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Fecal Incontinence

June 23, 2013 10:20 PM

By Dr. Michael Sossenheimer

Introduction:

Fecal incontinence is a difficult yet seldom talked about problem. The impaired ability to control gas or stool ranges from mild (difficulty with gas) to severe (loss of control of liquid and formed stools); symptoms can be continuous or recurrent. Nearly 18 million U.S. adults – about one in 12 – suffer from fecal incontinence. This number is likely underestimated as patients are reluctant to discuss this disabling problem. Incontinence causes emotional distress, loss of dignity, embarrassment, shame, frustration, anger, depression as well as social isolation. Perianal skin irritation may lead to pain, itching, and ulcers which may require medical or surgical treatments.

Causes of fecal incontinence include:

  • diarrhea
  • constipation
  • muscle or nerve damage (due to constant straining, spinal cord injury, stroke)
  • childbirth related trauma (episiotomy, forceps)
  • anal operations
  • traumatic injuries
  • rectocele (a weakness of the recto-vaginal septum allows rectal tissue to bulge into the vagina. Rectoceles are uncommon in men as the prostate gland provides structural support)
  • rectal prolapse
  • inflammation (colitis)
  • radiation
  • tumors
  • diseases such as diabetes, multiple sclerosis
  • dementia (the prevalence of fecal incontinence is estimated at 47% for nursing home residents )
  • aging (the prevalence of fecal incontinence is estimated at 15% in those 70 or older)

Other risk factors further include:

  • poor general health
  • physical disabilities
  • chronic obstructive pulmonary disease
  • irritable bowel syndrome
  • urinary incontinence
  • colectomy
  • chronic diarrhea
  • fecal impaction
  • depression

Anorectal function and continence depend on factors such as stool volume, stool consistency, colonic transit, rectal distensibility, anal sphincter function, anorectal sensation and intact anorectal reflexes. Anatomical structures which help preserve continence include the rectum, the internal and external anal sphincter muscles, and the pubo-rectalis muscle. Defecation is initiated when stool enters the rectum, leading to rectal distention with reflex relaxation of the internal anal sphincter. The urge to defecate increases as more stool passes into the rectum. During defecation the anorectal angle is straightened and abdominal pressure is increased; pelvic floor descent, rectal contraction, and external anal sphincter relaxation then lead to emptying of stool.

 

Workup:

To better understand incontinence, a detailed history, physical exam and supplemental studies are required.

The clinical history should assess for onset of disease, duration, frequency, severity, precipitating events, and look for a history of difficult or traumatic vaginal delivery, anorectal surgery, pelvic irradiation, diabetes, and neurologic diseases.

A physical exam should include inspection of the perianal area which may reveal dermatitis (suggesting chronic incontinence), fistulizing disease, prolapsing hemorrhoids, or even rectal prolapse. Perianal sensation should be tested, with the absence of an anal wink reflex suggesting nerve damage. A digital rectal exam may provide information about the resting anal sphincte tone and may detect obvious anal pathology such as masses or fecal impaction . Inspection of the anus, rectum and large intestine via anoscopy, flexible sigmoidoscopy or colonoscopy may help to exclude mucosal inflammation, masses, or other pathology.

Anorectal manometry measures resting anal pressures, amplitude and duration of squeeze pressures, the rectoanal inhibitory reflex, threshold of conscious rectal sensation, rectal compliance, and anal rectal pressures during straining. Rectal sensation can be assessed by balloon inflation. Pudendal nerve terminal latency may assess potential nerve damage.

Endorectal ultrasound and magnetic resonance imaging are helpful to define structural abnormalities of the anal sphincters, the rectal wall, and the puborectalis muscle.

Defecography assesses anorectal anatomy at rest and during defecation; it assesses the anorectal angle, pelvic descent and may detect occult or overt rectal prolapse.

 

Intervention:

Three treatment approaches are commonly used for fecal incontinence:

  • medical therapy such as dietary changes (i.e. avoidance of sphincter relaxing foods), constipating medications (treatment of diarrhea) and bulking agents (to enhance stool control)
  • biofeedback and muscle strengthening exercises
  • surgery, such a surgical sphincter muscle repair or implantation of an artificial anal sphincter

Medical therapy should be aimed at reducing stool frequency and improving stool consistency. Specific treatment for the underlying cause of diarrhea should be implemented, as formed stool is easier to control than liquid stool. While stool consistency can be improved with bulking agents (i.e. fiber supplements, bile binders), this may exacerbate incontinence in patients with decreased rectal compliance (i.e. in radiation proctitis or rectal stricture).
Stool frequency can be reduced with antidiarrheals such as loperamide (Imodium®) or diphenoxylate (Lomotil®); anticholinergic agents i.e. hyoscyamine (Levsin®, NuLev®, Anaspaz®, Levsinex®, Levbid®) may help with postprandial leakage if taken before meals.

