Paediatric Surgery SC043: Why Do You Wet Your Bed All The Time? Paediatric Urology Flashcards
Paediatric urology problems
- Wetting
- Urinary infection
- Obstructive uropathy
- Penile conditions
Common complaints (FUN):
1. Nocturnal enuresis
2. Urinary frequency
3. Urinary urgency
4. Uurinary tract infection (UTI)
Terminology and Definitions (ICCS definition)
- Incontinence: Uncontrollable leakage of urine
- Enuresis: Intermittent incontinence while sleeping
—> Primary enuresis: never been dry since birth for ***>=6 months
—> Secondary enuresis: previously dry >=6 months and now wet again
History taking of Urinary incontinence
- Age of patient (> / < 5yo)
- Continuous vs Intermittent urinary incontinence
- Wet only night time vs Other symptoms in daytime
- daytime frequency
- daytime incontinence
- daytime urgency
- symptoms of Bladder Bowel Dysfunction (BBD) (e.g. constipation, bowel incontinence) - Any holding maneuvers (忍尿) (things done by the child to avoid going to the bathroom, such as squatting, leg crossing or holding the genital area)
- Urinary habit
- fluid intake (type + volume) - Behavioural problems (e.g. ADHD, neurological problems)
Algorithm of Urinary incontinence
Classification:
- Continuous vs Intermittent
- Daytime vs Nocturnal
- Monosymptomatic (no other system involvement) vs Non-monosymptomatic
- Primary vs Secondary
Incontinence >=5 yo
—> Continuous urinary incontinence —> Refer specialist
—> Intermittent urinary incontinence
—> Daytime incontinence —> Refer specialist
—> Nocturnal enuresis
—> Monosymptomatic
—> Primary —> ***Primary monosymptomatic nocturnal enuresis (PMNE)
—> Secondary —> Refer specialist
—> Non-monosymptomatic —> Primary / Secondary —> Refer specialist
簡單而言: except for PMNE, all others —> Refer specialist
Primary monosymptomatic nocturnal enuresis (PMNE) vs Non-monosymptomatic nocturnal enuresis (NMNE)
***Very important to differentiate PMNE vs NMNE
PMNE:
- NOT need surgery
- Majority of wetting
Non-monosymptomatic nocturnal enuresis (NMNE):
- May be an underlying anatomical / surgical cause
- May need surgical investigations / interventions
P/E of Urinary incontinence
Abdomen:
- Palpable bladder
- Impacted stool
Perineum:
- Labial adhesion
- Ectopic ureteric opening (rare)
- Ureterocele
Back:
- ?Spina bifida occulta
Lower limbs:
- Weakness
- Increased jerk
Investigations of enuresis
Comprehensive evaluation of urinary + bowel pattern:
1. ***Bladder diary
- Enuresis chart: minimum of 7 continuous nights of recording
- Frequency / Volume chart: minimum of 48 hours of recording of volume voided + volume intake
- ***Bowel diary
- 7-day diary using Bristol stool scale
Rule out UTI (self notes):
1. ***MSU + RM (multistix), C/ST
Urodynamic tools:
1. **USG of urinary system
2. **Uroflow + residual urine
3. Urodynamic study (invasive)
- Bladder catheterisation (suprapubic vs transurethral)
- Catheter in rectum
***Causes of Urinary incontinence
- ***Primary nocturnal enuresis (most common)
- ***Anatomic incontinence
- Ectopic ureter (Extravesical)
- Obstruction (PUV, (PUJO, VUJO, Labial adhesions, Urethral prolapse, Ureterocele))
- Anomalies (Exstrophy, (Abnormal urethral opening)) - ***Neurogenic incontinence
- Congenital (Neural tube defects (Spina bifida, Myelomeningocele, Anorectal malformations))
- Acquired (Trauma, Tumour, Anoxic brain injury, Extensive pelvic surgery) - ***Functional incontinence (when no anatomical / neurological cause found)
- Detrusor overactivity
- Infrequent voider (Lazy bladder)
- Dysfunctional voiding (DSD) - Miscellaneous (**UTI, **Polyuria)
Primary monosymptomatic nocturnal enuresis (PMNE / PNE)
Pathophysiology:
3 major pathogenic mechanisms
1. Nocturnal polyuria
2. Increased arousal threshold
3. Detrusor overactivity
ICD definition:
- **>=2 times / week for **>3 months in a child ***>=5 yo
- Monosymptomatic (no other system involvement)
Epidemiology:
- 15-20% of 5 yo in UK
