Basics
Description
Delay or difficulty in defecation; infrequent (<2) stools per week, and resulting in pain, rectal bleeding, as well as fecal soiling. May also refer to a decrease in frequency of bowel movements compared with the patient's usual bowel pattern.
General Prevention
- Dietary measures: high-fiber diet, plenty of fluids, fruits, and vegetables; avoidance of excessive caffeine and milk (calcium) intake
- Regular physical activity
Pathophysiology
- Delay in colonic passage and/or retention of stool allows fluids mixed in stool to be resorbed across cellular membranes, increasing stool caliber and leading it to be harder in consistency.
- Decreased motility leads to a buildup of desiccated stool causing painful defecation that leads to ongoing stool retention.
- As the rectosigmoid enlarges with retained stool, a child's ability to sense rectal fullness diminishes, and he or she may not appreciate the need to defecate.
- Often there is a family history of motility disturbances or constipation.
Etiology
- Most patients have idiopathic or functional constipation with no identifiable cause.
- Personal history of constipation may be traceable to an acute event (i.e., passage of large, painful stool) followed by chronicity.
- Intentional or unintentional withholding of stool may result in hard stools, anal pain, and fissures that perpetuate and lead to constipation. Rectal dilatation, decreased sensation of the urge to defecate, shortening of the anal canal, decreased tone of the external anal sphincter, and encopresis can result.
- Precipitating events may include the following:
- Transition from breast milk to cow's milk
- Excessive cow's milk intake
- Insufficient water intake
- Refusal to use toilets outside the home
- Premature toilet training
- Perianal streptococcal infection
- Food allergies
- Transient viral illness (diarrhea followed by constipation)
- Constipation also can be caused by anatomic anomalies in the lower GI tract, decreased propulsion, increased rectal sensitivity threshold, a functional outlet obstruction (muscular spastic levator ani or impaired relaxation of the puborectalis).
- Neurologic causes:
- Abnormalities of the myenteric plexus
- Intestinal pseudoobstruction
- Congenital aganglionosis (Hirschsprung disease)
- Visceral neuropathies
- Visceral myopathies
- Familial dysautonomia
- Lesions of the spinal cord can result in loss of rectal tone and sensation and reduced anal closure, affecting the sacral reflex center (e.g., meningocele, myelomeningocele, tethered cord).
- Anatomic disorders of anus and rectum (stricture, stenosis, mass, ectopic anus, imperforate anus, fistula)
- Endocrine abnormalities (hypothyroidism), drugs, electrolyte abnormalities
Diagnosis
History
- Question: What was the timing after birth of passage of meconium?
- If it is delayed for >48 hours, consider Hirschsprung disease.
- Is the child able to pass a bowel movement unaided by a suppository or enema?
- If rectal stimulation is required for passage of a bowel movement, consider Hirschsprung disease or habituation to rectal stimulation.
- What are the size, frequency, and consistency of bowel movements?
- 1-3 normal (in size and consistency), painless bowel movements may be passed every 1-3 days. The size of bowel movements reflects the caliber of the colon.
- Does the child experience frequent urination, bed-wetting, or urinary tract infections?
- Chronic UTIs are frequently linked to chronic constipation.
- Does fecal soiling occur?
- Soiling occurs with stool impaction or with nerve damage involving the anus.
- Is there the presence of rectal sensation?
- Patients with long-standing constipation or stool withholding may develop a dilated rectum and lose the sensation of rectal distention.
- Is there a history of painful bowel movements or rectal fissure?
- Pain with defecation and/or fissuring can further lead to withholding secondary to fear of painful bowel movements.
- Is the child experiencing any stressful events (i.e., new sibling, family death)?
- Stress can precipitate stool withholding.
- Is there an unsteady gait?
- This may suggest neuromuscular problems.
- Did the child experience difficult toilet training?
- May be associated with encopresis
Physical Exam
- General: Look for evidence of systemic illness and alarm signals: weight loss, anorexia, delayed growth, delayed passage of meconium, urinary incontinence, passage of bloody stools (in the absence of anal fissure), fever, vomiting, and diarrhea.
- Abdomen: abdominal distention (indicative of the presence of stool or gas), presence of stool masses (size, location), distended bladder, and bowel sounds (may be decreased in intestinal pseudoobstruction)
- Rectal examination
- Perianal soiling
- Size and position of anus (evaluate for signs of imperforate, stenosed, or ectopic anus)
- Presence of skin tags and fissures
- Perianal or anal erythema (streptococcal proctitis)
- Evidence of child abuse
- Digital examination is not recommended to diagnose functional constipation. If suspicious for other etiologies, can use to assess anal tone (long and tight anal canal in Hirschsprung); amount and consistency of stool; size of rectum (dilated rectum with chronic constipation; tight and empty anus with Hirschsprung disease); presence of blood
- Absence of anal wink or cremasteric reflex suggests neurologic abnormalities.
