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225 Cards in this Set
- Front
- Back
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T/FL: Smoking cessation has been associated with an increased relative risk for the occurrence of Crohn's disease.
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False. Smoking is associated with an increased relative-risk for the occurrence of Crohn's disease by a factor of 2 to 5.
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Granulomas are a pathognomonic feature of Crohn's disease. Do these granulomas most resemble those seen in tuberculosis or sarcoidosis?
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Sarcoidosis. The granulomas found in sarcoid and Crohn's disease lack central caseation.
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Describe the earliest endoscopic features of inflammation in Crohn's disease.
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Mild mucosal hyperemia and edema are the earliest findings followed by aphthae or discrete ulcerations in more advanced cases.
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Describe how the mucosal surface acquires the "cobblestone" appearance frequently seen in Crohn's disease.
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Longitudinal and transverse serpiginous ulcerations form and the intervening edematous mucosa swells.
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Crohn's disease consists of transmural involvement of the intestinal tract. The bowel wall becomes thickened and the lumen narrows. Surgeons describe "creeping fat" in Crohn's disease. What is "creeping fat"?
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In Crohn's disease, the mesentery becomes thickened, edematous, hypervascular and fatty. Finger-like projections of this inflamed mucosa "creep" along the serosal surface of the intestine and encase the involved segment of the intestine.
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T/F: Sulfasalazine has been proven to maintain remission in Crohn's disease.
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False. Most clinicians realize a benefit, especially in Crohn's colitis; however, sulfasalazine has been shown to be a remission-maintaining drug in ulcerative colitis only.
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The GI presentation of Crohn's disease in children and adolescents is similar to adults. Children, however, have prominent systemic complaints that often precede their GI complaints by months to year. Name some systemic manifestations of Crohn's disease in children and adolescents.
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Arthralgias and arthritis are seen in approx 15%. Weight loss, failiure to thrive, growth failure, fever and anemia are all manifestations of Crohn's disease in children, particularly when the small bowel is involved.
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Small bowel barium x-ray in Crohn's disease may demonstrate separation of barium-filled loops of small bowel. Why does this occur?
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Edema of the bowel wall, especially the deeper layers of the bowel, produces this separation.
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When differentiating GI tuberculosis from Crohn's disease, which of the following can be seen in both: fistulae, granulomas and/or normal chest x-ray?
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All may be seen in both conditions. Fistulization occurs less frequently in tuberculosis. Grandulomas can be seen in mesenteric lymph nodes in tuberculosis when there are no granulomas of the bowel. Crohn's disease, however, only produces granulomas of the lymph nodes when they are also present in the bowel wall.
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T/F: 6-mercaptopurine and azathioprine are efficacious in treating active Crohn's disease and maintaining remission; however, acute pancreatitis develops in about 3%. Patients who develop pancreatitis while on one of these drugs should be challenged with the other drug.
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False. Pancreatitis is reversible on withdrawing the drug but recurs upon rechallege with 6-MP or azathioprine. Pancreatitis secondary to one drug is an absolute contraindication to either drug.
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What is the phenomenon called when a child develops inflammatory bowel disease at an earlier age than his/her parent?
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Genetic anticipation - a child develops the disease at an earlier age than did the affected parent.
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T/F: Ulcerative colitis is more common in nonsmokers than smokers.
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True. The relative risk of developing ulcerative colitis in nonsmokers compared with smokers is 2.6. The risk is particularly high in former smokers and especially former heavy smokers.
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T/F: There an association between ulcerative colitis and autoimmune disorders.
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True. There is an increased incidence of thyroid disease, pernicious anemia and diabetes.
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What % of ulcerative colitis patients are p-ANCA positive?
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Perinuclear antineutrophilic cytoplasmic antibody occurs in 60% to 80% of ulcerative colitis patients and 20% to 30% of patients with Crohn's disease. This antibody is of the IgG type and its titer does not change with disease activity. However, the titers have been reported to decline after colectomy for greater than 10 years or after very long-standing disease remission. The significance of this antibody remains to be defined. Anti-saccaromyces cereviseae antibody (ASCA), an antibody associated with Crohn's disease, is currently undergoing evaluation for specificity and sensitivity is the diagnosis of inflammatory bowel disease.
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Which is more common in patients with ulcerative colitis - pancolitis or distal colitis?
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Distal colitis. The disease is limited to rectosigmoid in 40% to 50%, is pancolomic in 20% and is left-sided in 30% to 40%.
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T/F: The rectum is always involved in ulcerative colitis.
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False. There are rare exceptions when, in severe acute disease, the proximal colon is more severely involved than the rectum. Another etiology of apparent rectal sparing is in patients being treated with topical agents.
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T/F: The shortening and narrowing of the colon in patients with history of recurrent attacks of ulcerative colitis is due to fibrosis.
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False. Fibrosis is uncommon in ulcerative colitis unlike Crohn's disease. The foreshortened colon is a result of abnormalities in the muscle layer.
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Inflammation is predominantly confined to the mucosa in ulcerative colitis. What specific area of the epithelium do the neutrophils attack?
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The crypts, giving rise to cryptitis.
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T/F: Pseudopolyps spare the rectum.
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True. The reason for this is unknown.
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T/F: Active ulcerative colitis with diarrhea is almost always associated with macroscopic blood.
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True. If blood is not present, the diagnosis should be questioned.
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Why will patients with proctitis or proctosigmoiditis sometimes complain of constipation instead of bloody diarrhea?
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Colonic motility is altered by inflammation. In distal proctitis, there is slowing of proximal colon transit and prolonged transit in the small bowel. Distal transit remains rapid.
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A 62-yr old woman presents with diarrhea and, during her evaluation, a flexible sigmoidoscopy is performed. The mucosa in the sigmoid is granular and slightly friable. Biopsies show a thick subepithelial collagen band. What is the diagnosis?