- 3.5% of 4-12 yo in HK
- M>F
Natural course:
- ***Resolution with age for most
- Some will wet till adults
Approach to PMNE
Clinical diagnosis:
- Primary + Monosymptomatic + Enuresis
Specific questions to rule out other causes:
- **Daytime urinary symptoms
- **Constipation —> **Always treat constipation before urinary incontinence
- **Neurological symptoms
Ask associated conditions:
- **ADHD, **OSA —> higher prevalence of PNE + more difficult to achieve continence
Investigations of PMNE
Most PNE patients do NOT need invasive investigations unless
- Doubt in Dx
- Treatment failure
Investigations:
1. ***MSU + RM (multistix), C/ST
2. USG urinary system
3. Urodynamic study
Management of PMNE
- Behavioural modification (mainstay)
- **Void before bed
- **Fluid + salt restriction 2 hours before sleep
- ***Star chart (encouragement) - ***Desmopressin (DDAVP) (Anti-diuretic hormone)
- ***Enuresis alarm
If above not successful —> Review Dx
4. Anticholinergics (2nd line treatment)
- only for those with component of detrusor overactivity
Anatomic incontinence
- Ectopic ureter (Extravesical)
- Duplex system —> extra ureter —> obstructing ureterocele / extravesicle ectopic ureter (e.g. insert into urethra directly causing leakage)
—> Wetting in between normal voids (normal void from normal side of ureter, wetting / leakage from ectopic ureter) - Obstruction (can lead to residual bladder problem)
- Posterior urethral valve
(- PUJO
- VUJO
- Labial adhesions
- Urethral prolapse
- Ureterocele) - Anomalies
- Exstrophy (bladder exposed on abdominal wall)
(- Abnormal urethral opening)
Neurogenic incontinence
Congenital:
- ***Neural tube defects (Spina bifida, Myelomeningocele, Anorectal malformations)
Acquired:
- **Trauma
- Tumour
- Anoxic brain injury
- **Extensive pelvic surgery
Initial diagnosis:
- Establish diagnosis + type of problem on Urodynamic studies
Aim of management:
- Achieve continence
- Prevent UTI
- **Prevent bladder deterioration
- **Prevent renal failure
Management:
1. Close + consistent follow up
- Regular urodynamic studies
- Use of clean intermittent catheterisation (CIC) (to resolve incomplete voiding)
- Regular USG urinary system
- Anticholinergic therapy
- Increase bladder capacity + lower bladder storage pressure + abolish overactive contractions - Others
- Botox injection to detrusor muscle
Functional incontinence
-
**Detrusor overactivity
- Premature detrusor contraction during **filling
- Antimuscarinic, Desmopressin, Urotherapy (e.g. Bladder training) - Infrequent voider (***Lazy bladder)
- Large capacity, excessively compliant bladder
- Urotherapy - ***Dysfunctional voiding
- Urethral sphincter contraction during voiding (DSD)
- Desmopressin, Urotherapy
***Urinary tract infection (UTI)
Causes:
1. Urinary stasis (∵ bacteria have time to grow)
- **VUR (relative obstruction)
- **Obstruction
—> Mechanical (PUV, (PUJO, VUJO))
—> Neuropathic
- ***Bladder dysfunction
—> ALL can lead to renal failure
- Others
- **Stones
- **Ascending UTI (esp. in girls with short urethra, e.g. bubble-bath —> bacteria can ascend into bladder)
History:
- Non-specific symptoms in infant, young child
- Specific urinary symptoms in older child
P/E:
- Abdominal mass
- Bladder
- External genitalia
- Sacrum
Investigations:
1. Urine culture before antibiotics
2. Investigate underlying cause (otherwise may relapse)
Anatomical assessment:
1. USG
2. ***MCUG (Micturating cystourethrography) (for Vesicoureteric reflux —> grade 1-5)
Functional assessment:
1. ***Radioisotope renography (preferred over IV urogram in children, ∵ lower ionising radiation risk + give specific renal function quantification —> guide intervention)
- MAG3 scan (mercaptoacetyl triglycerine): Renal tubules, Drainage, Differential renal function
- DTPA scan (diethylene triamine pentaacetic acid): Glomerular filtration, Drainage
- DMSA scan (dimercaptosuccinic acid): concentrated in renal parenchyma —> give Differential renal function
