Chronic Constipation

Persistently difficult, infrequent, or incomplete defecation. Rome IV: ≥2 of (straining, lumpy/hard stools, incomplete evacuation sensation, anorectal obstruction sensation, manual maneuvers needed, <3 spontaneous bowel movements/week) for ≥3 months, onset ≥6 months prior.

Classified: primary/functional (normal transit; most common; slow transit; defecatory disorders/pelvic floor dyssynergia) or secondary (opioids, anticholinergics, iron, CCBs, antacids; hypothyroidism, hypercalcemia, diabetes; Parkinson's, spinal cord lesion, MS; colorectal cancer, stricture, rectocele; pregnancy, immobility).

Infrequent defecation, hard/lumpy stools (Bristol type 1-2), straining, incomplete evacuation, bloating, need for digital evacuation (suggests defecatory disorder).

Red flags: rectal bleeding, weight loss, iron-deficiency anemia, family history of colorectal cancer/IBD, age >50 with new onset, palpable mass, change in bowel habit in older patients.

Clinical, Rome IV criteria. Investigate if red flags/refractory: FBC, TSH, calcium, glucose; colonoscopy if alarm features/screening-appropriate; anorectal manometry + balloon expulsion test if defecatory disorder suspected; colonic transit studies if slow transit suspected and refractory.

Differentials: IBS-C, colorectal malignancy, hypothyroidism, medication side effect, pelvic floor dysfunction.

• Lifestyle: fiber 25-30g/day (gradual increase), fluids, exercise, scheduled post-prandial toileting, footstool for correct posture

• Bulk-forming laxatives: ispaghula husk 1 sachet bd ; irst-line, avoid if suspected obstruction/severe slow transit

• Osmotic laxatives: macrogol/PEG 1-3 sachets/day : first-line if bulk-forming insufficient; lactulose 15-30mL bd alternative (more bloating)

• Stimulant laxatives: senna 7.5-15mg nocte, bisacodyl 5-10mg nocte: add if above insufficient

• Docusate: modest evidence, sometimes adjunctive

• Refractory: prucalopride 2mg od (prokinetic); linaclotide/lubiprostone (secretagogues); specialist-initiated

• Opioid-induced: peripherally-acting mu-opioid antagonists (methylnaltrexone, naloxegol)

• Defecatory disorder: biofeedback therapy; more effective than laxatives for this subtype

• Fecal impaction: high-dose macrogol disimpaction regimen, or enema/manual evacuation if severe

• Address underlying cause: review constipating medications, treat hypothyroidism/hypercalcemia

Referral: gastroenterology for red flags/refractory disease/biofeedback candidacy; colorectal surgery if structural cause found.