Pelvic Floor and Anorectal Disorders

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• ABIM-format MCQs
  5-option vignettes with full wrong-answer teaching.
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What this chapter covers

• Section 16.1: Chronic constipation: definitions and empiric management

  Chronic constipation is diagnosed by symptoms rather than by stool frequency alone, because the population that complains of constipation is dominated by patients who pass stool more than three times a week and still report straining, hard stools, incomplete evacuation, and dependence on manual maneuvers.

• Section 16.2: Prescription therapies for refractory CIC

  Prescription therapy in chronic idiopathic constipation begins when fiber, polyethylene glycol, and stimulant laxatives have failed to produce a satisfactory response, and the choice among the available drugs is mechanism-driven.

• Section 16.3: Defecation disorders and biofeedback

  Consider a defecatory disorder when a constipation patient has failed empiric therapy, because the mechanism is mechanical rather than transit-related and the right intervention is biofeedback rather than additional laxatives.

• Section 16.4: Slow-transit constipation

  Slow transit constipation is the diagnosis that emerges after a defecatory disorder has been excluded and the patient still has infrequent bowel movements and refractory symptoms.

• Section 16.5: Opioid-induced constipation and PAMORA

  Opioid-induced constipation is mechanistically distinct from chronic idiopathic constipation, and it needs a different drug class.

• Section 16.6: Fecal incontinence

  Fecal incontinence is the involuntary loss of solid or liquid stool, distinct from anal incontinence (which includes flatus) and from seepage (passage of small amounts of stool residue, typically in patients with internal sphincter dysfunction or perianal soiling).

• Section 16.7: Hemorrhoids, anal fissure, and pruritus ani

  The benign anorectal disorders that bring patients to clinic are anatomically distinguished by their relationship to the dentate line, so locate the lesion relative to the dentate line first.

Podcast episodes

1. 01

   Pelvic Floor and Anorectal: Chronic Constipation

   Chronic constipation is diagnosed by symptoms, and the episode's organizing idea is that the mechanism and the response to each step decide what comes next. It starts with the Rome four criteria and the separation from irritable bowel by dominant pain, then the three mechanisms. Patients without alarm features get empiric treatment: education, psyllium, stopping constipating drugs, polyethylene glycol, then stimulants. Alarm features send a patient to colonoscopy first. When fiber, polyethylene glycol, and stimulants fail, a prescription drug is chosen by its target, starting with the secretagogues and moving to prucalopride, which switches mechanism. After several failures, the next move is testing for an outlet or transit problem.

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2. 02

   Pelvic Floor Disorders: Refractory Constipation

   Constipation that fails the standard drugs usually has a mechanism the drugs cannot reach, and the episode sorts those mechanisms by where the lesion sits. It starts at the outlet with dyssynergic defecation, working through the rectal exam, balloon expulsion, manometry, defecography, and biofeedback, and notes that an absent rectoanal inhibitory reflex suggests Hirschsprung disease. It then turns to slow transit, which is diagnosed only after the outlet is cleared, using the marker study, then prucalopride and other medical options before a narrowly indicated colectomy. It closes with opioid-induced constipation, where standard laxatives come first, then a PAMORA unless obstruction is possible, and alvimopan stays an inpatient drug after bowel resection.

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3. 03

   Pelvic Floor and Anorectal: The Anal Canal

   Every complaint in this episode comes back to which part of the anal canal is involved and what keeps the problem going. Fecal incontinence is usually multifactorial, so the episode looks for every cause, matches urge or passive leakage to the failing sphincter, and tests with manometry and endoanal ultrasound before stepping from fiber, loperamide, and biofeedback to sacral nerve stimulation. It then uses the dentate line to separate painless internal hemorrhoids, which are graded and banded, from painful thrombosed external ones, which are excised within seventy-two hours. Fissures follow, treated stepwise by relaxing the internal sphincter, with lateral ones prompting a search for Crohn disease. Pruritus ani closes the episode, with secondary causes excluded first.

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Key topics

• ·Rome four criteria
• ·Chronic constipation versus irritable bowel with constipation
• ·Normal transit, slow transit, and defecatory disorders
• ·Alarm features
• ·Fiber, constipating drugs, and laxatives
• ·Secretagogues: lubiprostone, linaclotide, plecanatide
• ·Prucalopride and serotonin four selectivity
• ·Tenapanor
• ·Refractory constipation and when to test
• ·Board traps
• ·Dyssynergic defecation mechanism
• ·Digital rectal exam and balloon expulsion
• ·Anorectal manometry and defecography
• ·Biofeedback therapy
• ·Hirschsprung disease and the rectoanal inhibitory reflex
• ·Slow-transit constipation and the marker study
• ·Medical therapy and prucalopride
• ·Colectomy criteria and outcomes
• ·Opioid-induced constipation and PAMORAs
• ·Alvimopan after bowel resection
• ·Fecal incontinence causes
• ·Urge versus passive leakage
• ·Anorectal manometry and endoanal ultrasound
• ·Medical therapy and biofeedback
• ·Sacral nerve stimulation and other operations
• ·Overflow incontinence from impaction
• ·Hemorrhoids and the dentate line
• ·Goligher grades and rubber band ligation
• ·Thrombosed external hemorrhoid
• ·Anal fissure stepwise treatment