Renal: Micturition and Incontinence

Question 1

What is represented by the blue nerves?

Answer 1

•Sympathetic fibres (blue) originate from T11–L2

They run through the inferior mesenteric ganglia (plexus, IMP) and the hypogastric nerve (HGN)

Also enters via the paravertebral chain to enter the pelvic nerves at the base of the bladder and the ureter.

Question 2

What is the green nerve supply representative of?

Answer 2

•Parasympathetic preganglionic fibres (green) arise from the S2–S4

Travel in sacral roots and pelvic nerves (PEL) to ganglia in the pelvic plexus (PP) and in the bladder wall.

Question 3

What does the yellow nerve supply show?

Answer 3

Somatic motor nerves (yellow) supply the striated muscles of the external urethral sphincter

Arise from S2–S4 motor neurons and pass through the pudendal nerves

Question 4

Describe parasympathetic neural regulation of the bladder

Answer 4

•Parasymp postganglionic axons in the pelvic nerve release (ACh). This stimulates M3 receptors in the bladder smooth muscle which contracts it.

This helps to void urine

Question 5

Describe sympathetic neural regulation of the bladder

Answer 5

•Symp postganglionic neurons release NA. This activates β3 adrenergic receptors to relax bladder smooth muscle, so you can hold urine. It also activates α1 adrenergic receptors to contract urethral sm.

NOTE: Females don’t have an innervated alpha 1 receptor, so cannot take drugs for urinary retention that act on Aplha 1 receptors

Question 6

Describe somatic neural bladder regulation

Answer 6

Somatic axons in the pudendal nerve also release ACh

This activates nicotinic cholinergic receptors which contracts the external sphincter.

Question 7

Describe control of micturition

Answer 7

Partially filled detrusor sends slow impulses which stimulate the hypogastric nerve which releases NA.
This stimulates the a1 receptor which contracts the internal sphincter. You can hold urine.
Hypogastic nerve stimulates B3 receptors in detrusor sm. This relaxes the detrusor so it can retain more urine.
Pelvic nerve releases Ach, acts on M3 receptors and relaxes detrusor.
Pudendal nerve acts on nic receptors and contracts external sphincter so urine is not released

The opp happens when voiding. Symp is for urinary retention, para= void

Question 8

What are kidney stones and its symptoms?

Answer 8

Kidney stones can form in kidney, ureter or in bladder. Symptoms:

• Dysuria (painful urination)
• Haematuria
• back pain
• Reduced urine flow
• Urinary tract obstruction: pressure reaches 50mmHg - causes pain “renal colic”
• If stone approaches tip of urethra, intense pain can inhibit micturition – “strangury”
• CT scans better to diagnose stones, bc u cant see some stones on Xray

Question 9

What are the 4 major types of kidney stones?

Answer 9

• Calcium, struvite, uric acid and cystine
• Calcium is present in nearly all stones, as calcium oxalate or calcium phosphate
• Normal urine contains inhibitors (citrate) to prevent stones

Question 10

What are kidney stones caused by?

Answer 10

Caused by poor urine output/obstruction, altered urinary pH, infection, excess dietary intake of stone-forming substances.

Dehydration, metabolic acidosis, diarrhoea can decrease citrate in urine, which means the body is mas likely to produce stones

Question 11

how does aging hinder lower urine tract function?

Answer 11

Overactive bladder: caused by Ischaemia, Oxidative stress and inflammation from aging

Symptoms: Urgency, incontinence, frequency, nocturia (waking up Hz). Treated with anti-muscarinic for both male and female such as:

• Trospium [Regurin]
• Oxybutanin [Ditropan]
• Tolterodine [Detrusitol]

Question 12

Describe bladder dysfunction with aging in men

Answer 12

•BPH causes difficulty in emptying the bladder. This can be relieved by smooth muscle relaxation with α1 antagonists:

• Tamsulosin [Flomax]
• Doxazocin [Cardura], also used as an antihypertensive- can have dual action

Question 13

Outline urinary tract conditions and how they are managed

Answer 13

Question 14

Outline increased urine production conditions and how they are managed

Answer 14

Question 15

How would you treat stress incontinence?

Answer 15

• Pelvic muscle (Kegel) exercises
• Timed voiding and double voiding to avoid residual urine
• Topical estrogen to strengthen periurethral tissue (ineffective alone; oral estrogens contraindicated)
• Periurethral injections to provide bulking and support
• Surgical bladder neck suspension or sling for severe incontinence

Question 16

Outline treatments for Urge and overactive bladder symptoms

Answer 16

Pelvic muscle (Kegel) exercises

Other behavioral interventions-—timed voiding and double voiding to avoid residual urine

Antimuscarinic and beta-3 adrenergic drugs

Question 17

How would you treat:

Incontinence with incomplete bladder emptying

Incontinence with impaired physical and/or cognitive function

Answer 17

Incontinence with incomplete bladder emptying
α-Adrenergic antagonists (men)
Bladder training, double voiding
Intermittent catheterization

*Incontinence with impaired physical and/or cognitive function*
Behavioral interventions (prompted voiding, habit training)
Environmental intervention inc a bedside commode, safe lit path to toilet
Incontinence pads