Constipation
BASICS
- Unsatisfactory defecation characterized by infrequent bowel movements, difficult stool passage, or both.
- Characteristics may include <3 bowel movements a week, hard stools, excessive straining, a sense of incomplete evacuation, abdominal discomfort/bloating, painful bowel movements, and need for manual aid when defecating.
DESCRIPTION
Geriatric Considerations
Consider new-onset constipation after age 50 years a “red flag” for colorectal neoplasms that may require a colonoscopy. Use warm water enemas (instead of sodium phosphate enemas) for impaction in geriatric patients. Sodium phosphate enemas in older adults have been associated with hypotension, volume depletion, EKG changes (prolonged QT interval), and severe electrolyte disturbances.Pediatric Considerations
Consider Hirschsprung disease in pediatric cases. This accounts for 25% of all newborn intestinal obstructions and can present as milder cases in older children with chronic constipation, abdominal distension, and decreased growth. Hirschsprung has a 5:1 male-to-female ratio and is associated with inherited conditions (e.g., Down syndrome).Pregnancy Considerations
Constipation is common in pregnancy due to progesterone slowing GI motility, gravid pressure of uterus on colon, iron supplementation, and decreased physical activity.
EPIDEMIOLOGY
- More pronounced in children and elderly
- Predominant sex: female > male (2:1)
- Nonwhites > whites
Incidence
- 2.5 million office visits annually
- 92,000 hospitalizations annually
Prevalence
- 16% of adults >18 years of age, rising to 33% of adults >60 years of age
- 3% of pediatric visits relate to constipation.
ETIOLOGY AND PATHOPHYSIOLOGY
- Defecation reflex can be inhibited by voluntarily contracting the external sphincter or facilitated by straining to contract the abdominal muscles while voluntarily relaxing the anal sphincter. Rectal distention initiates the defecation reflex. The urge to defecate occurs with an increase in rectal pressure. Distention of the stomach also initiates rectal contractions and a desire to defecate (gastrocolic reflex).
- Constipation often runs in families, but no single gene has been identified. Identical twins are known to have higher concordance compared to non-identical twins.
RISK FACTORS
- Extremes of age
- Female sex
- Polypharmacy
- Sedentary lifestyle or condition
- Low fiber diet and inadequate fluid intake
- Increased stress or history of abuse
- Depression
- Low calorie intake
- Low income and low educational status
GENERAL PREVENTION
High-fiber diet, adequate fluids, exercise, and training to “obey the urge” to defecate
COMMONLY ASSOCIATED CONDITIONS
- General debilitation (disease or aging)
- Dehydration
- Hypothyroidism, metabolic endocrinopathies
- Electrolyte abnormalities: hypokalemia, hypercalcemia
- Myopathies and neuropathies
- History of abdominal or pelvic surgery
- Down syndrome
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