Renal Therapeutics 3: Renal dysfunction, controlling incontinence Flashcards
What are the three parts of the urinary tract and what are their functions?
- Ureters (tube that connects kidney to bladder)
- urinary bladder (stores the urine)
- Urethra- the tube which allows the urine to exit
Describe the micturition reflex and how it co-ordinates the process of urination?
- Sensory fibers in the pelvic nerve sense stretch due to the bladder filling
- Parasympathetic fibers control muscle contraction
- Interneurons communicate with hypothalamus via relays to the cortex
- Voluntary relaxation of external sphincter results in urination as urethra widens
Explain how the contraction occurs down the walls of the bladder?
- Bladder fills with urine
- Stimulus travels down the pelvic nerves which stimulate ganglionic neurons in wall of bladder
- Postganglionic neuron in intramural ganglion stimulates the detruscor muscle contraction
- Interneuron relays sensation to thalamus and deliver sensation to cerebral cortex
- Voluntary relaxation of external thus internal urethral sphincter
How does the micturition reflex differ in infants?
There is a lack of voluntary control over urination as the corticospinal connections are not established
How does the micturition reflex differ in age related changes in the urinary system?
- Decline in number of functional nephrons
- Reduced sensitivity to ADH
- Problems with micturition reflex
What are micturition reflex problems that can occur?
- Sphincter loses muscle tone which means incontinence
- Control of the system lost due to:
- stroke
- Alzheimers disease
- CNS problems that affect cerebral cortex or the hypothalamus - Urinary retention may develop if enlarged prostate gland compresses the urethra and restricts urine flow
What does urinary incontinence mean?
The involuntary loss of urine that is enough to cause a social or hygiene concern
What is stress incontinence and how is it caused?
- Caused by coughing, sneezing, laughing or carrying heavy weights- normal control weakened
- Urethra moves out of the normal position (prolapses)
- Weakening of level floor muscles
What is urge incontinence and how is it caused?
- Strong urge to pass frequent and small amounts of urine
- Caused by muscle of the bladder wall (detrusor muscle) being overactive or bladder infection (less urine produced)
- Can mean it contracts to squeeze out urine before the bladder is completely full
- Diabetes can cause excessive production of urine and frequent trips to toilet
What is overflow incontinence and how is it caused?
- Urine held in the bladder builds up to the point where the bladder can no longer expand
- Caused by obstruction in the urinary tract or damage to the nerves that supply the bladder
What other factors may cause incontinence?
- Medication- side effects of some drugs for hypertension such as parson, doxazosin and muscle relaxants like diazepam
- Urinary system problems like:
- Fistulas (abnormal opening between ureter, urethra or bladder into the uterus or vagina)
- Bladder stones
How do you treat stress incontinence with behavioural techniques
- Scheduled toileting every 2 to 4 hours
- Frequently emptying the bladder and keeping the patient dry- recommended for frail elderly or bed ridden patients
- Pelvic floor exercises
- Surgical treatments- usually successful
How do you treat incontinence with pharmacologic techniques?
MAIN ONES:
1. Solifenacin succinate: first line of treatment
- Tofranil (imipramine): similar effect on the bladder: 25mg nightly
Other ones:
1. Duloxetine: moderate to severe stress urinary incontinence
- Antimuscarinic drugs reduce contractions of bladder and increase its activity- urge incontinence
- Oxybutynin and tolterodine cause relation of smooth muscle of bladder
What is the prostate?
The prostate is a male reproductive gland that produces the fluid that carries sperm during ejaculation which surrounds the urethra
What is benign prostatic hypertrophy?
When the prostatic enlarges as they get older, this can press on the urethra and cause urination and bladder problems