- Neurologic examination: decreased reflexes in the lower extremities
- Back: Check for sacral dimple, tuft of hair (underlying sacral abnormality), flat buttocks, and patulous anus.
Alert
- Grunting baby syndrome: Infants cry, scream, and draw up their legs during a bowel movement. They respond to rectal distention by contracting their pelvic floor. This is not constipation.
- Always rule out an organic cause.
- Always consider medications as a cause.
Diagnostic Tests & Interpretation
Lab
Testing for possible underlying thyroid disease and/or celiac disease may be recommended in patients with likely functional constipation. Other lab testing is not routinely recommended.
Imaging
- Abdominal radiography:
- May demonstrate presence or absence of fecal impaction
- Should not be used routinely for the evaluation of functional constipation
- Water-soluble contrast enema:
- An unprepped study is useful to diagnose Hirschsprung disease.
- A prepped study is useful to diagnose a stricture.
- Most patients with constipation will not require this test, especially those with functional constipation.
Diagnostic Procedures/Other
- Measurement of abdominal transit time with radio-opaque markers may help discriminate between children with and without clinical constipation, but evidence does not support its routine use in diagnosis.
- Anorectal manometry: analyzes rectal sensation, resting and squeezing pressures, and pelvic floor dyssynergia (anismus)
Differential Diagnosis
- Celiac disease (more likely in younger children)
- Hypothyroidism, hypercalcemia, hypokalemia
- Diabetes mellitus
- Dietary protein allergy
- Drugs, toxics:
- Opiates, anticholinergics, antidepressants, chemotherapy, and heavy metal ingestion (lead)
- Vitamin D intoxication
- Botulism
- Cystic fibrosis
- Hirschsprung disease
- Anal achalasia
- Colonic inertia
- Anatomic malformations (imperforate anus, anal stenosis)
- Pelvic mass (sacrococcygeal teratoma)
- Spinal cord anomalies, trauma, tethered cord
- Abnormal abdominal musculature (prune belly, gastroschisis, Down syndrome)
- Pseudoobstruction
- Multiple endocrine neoplasia type 2B
Treatment
General Measures
- Treatment of functional constipation:
- Disimpaction
- The use of polyethylene glycol (e.g., MiraLAX or other generics) with or without electrolytes orally at 1-1.5 g/kg/24 h for 3-6 days is recommended as first line for children presenting with impaction.
- If the patient is not tolerating PO, enemas may be required for initial disimpaction.
- Children >2-3 years of age require adult-size enemas, whereas younger children require pediatric-size enemas. Enemas can be given once per day for 3-6 days.
- Evacuation
- Following rectal disimpaction, further evacuation can be achieved by using polyethylene glycol solution (Go-Lytely), orally or via nasogastric tube over 6-8 hours until the effluent is clear.
- Maintenance stool softeners.
- Infants ≤6 months of age may be given sorbitol or pectin-containing juices, lactulose, or Karo syrup.
- Children >6 months of age may be given lactulose (0.7-2 g/kg/24 h [1-3 mL/kg/24 h], max 40 g/24 h [60 mL/24 h]) or MiraLAX (0.5-1 g/kg, max 17 g/24 h).
- Mineral oil or Kondremul (>15 months of age 1-3 mL/24 h, >6 years 10-25 mL/24 h) is added as an adjunctive lubricant to aid in the passage of stool, but contraindicated in children <15 months as well as in children at risk for aspiration.
- Rescue stimulant laxatives:
- Bisacodyl or senna may be used as a stimulant laxative for short period of time. Long-term use has been associated with colonic nerve damage in adults.
- Diet: A balanced diet of whole grains, fruits, and vegetables is recommended. A normal-fiber diet is recommended (toddler 14 g/24 h; school-aged 17-25 g/24 h; adolescent 25-31 g/24 h). Fiber should be increased gradually to minimize side effects of flatulence. Caffeine and excessive milk-product intake (>16 oz/24 h of milk) may be constipating.
- Fluid intake: A normal fluid intake is important.
- Toilet sitting: Regular toilet sitting twice a day for 10 minutes, preferably 15-20 minutes after meals, is a key step in retraining the bowel.
