Urinary Obstruction And Altered Voiding

Question 1

What are some of the causes of altered voiding?

Answer 1

Brain/spinal cord damage/peripheral nerve lesion
Blockage in kidneys, ureters, bladder and urethra
Prostate problems
Pelvic floor muscle problems

Question 2

What are lower urinary tract symptoms (LUTS)?

Answer 2

LUTS involve problems with the bladder, prostate and urethra ->
Storage LUTS = incontinence, urgency, frequency, nocturia
Voiding LUTS = poor stream, hesitancy, dysuria, intermittency, double voiding (needing to go straight after going once), retention, straining, incomplete emptying
Post-micturition LUTS = terminal dribbling

Question 3

What is urinary incontinence and how can it affect a patient?

Answer 3

Involuntary loss of urine in sufficient amount of frequency to constitute a social/health problem -> major cause of morbidity + institutionalisation, not usually life-threatening but quality of life impact (skin breakdown, pressure sores, numerous social + population issues)

Question 4

What is the prevalence of urinary incontinence?

Answer 4

Increases with age (not normal at any age)

Question 5

What are the different types of incontinence?

Answer 5

Stress incontinence (sphincters)
Urge incontinence (overactive bladder) - mixed (urgency and exertion problems)
Overflow incontinence
Functional incontinence
Continuous incontinence (constant leakage due to congenital, spinal cord injury, bladder fistula etc.)
Childhood incontinence/abnormal bedwetting (can indicate emotional problems)

Question 6

What is stress incontinence, how is it caused, who is most likely to experience it and how can you manage i

Answer 6

• Pressure inside bladder becomes greater than the strength of urethra to stay closed = raised intra-pelvic pressure (e.g. pregnancy) leads to leakage due to poor sphincter resistance
• Involuntary urine leakage on effort, exertion, sneezing or coughing for e.g.
• Common in middle aged females e.g. females after child bearing with bladder neck hypermobility/poor pelvic floor muscles (rare in males except post-prostate surgery)
• Pelvic floor training, incontinence protection, duloxetine (not 1st line) + surgery

Question 7

What is urge incontinence, how is it caused, who is most likely to experience it and how can you manage it?

Answer 7

• Involuntary urine leakage accompanied by urgency i.e. abrupt desire to void which is difficult to control = overactive bladder (detrusor muscle contracts suddenly when bladder is not full)
• Commonest cause of incontinence > 50 yrs
• Idiopathic mostly
• Consider infection, tumor, stones, bladder cancer, atrophic vaginitis, stroke, Parkinsons & dementia
• Avoid stimulants, bladder retaining, anticholinergics (oxybutynin), B3 adrenergic agonists + surgery

Question 8

What is overflow incontinence, how it is caused and who is most likely to experience it?

Answer 8

• Prolonged problems with bladder emptying e.g. via enlarged prostate, bladder stones, constipation, spinal cord injury which lead to chronic retention and detrusor failure
• Pressure eventually rises due to tissue overdistention causing leakage
• Commonly at night and in men

Question 9

What is functional incontinence, how is it caused and who is most likely to experience it?

Answer 9

• Consequence of something not involving LUT but involves psychological, cognitive or physical impairment
• E.G. mobility problems, dementia, diuretics (fruosemide and time to urination as works 30 minutes after taking and will probably need to wee at night if took after 4pm)

Question 10

How can you investigate incontinence?

Answer 10

• History (quantify symptoms): precipitating events, duration, pad usage & bother (how much), medical/surgical history (parity, pelvic surgery, diabetes, CVA, other neuro disorder) + medications
• Examination: abdomen, pelvic (genitalia), digital rectum exam, neurologic exam, mental status + mobility
• Investigations: MSU, dipstick, m + c + s, cytology, FBC, U&Es, glucose, frequency-volume chart + urodynamics (cystometry)

Question 11

What is involved in a frequency-volume chart?

Answer 11

How much you have drunk
How much urine passed
If/when there was leakage

Question 12

What is a urodynamics investigation and how is it performed?

Answer 12

Study of pressure and flow during storage, transport and expulsion of urine in the LUT: Fill bladder (+/- contrast for imaging) -> pee -> urine flow rate -> residual urine - detrusor function measured at inflow + outflow cystometry

Question 13

What is outflow cystometry and how is it performed?

Answer 13

Urethral catheter into bladder + transducer in rectum/vagina -> fill bladder with fluid (+/- contrast for imaging) -> record pressure in bladder + rectum/vagina -> bladder emptied and pressures recorded = bladder pressure combines abdominal + detrusor pressure whereas rectal pressure is from abdominal muscles so bladder - rectum = detrusor

Question 14

What are some of the relevant neurological problems and their consequences?

