bowel diseases: large intestine Flashcards
Diseases of the Colon and Rectum
Irritable bowel syndrome Antibiotic-associated colitis Inflammatory Bowel Disease: Crohn disease Ulcerative colitis (UC)
Diseases of the Colon and Rectum 2
Diverticular disease Diverticulosis Diverticulitis Polyps Familial adenomatous polyposis Hamartomatous polyposis syndromes Lynch syndrome
IBS
An idiopathic clinical entity characterized by chronic (more than 6 months) abdominal pain or discomfort that occurs in association with altered bowel habits
Symptoms may be continuous or intermittent
Definition of irritable bowel syndrome is abdominal discomfort or pain that has two of the following three features:
- Relieved with defecation
- Onset associated with a change in frequency of stool
- Onset associated with a change in form (appearance) of stool
IBS: Other symptoms supporting the diagnosis include ??
abnormal stool frequency; abnormal stool form (lumpy or hard; loose or watery); abnormal stool passage (straining, urgency, or feeling of incomplete evacuation); passage of mucus; and bloating or a feeling of abdominal distention
IBS epi
Patients may have other somatic or psychological complaints such as dyspepsia, heartburn, chest pain, headaches, fatigue, myalgias, urologic dysfunction, gynecologic symptoms, anxiety, or depression
Common problem presenting to both gastroenterologists and PCPs
-Up to 10% of the adult population have symptoms compatible with the diagnosis, but most never seek medical attention
-Approximately two-thirds of patients with irritable bowel syndrome are women.
IBS Pathophysiologic mechanisms have been identified:
Abnormal Motility
Visceral Hypersensitivity
Enteric Infection
*Psychosocial Abnormalities
IBS presentation
Chronic condition
*Diagnosis of exclusion
Symptoms usually begin in the late teens to twenties
Abdominal pain usually is intermittent, crampy, and in the lower abdominal region
Patients with irritable bowel syndrome may be classified into one of three categories based on the predominant bowel habit:
- Irritable bowel syndrome with diarrhea
- Irritable bowel syndrome with constipation
- *Irritable bowel syndrome with mixed constipation and diarrhea
“Alarm symptoms” that suggest a diagnosis other than irritable bowel syndrome and warrant further investigation
Acute onset of symptoms
Nocturnal diarrhea, severe constipation or diarrhea, hematochezia, weight loss, and fever
Family history of cancer, inflammatory bowel disease, or celiac disease
-dx of exclusion
IBS s/s
The physical examination usually is normal
Abdominal tenderness, especially in the lower abdomen, is common but not pronounced.
IBS labs
The use of routine blood tests (complete blood count, chemistry panel, serum albumin, thyroid function tests, erythrocyte sedimentation rate) is unnecessary in most patients
Stool specimen examinations for ova and parasites should be obtained only in patients with increased likelihood of infection
Routine sigmoidoscopy or colonoscopy is not recommended in young patients with symptoms of irritable bowel syndrome without alarm symptoms but should be considered in patients who do not improve with conservative management
IBS labs2
In all patients age 50 years or older who have not had a previous evaluation, colonoscopy should be obtained to exclude malignancy
When colonoscopy is performed, random mucosal biopsies should be obtained to look for evidence of microscopic colitis
-In patients with IBS with diarrhea, serologic tests for celiac disease should be performed
-Routine testing for bacterial overgrowth with hydrogen breath tests are not recommended
(labs not usually helpful)
IBS tx
-General measures: Reassurance, education, and support
-Dietary Therapy: intolerances
-Pharmacologic Measures: Antispasmodic agents, Antidiarrheal agents,
Anticonstipation agents
-Psychotropic agents: SSRIs
-Nonabsorbable antibiotics, Probiotics
-Psychological Therapies: Cognitive behavioral therapies, relaxation techniques, hypnotherapy
Antibiotic-Associated Colitis
(C. diff is a subset) Common clinical occurrence
Occurs during the period of antibiotic exposure, is dose related, and resolves spontaneously after discontinuation of the antibiotic
In most cases, this diarrhea is mild, self-limited, and does not require any specific laboratory evaluation or treatment
Antibiotic-Associated Colitis labs
Stool examination usually reveals no fecal leukocytes, and stool cultures reveal no pathogens
