Chapter 21 Rumination, Pica, and Elimination (Enuresis, Encopresis) Disorders
21.1 Rumination Disorder
Rumination disorder is defined as the repeated regurgitation and rechewing of food for a period of at least 1 mo following a period of normal functioning. The rumination is not due to an associated gastrointestinal illness or other general medical condition (e.g., esophageal reflux). It does not occur exclusively during the course of anorexia nervosa or bulimia nervosa. Malnourishment with resultant weight loss or growth delay is a hallmark of this disorder. If the symptoms occur exclusively during the course of mental retardation or a pervasive developmental disorder, they must be sufficiently severe to warrant independent clinical attention.
Epidemiology
Rumination is a rare disorder that is potentially fatal, and some reports indicate that 5-10% of affected children die. In otherwise healthy children, this disorder typically appears in the 1st yr of life, generally between the ages of 3 and 6 mo. The disorder is more common in infants with severe mental retardation than in those with mild or moderate mental retardation.
Etiology and Differential Diagnosis
Proposed causes of rumination disorder include a disturbed relationship with primary caregivers; lack of an appropriately stimulating environment; and learned behavior reinforced by pleasurable sensations, distraction from negative emotions, and/or inadvertent reinforcement (attention) from primary caregivers. The differential diagnosis includes congenital gastrointestinal system anomalies, pyloric stenosis, Sandifer’s syndrome, increased intracranial pressure, diencephalic tumors, adrenal insufficiency, and inborn errors of metabolism.
Treatment
Treatment begins with a behavioral analysis to determine if the disorder serves as self-stimulation or is socially motivated. The behavior might begin as self-stimulation, but it subsequently becomes reinforced by the social attention given to the behavior. Treatment is generally directed at reinforcing correct eating behavior and minimizing attention to rumination. Aversive conditioning techniques (e.g., withdrawal of positive attention) are useful when a child’s health is jeopardized. Successful treatment requires the child’s primary caregivers to be involved in the intervention. The caretakers need counseling around responding adaptively to the child’s behavior as well as altering any maladaptive responses. There is no current evidence supporting a psychopharmacologic response to these disorders.
21.2 Pica
Pica involves the persistent eating of nonnutritive substances (e.g., plaster, charcoal, clay, wool, ashes, paint, earth). The eating behavior is inappropriate to the developmental level (e.g., the normal mouthing and tasting of objects in infants and toddlers) and not part of a culturally sanctioned practice.
Epidemiology
Pica appears to be more common in children with mental retardation, pervasive developmental disorders, obsessive-compulsive disorders, and other neuropsychiatric disorders (e.g., Kleine-Levin syndrome, schizophrenia). It usually remits in childhood but can continue into adolescence and adulthood. Geophagia (eating earth) is associated with pregnancy and is not seen as abnormal in some cultures (e.g., rural or preindustrial societies in parts of Africa and India). Children with pica are at increased risk for lead poisoning (Chapter 702), iron-deficiency anemia (Chapter 449), obstruction, dental injury, and parasitic infections.
Etiology
Numerous etiologies have been proposed but not proved, ranging from psychosocial causes to physical ones. They include nutritional deficiencies (e.g., iron, zinc, and calcium), low socioeconomic factors (e.g., lead paint), child abuse and neglect, family disorganization (e.g., poor supervision), psychopathology, learned behavior, underlying (but undetermined) biochemical disorder, and cultural and familial factors.
Treatment
A combined medical and psychosocial approach is generally indicated for pica. The sequelae related to the ingested item can require specific treatment (e.g., lead toxicity, iron-deficiency anemia, parasitic infestation). Ingestion of hair can require medical or surgical intervention for a gastric bezoar (Chapter 326). Nutritional education, cultural factors, psychologic assessment, and behavior interventions are important in developing an intervention strategy for this disorder.
