Constipation
Chronic constipation is diagnosed using the Rome IV criteria -- two or more of a defined set of symptoms (straining, hard stools, incomplete evacuation, fewer than 3 bowel movements a week, among others) for at least 3 months, with symptom onset at least 6 months prior.
Symptoms
Infrequent bowel movements, straining, hard or lumpy stools, and a sense of incomplete emptying.
Causes and risk
Low fiber intake, inadequate fluids, inactivity, certain medications (opioids especially), hypothyroidism, and pelvic floor dysfunction are common contributors.
How it is evaluated
Colonoscopy is reserved for alarm features (bleeding, unintended weight loss, anemia, a change in stool caliber, or family history of colorectal cancer) or age-appropriate screening -- constipation alone has not been associated with increased colorectal cancer risk on ASCRS meta-analysis.
Treatment
Fiber (psyllium, 20-30 g/day) and osmotic agents (polyethylene glycol, magnesium oxide, lactulose) are first-line per the joint AGA-ACG 2023 guideline. Stimulant laxatives (bisacodyl, senna) serve as rescue or second-line therapy. When those aren't enough, secretagogues and prokinetics are the next step -- plecanatide and prucalopride for chronic idiopathic constipation specifically, tenapanor for IBS-related constipation.
When to seek care
Inability to pass gas or stool, abdominal distension, vomiting (especially bilious or feculent), severe pain, or fever can indicate bowel obstruction and need emergency evaluation.