Answer 14

Damage to brain, spinal cord and sacral region can lead to -> incontinence, retention, UTI, kidney damage (hydrostatic pressure, pyelonephritis), stones (urine stasis) + cancer (metabolite retention)

Question 15

How can you manage continuous incontinence?

Answer 15

Usually requires surgical treatment of underlying anatomical disorder Catheterisation

Question 16

How can you manage urinary retention e.g. in BPH, overflow incontinence?

Answer 16

Restore bladder emptying e.g. intermittent self-catheterisation, surgical treatment of bladder outflow obstruction or long-term catheter
a blockers e.g. Doxazosin

Question 17

How can oxybutynin be used to treat urge incontinence/overactive bladder and what are its side effects?

Answer 17

• Detrusor muscle receptors include M2 + M3 and acetylcholine will stimulate these receptors to cause contraction as part of the parasympathetic pelvic nerve
• Oxybutynin is an anticholinergic that competitively inhibits M receptors, blocks acetylcholine and reduces detrusor responsiveness/activity
• Blocks M receptors throughout body so can cause dry mouth, dry eyes, constipation, heartburn, blurred vision, glaucoma, fatigue, tachycardia + urinary retention

Question 18

What causes urinary obstruction?

Answer 18

Obstruction
BPH (BPE to patient)
Prostate cancer
Prostatitis
Haematuria causing clots (think bladder cancer if patient is ~40-45 yrs)
Tumours
Stones
Structural (anatomy), physical or neurological

Question 19

What is BPH, who is most likely to experience it and what are the symptoms?

Answer 19

• Enlarged prostate compresses urethra via reduced apoptosis and increased proliferation (can be normal if does not cause retention)
• Common > 50 yrs old so risks are age, changes in androgens/oestrogens, genetic factors + diabetes
• Symptoms: hesitancy, straining, weak flow, stop-start peeing, increased urgency/frequency (at night commonly), incontinence + feeling of not fully emptying the bladder

Question 20

What is involved in the international prostate symptom score?

Answer 20

International prostate symptom score where there is 7 symptom questions: frequency, nocturia, urgency, hesitancy, poor stream, intermittency + incomplete emptying (score each one)
& 1 QOL question: If you were to spend the rest of your life with your urinary condition like this, how would you feel about that?

Question 21

How do you examine/investigate BPH?

Answer 21

• International prostate symptom score
• PSA (sensitivity?): may identify cancer (not used as screening tool), enlarged prostate (predicts volume), prostatitis or urinary infection - can even increase if you rub prostate
• Abdominal exam
• Digital rectal exam
• Imaging e.g. transrectal US scan -> CT or MRI if cancer is suspected

Question 22

How do you manage BPH and what are some of the complications of this?

Answer 22

• Watchful waiting whilst changing lifestyle e.g. less alcohol, caffeine, fizzy drinks, artificial sweeteners, exercise, drinking less in evening
• Drugs e.g. selective a1 blocker Doxazosin
• Surgery e.g. transurethral resection of prostate (TURP)
• Complications include UTI, acute urinary retention (emergency), incontinence + erectile problems following surgery

Question 23

How can Doxazosin be used to treat urinary retention and BPH?

Answer 23

• Bladder neck, urethra and prostate have sympathetic neurons + a1 adrenergic receptors where noradrenaline will cause smooth muscle contraction (retention)
• Doxazosin is a selective a1 blocker so relaxes smooth muscle facilitating urinary flow - flow proportional to vessel diameter (small increase in diameter = large increase in flow)
• Side effects as a1 blocked throughout body: nausea, dry mouth, fatigue, constipation but also anxiety, back pain, coughing, dyspnoea, fatigue, influenza-like symptoms, myalgia, paraesthesia, sleep disturbance and vertigo (BNF)

Question 24

What should a normal and abnormal prostate feel like? How can you differentiate between BPH and cancer?

Answer 24

Healthy: soft, smooth, symmetrical, regular + even
Abnormal: hard, lumpy + irregular

Peripheral zone: largest area, felt during rectal exam, most cancers start here so PZ will enlarge
Transition zone: surrounds urethra, increases with age and BPH
BPH causes symptoms but cancer has few although can be felt on prostate DRE

Question 25

What are urinary tract stones, when are they common and what can they cause?

Answer 25

• Common, seen in males more, around 20-30 years
• Varies with geography/climate, age, fluid intake, family history + affluence/diet/BMI
• Blockage + back pressure can cause renal failure
• Stones can cause infection, chronic inflammation + malignancy

Question 26

How are urinary stones formed?

Answer 26

Crystalline growth on organic scaffold -> urine normally supersaturated with salt + minerals but metastable -> stone formers produce more crystals than normal -> crystals aggregate to form small stones

Question 27

How do urinary crystals form stones?

