9.7 - Urinary incontinence and urinary tract symptoms Flashcards
What is the urinary tract composed of in most people?
Two kidneys, two ureters, urinary bladder and urethra
What is the role of the kidneys in the urinary tract?
Kidneys remove waste products of metabolism, excess water and salts from the blood, and maintain the pH
At what vertebral level is the hilum of the kidneys found?
L1
What is the role of the ureters in the urinary tract?
Convey urine from the kidneys to the urinary bladder
Describe the structure of the ureters.
- each one is about 25cm long, upper half lies in abdomen and lower half in pelvis
- approximately 3mm in diameter
- 3 layers of tissue - outer fibrous tissue, middle muscle layer and inner epithelium layer
What is the blood supply to the urinary tract?
Renal/lumbar/gonadal/common iliac, internal iliac and superior vesical arteries (depending on location) with corresponding venous drainage
What is the lymphatic drainage of the urinary tract - where do the left and right ureter drain into?
- left ureter drains into left para-aortic nodes
- right ureter drains into right paracaval and interaortocaval lymph nodes
What is the nerve supply to the urinary tract?
Autonomic nervous system
Describe the anatomical orientation of the organs in the pelvis.
- kidneys are retroperitoneal
- ureters descend in front of the tips of transverse spinous processes, cross sacro-iliac joint, then forwards next to rectum/vagina
- bladder is anterior in pelvis (behind the pubis)
What are some variations in kidney anatomy that some people have? (3)
- single kidney (1% of the population)
- horse-shoe kidney (also lays too low down)
- ectopic kidney
What are some variations in ureter anatomy that some people have? (2)
- partial duplication
- complete duplication (2 ureters)
What are the three constriction points in the ureter?
- pelvic ureteric junction (PUJ) - where the renal pelvis joins the top of the ureter
- pelvic brim - crossing the iliac vessels
- uretero-vesical junction/vesicoureteric junction (VUJ) - as it passes through the bladder wall
Why might the constriction points of the ureter cause problems?
They may block urine flow, especially if a kidney stone dislodges and becomes a ureteric stone (pain, ipsilateral impaired renal function)
How can we use contrast scans to see kidney dysfunction?
- initial - no contrast may be taken up due to the blockage, whereas normal side takes contrast
- after some time - dysfunctional side still has contrast (not cleared by excretion) whereas the normal side has none (bladder has contrast due to working kidney excretion)
What is the purpose of the urinary bladder?
Muscular reservoir of urine
What lines the detrusor muscle?
Waterproof urothelium - a transitional epithelium
Describe the shape of the urinary bladder and where it resides anatomically.
- when empty it is a pelvic organ, when distended it is an abdomino-pelvic organ
- an empty bladder is a 4-sided pyramid in shape and has 4 angles - apex, neck and 2 lateral angles
- it has 4 surfaces - base/posterior surface, 2 infero-lateral surfaces and a superior surface
What are the three layers of the urinary bladder?
- outer loose connective tissue
- middle smooth muscle and elastic fibres (detrusor)
- inner layer lined with transitional epithelium
What is the blood supply of the urinary bladder?
- superior and inferior vesical branches of internal iliac artery
- drained by vesical plexus which drains into internal iliac vein
What is the lymphatic drainage of the urinary bladder?
Internal iliac nodes and then para-aortic nodes
What is the nerve supply to the urinary bladder?
Autonomic nervous system
Where does the urethra carry urine from in the female urinary tract?
Urethra carries urine from bladder to the external urethral meatus in the vaginal vestibule (urethra 3-4cm long)
Describe the external urethral sphincter (and its nervous supply) in the female urinary tract.
- skeletal muscle
- tonic contraction and also voluntary ‘guarding’
- controlled by pudendal nerve
What is the blood supply of the female urinary tract?
Internal pudendal arteries and inferior vesical branches of the vaginal arteries with corresponding venous drainage
What is the lymphatic drainage of the female urinary tract?
- proximal urethra into internal iliac nodes
- distal urethra into superficial inguinal lymph nodes
What is the nerve supply to the female urinary tract?
- proximal - vesical plexus
- distal - pudendal nerve
What does the male urinary tract have that the female urinary tract does not?
Prostate gland
What is the role of the bladder neck in the male urinary tract?
- a sphincter which stays shut except when voiding (urinating)
- stays constricted during ejaculation to prevent urination
- controlled by the sympathetic nervous system
Where is the prostate?
- gland lying below the bladder in the male and surrounds the proximal part of the urethra
- measures 4x3x2cm and conical in shape
- connected to bladder by connective tissue
What are the three lobes of the prostate?
- left lateral lobe
- middle lobe
- right lateral lobe
What is the function of the prostate?
Secretes 75% of the seminal fluid which liquifies coagulated semen after deposition in the female genital tract
Describe the external urethral sphincter (and its nerve supply) of the male urinary tract.