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Collagenous colitis usually reveals a normal appearing mucosa on endoscopic exam; however, it can cause friable and granular mucosa. It can be differentiated from ulcerative colitis and infectious colitis by the thickened subepithelial collagen band. A normal collagen layer is 3 m to 6.9 m thick. In collagenous colitis, the layer is 7 to 93 m thick. The diagnosis of collagenous colitis is usually not made unless the collagen layer is at least 10 m thick. Of note, the disease can be patchy and more prominent in the colon than the rectum.
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A 20-yr old woman presents with rectal pain and pus coming from her rectum. Proctoscopic exam reveals granular rectal mucosa and a biopsy shows an intense neutrophil infiltration and Gram positive cocci. What is the diagnosis?
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Gonococcal proctitis, included in the differential of ulcerative colitis, rarely presents with diarrhea but instead with rectal pain. Biopsy confirms the diagnosis.
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A patient with active ulcerative colitis and erythema nodosum was hospitalized and treated with intravenous steroids. All symptoms subsided and the patient was discharged on sulfasalazine and oral steroids. The patient returned with erythema and nodosum over her lower extremities but no symptoms of active colitis. What is the etiology of the erythema nodosum?
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Erythema nodosum is usually associated with active colitis and presents as multiple tender and inflamed nodules usually over the shins. It occurs in 2-4% of cases of active colitis. Erythema nodosum can also occur as a reaction to sulfasalazine. Mesalamine is another rare cause of erythema nodosum.
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What haplotype is most often associated with primary sclerosing cholangitis?
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HLA-DR3 B8.
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Which of the following inflammatory bowel disease patient-types is most often associated with primary sclerosing cholangitis: fulminant colitis requiring colectomy, proctitis, mild pancolitis?
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Mild pancolitis. In fact, the inflammatory bowel disease may remain undiagnosed until after the diagnosis of their liver disease in some patients. Colectomy is not protective against future development of primary sclerosing cholangitis.
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T/F: Pseudopolyps or inflammatory polyps are a premalignant condition.
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False.
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What type of ulcerative colitis patient is at greatest risk of developing colorectal cancer?
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Pancolitis with frequent exacerbations > Pancolitis with infrequent exacerbations > Left-sided colitis > Proctocolitis
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When should colonoscopic surveillance for dysplagia begin for patients with chronic inflammatory bowel disease?
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In patients with pancolitis, after 8 years of disease. In those patients with disease confined to the left colon, surveillance should begin after about 15 years of disease. Repeat surveillance, if no dysplasia is found, should be undertaken every 1 to 3 years.
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T/F: The incidence of pyoderma gangrenosa is higher in ulcerative colitis compared to Crohn's disease.
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True. The incidence, while higher in ulcerative colitis, is only 1-5%. It is most often associated with extensive disease of long-standing duration. 1/2 to 1/3 of patients with pyoderma have inflammatory bowel disease.
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T/F: Pericholangitis is the most common hepatic complication of inflammatory bowel disease.
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True, with a prevalence as high as 50% to 80%. These patients usually present with asymptomatic elevations of alkaline phosphatase.
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T/F: The development of calcium oxalate stones in Crohn's disease occurs most often in patients with ileostomies.
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False. The presence of an ileostomy in a Crohn's patient predisposes to the development of urate stones resulting from decreased urine volumes related to high ostomy outputs. Calcium oxalate stones require an intact colon. With an absent or diseased ileum , fat malabsorption leads to unabsorbed fatty acids in the gut lumen. Calcium binds to the fatty acids instead of oxalate. Oxalate then binds to sodium (instead of calcium) and forms sodium oxalate, which is absorbed in the colon.
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Granulomas in Crohn's disease occur more commonly in the mucosa or submucosa?
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The submucosa. This explains why granulomas are found more commonly in surgical specimens rather than endoscopic specimens.
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T/F: Perforation of the colon occurs most often during the first acute attack of ulcerative colitis.
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True. Free perforation can occur w/o toxic megacolon and occurs more frequently in the left colon.
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A dermatologist refers you a patient with pyoderma gangrenosum. The patient has no gastrointestinal symptoms. What should you do?
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Evaluate for the presence of inflammatory bowel disease. At least 1/3 of patients with pyoderma have inflammatory bowel disease.
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T/F: Infliximab, a mouse-human chimeric tumor necrosis factor antibody, is currently approved for treating ulcerative colitis unresponsive to other agents.
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False. The approved use of infliximab is currently for the treatment of fistulizing Crohn's disease or Crohn's disease unresponsive to other treatments.
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T/F: Sacroileitis is symptomatic only when patients have active inflammatory bowel disease.
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False. Of the extraintestinal manifestations of IBD, sacroileitis is not one that follows the course of the bowel disease activity.
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T/F: Patients with ulcerative colitis and are p-ANCA positive often have a more aggressive course.
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True. These p-ANCA positive patients may have a more treatment-resistant (5-ASA products) disease and are more likely to develop chronic pouchitis after ileal pouch anastamosis.
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What effect does sulfasalazine have on fertility in males?
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Sulfasalazine reduces the total sperm count and sperm motility. These affects are reversible with discontinuation of the drug.
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T/F: Fertility problems occur commonly in women with Crohn's disease.
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True. Fertility is normal in ulcerative colitis but impaired in Crohn's disease. The exact explanation is yet unknown but contributing factors include impaired ovulation, fallopian tube blockage, dyspareunia and avoidance of pregnancy on medical advice. Nevertheless, many women with inflammatory bowel disease become pregnant w/o difficult and deliver healthy babies.
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Describe the clinical presentation of gastroduodenal Crohn's disease.
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Nearly all cases of gastroduodenal Crohn's present with symptoms of peptic ulcer disease. Most cases are associated with more distal small bowel involvement.
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T/F: All inflammatory bowel disease medication should be stopped if a woman with the disease becomes pregnant or desires to become pregnant.
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False. A flare of inflammatory bowel disease during pregnancy is associated with higher infant mortality; thus, it is desirable to continue the medications. Patients with quiescent disease before pregnancy tend to have well-controlled disease during pregnancy. Many of the drugs used to treat inflammatory bowel disease have not been extensively studied in pregnancy. The 5-ASA preparations are considered safe to use during pregnancy. There is data on azathioprine in pregnant renal transplant patients that suggests this drug is safe in pregnancy. Methotrexate, cirpofoxacin, and metronidazole are contraindicated during pregnancy. Extensive counseling should take place with each patient concerning the risks, benefits, and alternatives of medication use during and after pregnancy.
