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Unsatisfactory defecation characterized by infrequent stools, difficult stool passage, or both. Characteristics include <3 bowel movements a week, hard stools, excessive straining, prolonged time spent on the toilet, a sense of incomplete evacuation, and abdominal discomfort/bloating.
- System(s) affected: gastrointestinal (GI)
- Synonym(s): obstipation
Colorectal neoplasms may be associated with constipation; new-onset constipation after age 50 years is a “red flag.” Use warm water enemas (instead of sodium phosphate enemas) for impaction in geriatric patients. Sodium phosphate enemas have been associated with fatalities and severe electrolyte disturbances (1).
Consider Hirschsprung disease (absence of colonic ganglion cells) in cases of pediatric constipation. Hirschsprung disease accounts for 25% of all newborn intestinal obstructions and can present as milder cases diagnosed 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).
- More pronounced in children and elderly
- Predominant sex: female > male (2:1)
- Nonwhites > whites
- 5 million office visits annually
- 100,000 hospitalizations
- 16% of adults >18 years, rising to 33% of adults >60 years of age
- 3% of pediatric visits relate to constipation.
Etiology and Pathophysiology
- As food leaves the stomach, the ileocecal valve relaxes (gastroileal reflex), and chyme enters the colon (1 to 2 L/day) from the small intestine. In the colon, sodium is actively absorbed in exchange for potassium and bicarbonate. Water follows the osmotic gradient. Peristaltic contractions move chyme through the colon into the rectum. Chyme is converted into feces (200 to 250 mL).
- Normal transit time is 4 hours to reach the cecum and 12 hours to reach the distal colon.
- Defecation reflexively follows as stool reaches the rectal vault. This 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).
- Primary and secondary defecation disorders result from delay in colonic transit, altered rectal motor activity, and structural or functional problems with pelvic floor muscles (including paradoxical contractions, diminished sphincter relaxation, and/or poor propulsion).
Unknown but may be familial
- Very young and very old
- Sedentary lifestyle or condition
- Improper diet and inadequate fluid intake
High-fiber diet, adequate fluids, exercise, and training to “obey the urge” to defecate
Commonly Associated Conditions
- General debilitation (disease or aging)
- Nursing home resident