- tonic contraction / guarding
- opens for ejaculation
- controlled by pudendal nerve
Describe the blood supply of the male urinary tract (prostate and urethra).
- prostate - inferior vesical artery
- urethra - bulbourethral artery and internal pudendal artery
- corresponding venous drainage
Describe the lymphatic drainage of the male urinary tract.
- prostatic and membranous urethra –> obturator and internal iliac nodes
- spongy urethra –> deep and superficial inguinal nodes
Describe the nerve supply to the male urinary tract.
- proximal - vesical plexus
- distal - pudendal nerve
What is normal micturition?
Intermittent voiding of urine stored in bladder
What are the two phases of micturition and describe them?
- storage (sympathetic):
- bladder (detrusor) relaxed, serving as reservoir
- external sphincter (outlet) contracted, preventing leaks
- voiding (parasympathetic):
- bladder contracting, expelling the urine
- external sphincter (outlet) relaxed, permitting flow
- bladder should empty fully (<50ml ‘post void residual’)
- 6 pees daily, 20 seconds each = 2 mins per day spent voiding
What is the role of the prefrontal cortex in micturition?
- prefrontal cortex permits the pontine micturition centre in the brainstem to change from storage mode to voiding
- this activates the parasympathetic nucleus (bladder contraction) and inhibits Onuf’s nucleus (sphincter relaxation)
Describe the physiology of micturition in adults.
- periaqueductal gray (PAG) - receives sensory information from viscera (subconscious) and decides what goes to cortex (conscious)
- frontal cortex - decides actions based on planning ahead, social appropriateness etc
- pontine micturition centre (PMC - controlled by prefrontal cortex) - coordinates spinal centres; storage switches to voiding only if permitted
- sacral S2-S4 (parasympathetic nucleus –> detrusor contraction, Onuf’s nucleus inhibition –> sphincter relaxation) + thoracic T10-L2 (sympathetic nucleus - bladder neck of male)
What is the difference between micturition in infants and in adults?
- infants - micturition is a local spinal reflex in which bladder empties on reaching a critical pressure (hence potty training needed)
- adults - voiding can be initiated or inhibited by higher centre control of the external urethral sphincter keeping it closed until it is appropriate to urinate
Which urinary structures get sympathetic innervation from L1-L2? (3)
- kidney
- testicle
- bladder neck
What urinary tract structures do the pudendal nerve (S2-S4) supply? (2)
- penis
- vaginal vestibule/clitoris
Describe the innervation of micturition and its process.
- bladder has M3 muscarinic receptors that work with parasympathetic fibres S2-S4, which are stretched and stimulated as the bladder fills
- this results in contraction of the detrusor muscle for urination
- at the same time, parasympathetic fibres inhibit the internal urethral sphincter causing relaxation and allows for bladder emptying
- when bladder empties, stretch fibres become inactivated
- sympathetic nervous system (originating T10-L2) is stimulated to activate the beta 3 receptors
- this causes relaxation of the detrusor muscle allowing the bladder to fill again
What are the autonomic receptor drug targets of the bladder neck?
Alpha-adrenergic (alpha1) –> alpha blocker e.g. tamsulosin
What are the autonomic receptor drug targets of the detrusor?
- cholinergic M3/M2 –> antimuscarinic e.g. oxybutynin, solifenacin
- beta-adrenergic beta3 agonist e.g. mirabegron
What are the autonomic receptor drug targets for erectile issues?
Nitrergic e.g. PDE5 inhibitor
What does the International Continence Society define incontinence as?
Any involuntary loss of urine
Define stress urinary incontinence.
Complaint of involuntary leakage on effort or exertion, or on sneezing or coughing
What are the incidence rates of stress urinary incontinence and who does it affect more?
- can affect up to 40% of women
- more common in older women - 1/5 women over 40 have some degree of stress incontinence
What are the risk factors for stress urinary incontinence? (5)
- aging
- obesity (increases intra-abdominal pressure)
- smoking
- pregnancy (puts pressure on pelvic floor)
- route of delivery
Describe the pathology of stress urinary incontinence.
- impaired bladder and urethral support, and impaired urethral closure
- usually when you sneeze/cough no leaking occurs as external urethral sphincter is closed
- in stress incontinence, the sphincter is not closed so coughing/sneezing/increased intra-abdominal pressure causes leak
What are the signs and symptoms of stress urinary incontinence?
Involuntary leakage of urine from urethra with exertion/effort, or sneezing/coughing
What investigations do we do for stress urinary incontinence?
