Pelvic Floor and Anorectal Disorders: Pelvic Floor and Anorectal: The Anal Canal

0:00Welcome to Board Pearls. This is episode three of three of the Pelvic Floor and Anorectal Disorders chapter, in the Colorectal and Pelvic Floor Disorders module. This episode covers the anal canal itself. A woman who comes in about loose stools turns out to have fecal incontinence, and her case shows why the question has to be asked directly, why every cause is looked for, what urge versus passive leakage means, and which operation comes first. A nursing home resident shows the incontinence that's really constipation. A man with painless bleeding has hemorrhoids, and his case shows why the dentate line explains who hurts and how the grade picks the treatment, and a woman with a painful lump shows the seventy-two-hour window for a thrombosed external hemorrhoid. A woman with pain like broken glass has an anal fissure, and her case shows why sphincter spasm keeps it open, the stepwise treatment, and, with a young man, when location means Crohn disease. And a man with perianal itching shows why pruritus ani needs a workup.

1:00Here's the first patient. A sixty-three-year-old woman comes to clinic about loose stools. Only when asked directly does she say she's had accidents two or three times a week for two years. She feels the urge and can't make it to the toilet in time. She had three vaginal deliveries, one with forceps and a large tear. Her stools have been loose since her gallbladder was removed four years ago. She has occasional urinary leakage too.

1:28She has fecal incontinence, and she came in calling it loose stools. Fecal incontinence is the involuntary loss of solid or liquid stool. Anal incontinence is broader and includes flatus, and seepage is the passage of small amounts of stool residue, typically from internal sphincter dysfunction or perianal soiling. In national survey data, roughly eight to nine percent of adults have fecal incontinence, rising to twenty percent over seventy and approaching fifty percent in nursing home residents. Patients rarely volunteer it, and loose stools are a common way it presents, so asking directly is part of the visit.

2:05Her history already holds more than one cause, and that's typical. More than eighty percent of patients have more than one contributing cause, so the workup doesn't stop at the first explanation. Anal sphincter dysfunction comes first. The most common injury is obstetric, a third- or fourth-degree perineal tear, with symptoms appearing immediately or years to decades later as compensation wanes with age. Surgical injury comes from hemorrhoidectomy, lateral internal sphincterotomy, fistulotomy, and other anorectal surgery. And pudendal neuropathy comes from chronic straining, vaginal delivery, or diabetic autonomic neuropathy.

2:44The other causes are looked for too. Rectal disorders include radiation proctitis, which reduces rectal compliance and capacity, inflammatory bowel disease, IBD, and rectal prolapse. Neurologic causes include spinal cord injury, multiple sclerosis, stroke, and dementia, and myopathic disorders contribute too. Stool consistency and volume matter, because diarrhea from irritable bowel syndrome, microscopic colitis, IBD, or cholecystectomy can exceed the continence reserve. She has an obstetric injury and loose stools since her cholecystectomy, and each needs its own treatment.

3:25The kind of leakage points to which muscle has failed. Urge incontinence, with awareness of the need to go, suggests external sphincter weakness, because the voluntary muscle can't hold on. Passive incontinence, leakage without awareness, suggests internal sphincter dysfunction or neuropathy. She has urge incontinence.

3:44The rest of the history and the exam fill in the picture. The history covers onset and triggers; frequency, amount, and severity, with a stool diary and the Wexner and St. Mark's scores; stool consistency; deferment time, the interval from the urge to reaching a toilet; obstetric and surgical history; urinary symptoms, because pelvic floor disorders cluster; comorbidities such as diabetes, neurologic disease, irritable bowel, IBD, and celiac disease; and medications. The exam inspects for soiling and scars, and the digital rectal exam assesses resting tone, voluntary squeeze, perineal descent on a simulated push, and any mass or impaction. Her resting tone is normal, but her squeeze is weak.

