ELIMINATION DISORDERS

An infant is expected to achieve developmentally appropriate bowel control by ~18 months, bladder control by ~24 months during day-time and ~36 months during nights. Elimination disorders include problems related to these vegetative functions, e.g.

4.3.1 ENURESS_________________________________________

Enuresis is the commonest elimination disorder, characte­rized by repeated involuntary passage of urine, beyond the normal age of bladder-control, i.e. ~24 months during day-time and ~36 months during nights. However, occasional bed wetting is not uncommon till 9-10 years.

Depending on the time of occurrence, enuresis is termed as nocturnal (only during sleep) or mixed (nocturnal as well as diurnal). Isolated diurnal enuresis is extremely rare.

As per DSM V criteria, enuresis is defined as “repeated involuntary or intentional voiding of urine into bed/ clothes beyond 5 years of age, with:

a. Frequency of at least twice a week for at least 3 consecutive months, or

b. Presence of significant emotional distress or social or academic impairment, and

c. Without being the effect of a substance, drug or medical condition, e.g. urinary tract infection.

Incidence of enuresis varies with age, estimated to be ~3-7% at five years and ~2-3% at ten years, being more common in boys.

Etiology: Enuresis may be primary, in which the child has never achieved bladder control or secondary, in which the enuresis has re-started after a dry period of at least gt; 6 month. Over 75% cases on enuresis are primary.

Primary enuresis is mostly functional, due to delayed maturation in bladder functions. It is more common in boys (3:1) with similar family history. Various factors attributed in causation of primary enuresis include: (a) premature and/or coercive attempts for toilet-training,

(b) abnormal sleep-awake cycle, (c) lack of normal nocturnal surge in ADH secretion, (d) inadequate bladder capacity (e) mental sub-normality, and (f) emotional deprivation.

Secondary enuresis is usually due to recent emotional stress in family or school, e.g. birth of a sibling, change in school, etc., or more likely due to an underlying organic pathology. Important organic causes for secondary enuresis include: (a) urinary tract infections,

(b) obstructive uropathy, (c) diabetes mellitus or diabetes insipidus, (d) neurogenic bladder, and (e) seizure disorders. Involuntary passage of urine may be the only indicator of unobserved seizure at night.

Diagnostic evaluation of these cases includes:

• Detailed history, specially related to age of onset (primary vs. secondary), the time of enuresis (nocturnal, mixed), similar family history, co­existing problems, e.g. dysuria, encopresis, general development and behavioral profile of the child as well as family.

• Physical examination to exclude organic etiology, including palpation for enlarged kidneys or full bladder, examination of external genitals and urinary stream, spinal examination for spina-bifida and detailed neurological evaluation.

• Investigations should begin with routine urine analysis and culture to exclude urinary tract infection, followed by other relevant tests, e.g. renal function tests, spinal X-rays, urinary tract imaging and urodynamic studies.

Management needs to be individualized in each case, depending on suspected causative or precipitating factor. Organic causes, though rare, should be looked for and treated. Broad recommendations for behavioral management include:

a. Parental and child counseling, regarding the nature, probable cause, correct approach towards toilet training and expected results of therapeutic interventions.

b. Bladder stretching exercises, e.g. voluntary holding the urine as long as possible in daytime to increase bladder capacity and repeatedly starting/stopping of stream during micturation to increase the sphincter tone.

c. Habit modifications, e.g. early dinner (4 hours before sleep), restricted fluid intake after dinner, voiding before retiring, waking the child at night to pass urine, etc.

d. Behavioral modification with positive reinforcement, i.e. rewards for dry nights. Negative conditioning,

e. g. punishment or humiliation of the child should be strongly discouraged. Psychotherapy, e.g. play­therapy and hypnosis may be used in some cases.

e. Conditioning devices, e.g. bed-wetting alarms are useful in refractory cases, with success rate of gt;70%. In these devices, a sensor attached to the child's underwear or mattress is stimulated as soon as she/he wets the bed, completing an electronic circuit to buzz the alarm and wake the child.

f. Pharmacotherapy, should be reserved for selected cases of above 5 years of age and non-responsive to behavioral modification.

± Desmopressin acetate (PO 0.2 mg single dose ~2 hours before bedtime, maximum 0.6 mg/dose) is the drug of choice for enuresis, with success rate of gt;50%. Treatment should continue for at least 4-6 months (or gt;4 weeks of consecutive dry nights) to minimize relapse, which may occur in ~70% cases. Desmopressin nasal spray are no longer recommended due to potential but rare risk of hyponatremia and seizures.

± For resistant enuresis, anticholinergic therapy with PO Oxybutynin 5 mg or PO Tolterodine 2 mg may be used in combination with desmopressin to reduce uninhibited bladder contractions, specially in children with urge incontinence during daytime. Constipation is a potential side-effect.

± Imipramine (PO 1-2 mg/kg single dose ~2 hours before bedtime), a tricyclic antidepressant to alter arousal-sleep cycle, is rarely used nowadays due to higher relapse rate (90%) and side-effects, e.g. dry mouth, irritability, insomnia and urinary retention.

Giggling incontinence is an uncommon problem in otherwise continent children, characterized by sudden, involuntary, uncontrollable passage of urine during giggling or laughing heartily.

4.3.2 Encopresis

Encopresis, i.e. involuntary or intentional passage of feces in inappropriate places beyond the normal age of control, is less common than enuresis.

As per DSM V criteria, encopresis is defined as:

a. frequency of at least once a month for minimum 3 months,

b. persistence beyond 4 years of age, and

c. not due to a substance, drug or medical disorder.

Encopresis may be Primary, when toilet training was never achieved or Secondary (Regressive) when it reappears in previously continent children for over one year.

Incidence: Encopresis is more common in boys, with an estimated incidence of ~1% at 5 years of age.

Etiology: Encopresis may be classified as retentive or non-retentive.

• Retentive encopresis is usually due to chronic constipation with overflow incontinence, e.g. Hirschsprung's disease, anal fissures, hypothyroidism, substance (opiates) abuse and habitual use of laxatives.

• Non-retentive encopresis without evidence of fecal retention indicates serious emotional disturbance, often associated with suppressed anger and defiance to coercive toilet training, sexual abuse and negative defecation experiences.

Diagnostic evaluation includes: (a) detailed psychosocial history, (b) per-rectal examination and neurologic evaluation to exclude organic causes, and (c) relevant investigations, e.g. thyroid function tests, anal manometry and barium studies for congenital or acquired megacolon. Management includes: (a) initial treatment of constipation with laxatives, stool-softeners or enema, (b) prevention of further constipation by high-fiber diet, (c) voluntary toilet training to encourage the child to visit the toilet 10-15 minutes after each meal to induce gastrocolic reflex, (d) behavioral modification i.e. positive reinforcement (rewards) for better bowel control, and (e) psychotherapy for precipitating and secondary psychological events.

Prognosis: Encopresis is more difficult to control than enuresis and secondary psychological problems are common, e.g. loss of self-esteem, sense of guilt/ depression and frequent school absenteeism.

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