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T/F: Olsalazine frequently causes watery diarrhea.
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True. 16% of patients on olsalazine develop watery diarrhea. Gradual titration of the dose and the administration of osalazine with meals may reduce the incidence of diarrhea.
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In patients with ulcerative colitis requiring colectomy, which patients should not be considered for ileoanal pouch construction?
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Women with multiple pregnancies, women with difficult deliveries, older patients and patients with dimished anal sphincter tone. The most important contraindication to the ileoanal pouch anastomosis is poor anal sphincter function. The patient groups listed are all at risk for anal sphincter dysfunction.
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Crohn's disease patients that develop short fibrotic symptomatic strictures should be sent for surgical intervention and stricturoplasty. List contraindications of stricturoplasty.
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Sepsis, perforation, phlegmon, fistula (enteroenteric or enterocutaneous - in the area of the stricturoplasty), multiple strictures in a short segment that might lend itself better to a single resection, gross ulceration and fragile mucosa at the site, colonic stricture and carcinoma.
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A 41-yr old man with a 15 year history of pancolonic ulcerative colitis that is currently in remission undergoes surveillance colonoscopy. A single biopsy shows definite high-grade dysplasia (confirmed by a second expert pathologist). What should you recommend to the patient?
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Colectomy should be performed when high-grade dysplasia is found either in flat mucosa or a mass lesion (DALM).
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A 30-yr old woman with long-standing, well-controlled ulcerative colitis undergoes surveillance colonscopy. The colonoscopy is essentially normal but biopsies reveal low-grade dysplasia (confirmed by a second expert pathologist). What should you recommend to the patient?
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When low-grade dysplasia occurs in flat mucosa or a mass lesion (DALM), the high risk of progression to high-grade dysplasia or cancer warrant a policy of early colectomy. Some have recommended more rigorous surveillance colonoscopy in this situation, but this is controversial.
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Adenomatous polyps occur in patients with and without inflammatory bowel disease. The management of adenomas in patients with ulcerative colitis differs from that in patients without the colitis
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True. Colitis-associated cancer typically arises from a flat mucosa or a dysplasia-associated lesion or mass (DALM). A polyp should be presumed to represent a DALM if it occurs in involved mucosa. Predunculated or sessile polyps that occur in uninvolved mucosa in patients who do not have pancolitis should be managed as they would in a patient without colitis. If a sessile adenoma is found within involved bowel, a colectomy may be the most prudent clinical action. When a pendunculated adenoma arises in invovled bowel, the bowel around the polyp should be sampled after performing a polypectomy. If there is no evidence of dysplasia in the surrounding mucosa or elsewhere, a colectomy is not necessary.
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T/F: Prophylactic use of mesalamine or methronidazole has been proven to prevent postoperative recurrence of Crohn's disease.
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False
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What are common signs and symptoms of malabsorptive disorders?
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Patients usually describe diarrhea (typically large volume) and associated weight loss. Associated symptoms include fragile due to anemia, bloating and flatulence, bruising from vitamin K deficiency, skin rashes, muscle wasting and paresthesias.
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What clinical features suggest a functional cause in chronic diarrhea?
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Duration of symtpoms greater than 1 year, straining with defecation, lack of significant weight loss and absence of nocturnal diarrhea.
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How is the fecal osmotic gap calculated and how is it used?
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The following formula is used: 290-2 ([Na+] + [K+]). The normal osmolality of stool within the distal intestine (estimated as 290 mOsm/kg) should be used rather than the measured stool osmolality, because, in the collected specimen, bacterial fermentation of unabsorbed carbohydrates into osmotically active organic acids raises the measured osmolality. A osmotic gap > 125 mOsm/kg occurs in pure osmotic diarrhea whereas an osmotic gap < 50 occurs in pure secretory diarrhea.
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How is steatorrhea defined?
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Steatorrhea is defined as a daily fecal fat output > 7 grams/day (9% of dietary fat intake). A fecal fat > 14 grams/day is indicative of markedly impaired fat digestion of absorption.
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Describe a bedside test for laxative use/abuse.
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Alkalinization of 3 ml of stool supernatant or urine with one drop of concentrated (1 N) sodium hydroxide will result in a pink or red color if phenolphthalein is present. More sophisticated stool an durine tests are available for the detection of other laxatives. Stool sulfate, phosphate and magnesium analysis detects those factitious diarrheas caused by osmotic cathartics.
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What is pancreatic cholera?
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Pancreatic cholera is a rare type of secretory diarrhea caused by the release of vasoactive intestinal peptide into the circulation by a neuroendocrine tumor. It should be suspected in diarrhea lasting longer than 4 weeks with the clinical features of secretory diarrhea, a volume always greater than 1 liter/day, marked hypokalemia, hypochlorhydria and severe dehydration.
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What serologic tests are available for the diagnosis of celiac sprue?
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The antiendomysial IgA antibody, detected by indirect immunoflurescence, is the most sensitive and specific serologic test for celiac sprue. ELISA antigliadin IgA and IgG antibodies are inexpensive but less sensitive and specific. The antigliadin IgG antibody should be checked in patients with known or suspected IgA deficiency. The prevalence of IgA deficiency is increased approximately 10-fold among patients with celiac sprue.
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Describe the classic endoscopic appearance of the small intestine in celiac sprue.
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Scalloping, nodularity and/or absence of the small intestinal plicae (circular folds).
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Name 5 causes of chronic diarrhea in which an endoscopically normal colonic mucosa in present.
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Microscopic colitis (lymphocytic and collagenous), amyloidosis, Whipple's disease, granulomatous infections and helminthic infections.
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Name some diseases associated with chronic diarrhea that may be diagnosed by small intestinal biopsy.