4:30Her weak squeeze is then measured and imaged. Anorectal manometry is the most informative single test, changing treatment in roughly eighty-five percent of patients. A reduced resting pressure means internal sphincter dysfunction, and a reduced squeeze pressure means external sphincter weakness or pudendal neuropathy, and rectal sensation and compliance are measured too. Endoanal ultrasound is the test of choice for sphincter integrity. It shows the internal and external sphincters as concentric rings and finds defects, especially anterior obstetric defects, that examination can't.

5:04Two more tests have narrower roles. Magnetic resonance, MR, defecography helps when manometry and ultrasound are inconclusive or other pelvic floor problems are suspected, and translumbosacral anorectal magnetic stimulation tests lumbosacral nerve conduction at specialized centers. Her manometry shows a normal resting pressure and a low squeeze pressure, and her endoanal ultrasound shows an anterior external sphincter defect of about ninety degrees.

5:35Her treatment starts by reversing whatever can be reversed. Soluble fiber, one to two tablespoons of psyllium a day, bulks loose stool. Impaction is treated with disimpaction and maintenance, underlying diarrheal disease is managed, and stool-loosening medications are reviewed. Loperamide, typically four to sixteen milligrams a day, is the first-line drug. It's a peripheral mu-opioid agonist that slows transit, increases internal sphincter tone, and inhibits the rectoanal inhibitory reflex. Bile acid sequestrants, cholestyramine or colesevelam, are added when bile acid malabsorption contributes, as it can after her cholecystectomy. Second-line options have limited evidence: phenylephrine gel for internal sphincter tone, low-dose tricyclics, valproic acid in selected patients, and clonidine.

6:23Biofeedback is added to the drugs, not used instead of them. Anorectal biofeedback is offered for a reduced squeeze pressure, impaired sensation, or both, combining external sphincter strengthening with rectal sensory retraining. It works in roughly fifty to seventy percent of selected patients, best with some remaining sphincter function and intact nerves. She starts psyllium, colesevelam, and loperamide as needed and completes biofeedback. Her accidents fall to about two a month, but they still limit her.

6:54Her incontinence is now refractory to conservative care, which opens surgical options, and one comes first. Sacral nerve stimulation, also called sacral neuromodulation, is the preferred treatment for refractory fecal incontinence, with the strongest surgical evidence, and it has displaced sphincter repair as the first operation in most settings. An implanted lead and pulse generator stimulate the third sacral nerve root, modulating sensory signals from the rectum and pelvic floor, altering motility, and acting centrally on continence. It's staged: an external test stimulator for one to two weeks, then a permanent implant if symptoms improve by at least fifty percent. It works even with a sphincter defect. Her trial cuts her episodes by more than half, and she has the permanent implant.

7:41The other operations have narrower places. Sphincteroplasty, an overlapping repair of an external sphincter defect, is still offered for isolated defects, particularly in younger women with obstetric injury, but its efficacy declines over years. Anal bulking agents, such as dextranomer injected at four quadrants five millimeters above the dentate line, augment passive continence and are approved for selected patients, with modest, variable benefit. Radiofrequency remodeling, the SECCA procedure, is used in selected patients. An artificial bowel sphincter or dynamic graciloplasty, wrapping the gracilis muscle around the anal canal, is reserved for severe refractory cases at specialized centers because of its high morbidity. A colostomy is the last resort, and sometimes the right choice when the symptom dominates a patient's life.

8:31The second patient shows incontinence that's really constipation. An eighty-two-year-old nursing home resident has constant leakage of liquid stool labeled diarrhea, and a rectal exam finds a large, hard fecal impaction. That's overflow incontinence, with liquid stool from above seeping around the impacted mass. He needs disimpaction and a maintenance regimen. Loperamide would worsen the impaction, which is why the rectal exam comes before the antidiarrheal.

8:59The other complaints of the anal canal are organized by the dentate line, and the third patient shows why. A forty-eight-year-old man has had bright red blood on the toilet paper, and sometimes dripping into the bowl, after bowel movements for six months, without pain. Tissue bulges out when he strains and slips back on its own. He strains with hard stools, sits on the toilet reading for long stretches, and eats very little fiber. A colonoscopy two years ago was normal apart from hemorrhoids.