Patients with fecal impaction should be disimpacted and treated with a bowel training regiment to prevent recurrent impaction.

Pelvic floor exercise and biofeedback may help retrain pelvic floor and abdominal wall musculature and may enhance the ability to sense rectal distention, thereby improving sensory as well strength components required for continence. Pelvic floor exercises involve squeezing and relaxing pelvic floor muscles 50-100 times a day. A health care provider can help with proper technique. Biofeedback therapy may help to perform these exercises properly and may improve anorectal sensation. Biofeedback uses special anal and rectal pressure sensors, as well as rectal balloons to produce graded sensations of rectal fullness. Measurements are displayed on a video screen and are used to modify or change abnormal function. Success depends on the cause of fecal incontinence, its severity, and the person’s ability to follow instructions; the role of biofeedback in the management of fecal incontinence is still debated, as the optimal protocol, equipment, and duration of treatment are undefined.

Surgical approaches to fecal incontinence include direct sphincter repair, plication of the posterior part of the sphincter, anal encirclement, implantation of an artificial sphincter, and muscle transfer procedures with or without electrical stimulation. Patients with a sphincter tear (obstetric trauma, fistula surgery) can be cured with a sphincteroplasty. It is the most common fecal incontinence surgery and reconnects the ends of a torn sphincter muscle.

A synthetic sphincter device or magnetic anal sphincter may be available in highly specialized centers. The Acticon (TM) neosphincter, consisting of an occlusive cuff (implanted around the anal canal), a pressure-regulating balloon (implanted in the prevesical space) and a control pump (implanted in the labium or scrotum) enables users to squeeze the control pump to permit defecation.

Sacral nerve electrical stimulation may restore continence in patients with structurally intact muscles. This approach appears to be effective in patients with neurologic disorders. The FDA approved the sacral nerve stimulator (InterStim®, Medtronics) for the treatment of chronic fecal incontinence in patients who have failed or are not candidates for more conservative treatments.

Injectable materials allow augmentation of the function of the internal anal sphincter. Injection of dextranomer-hyaluronic acid (Solesta®), used for the treatment of urinary incontinence, has also been approved for patients with fecal incontinence.

Anal plugs have been studied as a possible treatment for fecal incontinence. Fecal incontinence improved only in a minority of patients, anal plugs were poorly tolerated and their usefulness is thereby limited.

In extreme cases patients may need a colostomy to improve quality of life as a colostomy may be the only option for patients with intractable symptoms who are not candidates for any other therapy, or in whom other treatments have failed.

Lynch Syndrome (Hereditary Nonpolyposis Colorectal Cancer)

June 6, 2013 9:30 PM

Guidelines for the management of Lynch syndrome (HNPCC) are summarized and adapted from recommendations of US and European experts.

 

Introduction

Although a family history of colon cancer increases an individual’s risk of colon cancer by two-to-threefold, some families have a very significantly increased cancer risk  due to proven genetic mutations. While most patients with a family history of colon cancer may be surveilled with a 5-yearly screening protocol (typically starting at age 40 or 10 years before the index relative’s disease), these special families require a much closer surveillance interval and consideration for multiple other cancers. Two major genetic conditions to be considered are Familial Adenomatous Polyposis (FAP) and Lynch Syndrome (LS).

 

Lynch syndrome (LS), also called hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal dominant disorder caused by a germline mutation in one of several DNA mismatch repair (MMR) genes. It is the most common inherited colon cancer susceptibility syndrome, accounting for approximately 1–3% of all colorectal cancers (CRC). The name HNPCC can be misleading as this disorder predisposes to multiple cancers:

  • colon cancer (risk ~25–70%)
  • endometrial cancer (EC) (risk ~30–70%)
  • stomach cancer
  • ovarian cancer
  • bladder cancer
  • upper urologic tract cancers (renal pelvis, ureter)
  • small bowel cancer
  • biliary/pancreatic cancer
  • skin cancer (sebaceous adenomas, carcinomas and keratoacanthomas)
  • brain cancers
  • possible prostate cancer

The frequency of extracolonic cancers in LS varied from 2-20%. LS is responsible for about 2 percent of all endometrial cancers. There is some debate whether even breast cancers may be part of the LS.

