Fecal Incontinence and Anorectal Disorders
What you must know
Fecal incontinence arises from sphincter disruption (obstetric injury, surgery), neuropathy (pudendal, diabetes), decreased rectal compliance, or stool consistency problems (diarrhea overwhelms a normal sphincter). Understand the continence mechanism: internal anal sphincter (resting tone), external anal sphincter and puborectalis (squeeze and sampling reflex), rectal reservoir, and rectoanal inhibitory reflex.
Evaluation: history (stool consistency, urgency, pad use), anorectal manometry (resting/squeeze pressures, rectoanal inhibitory reflex), endoanal ultrasound (sphincter defects), and pudendal nerve studies. Treatment ladder: dietary fiber and stool-bulking, antidiarrheals (loperamide), pelvic floor muscle training and biofeedback, sacral neuromodulation, sphincteroplasty for discrete defects, and diversion in severe refractory cases.
Also know anorectal disorders: hemorrhoids, fissure (lateral internal sphincterotomy for chronic), fistula, abscess (urgent drainage), and rectal prolapse (surgical repair).
Traps
Antidiarrheal therapy is often the highest-yield intervention - questions may push toward surgery prematurely. Another trap: assuming all incontinence is sphincter injury; diarrhea and impaction (overflow) are common. Don't confuse internal (resting) vs external (squeeze) sphincter function.
Rule of thumb
"Fix the stool first." Normalize consistency, then train the floor, then neuromodulate, then operate.
Worked example: A patient with urgency, frequent loose stools, and leakage after cholecystectomy. Stool consistency is the driver; loperamide plus fiber and PFMT is the first step, not sphincteroplasty.