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Crohn's disease, giardiasis, celiac sprue, intestinal lymphoma, eosinophilic gastroenteritis, hypogammaglobulinemic sprue, Whipple's disease, lymphangiectasia, abetalipoproteinemia, amyloidosis, mastocytosis, and various mycobacterial, fungal, protozoal and parasitic infections.
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Describe some clinical manifestations of celiac sprue.
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In addition to the signs and symptoms common to all malabsorptive disorders, the following may be seen in patients with celiac sprue: occult blood in the stool, thrombocytosis (hyposplenism), demyelinating central nervouce system lesions, seizures and liver enzyme abnormalities.
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What is the relationship between celiac sprue and dermatitis herpetiformis (DH)?
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More than 90% of patients with DH and the granular pattern of IgA deposition at the derma-epidermal junction, and at least 10% of patients with a linear pattern have coexisting celiac sprue. Many lack significant symptoms of the disease because the lesion is often mild and limited to the proximal intestine. Conversely, fewer than 10% of patients with celiac sprue have DH.
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Name some diseases associated with celiac sprue.
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Dermatitis herpetiformis, type 1 diabetes mellitus, Down's syndrome, selective IgA deficiency, autoimmune thyroid disease and microscopic colitis. Less convincing, but possible associations have been reported between celiac sprue and juvenile rheumatoid arthritis, epilepsy with cerebral calcification, primary biliary cirrhosis, primary sclerosing cholangitis and IgA nephropathy.
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Which D-xylose test is preferable, the 1-hour serum test, or the 5-hour urine test?
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The 1-hour serum D-xylose test is preferable. The 5-hour urine test can be falsely abnormal in patients with renal insufficiency, incomplete urine specimen collection and a variety of other conditions.
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What is the auto-antigen recognized by the antiendomysial antibody?
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The antigen is tissue transglutaminase (TTG), a calcium-dependent enzyme that catalyzes cross-links between glutamine and lysine residues in substrate proteins. TTG is believed to cross-link gliadin, rendering it immunogenic.
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T/F: The mucosal lesion seen in celiac sprue is specific for that disorder.
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False. Identical or very similar mucosal lesions (villous atrophy and infiltration of the lamina propria with chronic inflammatory cells) can be seen with other inflammatory disorders including tropical sprue, giardiasis, diffuse lymphoma, autoimmune enteritis, Crohn's disease, bacterial overgrowth, viral gastroenteritis, and the marked gastric acid hypersecretion associated with gastrinoma. However, a completely flat mucosa is most suggestive of celiac sprue.
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Name clinical conditions associated with bacterial overgrowth of the small intestine.
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1) Small intestinal stagnation due to anatomical derangements (Billroth II gastrectomy, duodenal or jejunal diverticulosis, surgical blind loop, obstruction).
2) Motor disorders (scleroderma, intestinal pseudo-obstruction, diabetic gastroenteropathy). 3) Intestinal fistulae or resected ileocecal valve. 4) Other conditions such as achlorhydria, immunodeficiency states and chronic pancreatitis. |
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What is the suggested pathophysiology of "diabetic diarrhea"?
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Since most patients with diabetic diarrhea also have autonomic neuropathy, this condition was classically thought to be due to disordered motility. More recently, sympathetic denervation with decreased enterocyte x-2 adrenergic receptors has been described and this is thought to result in decreased intestinal absorptive function. Steatorrhea and bile salt malabsorption may also occur in these patients. Other causes of diarrhea in diabetic patients include bacterial overgrowth, celiac sprue, microscopic colitis, pancreatic dysfunction and, rarely, islet cell tumors (glucagonoma, vipoma, somatostatinoma).
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How does eosinophilic gastroenteritis present?
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Eosinophilic gastroenteritis may involve any layer of the gut, from the mucosa to the serosa. Manifestations of eosinophilic gastroenteritis include nausea, vomiting, diarrhea, weight loss, iron deficiency, malabsorption, protein-losing enteropathy, pyloric outlet or intestinal obstruction, and eosinophilic ascites.
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A 72-yr old woman presents with meory loss and a borderline low vitamin B12 level (<250 pg/mL) is found. How can a definitive diagnosis of vitamin B12 deficiency be made?
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Elevated serum methylmalonic acid and homocysteine levels establish the presence of vitamin B12 deficiency at the tissue level.
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What are the most common causes of chronic diarrhea?
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Irritable bowel syndrome, inflammatory bowel disease, microscopic colitis, malabsorption due to small intestinal or pancreatic diseases, enteric infection, medications and post gastrectomy/vagotomy state.
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What is the most consistent laboratory abnormality that may occur in small bowel bacterial overgrowth?
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Vitamin B12 malabsorption is the most consistent abnormality and can be documented with a Schilling test. Normalization of the Schilling test after treatment with antibiotics (also called the stage IV Schilling test) confirms that bacterial overgrowth is the source of vitamin B12 malabsorption. Interestingly, serum folate levels are frequently elevated because of bacterial production of folate.
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What tests are available to diagnose small bowel bacterial overgrowth syndrome?
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The gold standard for the diagnosis of bacterial overgrowth is quantitative small bowel culture. Bacterial concentrations greater than 10^5 colony forming units/ml indicate bacterial overgrowth. Several different breath tests (C^14-D-xylose, glucose-H^2 and lactulose-H^2) are also available; however, there is controversy regarding the sensitivity and specificity of these tests. A therapeutic trial of antibiotics is often also used as a "diagnostic" tool.
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Explain the mechanisms of calcium oxalate stone formation in Crohn's disease.
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This condition is termed enteric hyperoxaluria. Bile salt malabsorption due to ileal disease or resection may result in fat malabsorption. Intraluminal fatty acids bind calcium cations, which would otherwise bind to intestinal oxalate. Free oxalate thus enters the colon where it is absorbed and then renally excreted, causing calcium oxalate stones. Prevention of calcium oxalate stones in patients with Crohn's disease involves limitation of fat and oxalate intake, as well as calcium supplementation. A patient who has undergone a colectomy cannot develop enteric hyperoxaluria.