9:28Painless bright red bleeding with prolapse that reduces on its own, in a man who strains, is internal hemorrhoids, and the dentate line explains why they don't hurt. Internal hemorrhoids arise above it, from the superior hemorrhoidal venous plexus. They're covered by columnar mucosa with visceral nerves that don't transmit somatic pain, so they bleed and prolapse without hurting. External hemorrhoids arise below it, from the inferior hemorrhoidal venous plexus. They're covered by squamous epithelium and skin, densely supplied by somatic nerves from the inferior rectal nerve, so they hurt sharply when they thrombose. Anal fissures sit below the line too.

10:05His hemorrhoids are the anal cushions of the upper canal, which normally help seal the canal at rest. They become symptomatic when their supporting connective tissue, including the Treitz ligament and the smooth muscle attachments, degenerates, so the cushions slide down with straining, engorge, and prolapse. The risk factors are chronic straining from constipation, prolonged toilet sitting, a low-fiber diet, pregnancy, obesity, and aging, and he has the first three. The classic presentation is painless bright red bleeding, coating the stool, on the paper, or dripping into the bowl, with intermittent prolapse.

10:43His treatment depends on the grade, by the Goligher classification. Grade one bulges into the lumen without prolapsing. Grade two prolapses with defecation and reduces on its own. Grade three prolapses and has to be pushed back by hand. Grade four is permanently prolapsed and irreducible and may incarcerate or strangulate. He has grade two. Grades one and two respond to conservative measures and banding, grade three often responds to banding but may need surgery, and grade four typically needs excisional hemorrhoidectomy.

11:16Conservative care is the foundation for every grade. It's fiber, with psyllium toward twenty-five to thirty grams a day and plenty of fluid; warm sitz baths for ten to fifteen minutes two to three times a day; no prolonged toilet sitting or straining; topical analgesics; and topical hydrocortisone for no more than a week, because longer use thins the skin. Six weeks later his stools are soft and he isn't straining, but he still bleeds and prolapses with most bowel movements.

11:45With conservative care failing at grade two, his next step is rubber band ligation, the office procedure of choice for grades two and three. A band at the base of each hemorrhoid, above the dentate line, cuts off the blood supply, and the tissue necroses and sloughs over five to seven days. It's essentially painless because the band sits where there's no somatic innervation, while a band below the line would be very painful. The typical complication is bleeding at seven to ten days, as the band and dead tissue come away, which patients should be warned about. Urinary retention can occur, and rarely pelvic sepsis. Sclerotherapy and infrared coagulation are office alternatives. After two banding sessions his bleeding and prolapse resolve, with one expected episode of minor bleeding on day eight.

12:31Surgery is kept for the patients banding can't help. Excisional hemorrhoidectomy, open Milligan-Morgan or closed Ferguson, is reserved for grade four disease, mixed internal and external disease, symptoms that persist after office treatment, and acute incarcerated or strangulated prolapse. Stapled hemorrhoidopexy removes a ring of redundant mucosa above the hemorrhoids to lift the cushions, with quicker recovery and a different complication profile. The grade can change over time, and the treatment follows it. Calling his bleeding hemorrhoidal was safe because his colonoscopy was recent. A patient his age with new rectal bleeding and no recent colonoscopy needs one first.

13:14Below the dentate line, the same vein causes pain, and the fourth patient shows it. A thirty-four-year-old woman developed an exquisitely tender, firm, blue-purple lump at the anal edge yesterday, after a long drive. She has a thrombosed external hemorrhoid, a clot in an external hemorrhoidal vein below the dentate line. The pain is worst on the day it starts and improves over seven to ten days as the clot organizes.

