Description of Medical Condition
A combination of changes in the frequency, size, consistency, and ease of stool passage, which leads to an overall decrease in volume of bowel movements. Very subjective, each individual has their own threshold level.
System(s) affected: Gastrointestinal
Genetics: Unknown (the condition may be familial)
Incidence/Prevalence in USA:
Higher at extremes of life, i.e., among infants/children and the elderly
Common; affects a majority of persons during their lifetimes
Predominant age: All ages can be affected; more frequent at the extremes of life (infancy and old age)
Predominant sex: Female > Male
Medical Symptoms and Signs of Disease
- Less frequency of stooling than the patient perceives as ‘normal” (normal is 3-5 times/week)
- Harder stool than “normal”
- Smaller stools than normal (average < 35 grams/day is abnormal)
- Impaction of stool secondary to hardness
- Inspissated stool
- Lack of consistent urgency to stool
- Difficulty expelling feces from the rectum
- Painful evacuation of feces
- Lingering sense of incomplete emptying of the bowel
- Abdominal fullness or a feeling of malaise secondary to inadequate bowel evacuation
- Tenesmus
What Causes Disease?
1. Electrolyte abnormalities
- Hypercalcemia
- Hypokalemia
2. Hormonal abnormalities
- Hypothyroidism
- Diabetes
3. Congenital impediments, e.g., aganglionic megacolon (Hirschsprung disease) or excessively elongate, redundant, capacious bowel (dolichocolon)
4. Congenital or acquired neuromuscular bowel impairment (“pseudo-obstruction“)
5. Concomitant illness, injury, or debility
6. Mechanical bowel impediment (obstruction or ileus, due to any cause)
7. Inadequate fluid intake
Side-effect of drugs (e.g., anticholinergic agents, opiates)
- Chronic abuse of laxatives or cathartics
- Psychiatric, cultural, emotional, environmental factors
- Painful fecal evacuation from anal disease (e.g., fissures)
Risk Factors
- Extremes of life (very young and very old)
- Neurosis
- Polypharmacy
- Sedentary life style or condition
- Diet and fluid intake
Diagnosis of Disease
Differential Diagnosis
- Congenital
– Hirschsprung
– Hypoganglionosis
– Congenital dilation of the colon
– Small left colon syndrome
- Meconium ileus
- “Normal” stooling with anxious patient or parent
- Illnesses predisposing to constipation
– Dehydration
– Hypothyroidism
– Hypokalemia
– Hypercalcemia
- Other causes of abdominal pain
Laboratory
Only necessary when other disorders are being considered
– CBC to detect anemia that may indicate colorectal neoplasm
– Thyroid functions
– Electrolytes, glucose, calcium
Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A
Pathological Findings
None in common, “functional” constipation
Paucity or absence of intramural enteric ganglia in certain cases of congenital or acquired megacolon
Neuromuscular abnormalities in certain cases of “pseudo-obstruction”
Special Tests
- Endoscopic evaluation
– Flexible sigmoidoscopy
– Colonoscopy
- In selected cases of long-standing constipation, timed measure of passage of ingested stool markers may help discern differing impediments
- Anorectal motility in patients with suspected Hirschsprung or anorectal motility disorders
Imaging
- Plain (KUB) film of the abdomen may help to discern the extent and nature of the problem
- Barium enema or barium swallow with small bowel follow through looking for anatomical defects (mass lesions, ileus)
- Cineradiography of passage of barium, instilled in, then expelled from the rectosigmoid segment (“defecography”), may help define evacuation disorders in selected cases
Diagnostic Procedures
Digital rectal exam to rule out a rectal mass, check for blood in the stool, and define stool consistency
Sigmoidoscopy or colonoscopy is seldom required, unless needed to define an abnormality discovered by barium enema or when there is evidence of iron deficiency anemia or blood in the stool
Treatment (Medical Therapy)
Appropriate Health Care
Outpatient usually, except when investigation discloses an underlying lesion or obstruction that requires hospitalization
General Measures
- Attempt to eliminate medications that may cause or worsen constipation
- Increase fluid intake
- Modify diet
- Enemas if other methods fail
Activity
Encourage exercise
Diet
If no anatomic abnormalities, increase fiber to approximately 15 gm/day (bran, fruit, green vegetables, and whole grain cereals and breads)
Encourage liberal intake of fluids
Patient Education
Define constipation and normal variations
Occasional mild constipation is normal
Instruction in consistent “bowel training” i.e., allowing adequate time for bowel evacuation in a quiet, unhurried environment; instruction in facilitating posture on commode, e.g., thighs flexed toward abdomen
Parents sometimes need more treatment/advice than the constipated child
Medications (Drugs, Medicines)
Drug(s) of Choice
- Hydrophilic colloids (bulk-forming agents; not really drugs)
– Psyllium (Konsyl, Metamucil, Perdiem)
– Methylcellulose (Citrucel)
– Polycarbophil (Mitrolan, FiberCon)
- Osmotic laxatives — appropriate for short-term use. The usual dose is 15 mL to 30 mL once or twice a day.