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How does ileal resection lead to diarrhea?
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1) Resection of less than 100 cm leads to bile salt wasting. Bile salts are decongugated in the colon where they cause a secretory diarrhea. Bile salt wasting is compensated by increased bile salt synthesis in the liver leading to normal fat absorption.
2) Resection of greater than 100 cm of ileum leads to depletion of the bile salt pool, steatorrhea and a secretory diarrhea related to the laxative effect of hydroxylated fatty acids. |
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What disorders can be diagnosed on the basis of an endoscopic small bowel biopsy?
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Whipple's disease, common variable immunodeficiency, abetalipoproteinemia and Mycobacterium avium complex infection causes characteristic lesions that involve the small bowel mucosa diffusely. Characteristic, but patchy lesions may also be seen with lymphoma, lymmphangiectasia, eosinophilic enteritis, mastocytosis, amyloidosis, Crohn's disease, collagenous sprue, giardiasis and cryptosporidiosis. These diseases may therefore be missed on endoscopic small bowel biopsy.
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Name some complications specific to celiac sprue?
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Development of malignancy (small bowel lymphoma, extra0intestinal lymphoma, small bowel adenocarcinoma, esophageal squamous cell carcinoma), refractory sprue, collagenous sprue and ulcerative jejunoileitis.
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What is collagenous sprue?
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Collagenous sprue is a rare disorder that presents with symptoms identical to celiac sprue. However, small intestinal biopsies show excess collagen deposition in the lamina propria beneath the epithelial layer. Patients with this condition have a poor prognosis as they do not respond to a gluten-free diet.
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What mechanisms may be responsible for diarrhea in Crohn's disease?
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Small bowel inflammation, small bowel bacterial overgrowth, surgical resection, fistulae, cholerrhetic diarrhea and steatorrhea.
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What are some components of prescription and non-prescription medication that may cause malabsorption in certain individuals?
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Gluten, lactose and polyols (sorbitol, mannitol, and xylitol).
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A 15-yr old boy presents with chronic diarrhea. You elicit a history of recurrent upper respiratory infections. What is your next test?
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A sweat test to rule out cystic fibrosis.
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What are the sites of protein digestion?
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Lumen of the stomach and small intestine (pepsin, pancreatic proteases), brush border of the enterocyte (peptidases), and cytoplasm of the enterocyte (peptidases).
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What are the enzymes involved in fat digestion?
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Acid lipases (lingual lipase, gastric lipase) and the pancreatic lipases. Pancreatic carboxyl ester lipase hydrolyzes triglycerides, cholesterol, vitamin esters and other substrates. Pancreatic phospholipase A2 hydrolyzes phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and cardiolipin.
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What medications may result in malabsorption of vitamins and other nutriets?
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Antacids, mineral oil, cholestyramine, methotrexate, chemotherapeutic agents, phenytoin, orlistat, sulfasalzine and sucralfate.
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Name some medications that can cause secretory diarrhea.
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Laxatives, cholinergic agents, quinidine and quinine, colchicine, metoclopramide, misoprostol, olsalazine, theophylline and thyroid preparations.
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What enteric infections may cause a protracted diarrhea?
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Enteropathogenic E. coli, Giardia, Amoeba, Cryptosporidium, Microsporidia and Isospora. Aeromonas and Yersinia enterocolitica can both present with an acute or chronic watery diarrhea syndrome, or colitis. Clostridium difficile infection frequently relapses.
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What are the mechanisms causing diarrhea in Zollinger-Ellison (ZE) syndrome?
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High volumes of secreted hydrochloric acid, fat maldigestion due to inactivation of pancreatic lipase, and bile acid precipitation due to the low duodenal pH. Diarrhea occurs in up to 1/3 of patients with the ZE syndrome, may precede the other symptoms and may be the major clinical manifestation of the disease.
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What is the Cronkhite-Canada syndrome?
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It is a non-inherited polyposis syndrome characterized by h amartomatous polyps found throughout the GI tract and by a severe protein-losing enteropathy due to a diffuse mucosal injury of obscure etiology. Clinical features also include cutaneous hyperpigmentation, alopecia and nail atrophy.
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A 44 yr-old man with chronic diarrhea has a fecal osmotic gap <50 and fecal sodium ?90. The diarrhea ceases with fasting. What is the diagnosis?
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The fecal osmotic gap and sodium concentration are consistent with a secretory diarrhea. However, the cessation of diarrhea with fasting argues against secretory diarrhea. Ingestion of sodium sulphate or sodium phosphate would cause an osmotic diarrhea that mimics a secretory diarrhea because of the high sodium content.
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How is the Schilling test performed?
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An intramuscular dose of nonlabeled vitamin B12 (usually 1000 micrograms) is administered in order to saturate liver binding sites. Oral radiolabeled vitamin B12 is then administered and urine radioactivity is measured over 24 hours. Appearance of less than 10% of the radiolabeled vitamin B12 in the urine is considered diagnostic of vitamin B12 malabsorption. If vitamin B12 malabsorption is corrected by adminstration of intrinsic factor, this establishes intrinsic factor deficiency (Stage II Schilling test). If vitamin B12 malabsorption is corrected with pancreatic enzymes (Stage III) or with antibiotics (Stage IV), then the test establishes pancreatic insufficiency or bacterial overgrowth, respectively. If the test does not correct with any of these maneuvers, then the cause of malabsorption is ileal disease or resection.
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What tests are useful for determining enteric protein loss?
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24 hour stool collection for determination of chromium^51-albumin clearance and x1-antitrypsin clearance.
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|
What tests are available to test pancreatic function?
|
The pancreatic stimulation tests (secretin test, cholecystokinin test and Lundh test meal) require intestinal intubation and collection of pancreatic secretions, and are time consuming. The so-called "tubeless" tests include the bentiromide test, the pancreolauryl test and the dual-label Schilling test.
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Name some causes of lactase deficiency.
|
Acquired deficiency in adulthood, small intestinal disease or resection, and autosomal recessive congenital deficiency.