Management:
1. Underlying cause
2. Antibiotics
***Vesicoureteric reflux (VUR)
- 1% prevalence
Classification:
1. Primary
- deficiency in formation of VUJ —> abnormal insertion of ureter into bladder —> shorter segment of ureter embedded in detrusor —> lose normal “valve” mechanism by detrusor contraction during micturition
- majority resolve with time
- Secondary
- a result of urinary tract ***dysfunction
—> dysfunctional voiding
—> neuropathic bladder
—> obstruction
—> ?infection
- must correct the predisposing factor
Complications:
1. VUR-UTI
2. Reflux nephropathy
3. Renal scarring
4. Renal failure, renal hypertension
Investigations:
1. **MCUG (Grade 1-5)
2. **DMSA (assess whether there is renal scarring)
Management:
1. Antibiotic prophylaxis
- **Trimethoprim / **Septrin (once a night for first 4 years of life)
- Surgery
- **Endoscopic “Deflux” injection (inject gel into ureteric insertion as a blockage mechanism)
- **Ureteric reimplantation (Open / Minimally invasive)
Indications for surgery:
- Recurrent infection
- Breakthrough infection (infection despite antibiotic prophylaxis)
- Progressive renal injury (deteriorating DMSA scan)
- Non-compliance with medical treatment
- Associated anomalies, grade 5 VUR (older child)
Prognosis (Resolution % without treatment):
- Grade 1: 90%
- Grade 2: 75%
- Grade 3: 50%
- Grade 4: 25%
- Grade 5: 0-5% (newborns 35%)
***Posterior urethral valve
- Folds from distal verumontanum extending anterolaterally
- Most common obstructive uropathy leading to renal failure in newborn boys
Types:
- Extend distally 95%
- Extend proximally 0%
- Membrane 5%
Diagnosis:
- Antenatal diagnosis (by USG: bilateral dilated pelvicalyceal system)
- Other symptoms later in life (present later ∵ incomplete valve)
—> Urinary incontinence
—> UTI
Presentation:
1. Antenatal
- Urinary ascites
- Keyhole sign
- Postnatal
- ***Respiratory distress due to pulmonary hypoplasia (∵ absence of urine in amniotic fluid —> low amniotic fluid volume)
- Urinary retention - Urinary symptoms
- Weak stream
- Voiding dysfunction (“Valve bladder”)
- UTI
Investigations:
1. USG
2. ***MCUG (show dilated posterior urethra)
3. Endoscopy
- Diagnosis
- Valve ablation
Management:
- ***Endoscopic valve ablation
- Severe: Bladder drainage, Stabilisation before surgery
Long term sequalae:
- Bladder damage
- Renal damage
Phimosis
Phimosis =/= Non-retractile foreskin
Retractile foreskin:
- Newborn: 0-4% (almost all baby cannot retract foreskin, prepuce is tight for most newborn boys and is normal)
- 1 yo: 50%
- 4 yo: 90%
—> need to counsel parents + teach correct technique to retract foreskin (need perseverance) —> rmb to pull forward foreskin afterwards —> otherwise paraphimosis
Phimosis:
- Pathological condition
- True phimosis: 1% boys
- Secondary to ***Balanitis xerotica obliterans (BXO)
BXO:
- chronic + progressive inflammatory condition characterised by hyperkeratosis (~ lichen sclerosis in skin) affecting glans + prepuce —> scarred + non-retractile foreskin, narrow preputial ring, meatal stenosis if glans involved
Indications for circumcision
Absolute:
- **Phimosis
- **Paraphimosis (inability to pull forward retracted foreskin)
Relative:
- Recurrent balanitis
Non-medical:
- Religious
- Social
Controversial:
- Prevent UTI, carcinoma, HIV
Non-indications:
- Non-retractile foreskin <4 yo
Contraindications (∵ require foreskin for reconstruction):
- **Hypospadias
- **Micropenis
- ***Webbed penis
- Buried penis (apparent absence of penis exist when it lacks it proper sheath of skin, lies buried beneath the integument of abdomen / scrotum) (vs Concealed penis: acquired condition with thick suprapubic SC fat pad in an obese boy, self-correcting in adolescence)
Alternatives to circumcision
- ***Steroid cream (encourage separation of non-retractile foreskin)
- ***Preputial stretching (require perseverance)
- Preputioplasty
