Case Study: Urology 1: BPH Flashcards
Causes of difficulty in passing urine
- BPH (a histological diagnosis —> require biopsy / surgery) (clinical diagnosis —> BPE (enlargement))
- Urethral stricture (***younger patients)
- Malignant enlargement of prostate
- Haematuria / Clot related
- Bladder / Urethral stone (usually a consequence rather than cause of ROU)
- UTI / Prostatitis
- Neurological (e.g. spinal cord injury, spina bifida, MS, DSD) —> Storage + Voiding LUTS
- Penile / Urethral tumours (very rare)
History taking of Difficulty passing urine
- Voiding LUTS
- Hesitancy
- Poor stream
- Straining
- Incomplete emptying
- Terminal dribbling
- Double micturition to complete voiding - Storage LUTS
- Frequency
- Urgency
- Nocturia
- Overflow incontinence
- ?Sexual dysfunction - Symptoms suggestive of ***UTI
- ***Haematuria (often coexist with LUTS e.g. Ca bladder esp. in trigone area —> can cause Storage LUTS)
- **Bedwetting during night time (suggestive of HPCR (high pressure chronic retention (CROU)) —> **Overflow incontinence)
- ***Pelvic pathology / Pelvic surgery (e.g. colorectal / gynaecological surgery)
- ***Back pain, back pathology history
- ***Neurological symptoms
- Lifestyle
- Drinking habit (tea, coffee, alcohol)
- Sleeping pattern
- OSA symptoms (waking up at night)
- Cardiac / Renal history + drugs
P/E of Difficulty passing urine
- General
- Uraemia - Abdominal
- Presence / Absence of distended bladder
- Ballotable kidneys - DRE
- Prostate: Consistency, Symmetry, Size (1 finger breadth: 20g (normal prostate <20g)), Induration (in prostatitis)
- Rectal mass (e.g. impacted faeces)
- Anal tone - External genitalia
- Prepuce / Penile shaft skin changes (e.g. lichen sclerosus et atrophicus / BXO —> Phimosis + Urethral stricture)
- Excoriation of genitals (secondary to incontinence —> irritation of genitalia)
- Urethral discharge (UTI) - Vaginal examination
- Pelvic mass - Focused back + neurological examination
How useful is DRE at detecting prostate cancer?
- PPV of abnormal DRE to diagnose Ca prostate: 26-34% (***very low)
- PPV increase to 51% with addition of ***PSA (still not very good)
- Poor predictor of actual prostate volume >30ml (vs TRUS)
—> but at least can tell whether it is enlarged
Investigations of Difficulty passing urine
- Urine + MSU + C/S (rule out UTI, but cannot effectively rule out prostatitis (not necessarily caused by infection))
- Blood + Cr (esp. in CROU)
- Uroflowmetry assessment
- Post-void residual urine measurement
- Frequency-volume chart (esp. if Storage LUTS)
- IPSS questionnaire
- ?PSA (case by case, needs PSA counselling first)
- Optional
- KUB / USG of urinary tract if suspected bladder / urethral stone (uncommon)
Uroflowmetry
- Electronic recording of urinary flow rate through course of micturition
- Provide visual image of “strength” of patient’s urine stream
- Interpret with caution: **non-diagnostic, **non-specific for causes of symptoms
- Must void >150ml to be representative
- Drink 500-1000ml fluid and wait until the patient has a comfortably full bladder
- Pass urine into machine
- Avoid squeezing of penis
- Avoid stream wandering around the funnel (give inaccurate result)
- Avoid straining - Aim pass >=150ml (∵ voided volume too small —> flow will definitely weak —> inconclusive)
- Repeat if voided volume <150ml
Interpretation:
1. Look at voided volume
- >=150ml —> Representative
- <150ml —> Inconclusive
- Maximum flow (**Qmax)
- **predict risk of Urodynamical bladder outlet obstruction (BOO)
—> <10 ml/s: 90% of patients has BOO
—> 10-15 ml/s: 60%
—> >15 ml/s: 30%
(Normal values:
- Men <40: >=21 ml/s
- Men 40-60: >=18 ml/s
- Men >60: >=13 ml/s
- Women <50: >=25 ml/s
- Women >50: >=18 ml/s)
-
**Pattern
- Normal: Bell shape
- **Prolonged voiding + **Low Qmax: BPH
- **Plateau shape (Fixed Qmax): Stricture (pathognomonic: peak flow limited by diameter of stricture)
- Very high Qmax + Short voiding time: Detrusor overactivity (Dysfunctional voiding curve)
- Intermittent flow curve: Neurogenic bladder - ***Post-void residual urine (PVR)
- Normal: <50-100ml
Post-void residual urine volume (PVRU)
- Volume of urine remaining in bladder after micturition
- Considerable variability (e.g. diurnal)
- NOT diagnostic!