21.3 Enuresis (Bed-Wetting)
Enuresis is defined as the repeated voiding of urine into clothes or bed at least twice a week for at least 3 consecutive months in a child who is at least 5 yr of age. The behavior is not due exclusively to the direct physiologic effect of a substance (e.g., a diuretic) or a general medical condition (e.g., diabetes, spina bifida, a seizure disorder). Diurnal enuresis defines wetting while awake and nocturnal enuresis refers to voiding during sleep. Primary enuresis occurs in children who have never been consistently dry through the night, whereas secondary enuresis refers to the resumption of wetting after at least 6 months of dryness. Monosymptomatic enuresis has no associated daytime symptoms (urgency, frequency, daytime enuresis), and nonmonosymptomatic enuresis, which is more common, often has at least one subtle daytime symptom. Monosymptomatic enuresis is rarely associated with significant organic underlying abnormalities.
Normal Voiding and Toilet Training
Urine storage consists of sympathetic and pudendal nerve–mediated inhibition of detrusor contractile activity accompanied by closure of the bladder neck and proximal urethra with increased activity of the external sphincter. The infant has coordinated reflex voiding as often as 15-20 times per day. Over time, bladder capacity increases. In children up to the age of 14 yr, the mean bladder capacity in ounces is equal to the age (in years) plus 2.
At 2-4 yr, the child is developmentally ready to begin toilet training. To achieve conscious bladder control, several conditions must be present: awareness of bladder filling, cortical inhibition (suprapontine modulation) of reflex (unstable) bladder contractions, ability to consciously tighten the external sphincter to prevent incontinence, normal bladder growth, and motivation by the child to stay dry. The transitional phase of voiding is the period when children are acquiring bladder control. Girls typically acquire bladder control before boys, and bowel control typically is achieved before bladder control.
Epidemiology
Prevalence estimates vary significantly. At age 5 yr, 7% of boys and 3% of girls have enuresis; by age 10 yr the percentages are 3% and 2%, respectively: by age 18 yr, 1% for men and less than 1% for women. Primary enuresis accounts for 85% of cases. Enuresis is more common in lower socioeconomic groups, in larger families, and in institutionalized children. There is an estimated spontaneous cure rate of 14-16% annually. Diurnal enuresis is more common in girls and rarely occurs after the age of 9 yr; overall, 25% of children have diurnal enuresis.
Diagnosis and Differential Diagnosis
Secondary etiologies of urinary incontinence include urinary tract infections (UTIs), chronic kidney disease, hypercalcemia, hypokalemia, chemical urethritis, constipation, diabetes mellitus or insipidus, sickle cell anemia, seizures, pinworm infection, spinal dysraphism, neurogenic bladder, hyperthyroidism, sleep-disordered breathing, drugs (selective serotonin reuptake inhibitor, valproic acid, clozapine) and giggle or stress incontinence. Children with combined nocturnal and diurnal enuresis are more likely to have abnormalities of the urinary tract, making ultrasonography or uroflowmetry indicated. Otherwise, anatomic abnormalities are rarely associated with either nocturnal or diurnal enuresis such that invasive studies are generally contraindicated. Urinalysis and urine culture will rule out infectious causes and the elevated urine osmolality associated with diabetes mellitus.
Etiology
The cause of enuresis likely involves biologic, emotional, and learning factors. Compared with a 15% incidence of enuresis in children from nonenuretic families, 44% and 77% of children were enuretic when one or both parents, respectively, were themselves enuretic. Twin studies show a marked familial pattern, with documented concordance rates of 68% in monozygotic twins and 36% in dizygotic twins. Linkage studies have implicated several chromosomes with varying patterns of transmission.
Children with nocturnal enuresis might hyposecrete arginine vasopressin (AVP) and may be less responsive to the lower urine osmolality associated with fluid loading. Many affected children also appear to have small functional bladder capacity. There is some support for a relationship among sleep architecture, diminished capacity to be aroused from sleep, and abnormal bladder function. A subgroup of patients with enuresis has been identified in whom there is no arousal to bladder distention and an unusual pattern of uninhibited bladder contractions before the enuretic episode. One specific sleep disorder, sleep apnea, has been associated with enuresis (Chapter 17
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