urinary continence & BPH Flashcards
What are the filling phase and voiding phase of micturition?
- Filling phase: bladder fills & distends without rise in intravesical pressure. Urethral sphincter contracts & closes urethra.
- Voiding phase: bladder contracts to expel urine, urethral sphincter relaxes & urethra opens.
What is difference in micturition in infants and adults?
- In infants micturition is local spinal reflex where bladder empties when it reaches critical pressure.
- In adults it can be initiated or inhibited by higher centre control of external urethral sphincter keeping it closed until it is appropriate to urinate.
What is innervation involved in micturition?
- M3 receptors (parasympathetic S2-S4) are stimulated as the bladder fills.
- As they become stretched & stimulated results in contraction of detrusor muscle for urination.
- Parasympathetic fibres inhibit internal urethral sphincter relaxing it and allowing bladder emptying.
- When bladder empties stretch fibres inactivated and sympathetic nervous system (T11-L2) stimulated to activate beta-3 receptors causing relaxation of detrusor allowing bladder to fill
What is stress incontinence?
Involuntary leakage on effort or exertion or sneezing/coughing.
What are investigations for stress urinary incontinence?
History & exam, positive stress test (demonstrate loss of urine on examination), urodynamics (urinary leakage during increase in intra-abdominal pressure in absence of detrusor contraction).
What is management for stress urinary incontinence?
- Non surgical physiotherapy with PFE.
- Surgical mid-urethral sling, colposuspension, periurethral bulking agents.
What is urge urinary incontinence (overactive bladder)?
Urinary urgency usually with urinary frequency and nocturia, with or without urge urinary incontnience
What is incidence of urge urinary incontinence?
16% in men and women over 40.
What are risk factors for urge urinary incontinence?
Age, prolapse, increased BMI, IBS, bladder irritants (caffeine, nicotine)
What is the pathology behind urge urinary incontinence?
- Involuntary detrusor muscle contractions.
- Cause can be idiopathic, neurogenic (loss of CNS inhibitory pathways) or bladder outlet obstruction
What are symptoms of urge urinary incontinence?
Urgency, frequency, nocturia & urgency incontinence, impact on QOL - sleep disorders, anxiety, depression.
What are investigations of urge urinary incontinence?
- Exclude infection with urine dipstick/MSU, voiding diaries, assess post-void residual, urodynamics, cytoscopy.
- Assess for enlarged prostate in men & prolapse in women
What is management of urge urinary incontinence?
Behaviour/lifestyle changes, bladder retraining, anti-muscarinic drugs, beta-3 agonists, BOTOX, neuromodulation (PTNS/SNS), surgical augmentation cytoplasty & urinary diversion
What is overflow incontinence?
Involuntary leakage of urine when bladder is full.
What are causes of overflow incontinence?
Usually due to chronic retention secondary to obstruction or atonic bladder. Eg. Outlet obstruction (faecal impaction/BPH), under-active detrusor muscle, bladder neck stricture, urethral stricture, drug history of alpha-adrenergics, anti-cholinergics, sedative, bladder denervation following surgery
What is continuous incontinence? Causes?
Continuous loss of urine all the time.
Can be due to vesicovaginal fistula, ectopic ureter (from kidney to urethra or vagina)
What is functional incontinence?
Due to severe cognitive impairment or mobility limitations preventing use of the toilet. Bladder function otherwise normal.
What is mixed urinary incontinence?
More than 1 type, usually in elderly
What is benign prostatic hyperplasia? what is it a common cause of?
Non-malignant growth or hyperplasia of prostate tissue, common cause of lower urinary tract symptoms in men.
What is incidence of BPH?
Increases with age, 50-60% fore males in 60s, increasing to 80-90% for those over 70 years old
What are risk factors for BPH?
Hormonal effects of testosterone on prostate
What is pathophysiology of BPH?
Hyperplasia of both lateral and median lobes leading to compression of urethra and thus bladder outflow obstruction. Hyperplasia of stroma (smooth muscle & fibrous tissue) & glands.
What are signs and symptoms of BPH?
Hesitancy in starting urination, poor stream, dribbling post-micturition. Frequency, nocturia. Can present with acute retention
What are other causes of symptoms of BPH and how do you exclude these causes?
-Bladder/prostate cancer, cauda equina, high pressure chronic retention, UTI/STI, prostatis, neurogenic bladder (secondary to PD, MS), urinary tract stones, urethral stricture.
To exclude, do abdo, pelvic and rectal examination
What investigations for BPH?
- Urine dipstick/MCS, post void residual, voiding diary.
- Bloods: PSA prostate specific antigen - to predict prostate volume (with caution if concerned about cancer).
- Imaging –> ultrasound to assess upper renal tracts, flow studies/urodynamics, cytoscopy if worried about cancer
What is management for BPH?
- Lifestyle (weight loss, reduce caffeine and fluids in evening, avoid constipation)
- medical –>
1. alpha blocker - alpha 1-AR present on prostate stromal smooth muscle & bladder neck with blockage resulting in relaxation so improves urinary flow rate
2. 5-alpha reductase inhibitor - prevents conversion of testosterone to DHT (which promotes growth of prostate) so results in shrinkage and improves urinary flow and obstructive symptoms
3. surgery - transurethral resection of prostate (TURP) which debulks prostate to produce adequate channel for urinary flow
What are complications of BPH?
- Progressive bladder distention causing chronic painless retention & overflow incontinence.
- If undetected can lead to bilateral upper tract obstruction & renal impairment with patient presenting with chronic renal disease