- Calendar: It is important to keep a record of stools, accidents, toilet sitting, and medications in order to identify causes of failure.
- Biofeedback has not been shown to be helpful in patients who fail conventional therapy and who have abnormalities on anorectal manometry.
- There may be some benefit in referring a patient with constipation and behavioral abnormalities to a mental health specialist.
Alert
Multiple phosphate enemas can cause severe electrolyte imbalances (hyponatremia, hypokalemia, hypocalcemia, hypomagnesemia).
Ongoing Care
Follow-up Recommendations
- Schedule regular visits to make certain therapy is maintained, decreasing the frequency of visits when patient is doing well.
- Parents should call when problems develop.
- Compliance and good follow-up are key to successful management of constipation.
Prognosis
For functional constipation, the success rate is variable (45-90%). Presence of abdominal pain at the time of presentation, close follow-up, and maintenance use of stool softeners are good prognostic factors. Presence of soiling, use of stimulant laxatives, and lack of follow-up were associated with failure.
Complications
- Anal fissures: Infrequent hard stools can cause a tear of the anal mucosa, causing pain and withholding.
- Encopresis: Chronic constipation leads to progressive rectal dilatation and decreased rectal sensation. Fecal impaction results in secondary soiling or encopresis.
- Intestinal obstruction: manifests as vomiting, abdominal pain, and constipation. Abdominal radiograph films show intestinal obstruction and presence of large amounts of stool.
- Sigmoid volvulus: A chronically constipated child may present with symptoms of acute abdomen, fever, tender abdomen, and palpable mass. Abdominal radiograph shows obstruction in the colon. Barium enema may be both diagnostic and therapeutic by achieving reduction.
- Treatment of complications:
- Encopresis (soiling or diarrhea): Disimpaction and clean out as necessary, followed by treatment of constipation, is recommended (see previous discussion).
- Intestinal obstruction from fecal mass: Presents with vomiting, abdominal pain, and constipation. Abdominal radiograph film shows intestinal obstruction. Make nil per os (NPO), provide IV fluids, and rule out an acute abdomen. Then give enemas and clear out stool from below. Avoid oral laxatives or a polyethylene glycol solution in a case of obstruction.
- Sigmoid volvulus: Chronically constipated child with symptoms of acute abdomen, fever, tender abdomen, and palpable mass. Abdominal radiograph shows obstruction in the colon. Contrast enema may reveal and possibly reduce a volvulus.
Additional Reading
- Bekkali NLH, van den Berg MM, Dijkgraaf MGW, et al. Rectal fecal impaction treatment in childhood constipation: enemas versus high doses oral PEG. Pediatrics. 2009;124(6):e1108-e1115. [View Abstract]
- Croffie JM, Fitzgerald J. Idiopathic constipation. In: Walker WA, Kleinman RE, Sherman PM, et al, eds. Pediatric Gastrointestinal Disease. 4th ed. Philadelphia: BC Decker; 2004:1000-1055.
- Hyman PE, Milla PJ, Benninga MA, et al. Childhood functional gastrointestinal disorder: neonate/toddler. Gastroenterology. 2006;130(5):1519-1526. [View Abstract]
- Rasquin A, DiLorenzo C, Forbes D, et al. Childhood functional gastrointestinal disorders: child/adolescent. Gastroenterology. 2006;130(5):1527-1537. [View Abstract]
- Tabbers MM, Dilorenzo C, Berger MY, et al. Evaluation and treatment of functional constipation in infants and children: evidenced-based recommendations from ESPGHAN and NASPGHAN. J Pediatr Gastroenterol Nutr. 2014;58(2):265-281.
- U.S. Department of Health and Human Services. Dietary guidelines for Americans, 2010. http://www.health.gov/dietaryguidelines/2010.asp. Accessed March 1, 2015.
Codes
ICD09
- 564.00 Constipation, unspecified
- 564.09 Other constipation
- 564.02 Outlet dysfunction constipation
ICD10
- K59.00 Constipation, unspecified
- K59.09 Other constipation
- K59.02 Outlet dysfunction constipation
SNOMED
- 14760008 Constipation (disorder)
- 197118003 Constipation - functional (disorder)
- 85920003 Constipation by outlet obstruction
FAQ
- Q: When is constipation an emergency?
- A: When intestinal obstruction, sigmoid volvulus, or Hirschsprung enterocolitis occurs.
- Q: Does polyethylene glycol-3350 taste bad?
- A: Advantages of polyethylene glycol-3350 include its lack of taste, smell, or odor and that it can be mixed in any liquid.