- Although C difficile is identified in the stool of 15–25% of cases of antibiotic-associated diarrhea, it is also identified in 5–10% of patients treated with antibiotics who do not have diarrhea
- Most cases of abx-associated diarrhea are due to changes in colonic bacterial fermentation of carbohydrates and are not due to C difficile
Antibiotic-Associated Colitis epi
- C difficile colitis is the major cause of diarrhea in patients hospitalized for more than 3 days, affecting 22 patients of every 1000
- Fastidious hand washing and use of disposable gloves are helpful in minimizing transmission
- C difficile is acquired in approximately 20% of hospitalized patients, most of whom have received antibiotics difficile colitis will develop in approximately one-third of infected patients
Antibiotic-Associated Colitis tx
Prophylactic administration of the probiotics who are receiving antibiotics reduced the incidence of C difficile–associated diarrhea
-Symptoms usually begin during or shortly after antibiotic therapy but may be delayed for up to 8 weeks
Antibiotic-Associated Colitis presentation
- Most patients report mild to moderate greenish, foul-smelling watery diarrhea 5–15 times per day with lower abdominal cramps
- Normal abdominal exam or mild left lower quadrant tenderness
- Colitis is most severe in the distal colon and rectum
- Over half of hospitalized patients diagnosed with C diff colitis have a white blood count greater than 15,000/mcL
- Severe or fulminant disease occurs in 10–15% of patients
Antibiotic-Associated Colitis: labs/imaging
Stool studies: Rapid enzyme immunoassays (EIAs)
Nucleic acid amplication tests (PCR assays)
Flexible sigmoidoscopy: Not needed with typical symptoms and positive stool toxin assay
Can see true pseudomembranous colitis in severe cases
Imaging studies:
For severe disease
Abnormal radiographs or noncontrast abdominal CT
Antibiotic-Associated Colitis tx
Antibiotic therapy should be discontinued
- Start metronidazole, PO vancomycin, or fidaxomicin (PO flagel for mild cases)
- For patients with severe disease, PO vancomycin and IV metronidazole
- Early sx consult is recommended for all patients with severe or fulminant disease
- Total abdominal colectomy or loop ileostomy with colonic lavage may be required in patients with toxic megacolon, perforation, sepsis, or hemorrhage
Antibiotic-Associated Colitis: Treatment of relapse
- Up to 25% of patients have a relapse of diarrhea from C diff within 1-2 weeks after stopping initial therapy
- Most relapses respond promptly to a second course of the same regimen used for the initial episode
- For patients with two relapses, a 7-week tapering regimen of vancomycin is recommended
- Probiotic therapy is recommended as adjunctive therapy in patients with relapsing disease
For patients with 3+ relapses of Antibiotic-Associated Colitis, updated 2013 guidelines recommend consideration of an ??
installation of a suspension of fecal bacteria from a healthy donor “fecal transplantation” into the terminal ileum or proximal colon (by colonoscopy) or into the duodenum and jejunum (by nasoenteric tube)
IBD: Know the differences between Crohn disease and Ulcerative Colitis (UC)
slide 19, first aid 362
For Crohn, think of a FAT GRANny and an old crone SKIPping down a COBBLESTONE road away from the wRECk (rectal sparing).
Ulcerative colitis causes ULCCCERS: Ulcers
Large intestine
Continuous, Colorectal carcinoma, Crypt abscesses
Extends proximally Red diarrhea Sclerosing cholangitis
Crohn Disease (worse of the 2)
One-third of cases of Crohn disease involve the small bowel only, most commonly the terminal ileum (terminal ileitis, B12 def)
-Half of all cases involve the small bowel and colon, most often the terminal ileum and adjacent proximal ascending colon (ileocolitis)
-In 20% of cases, the colon alone is affected
One-third of patients have associated perianal disease
-Less than 5% patients have symptomatic involvement of the upper intestinal tract
Unlike ulcerative colitis, Crohn disease is a ??
?? is strongly associated with the development of Crohn disease, resistance to medical therapy, and early disease relapse
transmural process that can result in mucosal inflammation and ulceration, stricturing, fistula development, and abscess formation
Cigarette smoking (in UC get better if smoke!)
Crohn disease May present with a variety of symptoms and signs
Physical examination should focus on the ??
