Peak incidence: Transitions in child’s life (infancy with solid food introduction, toilet training at 2-3 yrs, and school entry). c
Withholding behavior: Painful bowel movement (BM) leads to fear of defecation, initiating a vicious cycle of voluntary stool retention.
Low-fiber diet and excessive cow’s milk intake (>24 oz/day).
Emotional stressors (e.g., starting school, new sibling, lack of toilet privacy).
Clinical Features
History:
<2 defecations per week.
History of stool withholding (e.g., stretching, arching, hiding, rocking during urges).
Large-diameter, hard stools that may clog the toilet.
Intermittent abdominal pain, bloating, and early satiety.
Encopresis (fecal incontinence due to leakage of liquid stool around a hard impaction; often mistaken for diarrhea). c
The constant pressure of the fecal mass causes chronic, involuntary relaxation of the internal anal sphincter (the rectosphincteric reflex).
Because the sphincter is relaxed and the Pt cannot feel the rectal fullness, the bypassed liquid stool leaks out involuntarily onto underwear without the Pt’s awareness.
Physical Exam:
Palpable, firm abdominal mass in the left lower quadrant (LLQ) or suprapubic area.
Anal fissures or skin tags from chronic hard stools. c
Digital Rectal Exam (DRE): Rectum filled with large, hard stool, normal sphincter tone (avoid routine DRE unless diagnosis is unclear).
Normal spine/gluteal cleft (no dimples, tufts of hair, or sacral abnormalities).
Diagnosis
Initial/Screening: Clinical Dx based on Rome IV criteria (requires ≥2 criteria for at least 1 month: ≤2 BMs/wk, history of withholding, painful/hard BMs, large fecal mass, fecal incontinence).
Confirmatory/Gold Standard: Clinical Dx based on history and physical exam; no routine labs or imaging required.
Key Labs:
Generally not indicated unless organic red flags are present (e.g., poor growth, delayed development).
If organic cause suspected: TSH/free T4 (hypothyroidism), tTG IgA (celiac disease), serum calcium.
Imaging:
Abdominal X-ray: Shows fecal loading in the rectosigmoid. Not routinely recommended; reserved for obese pts or when physical exam is impossible/uncooperative.
Biopsy:
Rectal suction biopsy: Gold standard if Hirschsprung disease (HD) is suspected; demonstrates the absence of ganglion cells and hypertrophied nerve fibers.
Differential Diagnostics
Hirschsprung Disease:
Diff by delayed meconium passage (>48 hrs of life), failure to thrive (FTT), explosive release of stool/gas upon DRE (squirt sign), and an empty rectal vault.
Infant Dyschezia
Infants < 9 months of age; Soft, normal, or loose stools; Reassurance only; avoid laxatives and rectal stimulation
Celiac Disease:
Diff by poor growth/FTT, chronic diarrhea alternating with constipation, abdominal distension, and (+) tTG IgA.
Hypothyroidism:
Diff by hypotonia, lethargy, poor linear growth, umbilical hernia, macroglossia, and ↑ TSH / ↓ free T4.
Spina Bifida Occulta / Spinal Cord Pathology:
Diff by lumbosacral abnormalities (tuft of hair, dimple, birthmark), abnormal lower extremity reflexes, and decreased anal sphincter tone.
Cystic Fibrosis:
Diff by history of meconium ileus at birth, recurrent respiratory infections, pancreatic insufficiency, and (+) sweat chloride test.
Management
Disimpaction (if fecal mass/impaction present):
First-line: High-dose oral polyethylene glycol (PEG) (osmotic laxative) titrated to effect. c
Second-line: Enemas (saline or mineral oil) if oral route is refused or unsuccessful.
Maintenance Therapy (First-line):
Daily PEG (maintenance dose) for at least 3-6 months. Do not stop laxatives early; bowel must shrink to normal size.
Dietary modifications: ↑ fiber, ↑ water intake, and limiting cow’s milk to <16-24 oz/day.
Behavioral training: Timed toilet sits for 5-10 mins post-meals (utilizing gastrocolic reflex) with positive reinforcement (e.g., reward charts).
Refractory Cases (Second-line / Referral):
Add stimulant laxatives (e.g., senna, bisacodyl) for short-term rescue use.
Refer to pediatric GI for further workup (e.g., anorectal manometry to rule out HD or dyssynergic defecation).
Complications
Anal fissures: Painful defecation that perpetuates the withholding cycle.
Encopresis: Overflow fecal incontinence causing significant social and psychological distress.
Recurrent UTIs or urinary incontinence: Large rectosigmoid fecal mass compresses the bladder, causing urinary stasis.