Chronic Constipation and Encopresis
Vctor M. Pieiro, M.D. Uniformed Services University Bethesda, Maryland
Definition and Frequency
Constipation is a symptom, not a disease Stools are small, hard or infrequent 3% of outpatient pediatric visits 10-25% prevalence in Pediatric GI practice
Constipation
Most common GI outpatient problem
May start at any age
Rarely due to structural abnormality or systemic disease Children DO NOT outgrow it spontaneously Prognosis is good if treated appropriately
Normal Bowel Habit
Stool frequency
Stool weight Transit time
Pre school children
QOD - TID (95%)
25 gms 33 hrs
Toilet training
ages 2-3 yrs.
Colonic Motility
Colon has complex motility patterns Colonic contents moved to the cecum by waves of "antiperistalsis" Colonic haustrations prominent in transverse and descending colon Giant migrating contractions originate in transverse colon and rapidly reach the rectum (gastrocolic reflex)
Mechanisms of Defecation
Inflation Reflex
Seen after age 2 Distension of rectum Stimulus sensory nerves
Conscious awareness
Transient relaxation of external anal sphincter (EAS)
Mechanisms of Defecation
Rectosphincteric Relaxation Reflex
Distension of rectum
Sensory nerves (via myenteric plexus) Inhibition of smooth muscle internal anal sphincter Relaxation of IAS
Chronic Idiopathic Constipation
Male predominance 1.5:1
Age of onset Event at onset
Large stools
0-1 yr 25% 0-5 yr 70% 30%
75%
Withholding behaviors
Failed toileting
40%
30%
Clinical Presentation
Family history 10-50%
Rectal bleeding
Enuresis/UTIs Abdominal Pain Psychologic problems Rectal prolapse Poor appetite Previous therapy
25%
15% 10-50% 20% 3% 26% 90%
Clinical Presentation
Physical examination
Abdominal distention
Abdominal mass
20%
30-50%
Fecal impaction
Weight < 5%
40-50%
0-10%
Anorectal Manometry
Proximal rectal balloon to distend the rectum Pressure sensors used to measure IAS and EAS
Distention of rectum triggers the Inflation and Rectosphincteric relaxation reflexes
Pathophysiology
I. Resting anal sphincter pressure Increased, normal or decreased II. Rectosphincteric relaxation reflex Critical volume ( minimal volume of rectal distention required to elicit the relaxation reflex) is often increased
Pathophysiology II
III. Rectal Sensitivity - Conscious Awareness
Threshold volume (volume required to produce conscious awareness) is often increased
In encopresis IAS relaxation occurs at volumes that do not stimulate conscious awareness
Pathophysiology III
IV. External anal sphincter Paradoxical EAS contraction (unconscious EAS contraction during defecation) in severe constipation
V. Expulsion failure
Patients with severe constipation and encopresis may have an inability to defecate balloons
Potentiation of Risk for Encopresis
Stage I Infancy and Toddler Years Simple constipation Congenital anorectal problems
Parental overreaction
Coercive medical interventions
Potentiation of Risk for Encopresis
Stage II 2 to 5 years
Psychosocial stresses Coercive or permissive training Toilet fears Painful or difficult defecation
Potentiation of Risk for Encopresis
Stage III Early School Years
Avoidance of school bathrooms
Prolonged gastroenteritis
Attention deficit disorder
Frenetic life-styles
Psychosocial stress
Differential Diagnosis
Medical
Hypothyroidism
Hypokalemia
Diabetes insipidus
RTA
Hypercalcemia
Uremia
Botulism
CNS disorders
Depression
Anorexia nervosa
Gastrointestinal Disorders
Intestinal Pseudo-obstruction
Cystic fibrosis
Crohn's disease
Celiac disease
Drugs and Toxins
Anticholinergics Iron
Anticonvulsants
Opiates
Bismuth
Lead
Antidepressants
Barium
Anatomic
Anorectal anomalies
Spinal cord injury
Sacrococcygeal teratoma
Hirschsprung's disease
Meningomyelocele
Anterior Anal Displacement
Anterior ectopic anus Anal canal + IAS anteriorly located EAS in normal position
Anteriorly located anus
Anal canal + both sphincters anteriorly located
Anterior Anal Displacement
Rectal exam Posterior angulation of anal canal Posterior shelf
Treatment
Often conservative
Surgical repair if severe
Hirschsprung's Disease
Congenital Aganglionosis of colon
Rectosigmoid colon
Transverse/Ascending Total aganglionosis Ultrashort
80%
15% 5% Rare
Hirschsprung's Disease
Barium enema Distal narrowed segment, transition zone, "saw-toothed" contractions Anorectal manometry Lack of rectosphincteric relaxation reflex
Rectal biopsy
Diagnostic (adequate specimen, expert pathologist)
Encopresis
Weissenberg - 1926
Involuntary passage of whole bowel movements in the underwear or on abnormal place
Now commonly used synonymously with fecal incontinence or soiling
Treatment
Must explain the pathophysiology of the problem
Improves compliance with therapy
Alleviates the guilt and blame the parents may feel Decreases embarrassment child is experiencing
Treatment
Three Stages
Education
Initial Catharsis (Whoosh)
Maintenance
Catharsis
Day 1 Magnesium citrate 5-10 oz. P.O. Days 1-3 Mineral oil enema 3-4 oz. PR Days 1-3 Fleet enema 2-4 oz. PR
Days 2-4 Dulcolax 5-10 mg. P.O. QD
Maintenance Regimen
High Fiber Diet
MOM 0.5-1 ml/kg/dose BID Mineral oil 0.5-1 ml/kg/dose BID Behavior modification (Toilet training)
Follow up visits every month
Anal Position Index
Ratio of anus-fourchette distance to coccyx-fourchette distance (scrotum in males)
Normal Ratios A/B > 0.34 in females > 0.46 in males
}A
Diagnostic Evaluation
Complete History and Physical Examination Laboratory Studies CBC, ESR, U/A, Urine culture Stool culture, O & P, occult blood
Serum glucose, calcium, phosphorus
Thyroid function studies
Diagnostic Evaluation
Radiographic Studies Abdominal plain film, BE Special diagnostic Studies Rectal suction biopsy
Anorectal manometry Indicated Studies
UGI/small bowel series Proctosigmoidoscopy, colonoscopy Pelvic MRI