Answer 27

Crystal growth is dependent on degree of supersaturation -> crystal aggregation dependent on collision of small crystals in urine -> particle retention static in urine in urological tract (urine samples contain small calcium oxalate crystals but only 5-10% form kidney stones)

Question 28

Where are the 4 places urinary stones get stuck?

Answer 28

Pelvic ureteric junction (PUJ)
Pelvic brim
Vesicoureteric junction
Bladder urethra outlet

Question 29

What are calcium oxalate stones and how does hypercalciuria + hyperoxaluria occur?

Answer 29

Commonest (80%) - Ca oxalate (60%) + Ca phosphate (20%) - large + smooth/spiky + rough - visible on X-ray - caused by:
Hypercalciuria: idiopathic, rare genetic disorders, hyperparathyroidism, malignancy + sarcoidosis/TB
Hyperoxaluria: primary (I & II) - genetic, secondary - dietary + enteric

Question 30

What are struvite stones and how are they caused?

Answer 30

• Form in alkaline urine that contains ammonia so they are caused by UTIs by urea-splitting bacteria e.g. Klebseilla, Pseudomonas (even low colony no.’s produce urease)
• Urea is converted to CO2 + NH3 via urease -> NH3 increases urine pH -> precipitation of magnesium, ammonium + phosphate to form stone (staghorn)
• Smooth, brown + softer than others, visible on X-ray

Question 31

What are the risk factors for struvite stones?

Answer 31

All related to UTIs; 
Female
Indwelling catheters
Neurogenic bladders
Urinary tract abnormalities 
Stagnant urine

Question 32

What are cystine stones and how are they formed?

Answer 32

Rare autosomal recessive tubular disorder causing cystinuria (homozygotes excrete much more cystine a day than normal people) -> cystine is not reabsorbed ->, it crystalizes -> young, multiple stones (often yellow, crystal-like, staghorn, weakly seen on X-ray) that are difficult to manage

Question 33

What are uric acid stones, how are they formed and what causes them?

Answer 33

Accumulation of urate in urine from purine metabolism for protein esp. red meat + alcohol, horn-shaped + large, visible on USS/CT not X-ray, can be caused by:
Gout (uric acid deposites)
Some medications e.g. chemo
Hyperuricaemia/hyperuricosura

Question 34

What is nephrocalcinosis?

Answer 34

Diffuse Ca2+ deposition seen as tiny speckles throughout kidneys or in cortex specifically (cortical calcinosis)

Question 35

How do patients with urinary stones present?

Answer 35

Loin to groin pain (ureteric colic) so can’t get comfy - radiates to testicle
Haematuria
Vomiting
Irritative voiding symptoms
Make sure to exclude AAA: pancreatitis, pyelonephritis, diverticular disease

Question 36

How do you investigate stones?

Answer 36

History e.g. previous stone information
Urine dipstick, m + c + s
U&Es, serum Ca + urate and if fever, WBC + CRP
Imaging is urgent but immediate if there is fever due to pyonephrosis - X-ray, US and CT of KUB

Question 37

How do you manage stones?

Answer 37

Observe (4-5mm can be passed, >7 cant)
Medication:
- Calcium stones: diuretics if hypercalciuria; normalise mineral homeostasis
- Struvite stones: antibiotics for UTI
- Uric acid stones: allopurional to decrease uric acid levels/medication to alkalise urine
- Cystine stones: medication to lower cystinuria
Removal

Question 38

When would you need to remove stones and what are the 3 ways you can do this?

Answer 38

Infected obstructed kidney requires immediate drainage but also pain/failure to pass, recurrent infection, renal impairment, obstruction, bleeding, increasing in size + some jobs (airline pilot)

Can be removed via fragmentation (most common), picking them out or rarely (<1%) removed surgically

Question 39

How are stones fragmented and what are the complications of this?

Answer 39

Extracorporeal shockwave lithotripsy (ESWL) is a focused US shockwave that fragments into pieces small enough to pass - sometimes need to insert stent into ureter to aid the passing of the stone (99% effective for stones up to 20mm)

May get pain, haematuria, UTI, steinstrasse or tubular damage

Question 40

How are stones removed via ureteroscopic removal?

Answer 40

Ureteroscope via urethra + bladder so stones can be removed but usually broken up by laser under GA
Stent is temporarily inserted to allow stone fragments to drain into bladder
(stones in upper ureter reached by percutaneous puncture of kidney where ureteroscope can be passed down to stone from above) (for stones up to 15mm 59-80% effective)

Question 41

How are stones removed via percutaneous nephrolithotomy?

Answer 41

Suitable for large kidney stones as flexible ureteroscopy would not work
Kidney punctured via back using nephroscope + X-ray or US guidance and stones < 1cm removed or broken into fragments by laser (good as do not need to solely rely on natural passage of stones)