).
• Urge incontinence leaks after a sudden, strong need to urinate - the bladder itself is overactive.
• Overflow incontinence is most often seen in males and involves constant dribbling because the bladder never empties completely.

UI can occur for many reasons, including damage to the nerves that control the bladder, weak or overactive bladder muscles, diseases that limit mobility, urethral blockages (e.g., enlarged prostate), an increase in urine volume, UTI, and constipation. Persistent incontinence can come from pregnancy, childbirth, menopause, pelvic surgery, aging, prostate diseases, obstructions, and neurologic disorders. Accidental leakage of urine, urgency, constant dribbling, and inability to empty the bladder are possible signs and symptoms.

Procedures used to diagnose incontinence include urinalysis, postvoid residual measurement, cystoscopy, cystogram, and pelvic ultrasound. The patient may keep a bladder diary, recording the amount of fluid consumed and urinated, the number of incontinence episodes, and frequency and urgency feelings. Urodynamic testing may also be done, which involves the bladder being filled via a catheter while the bladder pressure is measured. Treatments can vary based on the type of incontinence:

• Behavior techniques: Bladder training, double voiding, scheduled toilet trips, and management of fluid and diet.
• Kegel exercises and electrical stimulation: Used to strengthen pelvic floor muscles.
• Medications: Anticholinergics, mirabegron, alpha-blockers, Botox, and topical estrogen.
• Surgical procedures: Can also be performed to treat certain types of incontinence.
• Medical devices: A urethral insert is a disposable device inserted into the urethra before activities that trigger incontinence. A pessary is a stiff ring that is inserted into the vagina and holds up the bladder, related to a prolapsed bladder. A nerve stimulator is an implanted device that delivers electrical pulses to the nerves that control the bladder.