– Milk of magnesia 15-30 mL bid
– Magnesium citrate 15-30 mL bid
– Phosphate of soda 15-30 mL bid
– Lactulose (Chronulac) 15-30 mL bid O
– Sorbitoh 5-30 mL bid
– Alumina-magnesium (Maalox, Mylanta)
– Polyethylene glycol (MiraLax) 17 g in 8 oz of water q day
- Stool softeners
– Docusate sodium (Colace) 100 mg bid
Contraindications:
Any impediment to bowel transit, such as an obstructing lesion or ileus. Osmotic laxatives may result in overdistension or bowel perforation
Any acute intra-abdominal inflammatory condition
Renal and heart failure are relative contraindications
Precautions:
Advise patient against chronic use of irritant and osmotic laxatives
Significant possible interactions:
Magnesium containing laxatives
– Bind tetracyclines preventing their absorption
– Reduce the effectiveness of digitalis and phenothiazines
– Sodium polystyrene sulfonate (Kayexalate) bind and prevent neutralization of bicarbonate, leading to systemic alkalosis, which may be severe
Alternative Drugs
- Lubricants (e.g., mineral oil) are unpalatable to many patients, subject to leakage, and impose the risk of aspiration
- Emollient suppositories are useful, if at all, in allaying anorectal soreness
- Irritant cathartics (stimulants)
– Ricinoleic acid or castor oil (Neoloid); 30-60 mL/day
– Phenolphthalein (Ex-Lax, Modane)
– Bisacodyl (Dulcolax); 2-3 tabs swallowed whole or 1 suppository bid
- Motor and secretory properties
– Anthraquinones: senna (Senokot); 1 -2 cap or 15-30 mL qhs
- Enemas (avoid soap suds — may lead to colitis)
– Sodium phosphate (Fleet enema)
- Suppositories
– Osmotic: sodium phosphate
– Lubricant: glycerin
– Stimulatory: bisacodyl
- Prokinetic agents
Patient Monitoring
What seems to be simple, “functional” constipation, if it persists, should be further investigated for a possible “organic” cause
Prevention / Avoidance
Because for some patients a tendency to constipation is habitual, instruction in proper diet, bowel training, and use of bulk-forming supplements must be reinforced
Possible Complications
- Volvulus
- Cancer risk
- Acquired megacolon: in severe, long-standing cases
- Cathartic colon: repeated laxative abuse
- Fluid and electrolyte depletion: laxative abuse
- Rectal ulceration (“stercoral ulcer”) related to recurrent fecal impaction
- Anal fissures
Expected Course / Prognosis
Constipation that is only occasional, brief, and responsive to simple measures is harmless. That which is habitual can be a lifelong nuisance.
Miscellaneous
Associated Conditions
Debility either general, as in the aged, or that imposed by specific, underlying illness
Age-Related Factors
Pediatric:
Consider Hirschsprung disease
Geriatric:
Elderly persons, who have enjoyed regular bowel action throughout their lives, seldom suffer constipation due to age alone
Persons with a lifelong tendency to constipation often encounter increasing difficulty with advancing age
There is an increased incidence of colorectal neoplasms with age that may be associated with constipation.
Pregnancy
Women with a tendency to constipation may find the condition more troublesome in the third trimester and require dietary adjustment and supplements
Synonyms
Costive bowel
Locked bowels
International Classification of Diseases
564.00 Constipation, unspecified
564.7 Megacolon, other than Hirschsprung
564.89 Other functional disorders of intestine
751.3 Hirschsprung disease and other congenital functional disorders of colon
See Also
Congenital megacolon Encopresis
Other Notes
– Obstipation refers to intractable constipation
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