History of fevers, general sense of well-being, weight loss, the presence of abdominal pain, the number of liquid bowel movements per day, and prior surgical resections
patient’s temperature, weight, and nutritional status, the presence of abdominal tenderness or an abdominal mass, rectal examination, and extraintestinal manifestations
Crohn’s: 5 common presentations (can overlap)
Chronic inflammatory disease Intestinal obstruction Penetrating disease and fistulae Perianal disease Extraintestinal disease (arthralgia, pyoderma gangrenosum, slide 27)
Crohn’s labs
Poor correlation between laboratory studies and the patient’s clinical picture
- Laboratory values may reflect inflammatory activity or nutritional complications of disease
- A complete blood count and serum albumin should be obtained in all patients
- Anemia may reflect chronic inflammation, mucosal blood loss, iron deficiency, or vitamin B12 (mixed picture) malabsorption secondary to terminal ileal inflammation or resection
- Leukocytosis may reflect inflammation or abscess formation or may be secondary to corticosteroid therapy
Crohn’s labs 2
Hypoalbuminemia may be due to intestinal protein loss (protein-losing enteropathy), malabsorption, bacterial overgrowth, or chronic inflammation
- The sedimentation rate or C-reactive protein level is elevated in many patients during active inflammation
- Autoantibodies to P-ANCA* as well as antibodies to the yeast Saccharomyces cerevisiae
Crohn’s imaging
Colonoscopy usually is performed first to evaluate the colon and terminal ileum and to obtain mucosal biopsies
Typical endoscopic findings include aphthoid, linear or stellate ulcers, strictures, and segmental involvement with areas of normal-appearing mucosa adjacent to inflamed mucosa
Crohn’s imaging 2
CT or MR enterography or a barium upper gastrointestinal series with small bowel follow-through often is obtained in patients with suspected small bowel involvement
Suggestive findings include ulcerations, strictures, and fistulas; in addition, CT or MR enterography may identify bowel wall thickening and vascularity, mucosal enhancement, and fat stranding
Crohn’s complications
Abscess Obstruction Abdominal and Rectovaginal Fistulas Perianal Disease Colon carcinoma Hemorrhage (unusual, more in UC)) Malabsorption (more hemorrhage in US)
Crohn’s tx
Nutrition, Diet, Enteral Therapy, TPN
Symptomatic Medications:
Antidiarrheal in non-severe cases
Crohn’s tx 2
Specific Drug Therapy:
5-Aminosalicyclic acid (5-ASA) agents
Antibiotics, Corticosteroids (reserved for acute flares, do not dec. morbidity, mortality)
Immunomodulators: Azathioprine, mercaptopurine, or methotrexate
Anti-TNF therapies (life-long)
Anti-intergrins
Surgery for Crohn’s
Over 50% of pts will require at least one surgical procedure
-Main indications for surgery are intractability to medical therapy, intra-abdominal abscess, massive bleeding, symptomatic refractory internal or perianal fistulas, and intestinal obstruction
UC ??
is an idiopathic inflammatory condition that involves the mucosal surface of the colon, resulting in diffuse friability and erosions with bleeding
- Approximately one-third of patients have disease confined to the rectosigmoid region (proctosigmoiditis)
- One-third have disease that extends to the splenic flexure (left-sided colitis)
- One-third have disease that extends more proximally (extensive colitis)
- The disease is characterized by periods of symptomatic flare-ups and remissions
UC and smoking
Ulcerative colitis is more common in nonsmokers and former smokers
Disease severity may be lower in active smokers and may worsen in patients who stop smoking
UC presentation
Presentation is highly variable
Bloody diarrhea is the hallmark
Severe based on stool frequency, the presence and amount of rectal bleeding, cramps, abdominal pain, fecal urgency, and tenesmus
Vitals are key (tachy, Hgb drops)
Look for tenderness and evidence of peritoneal inflammation
Red blood may be present on digital rectal examination.
UC slide 40
sev:
>6 stools (typ. bloody), >100 bpm, HCT less than 30, more than 10% weight loss, greater than 100 temp, ESR>30, albumin less than 3
UC: mild-mod colitis tx
5-ASA agents Corticosteroids Immunomodulating agents Anti-integrin therapy Probiotics
UC: Severe and fulminant colitis tx
NPO Corticosteroid therapy Anti-TNF therapies Cyclosporine Surgical therapy! (take out colon: cured!)