13:40Timing decides her treatment. Excision under local anesthesia within the first seventy-two hours gives faster relief than conservative care. After seventy-two hours, the pain is already declining and surgery only adds a wound, so sitz baths, analgesics, stool softeners, and topical agents are preferred. The whole thrombosed hemorrhoid is excised, because incision and drainage leaves the clot pocket, and it frequently thromboses again. At twenty-four hours, she has it excised in the office, and she feels better the same day.

14:14The other painful lesion below the line is a fissure, and the fifth patient shows how it's treated. A thirty-one-year-old woman has had sharp pain with every bowel movement for three months, like passing broken glass, lasting an hour afterward, with bright red blood on the paper. She's been constipated since her second baby was born, and that delivery involved a perineal tear. Gentle examination shows a linear tear in the posterior midline with a small skin tag at its outer end.

14:42She has a chronic anal fissure, and its cause explains every treatment. A fissure is a linear tear in the squamous-lined canal below the dentate line, which is why it hurts. It starts with a hard stool, and then the internal anal sphincter goes into spasm. The spasm reduces blood flow to the posterior commissure, the watershed area of the canal, so the tear can't heal, and the open fissure keeps the spasm going. Every treatment beyond fiber relaxes the internal sphincter to restore blood flow.

15:12Her fissure is chronic and in the typical place. Acute fissures, present for less than six weeks, usually heal with conservative care. Chronic fissures, present for more than six weeks, may show a sentinel skin tag at the outer end, a hypertrophied anal papilla at the inner end, and exposed internal sphincter fibers at the base. About ninety percent of fissures are in the posterior midline in both sexes, and the anterior midline is the second most common site in women, related to the less supported front of the female pelvic floor.

15:41Her treatment climbs in steps. The first is conservative care: fiber and water to soften the stool, warm sitz baths, topical analgesics, and no straining, and she's done a month of it without healing. The second is topical therapy for six to eight weeks. Nitroglycerin ointment, zero point two to zero point four percent two or three times a day, heals roughly fifty to sixty percent, with headache from systemic vasodilation as the dominant side effect. Topical diltiazem two percent or nifedipine zero point two percent works about as well with fewer systemic effects and is increasingly the first choice, so a nitroglycerin headache means switching, not failure. She uses diltiazem twice a day for eight weeks, and her pain eases, but the fissure stays open.

16:30The third step is botulinum toxin. Twenty to fifty units of onabotulinumtoxinA injected into the internal sphincter at one or two sites produces a chemical denervation lasting two to three months, long enough for the fissure to heal. It heals sixty to eighty percent in randomized trials, with transient mild incontinence to gas or stool as the main side effect. The fourth step is lateral internal sphincterotomy, which divides part of the internal sphincter and permanently lowers its pressure. It heals more than ninety percent, with a small but real risk of incontinence, mostly to gas, that's higher in women with a prior obstetric injury and in older adults.

17:08The steps run from removing the trigger, to temporary relaxation, to longer relaxation, to permanent relaxation, each with slightly more risk of incontinence, which is why they're climbed in order. Her perineal tear raises her risk of incontinence after sphincterotomy, so she has botulinum toxin, and six weeks later her fissure has healed, and she stays on psyllium. Failure of botulinum toxin wouldn't rule out sphincterotomy, but her obstetric history would be weighed and discussed with her openly.

17:37Location can change everything, and the sixth patient shows it. A twenty-four-year-old man has two fissures, one on each side of the canal, and a few months of loose stools. Lateral or multiple fissures are atypical and need a workup for a secondary cause. Crohn disease is the most important, since a fissure is sometimes the first sign of IBD, and the others are human immunodeficiency virus, HIV, infection with an opportunistic infection, syphilis, tuberculosis, anal cancer, leukemia, and trauma. With his loose stools, Crohn disease leads, and he needs that workup before any routine fissure treatment.

18:15The last patient's complaint has no single anatomic source. A fifty-two-year-old man has had intense perianal itching for a year, worse at night. He scrubs with soap after every bowel movement and uses moist wipes. His perianal skin is thickened and pale. Pruritus ani is a symptom, not a single diagnosis, and repeated scratching causes lichenification and sensitizes the nerves, which keeps the itch going after the trigger is gone.