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Describe the clinical features and genetic defect of abetalipoproteinemia?
|
Abetalipoproteinemia is a rare autosomal recessive disorder or lipoprotein metabolism characterized by extremely low levels of serum cholesterol and triglycerides and the absence of apoB-containing lipoproteins. Clinical manifestations include malabsorption, neurological symptoms such as spinocerebellar dysfunction, retinopathy that causes impairment of night and color vision, and acanthotic erythrocytes. Mutations of the microsomal triglyceride transfer protein have been shown to cause abetalipoproteinemia.
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What are the clinical features of intestinal lymphatic obstruction?
|
Hypoalbuminemia, hypoglubulinemia, lymphopenia, peripheral edema, ascites, and even anasarca. The differential diagnosis of intestinal lymphatic obstruction includes congenital intestinal lymphangiectasia, cardiac disease, Whipple's disease, Crohn's disease, mesenteric tuberculosis, mesenteric sarcoidosis, lymphoma and lymphenteric fistula.
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What are causes of iron deficiency occurring after gastric surgery?
|
Gastric acid dissociates iron salts from food and dissolves them. The achlorhydric stomach cannot release food-bound iron. In addition, patients who have undergone antrectomy have defective meat digestion so that heme proteins (myglobin, hemoglobn), cannot be digested properly by pancreatic proteases to liberate the heme-iron complexes. Finally, iron deficiency may result from decreased food intake and blood loss from gastritis.
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Name some systemic diseases associated with malabsorption.
|
Thyrotoxicosis, hypothyroidism, Addison's disease, hypoparathyroidism, diabetes mellitus, scleroderma and AIDS.
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What is the (14)C-glycocholic acid breath test?
|
This test is used in the diagnosis of bacterial of bacterial overgrowth. (14)C-glycocholic acid undergoes peptide hydrolysis by bacteria, releasing (14)C-glycine. (14)C-glycine is then absorbed and metabolized to (14)CO2 which is then excreted in expired air. Increased (14)CO2 excretion occurs with bacterial overgrowth but also can be seen with bile acid malabsorption. Measurement of fecal radioactivity helps distinguish between these two possibilities.
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How is tropical sprue treated?
|
Initial treatment includes correction of fluids, electrolytes and deficient nutrients. Tetracycline and folic acid are given as pharmacotherapy. The beneficial effect of treatment with folic acid suggests that folate deficiency plays a role in perpetuating the intestinal lesion of tropical sprue. It is recommended that treatment be continued for several months.
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What are clinical features of Whipple's disease?
|
Diarrhea with steatorrhea, fever, arthritis, lymphadenopathy, pericarditis, endocarditis, myocarditis, dementia, depression, choreoathetosis and ophthalmoplegia. This condition is caused by a Gram positive bacillus called Tropheryma whippelii. Treatment usually consists of double-strength trimethoprim-sulfamethoxazole twice daily for one year.
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What are causes of PAS-positive macrophages present in the lamina propria seen on intestinal biopsy?
|
In the past, the finding of lamina propria PAS-positive macrophages was diagnostic of Whipple's disease. More recently, it has been recognized that PAS-positive macrophages are also seen with atypical mycobacterial infections. The acid-fast stain distinguishes between the two.
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What are the most common cause of short bowel syndrome in adults?
|
Crohn's disease requiring multiple bowel resections (60-80%). The next most common cause is small intestinal resection secondary to thrombosis of the mesenteric arteries and veins.
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What is the pathophysiology and clinical features of D-lactic acidosis?
|
D-lactic acidosis is a rare complication of short bowel syndrome that occurs as a result of carbohydrate overfeeding and, possible, antibiotic use. Malabsorbed carbohydrate is metabolized by colonic bacteria to short-chain fatty acids and lactate which, in turn, lower colonic pH. A lower colonic pH favors the growth of D-lactate-producing enteric flora. D-lactate is absorbed but is poorly metabolized due to a lack, in humans, of D-lactic acid dehydrogenase. Patients present with acidosis with a normal L-lactate level, nystagmus, ophthalmoplegia, ataxia, confusion and inappropriate behavior. The mediator of the neurologic symptoms is unknown. Treatment consists of bicarbonate administration and fasting. Prevention may be attempted with a low carbohydrate diet and, possibly, probiotics.
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What pancreatic enzyme formulations are used for the treatment of the pain of chronic pancreatitis?
|
Non-enteric-coated formulations are potentially beneficial in the treatment of chronic pain in some patients with chronic pancreatitis. Enteric-coated formulations are used to treat pancreatic maldigestion. To prevent steatorrhea, the recommended dose is 30,000 IU of lipase with each meal.
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What are the mechanisms of malabsorption in patients with scleroderma?
|
Cillous atrophy, enterocyte dysfunction and submucosal collagen deposition. Bacterial overgrowth often occurs secondary to small intestinal stasis, loss of the migrating motor complex and the presence of small intestinal diverticula. Pancreatic insufficiency may also be present.
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What are the mechanisms of diarrhea in patients with radiation enteritis?
|
Altered absorption of fluids and electrolytes bile-salt malabsorption, bacterial overgrowth due to stasis, entero-enteric fistuale and short bowel syndrome secondary to resection.
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What is the rationale for using medium chain triglycerids (MCT) as nutritional supplements in patients with malabsorption syndromes?
|
Normal fat digestion and absorption requires a multi-step process including emulsification in the stomach, release of free fatty acids by gastric acids, breakdown of triglycerides by pancreatic lipases, formation of micelles with bile salts in the duodenum and enterocyte absorption. MCT are rapdily hydrolyzed and absorbed directly w/o requiring pancreatic lipase, bile salts or micelle formation.
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What conditions are associated with Vitamin B12 malabsorption?
|
Pernicious anemia, bacterial overgrowth, old age (incomplete release of food-bound vitamins B12), fastric surgery (achlorhydria, decreased intrinsic factor), therapy with proton pump inhibitors and H2 receptor antagonists (incomplete release of food bound vitamin B12; rare), HIV infection (ileal disease, achlorhydria), Crohn's disease (ileal disease or resection) and other diseases of the small intestine, multiple sclerosis (idiopathic) and chronic pancreatitis (incomplete cleavage of the R protein-intrinsic factor complex).
