Renal Therapeutics IV: Urine Transport, Storage & Elimination

Question 1

Name the 3 parts of the urinary tract

Answer 1

Ureters
Urinary bladder
Urethra

Question 2

What is the micturition complex?

Answer 2

Nervous system which co-ordinates the process of urination

Question 3

Explain the micturition reflex

Answer 3

Sensory fibres in the pelvic nerve sense the stretch due to bladder filling
Parasympathetic fibres control muscle contraction (bladder)
Interneurons communicate signals up to the hypothalamus. with relays into the cortex
Voluntary relaxation of the external sphincter results in urination

Question 4

Explain in detail what happens as the bladder fills with urine in the micturition reflex

Answer 4

Stretch receptors in urinary bladder stimulate pelvic nerve
Stimulus travels from pelvic nerves and stimulates ganglionic neurons in the wall of the bladder
Post-ganglionic neuron in intramural ganglion stimulates detrusor muscle contraction
Inter-neuron relays sensation to the thalamus and delivers sensation to cerebral cortex
Voluntary relaxation of external and so internal urethral sphincters
= Urine released

Question 5

List groups of people who may have problems with their micturition reflex

Answer 5

Infants

Older people - age-related changes in the urinary system

Question 6

Why do infants have issues with their micturition reflex?

Answer 6

Cortico-spinal connection are not established so they lack voluntary control over urination

Question 7

List 3 age-related changes to the urinary system that some older people suffer from

Answer 7

1. Decline in the number of functional nephrons
2. Reduced sensitivity to ADH
3. Problems with the micturition complex

Question 8

List 3 problems which may affect the micturition complex

Answer 8

1. Sphincter muscle loses tone - leads to incontinence
2. Control of micturition can be lost due to a stroke, Alzheimer’s, CNS problems affecting cerebral cortex or hypothalamus
3. In males - urinary retention may develop if enlarged prostate gland compresses the urethra and restricts urine flow

Question 9

Define: Incontinence

Answer 9

An involuntary loss of urine that enough to cause a social or hygiene concern

Question 10

What is stress incontinence?

Answer 10

Caused by coughing, sneezing, laughing or carrying heavy weights as the normal control mechanism is weakened
Can happen when the urethra is moved out of the normal position (prolapses) after weakening of the pelvic floor muscles

Question 11

What is urge incontinence?

Answer 11

Strong urge to pass frequent, small amounts of urine
Caused by the muscle of the bladder wall (detrusor muscle) being overactive
= It contracts to squeeze out urine before the bladder is completely full

Question 12

What is mixed incontinence?

Answer 12

Some women may get both urge and stress incontinence

The 2 may or may not be linked

Question 13

What is overflow incontinence?

Answer 13

When the urine held by the bladder builds up to the point where the bladder can no longer expand
Can be caused by an obstruction in the urinary tract or damage to the nerves that supply the bladder

Question 14

Explain some other causes of incontinence

Answer 14

Medication - side effects of some drugs for high BP (prazosin, doxazosin) and muscle relaxants (diazepam)
Problems with the urinary system e.g. fistulas = abnormal openings between the ureter, urethra or bladder into the uterus or vagina

Question 15

List the 4 types of incontinence

Answer 15

Sress incontinence
Urge incontinence
Mixed incontinence
Overflow

Question 16

What are the 3 methods used to treat incontinence?

Answer 16

1. Behavioural techniques
2. Surgical treatments
3. Pharmacologic treatments

Question 17

Explain the behavioural technique used to treat incontinence

Answer 17

Scheduled toileting (every 2-4 hours)
Frequently empty the bladder to prevent incontinence
Recommended for frail, elderly or bedridden patients who are not able to make it to the toilet

Question 18

Explain the surgical option used to treat incontinence

Answer 18

Should be considered only after all conservative options have been exhausted
Long-term success rates = excellent
However rare complications = infection, bleeding, continued incontinence, inability to urinate

Question 19

Which methods are usually used to manage stress incontinence?

Answer 19

Non-drug methods

Question 20

Which methods are generally used to manage urge incontinence?

Answer 20

Oral medications

Question 21

List 4 drugs which are used to manage urge incontinence

Answer 21

Duloxetine
Oxybutynin and tolterodine
Solifenacin succinate
Tofranil

Question 22

How does Duloxetine work to prevent urge incontinence?

Answer 22

Antimuscarinic = reduces contractions of the bladder and increase bladder activity
Can also be used to treat moderate-severe stress incontinence

Question 23

How do Oxybutynin (Ditropan) and Tolterodine (Detrusitol) work to prevent urge incontinence?

Answer 23

They cause relaxation of smooth muscle of bladder

Question 24

List 4 possible side effects of using the highlighted drugs to treat urinary incontinence

Answer 24

All of these drugs may show anti-cholinergic effects:
Dry mouth and eyes
Constipation
Blurred vision
Inability to urinate

Question 25

What is Benign Prostate Hypertrophy?

Answer 25

An enlarged prostate

As the prostate gets bigger it may squeeze or partially block the urethra, causing problems with urination

Question 26

What is the prostate?

Answer 26

The male reproductive gland which produces the fluid that carries sperm during ejaculation
It surrounds the urethra (tube which passes out of the body)

Question 27

What is benign prostate hypertrophy also known as?

Answer 27

Benign prostate hyperplasia

Question 28

List 4 symptoms of benign prostate hypertrohpy

Answer 28

Dribbling at the end of urination
Inability to urinate (urinary retention)
Incomplete emptying of bladder
Needing to urinate 2 or more times at night

Question 29

Name 3 tests which may be performed for benign prostate hypertrophy

Answer 29

Digital rectal exam to feel the prostate gland
Urine flow rate
Post-void residual urine test = see how much urine is left in the bladder after urination

Question 30

Name 3 types of medication which may be prescribed to treat benign prostate hypertrophy

Answer 30

Alpha-1 blockers
Finasteride and dutasteride
Antibiotics

Question 31

How do alpha-1 blockers treat benign prostate hypertrophy?

Answer 31

Relax the muscles of the bladder, neck and prostate - allows for easier urination
Also used to treat hypertension

Question 32

How do Finasteride and Dutasteride treat benign prostate hypertension?

Answer 32

Lower the levels of hormones produced by the prostate
Reduce size of the prostate gland
Increase urine flow rate
Decrease symptoms of BPH

Question 33

Why may antibiotics be prescribed to treat benign prostate hypertrophy?

Answer 33

May be prescribed to treat chronic prostatitis = inflammation of the prostate, which may accompany BPH

Question 34

List 4 symptoms of BPH which may lead to prostate surgery being recommended

Answer 34

Incontinence
Recurrent blood in the urine
Inability to fully empty bladder (urinary retention)
Recurrent UTIs

Question 35

List 4 complications which those with long-standing BPH may experience

Answer 35

Sudden inability to urinate
UTIs
Damage to the kidneys
Blood in the urine