- history and examination, descent of pelvic floor on vaginal examination, positive stress test (visible loss of urine on inspection)
- urodynamics - urinary leakage during an increase in intra-abdominal pressure in the absence of detrusor contraction (when patient coughs, you see spike in intra-abdominal Pa, spike in bladder Pa but no bladder contraction, and urine flow)
How do we manage stress urinary incontinence? (4)
- non-surgical: physiotherapist teaching pelvic floor muscle exercises
- surgical:
- sling placed to support urethra (mid-urethral sling)
- colposuspension - using anterior vaginal wall to support urethra, reduces how much bladder moves when intra-abdominal Pa increases
- periurethral bulking injection - injected around sphincter to obstruct it to prevent leakage
Define overactive bladder (urgency, +/- urgency incontinence)
Urinary urgency, usually with urinary frequency and nocturia, +/- urgency urinary incontinence
What is the incidence of overactive bladder?
Overall prevalence of 16.6% in men and women over 40
What are the risk factors for overactive bladder? (5)
- age
- prolapse
- increased BMI
- bladder irritants (caffeine, nicotine, alcohol - increase urination)
- IBS
Describe the pathology of overactive bladder.
- not well understood
- involuntary ‘overactive’ detrusor (bladder wall) muscle contractions
- cause can be idiopathic or neurogenic (loss of CNS inhibitory pathways)
What are the signs and symptoms of overactive bladder? (6)
- urgency
- frequency
- nocturia
- urgency incontinence
- impact on QoL - sleep disruption
- anxiety and depression
What do we assess for in males vs females in overactive bladder?
- assess for enlarged prostate in males (can cause obstruction)
- assess for prolapse in women (urethra sits in anterior vaginal wall, if this prolapses urethra is dragged down to form obstruction)
How do we investigate overactive bladder? (4)
- exclude infection with urine dip/MSU
- bladder diary
- bladder scan (post-void residual)
- urodynamics - storage phase has detrusor overactivity (should be inactive) with incontinence (should be no urine flow)
How do we manage overactive bladder? (7)
- behavioural/lifestyle changes
- bladder retraining
- antimuscarinic drugs (block M3 = relax detrusor e.g. oxybutinin)
- beta-3 agonist (relax detrusor)
- bladder injections with botox (paralyse bladder)
- neuromodulation
- augmentation cystoplasty
Oxybutinin can however cause overflow incontinence
What is benign prostatic hyperplasia?
- non-malignant growth or hyperplasia of prostate tissue
- common cause of lower urinary tract symptoms in men
- outward enlargement can be felt with rectal exam
Describe the incidence of benign prostatic hyperplasia in men of different ages?
- increases with advancing age
- 50-60% for males in their 60s
- 80-90% for males 70+
What risk factor is there for benign prostatic hyperplasia?
Hormonal effects of testosterone on prostate tissue
Describe the pathology of benign prostatic hyperplasia.
- enlargement of the prostate due to hyperplasia/hypertrophy of both lateral lobes and the medial lobe –> compression of the urethra –> bladder outflow obstruction (reduction in urinary stream)
- you would see hyperplasia of the stroma (smooth muscle and fibrous tissue) and glands
- some men experience relatively little urethral compression, as the prostate enlargement goes outwards into the rectum rather than inwards
What are the signs and symptoms of benign prostatic hyperplasia? (5)
- hesitancy in starting urination
- poor stream (intermittent flow)
- dribbling post-micturition
- can present with acute retention
- frequency, nocturia
What other causes could there be instead of benign prostatic hyperplasia that we need to exclude? (4)
- bladder cancer (haematuria)
- prostate cancer (raised PSA)
- UTIs / prostatitis
- urethral stricture
What investigations (including bloods and imaging) do we do for benign prostatic hyperplasia? (7)
- urine dipstick/culture
- post-void residual
- bladder diary
- bloods - PSA
- imaging - ultrasound to assess upper renal tracts
- urinary flow studies/urodynamics
- cystoscopy if concerned about bladder cancer
What lifestyle changes do we suggest for benign prostatic hyperplasia? (3)
- weight loss
- reduce caffeine and fluid intake in evening
- avoid constipation - puts added pressure
What medical treatments are there for benign prostatic hyperplasia, and how do they work? (2)
- alpha blocker - alpha1 receptors on prostate stromal smooth muscle and bladder neck and blockage results in relaxation –> improved flow e.g. tamsulosin
- 5-alpha-reductase inhibitor - prevents conversion of testosterone into dihydrotestosterone (which promotes prostate growth) so slowly results in shrinkage = improved flow and obstructive symptoms e.g. finasteride
What surgical intervention is there for benign prostatic hyperplasia?
Transurethral resection of the prostate (TURP) - debulks prostate to produce adequate channel for urine to flow, can also be done with laser (not the same as radical prostatectomy for cancer)
What are some complications of benign prostatic hyperplasia?
- progressive bladder distention causing chronic painless retention and overflow incontinence
- if undetected can lead to bilateral upper tract obstruction and renal impairment with patient presenting with chronic renal disease