- Indicate **severity + likelihood of **back pressure on kidneys —> helps to decide if safe to WW / Early intervention
- NOT predict outcomes of treatment
Causes:
- Detrusor underactivity
- Bladder outflow obstruction (BOO)
- Combination
Measurement:
- USG: Bladder height x width x depth x 0.7
IPSS + QOL scores
***IPSS: International Prostatic Symptom Score
1. 7 questions on LUTS
- How often do you experience:
—> Storage: Frequency, Urgency, Nocturia (times)
—> Voiding: Intermittency, Straining, Slow stream, Sense of incomplete voiding
- Frequency: 0 (not at all) - 5 (all the time, except Nocturia)
- 0-7: Mild
- 8-19: Moderate
- 20-35: Severe
- 1 question on QOL
- 0 (delighted) - 6 (terrible)
Role:
1. Assess severity (guide treatment)
2. Monitor treatment response
3. Predict risk of progression of BPH (i.e. risk of future ROU, future need of surgery)
(Symptoms questionable when correlated with home uroflowmetry, only correlation with nocturia is good —> should do both together)
Frequency-volume chart
- for Storage LUTS
- 3 days of recording of fluid input + urine output + incontinence issue over 24 hours by patient
- 40% correlation with number of voids, 60% with time of voids, 70% with episodes of nocturia
- enables diagnosis of ***nocturnal polyuria (different entity (e.g. congestive heart failure, OSA, venous stasis, disruption of diurnal secretion of ADH) —> require different treatment)
- distinguish ***drinking habit vs genuine frequency
Urodynamics
- More invasive than Uroflowmetry
- also can see ***Detrusor contractility
- study function of LUT
- parameters measured:
—> **Intravesical + Rectal pressure
—> **Detrusor pressure (Intravesical - Rectal pressure)
—> **Uroflow rate
—> **Sphincter function EMG
—> ***Bladder volume - Cystogram + Reflux (Video)
- **High pressure (normal: 60) + **Low flow pattern —> ***Definitive of BOO (記)
Obstructed voiding =/= BOO
- Uroflowmetry NOT sufficient to diagnose BOO (∵ cannot distinguish obstruction from poor detrusor contractility: low detrusor pressure)
- Maximum flow rate (Qmax)
—> Qmax **15-20 ml/sec: Normal
—> Qmax <10 ml/sec: Abnormal
- **18% have BOO despite Qmax normal
Indication:
1. **Younger men (<50 yo)
2. **Equivocal uroflowmetry
- Elderly
- Flow rate >15 ml/s
- Very low flow and suspected bladder failure
3. Patients with **neurological symptoms / after radical pelvic surgery / neurological history (e.g. spina bifida, MS, Parkinson’s)
4. Previous **unsuccessful invasive treatment
5. Severe Irritative symptoms (may consider cystoscopy to check for bladder lesions)
Urethro-cystoscopy
- May find occlusive / vascular prostate, bladder diverticula, trabeculation, stones, bladder neck anatomy, urethral pathology
- Low prognostic value for diagnosis of BOO —> should NOT be done as a routine
- Only potentially helpful:
—> Haematuria
—> Urethral stricture
—> Suspicious of bladder cancer
—> Previous LUT surgery
Case:
- 72 yo man
- Increasing difficulty in passing urine
History:
- 1 year gradual onset
- Poor flow
- Terminal dribbling
- Straining
- Impact on QoL +++
- PMH: Haemorrhoids
P/E:
- Abdomen soft, non-tender
- No palpable bladder / mass
- External genitalia: circumcised penis, no abnormal skin changes, meatus normal
- Back / neurological exam: unremarkable
- DRE: smooth, benign-feeling, non-tender prostate, ***4 FB
Investigations:
- MSU: no growth, no blood
- Cr: 58 (normal)
- PSA: 1.8
- Uroflowmetry: low Qmax + prolonged voiding —> obstructive causes
BPH Terminology
- Prostatitism: Old terms (LUTS due to prostate, not used now)
- BPE: Clinical diagnosis of large prostate
- BPH: Histological diagnosis
- BOO: Blockage at outflow of urine, a ***Urodynamic diagnosis (High pressure + Low flow)
Hald diagram:
- BOO
- BPE
- LUTS
—> Can overlap but can occur on its own