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How common is pill-induced esophageal injury?
|
The prevalence is very difficult to determine; however, the incidence is believed to be 3.9 per 100,000 population per year based upon one prospective Swedish study.
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Which patients are more likely to develop drug-induced esophageal injury?
|
Most reports reveal a predominance of elderly and female patients. The elderly are more prone due to a higher prevalence of esophageal motility disorders and obstructing lesions of the esophagus. In addition, the elderly ingest more drugs in general, produce less saliva and are more likely to forget proper dosing instruction and spend more time in the recumbent position. Drug-induced injury is about twice as common in females due to greater use of potassium supplements and alendronate.
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What are the major pathogenic factors contributing to drug-induced esophageal damage?
|
The chemical content, formulation of the drug and the manner in which the drug was taken by the patient are the major factors. Most patients with drug-induced esophageal injury have no detectable esophageal dysmotility or structural abnormality.
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What are the common locations in the esophagus for drug-induced esophageal injury?
|
The level of the aortic-arch (more prevalent in older patients) and the distal esophagus.
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What are the most common clinical manifestations of drug-induced esophageal injury?
|
Retrosternal chest pain is the most common manifestations (61%-72%) followed by odynophagia (50%-74%) and dysphagia (20%-40%). Symptoms can develop within hours to days after starting the medication. In almost all cases, the diagnosis can be determined on the basis of the history.
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What medications are commonly implicated in drug-induced esophageal injury?
|
The most common is tetracycline or one of its derivatives. Other medications include nonsteroidal anti-inflammatory drugs, potassium chloride, iron sulfate, quinidine, corticosteroids, pancreatic enzymes, cloxacillin, dicloxacillin, oral contraceptives and alendronate.
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What is the best diagnostic modality in drug-induced esophageal injury?
|
Although not necessary in every patient, endoscopy is clearly the best diagnostic modality with considerable superiority in sensitivity over a barium contrast esophagogram.
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T/F: In chemotherapy-related esophagitis, esophageal involvement correlates with involvement of oropharyngeal mucosa.
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True. It is very unusual to have esophageal damage in the absence of oral changes.
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How does radiation dosage correlate with esophageal symptoms and signs?
|
30 Gy- retrosternal burning and odynophagia
40 Gy- mucosal erythema and edema 50 Gy- incidence and severity of esophagitis increases 60-70 Gy- strictures, perforations and fistulae |
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What other factors potentiate radiation-induced esophageal damage?
|
The manner of delivery with an accelerate fractionation schedule may result in more injury. Concomitant chemotherapy may also potentiate radiation injury and is particularly common with doxorubicin.
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|
What are late effects of esophageal radiation?
|
Motor dysfunction of the esophagus, strictures, fistulae and squamous cell carcinoma may appear months to years after radiation.
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|
A 35 year old man with acute lymphocytic leukemia underwent bone marrow transplantation 120 days ago and now presents with dysphagia and retrosternal pain. Barium swallow reveals a mid-esophageal stricture. What is the most likely etiology?
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Chronic graft versus host disease is the most likely etiology and is manifested by webs, rings and strictures of the upper an dmid esophagus. The clinical presentation resembles that of progressive systemic sclerosis. Immunosuppressive drugs are commonly employed in this situation and endoscopy with dilatation in selected cases may be helpful.
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T/F: Lymphocytic and collagenous colitis are distinct clinical entities.
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This question continues to be debated. Although they differ slightly in the histologic criteria for diagnosis, growing evidence suggests that lymphocytic and collagenous colitis are two manifestations of the same disorder, with similar presentation, response to treatment and prognosis.
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How does lymphocytic/collagenous colitis typically present?
|
Patients with lymphocytic/collagenous colitis are typically middle-aged or elderly females with large-volume watery diarrhea. A prior history of nonsteroidal anti-inflammatory drug ingestion is common and was suggested to be a risk factor in a published case-control study.
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What is the sensitivity of rectal biopsy for detecting collagenous/lymphocytic colitis?
|
Only 27% of cases of collagenous colitis are detected on rectal biopsy. To exclude the diagnosis, full colonscopy is usually required. Histologic changes are seen in the cecum in 82% of patients and the transverse colon in 83%.
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What proportion of patients with celiac disease have features of lymphocytic colitis on colonic biopsies?
|
20% to 30%
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T/F: Lymphocytic colitis usually responds to a gluten-free diet.
|
False.
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|
What treatments may be prescribed for lymphocytic/collagenous colitis?
|
Patients should avoid secretagogues such as caffeine and lactose. Medical treatment options include sulfasalazine and other 5-aminosalicylate derivatives, cholestyramine, bismuth subsalicylate and systemic corticosteroids. Anti-diarrheal agents such as diphenoxylaate and loperamide are often ineffective. Refractory cases have required surgical diversion of the fecal stream.
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Which of the above treatment options is/are supported by evidence from controlled clinical trials?
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None
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Characterize the natural history of lymphocytic/collagenous colitis.
|
Lymphocytic and collagenous usually enter remission spontaneously in the short-term but may ultimately follow a chronic relapsing course. Between one-quarter and two-thirds of patients will require long-term medication for chronic intermittent diarrhea.
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T/F: Collagenous/lymphocytic colitis is associated with an increased risk of inflammatory bowel disease.
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False
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T/F: Collagenous/lymphocytic colitis increases the risk of developing colorectal carcinoma.
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False
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|
Following proximal diversion of the fecal stream, how common is diversion colitis?
|
Approx 1/3 of patients will develop diversion colitis in the excluded segment.
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T/F: Diversion colitis occurs more commonly after colectomy for inflammatory b owel disease than for cancer.
|
True. Diversion colitis develops more frequently among patients who undergo surgery for inflammatory bowel disease (89%) than for cancer (23%).