UC: Risk of Colon Cancer
Disease proximal to the rectum
- Colonoscopies are recommended every 1–2 years in patients with colitis, beginning 8 years after diagnosis*
- At colonoscopy, all adenoma-like polyps should be resected, when possible, and biopsies obtained of non-endoscopically resectable mass lesions
Diverticulosis
Colonic diverticulosis increases with age, ranging from 5% in those under age 40, to 30% at age 60, to more than 50% over age 80 years in Western societies
- Most are asymptomatic, discovered incidentally at endoscopy or on barium enema
- Complications occur in less than 5%, including gastrointestinal bleeding and diverticulitis
Diverticulosis 2
Colonic diverticula may vary in size from a few millimeters to several centimeters and in number from one to several dozen
- Almost all patients with diverticulosis have involvement in the sigmoid and descending colon
- Only 15% have proximal colonic disease
diverticulosis etiology
For over 40 years, it has been believed that diverticulosis arises after many years of a diet deficient in fiber ** (reduce red meat, switch to low fat diet)
-May develop more commonly in the sigmoid because intraluminal pressures are highest in this region
-True etiology of diverticulosis is uncertain
The extent to which abnormal motility and hereditary factors contribute to diverticular disease is unknown
Patients with ?? are also disposed to development of diverticulosis, including ??
abnormal connective tissue
Ehlers-Danlos syndrome, Marfan syndrome, and scleroderma
diverticulosis presentation
More than 90% of patients with diverticulosis have uncomplicated disease and no specific symptoms
-In most, diverticulosis is an incidental finding detected during colonoscopic examination or barium enema examination
Some patients have nonspecific complaints of chronic constipation, abdominal pain, or fluctuating bowel habits
diverticulosis PE and advice
Physical examination is usually normal but may reveal mild left lower quadrant tenderness with a thickened, palpable sigmoid and descending colon
-Pts in whom diverticulosis is discovered, especially patients with symptoms or a history of complicated disease, should be treated with a high-fiber diet or fiber supplements (drink lots of water with it)
Diverticulitis
Perforation of a colonic diverticulum results in an intra-abdominal infection that may vary from microperforation (most common) with localized paracolic inflammation to macroperforation with either abscess or generalized peritonitis
diverticulitis presentation
Constipation or loose stools may be present
- Nausea and vomiting are frequent
- Low-grade fever, left lower quadrant (LLQ) tenderness, and a palpable mass*
diverticulitis: Mild symptoms and a presumptive diagnosis of diverticulitis, tx ??
empiric medical therapy is started without further imaging in the acute phase
Patients who respond to acute medical management should undergo complete colonic evaluation with colonoscopy or radiologic imaging after resolution of clinical symptoms to corroborate the diagnosis or exclude other disorders such as colonic neoplasms
diverticulitis pts who do not improve rapidly after 2–4 days of empiric therapy and in those with severe disease, tx ??
CT scan of the abdomen is obtained to look for evidence of diverticulitis and determine its severity
Endoscopy and colonography are contraindicated during the initial stages of an acute diverticulitis attack because of the risk of ?
free perforation
need to do later to check for colon cancer
diverticulitis tx: Patients with mild symptoms and no peritoneal signs
may be managed initially as outpatients on a clear liquid diet (not done often)
Although broad-spectrum oral antibiotics with anaerobic activity commonly are prescribed (ciproflagil, etc.)
Symptomatic improvement usually occurs within 3 days, at which time the diet may be advanced
Once the acute episode has resolved, a high-fiber diet is often recommended
Patients with increasing pain, fever, or inability to tolerate oral fluids require hospitalization
diverticulitis tx 2: Patients with severe diverticulitis
(high fevers, leukocytosis, or peritoneal signs) and patients who are elderly or immunosuppressed or who have serious comorbid disease require hospitalization acutely
- Patients should be given nothing by mouth and should receive intravenous fluids. If ileus is present, a nasogastric tube should be placed
- Intravenous antibiotics should be given to cover anaerobic and gram-negative bacteria
diverticulitis sx
sx consult and repeat abd CT imaging should be obtained on all patients with severe disease or those who do not improve after 72 hours of medical management
- Patients with a localized abdominal abscess 4 cm in size or larger are usually treated urgently with a percutaneous catheter drain placed by an interventional radiologist
- Indications for emergent surgical management include generalized peritonitis, large undrainable abscesses, and clinical deterioration despite medical management and percutaneous drainage
Polyps are discrete mass lesions that??