 

Clinical features/genetics

Early age of onset and multiplicity of cancers have been considered hallmarks of LS. 7-10% of LS patients have more than one cancer at diagnosis (i.e. synchronous CRC), metachronous CRC are also common (developing another CRC after an initial resection if a subtotal colectomy is not performed). The overall CRC rate appears moderately higher for men than women. LS is an autosomal dominant disorder caused by a defect in one of the mismatch repair (MMR) genes: MLH1, MSH2, MSH6 or PMS2.

  • MLH1 (MutL homolog 1), located on chromosome 3p21
  • MSH2 (MutS homolog 2), located on chromosome 2p16
  • MSH6 (MutS homolog 6), located on chromosome 2p16
  • PMS1 and PMS2 (postmeiotic segregation 1 and 2), located on chromosomes 2q31 and 7p22, respectively

These gene defects lead to a loss of MMR function and result in an accumulation of microsatellite mutations. These microsatellite instabilities (MSI) refer to an expansion or contraction of short repetitive DNA sequences (microsatellites) due to loss of DNA mismatch repair. These mutations lead to alterations in cancer related genes, likely driving the process of carcinogenesis. The overall cancer risk (~80%) and the colorectal cancer risk (50-70%) are similar in MLH1 and MSH2 families, but the risks of endometrial and other extracolonic cancers appear to be substantially higher in MSH2 families. Families with MSH6 and possibly PMS2 mutations appear to have an attenuated cancer phenotype (later age of cancer diagnosis and lower penetrance) compared to MLH1 and MSH2 families. Homozygous or compound heterozygous carriers of MLH1, MSH2, MSH6, or PMS2 often develop hematologic and brain malignancies during childhood. Most had a family history of LS on both the maternal and paternal sides of their families.

The term Lynch syndrome should only be used in individuals and families known to have a detectable MMR gene mutation. Individuals without gene testing are no longer labeled as having LS even if Amsterdam criteria are met.

 

Amsterdam criteria have been used to identify  patients and families at risk for LS.

  • “3-2-1 rule”: 3 affected members, 2 generations, 1 under age 50 – (3 or more relatives with LS-associated cancers (colorectal, endometrial or small bowel cancers, transitional cell carcinoma of the ureter or renal pelvis), one being a first degree relative of the other two, involvement of at least two generations, one or more cancers diagnosed before the age of 50).

 

Bethesda guidelines identify individuals with LS-associated cancers who should be tested for microsatellite instability (and MMR gene testing in those with MSI-H tumors). LS is suggested in colon cancer patients if certain characeristics  are present such as young age and strong familial clustering of colon cancer. LS cancers appear to evolve from adenomas, tend to be larger, flatter, more proximal, and have high-grade dysplasia and/or villous histology, with a more rapid progression of the adenoma-carcinoma sequence. Cancers are more proximal, poorly differentiated , and often mucinous. Histologic features such as tumor-infiltrating lymphocytes, Crohn’s-like lymphocytic reaction, mucin/signet ring cell differentiation, and medullary growth pattern can be used to select patients who might have LS. These patients should have their colon cancers tested for microsatellite instability (if positive, proceed with germline MMR gene testing).

 

  • Benefits of genetic testing in high risk families including a more accurate diagnosis and risk assessment as well as better implementation of surveillance protocols.
  • Family members who do not need intensive surveillance can also be better identified; these members without high risk mutations carry a similar cancer risk as the general population and do not need heightened surveillance.
  • Once high risk individuals are identified, germline testing is recommended in the affected individual. If possible, gene testing should be performed on the family member most likely to have the syndrome (i.e. the youngest family member with colorectal cancer).
  • Practitioners should ensure that patients received appropriate counseling. Informed consent should include a general description of the test, the disorder to be tested for, the meaning of positive and negative results, and the level of certainty that a positive or negative test is a predictor of disease. Counseling about benefits of early cancer  detection and prevention or treatment modalities should be offered.

 

Muir-Torre and Turcot Syndrome 

Two variants of Lynch syndrome had been considered distinct entities: Muir-Torre (Lynch syndrome with associated sebaceous tumors, cutaneous keratoacanthomas, and visceral carcinomas) and Turcot syndrome (Lynch syndrome with associated brain tumors, typically gliomas). These families with extracolonic cancers (brain, sebaceous tumors, skin acanthomas, and visceral carcinomas) are considered part of the spectrum of LS.

