Paediatric Surgery SC043: Why Do You Wet Your Bed All The Time? Paediatric Urology

Question 1

Paediatric urology problems

Answer 1

1. Wetting
2. Urinary infection
3. Obstructive uropathy
4. Penile conditions

Common complaints (FUN):
1. Nocturnal enuresis
2. Urinary frequency
3. Urinary urgency
4. Uurinary tract infection (UTI)

Question 2

Terminology and Definitions (ICCS definition)

Answer 2

• 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

Question 3

History taking of Urinary incontinence

Answer 3

1. Age of patient (> / < 5yo)
2. Continuous vs Intermittent urinary incontinence
3. 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)
4. 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)
5. Urinary habit
   - fluid intake (type + volume)
6. Behavioural problems (e.g. ADHD, neurological problems)

Question 4

Algorithm of Urinary incontinence

Answer 4

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

Question 5

Primary monosymptomatic nocturnal enuresis (PMNE) vs Non-monosymptomatic nocturnal enuresis (NMNE)

Answer 5

***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

Question 6

P/E of Urinary incontinence

Answer 6

Abdomen:
- Palpable bladder
- Impacted stool

Perineum:
- Labial adhesion
- Ectopic ureteric opening (rare)
- Ureterocele

Back:
- ?Spina bifida occulta

Lower limbs:
- Weakness
- Increased jerk

Question 7

Investigations of enuresis

Answer 7

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

2. ***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

Question 8

***Causes of Urinary incontinence

Answer 8

1. ***Primary nocturnal enuresis (most common)
2. ***Anatomic incontinence
   - Ectopic ureter (Extravesical)
   - Obstruction (PUV, (PUJO, VUJO, Labial adhesions, Urethral prolapse, Ureterocele))
   - Anomalies (Exstrophy, (Abnormal urethral opening))
3. ***Neurogenic incontinence
   - Congenital (Neural tube defects (Spina bifida, Myelomeningocele, Anorectal malformations))
   - Acquired (Trauma, Tumour, Anoxic brain injury, Extensive pelvic surgery)
4. ***Functional incontinence (when no anatomical / neurological cause found)
   - Detrusor overactivity
   - Infrequent voider (Lazy bladder)
   - Dysfunctional voiding (DSD)
5. Miscellaneous (**UTI, **Polyuria)

Question 9

Primary monosymptomatic nocturnal enuresis (PMNE / PNE)

Answer 9

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

Question 10

Approach to PMNE

Answer 10

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

Question 11

Investigations of PMNE

Answer 11

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

Question 12

Management of PMNE

Answer 12

1. Behavioural modification (mainstay)
   - **Void before bed
   - **Fluid + salt restriction 2 hours before sleep
   - ***Star chart (encouragement)
2. ***Desmopressin (DDAVP) (Anti-diuretic hormone)
3. ***Enuresis alarm

If above not successful —> Review Dx
4. Anticholinergics (2nd line treatment)
- only for those with component of detrusor overactivity

Question 13

Anatomic incontinence

Answer 13

1. 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)
2. Obstruction (can lead to residual bladder problem)
   - Posterior urethral valve
   (- PUJO
   - VUJO
   - Labial adhesions
   - Urethral prolapse
   - Ureterocele)
3. Anomalies
   - Exstrophy (bladder exposed on abdominal wall)
   (- Abnormal urethral opening)

Question 14

Neurogenic incontinence

Answer 14

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

2. Anticholinergic therapy
   - Increase bladder capacity + lower bladder storage pressure + abolish overactive contractions
3. Others
   - Botox injection to detrusor muscle

Question 15

Functional incontinence

Answer 15

1. **Detrusor overactivity
   - Premature detrusor contraction during **filling
   - Antimuscarinic, Desmopressin, Urotherapy (e.g. Bladder training)
2. Infrequent voider (***Lazy bladder)
   - Large capacity, excessively compliant bladder
   - Urotherapy
3. ***Dysfunctional voiding
   - Urethral sphincter contraction during voiding (DSD)
   - Desmopressin, Urotherapy

Question 16

***Urinary tract infection (UTI)

Answer 16

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

2. 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

Question 17

***Vesicoureteric reflux (VUR)

Answer 17

• 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

2. 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)

2. 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%)

Question 18

***Posterior urethral valve

Answer 18

• 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

2. Postnatal
   - ***Respiratory distress due to pulmonary hypoplasia (∵ absence of urine in amniotic fluid —> low amniotic fluid volume)
   - Urinary retention
3. 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

Question 19

Phimosis

Answer 19

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

Question 20

Indications for circumcision

Answer 20

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)

Question 21

Alternatives to circumcision

Answer 21

1. ***Steroid cream (encourage separation of non-retractile foreskin)
2. ***Preputial stretching (require perseverance)
3. Preputioplasty