protrude into the intestinal lumen
Although most commonly sporadic, they may be inherited as part of a familial polyposis syndrome
Polyps may be divided into four major pathologic groups
- Mucosal adenomatous polyps (tubular, tubulovillous, and villous)
- Mucosal serrated polyps (hyperplastic, sessile serrated polyps, and traditional serrated adenoma)
- Mucosal nonneoplastic polyps (juvenile polyps, hamartomas, inflammatory polyps)
- Submucosal lesions (lipomas, lymphoid aggregates, carcinoids, pneumatosis cystoides intestinalis)
Familial Adenomatous Polyposis
Syndrome affecting 1:10,000 people and accounts for approximately 0.5% of colorectal cancer
- Classic form of FAP is characterized by the development of hundreds to thousands of colonic adenomatous polyps and a variety of extracolonic manifestations
- Approximately 90% have a mutation in the APC gene that is inherited in an autosomal dominant fashion
Familial Adenomatous Polyposis complications
- Colorectal polyps develop by a mean age of 15 years and cancer at 40 years
- Unless prophylactic colectomy is performed, colorectal cancer is inevitable by age 50 years
- Development of a variety of other benign extraintestinal manifestations, including soft tissue tumors of the skin, desmoid tumors, osteomas, and congenital hypertrophy of the retinal pigment
Familial Adenomatous Polyposis testing/tx
- Genetic counseling and testing should be offered to patients found to have multiple adenomatous polyps at endoscopy and to first-degree family members of patients with FAP
- Once dx w. FAP, complete proctocolectomy with ileoanal anastomosis or colectomy with ileorectal anastomosis is recommended, usually before age 20 years
Hamartomatous Polyposis Syndromes
*Peutz-Jeghers syndrome
Familial juvenile polyposis
PTEN multiple hamartoma syndrome (Cowden disease)
Peutz-Jeghers syndrome
Autosomal dominant condition characterized by hamartomatous polyps throughout the gastrointestinal tract as well as mucocutaneous pigmented macules on the lips, buccal mucosa, and skin
Familial juvenile polyposis
Autosomal dominant and is characterized by several juvenile hamartomatous polyps located most commonly in the colon
PTEN multiple hamartoma syndrome (Cowden disease)
Hamartomatous polyps and lipomas throughout the gastrointestinal tract, trichilemmomas, and cerebellar lesions
Lynch syndrome (also known as hereditary nonpolyposis colon cancer [HNPCC]) is an ??
autosomal dominant condition in which there is a markedly increased risk of developing colorectal cancer as well as a host of other cancers, including endometrial, ovarian, renal or vesical, hepatobiliary, gastric, and small intestinal cancers
Lynch syndrome epi
Estimated to account for up to 3% of all colorectal cancers
Affected individuals have a 22–75% lifetime risk of developing colorectal carcinoma and a 30–60% lifetime risk of endometrial cancer, depending on the affected gene
Lynch Syndrome screening
A thorough family cancer history is essential to identify families that may be affected with Lynch syndrome so that appropriate genetic and colonoscopic screening can be offered
If genetic testing documents a Lynch syndrome gene mutation, affected relatives should be screened with colonoscopy every 1–2 years beginning at age 25 (or at age 5 years younger than the age at diagnosis of the youngest affected family member)
If cancer is found, subtotal colectomy with ileorectal anastomosis (followed by annual surveillance of the rectal stump) should be performed
Lynch Syndrome screening 2
-Women should undergo screening for endometrial and ovarian cancer beginning at age 30–35 years with pelvic examination, transvaginal ultrasound, and endometrial sampling
Prophylactic hysterectomy and oophorectomy is recommended to women at age 40 or once they have finished childbearing
Screening for gastric cancer with upper endoscopy should be considered every 2–3 years beginning at age 30–35 years