18:41Before his itch is called idiopathic, the causes are excluded. They include dermatoses, such as eczema, psoriasis, lichen sclerosus, and contact dermatitis from soaps, wipes, topical products, or fabric; infections, such as Candida, group A streptococcus, herpes simplex, condylomata, scabies, and pinworms, which are common in children but rare in adults; seepage and soiling, from incontinence or hemorrhoids; neoplasm, including Bowen disease, anal intraepithelial neoplasia, anal cancer, and extramammary Paget disease; and dietary triggers, such as caffeine, chocolate, citrus, spicy food, beer, and tomatoes, though responses vary. The perianal skin is inspected under good light, and any persistent or atypical lesion is biopsied.

19:21His workup points to his own routine. His exam shows no mass, ulcer, or atypical lesion, a fungal scraping is negative, and he has no leakage, so his soap and moist wipes, both recognized contact irritants, are the likely trigger. Idiopathic pruritus ani is managed with gentle cleansing with water, without soap or vigorous wiping; gentle drying; no moist wipes, which often contain sensitizers; a zinc oxide or other barrier ointment; short courses of one percent hydrocortisone for flares; and a trial of eliminating dietary triggers. Topical capsaicin and tacrolimus are second line. He stops the soap and wipes, uses zinc oxide, and his itch settles over a month.

20:03Here are the traps the boards set in these patients. Incontinence has to be asked about, and loose stools aren't always the whole story. Most patients have several causes, not one. Urge leakage means the external sphincter and passive leakage the internal sphincter. A suspected defect needs an endoanal ultrasound. Overflow around an impaction isn't treated with loperamide. Biofeedback is added to medical therapy, not offered instead of it. And sacral nerve stimulation comes before sphincteroplasty, even with a sphincter defect.

20:35The hemorrhoid traps follow. Painful perianal symptoms don't come from internal hemorrhoids. Grade two reduces on its own, and grade three has to be pushed back. Topical steroids aren't used for more than a week. Grade two and three disease is banded before surgery, and a band never goes below the dentate line. Bleeding a week after banding is expected. And a thrombosed external hemorrhoid isn't excised after seventy-two hours, and it's never just incised and drained.

21:04The fissure and itch traps close the list. A lateral or multiple fissure isn't treated as routine. A nitroglycerin headache isn't a reason to abandon topical therapy. Sphincterotomy doesn't come first, and it isn't offered without weighing obstetric injury and age. And pruritus ani isn't called idiopathic until infection, skin disease, seepage, and neoplasia are excluded, with soap and wipes high on the list of causes.

21:36So, start to finish. Fecal incontinence is common, underreported, and usually multifactorial, so ask directly and look for every contributor. Urge leakage points to the external sphincter and passive leakage to the internal sphincter. Manometry changes management in most patients, and endoanal ultrasound shows the defects. Firm the stool with fiber, loperamide, and sequestrants when bile acids contribute, add biofeedback, and use sacral nerve stimulation first for refractory disease, even with a defect.

22:08Internal hemorrhoids arise above the dentate line and are painless. Grade them by prolapse, start conservative care for every grade, band grades two and three, and save excision for grade four, mixed disease, refractory symptoms, or strangulation. A thrombosed external hemorrhoid sits below the line and is painful, and it's excised whole within seventy-two hours.

22:32A fissure is a tear kept open by sphincter spasm. Treat it with fiber and sitz baths, then topical diltiazem or nitroglycerin, then botulinum toxin, then sphincterotomy if the incontinence risk is low, and search for Crohn disease and other causes when a fissure is lateral or multiple. Pruritus ani needs its secondary causes excluded before gentle hygiene and a barrier.

22:55That completes the Pelvic Floor and Anorectal Disorders chapter. The next chapter starts the liver: interpreting abnormal liver tests.

23:03For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode three of three of chapter sixteen, and I'll see you in the next one.