 

General cancer surveillance in LS

Analysis of all causes of cancer deaths in LS revealed that 61% of cancer deaths were associated with non-CRC non-EC cancers. Testing of all patients (<70 years) with CRC or EC for loss of MMR function by means of MSI or immunohistochemistry has been recommended, as testing remains one of the first steps to identify individuals who are at increased risk for LS.

CRC surveillance

  • Colorectal surveillance by regular colonoscopy is the only surveillance protocol proven to be effective. Due to advanced CRC in LS detected between 2 and 3 years after surveillance colonoscopy, an interval of 1-2 years is recommended. Colonoscopy is recommended to begin at age 20-25, or 10 years prior to the earliest age of colon cancer in the family (whichever comes first). In families with MSH6 mutations, surveillance starts at age 30, since onset of colon cancer is seen later in these families. Since the risk of developing a second CRC after partial colectomy for primary CRC is estimated at approximately 16% after 10 years (despite following close surveillance), more extensive surgery(total or subtotal colectomy) for the primary CRC might be considered.

EC surveillance

  • Although the value of surveillance for EC is unclear, routine annual surveillance (gynecological exam, transvaginal ultrasound, biopsy starting at age of 35–40, or 5-10 years earlier than the earliest age of diagnosis of these cancers) may lead to early detection of premalignant disease or cancers and should be offered to mutation carriers. A CA 125 may be of benefit. Hysterectomy and bilateral oophorectomy prevents the development of endometrial and ovarian cancer and could be discussed with patients after the age of 35-40, who have completed their family planning. If CRC surgery is scheduled, prophylactic hysterectomy and bilateral oophorectomy at the same time should be considered.

Gastric cancer surveillance

  • The cumulative risk of developing gastric cancer in LS by the age of 70 is approximately 5%. Most gastric cancers in LS are of the intestinal type, so regular EGDs may be of benefit. Given the relatively low risk of gastric cancer and the lack of established surveillance benefit, European guidelines advise against surveillance for gastric cancer.

Small bowel cancer surveillance

  • The risk of developing small bowel cancer in carriers of an MLH1 or MSH2 mutation is approximately 5%. Currently European guidelines advise against surveillance for small bowel cancer, but inspection of the distal duodenum during upper endoscopy and ileum during colonoscopy (if performed) is recommended. Evaluation of the small bowel in patients with unexplained abdominal complaints or iron deficiency anemia has been suggested.

Urinary tract cancer surveillance

  • Increased risks of bladder cancer as well as urothelial cancers of the upper urinary tract in LS have been demonstrated. Given lack of evidence of surveillance benefits for urinary tract cancer, European guidelines advise against surveillance for urinary tract cancer in LS.

Prostate cancer surveillance

Pancreatic cancer surveillance

  • Recent studies have revealed an increased risk of developing pancreatic cancer in LS. Still, the benefit of surveillance for pancreatic cancer in high-risk groups is unknown and European guidelines advise against surveillance for this cancer in LS families.

Breast cancer surveillance

  • Whether breast cancer is part of the tumor spectrum of LS is controversial. The cumulative risk by the age of 70 years may be 14% in all female carriers, with the highest risk in MLH1 carriers (MLH1: 17%; MSH2: 14.4%; MSH6: 11%). At present, female carriers of an MMR gene mutation should be advised to participate in population screening programs for breast cancer (biannual mammography from the age of 45 or 50) as per European guidelines. Since most patients with Lynch syndrome who develop breast cancer do so after the age of 50 years, standard screening approaches for breast cancer are likely appropriate.

 

In summary

As a practical expert opinion approach to surveillance strategies in LS, the reviewers for UpToDate® suggest annual colonoscopy starting at age 20-25 (or 10 years prior to the earliest age of colon cancer in a given family), annual screening for EC with endometrial biopsy and ovarian cancer with CA 125 as well as transvaginal ultrasound beginning at age 30-35 (or 5 to 10 years earlier than the earliest age of first diagnosis of these cancers, whichever is earlier), discussion of prophylactic hysterectomy and salpingo-oophorectomy at the end of childbearing, annual urinalysis beginning at age 25-35, annual skin surveillance and periodic upper endoscopy.