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How does the endoscopic appearance of diversion colitis differ from that of ulcerative proctitis?
|
Diversion colitis cannot be differentiated endoscopically from ulcerative proctitis. Endoscopy typically reveals an erythematous and friable rectal mucosa with superficial ulceration.
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What histologic feature is the hallmark of diversion colitis?
|
Lymphoid follicular hyperplasia with germinal centers is found in almost all cases. Cryptitis and neutrophil infiltration develop in at least 60% after 3 months.
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What causes diversion colitis?
|
Diversion colitis occurs when a segment of bowel is excluded from the fecal stream. Current evidence implicates deficiency of luminal short-chain fatty acids such as acetate, proprionate and butyrate. Butyrate normally provides 70% of the oxidative energy for coloncytes.
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How is diversion colitis treated?
|
The best treatment for diversion colitis is to restore the fecal stream. Short-chain fatty acid enemas induce remission in many patients but are not commercially available. A suggested formulation contains 60 mmol/L acetate, 30 mmol/L propionate and 40 mmol/L butyrate. Hydrocortisone enemas are ineffective and little evidence exists to support the use of aminosalicylate preparations.
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How does acute radiation proctosigmoiditis present?
|
Acute injury presents with diarrhea and tenesmus during radiation treatment or w/in 6 weeks of exposure. The endoscopic appearance of the rectum is normal.
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What are the clinical manifestations of chronic radiation proctitis?
|
The typical symptoms of chronic injury are rectal bleeding, diarrhea and tenesmus. Rectal strictures may develop as can fistulae to the vagina, bladder or uterus.
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Describe the typical endoscopic appearance of chronic radiation proctitis.
|
Mucosal pallor with friability and telangiectasia.
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How long after radiation exposure does chronic radiation proctitis develop?
|
On avg, symptoms develop after one year, fistulae after 18 months and strictures after 3 years.
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|
What treatments are effective in controlling hemorrhage from radiation proctitis?
|
Oran 5-aminosalicylic acid and corticosteroid enema do not appear to control bleeding or tenesmus. Local instillation of 4% formalin, sucralfate and 5-ASA may be effective. Nd:YAG or argon laser ablation or electrocoagulation of the rectal mucosa are useful endoscopic approaches. Hyperbaric oxygen therapy may also be beneficial by attenuating tissue hypoxia from obliterative endarteritis. Proctectomy may be considered for refractory cases but the colo-anal anastomosis is prone to leakage.
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|
At what age is the incidence of milk protein allergy highest?
|
The peak incidence is at 6 weeks. Symptoms may include vomiting, colic, diarrhea and rectal bleeding from colonic ulcers. Since the allergy is usually IgE-mediated, eczema, urticaria and angioneurotic edema may also be seen.
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How is the diagnosis of milk protein allergy made?
|
Resolution of symptoms with milk withdrawal and recurrence w/in 48 hours of rechallenge makes the diagnosis. Rechallenge is often omitted since it may result in anaphylaxis. If performed, rechallenge should be conducted in a hospital setting.
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At what age can children with milk protein allergy resume drinking cow's milk?
|
Allergy to milk protein usually resolved between 9 months and 3 years.
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Which laxatives are associated with melanosis coli?
|
Anthraquinones, including cascara sagrada, aloe, rhubarb, senna and frangula
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How soon does melanosis appear and how quickly does it resolve?
|
Melanosis coli can develop w/in 4 months of starting a laxative and usually resolves w/in approx 9 months after they are discontinued.
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|
Name the pigment that is deposited in the mucosa in melanosis coli?
|
The identity of the pigment is unknown. It has been found to bear some biochemical similarity to lipfuscin, melanin and the hepatic pigment of Dubin-Johonson syndrome.
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|
Describe the location and endoscopic appearance of the solitary rectal ulcer syndrome (SRUS).
|
Endoscropy reveals a lesion on the anterior rectal wall between 6 and 10 cm from the anal verge. The lesion itself is variable and may appear as a single ulcer, a cluster or ulcers, a polypoid lesion or an area of erythema.
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What are the typical histologic findings in the SRUS?
|
The appearance on biopsy is describe as fibromuscular obliteration of the lamina propria. As this term suggests, the lamina propria is replaced with fibroblasts, smooth muscle and colalgen with hypertrophy and disorganization of the muscularis mucosa.
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|
Describe hypotheses regarding the pathogenesis of SRUS
|
Self-digitation has been suggested as the cause of SRUS and is documented in up to 50% of patients. An alternate hypothesis suggests that SRUS results from prolapse and inschemia of the rectal mucosa in the setting of a high fecal voiding pressure. The latter may result from inadequate relaxation of the puborectalis during defacation.
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|
How is SRUS treated?
|
Initial conservative therapy with bulk laxatives, avoidance of straining and reassurance is recommended. Topical anti-inflammatory medication is generally ineffective. For refractory cases, the surgical procedure of choice is abdominal rectopexy.
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|
What complication of nonsteroidal anti-inflammatory drugs (NSAIDs) have been described in the colon?
|
Acute colitis, ischemic colitis, perforation of colonic diverticula and diaphragm-like stricture formation have been reported after NSAID ingestion. NSAIDs may also exacerbate or trigger relapse of Crohn's disease and ulcerative coitis.
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|
Which disease-modifying anti-rheumatic drug has been associated with an acute colitis?
|
Gold salts may induce an acute colitis characterized by ulceration and friability of the rectosigomoid mucosa. Symptoms typically resolve w/in 2 weeks of drug withdrawal.
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|
Name 5 classes of drugs which have been associated with ischemic injury of the colon.
|
Non-steroidal anti-inflammatory drugs, oral contraceptives, vasopressin, ergotamine, cocaine, dextroamphetamine, neroleptics and digitalis.
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|
What is typhlitis?
|
The Greek word typhlos refers to a blind sac. Typhlitis is an acute necrotic inflammation of the cecum. It has also been called neutropenic enterocolitis, necrotizing enterocolitis and ileocecal syndrome.
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|
In what clinical setting does typhlitis occur?
|
Typhlitis classically affects leukemic patients with severe neutropenia but has also been describe in a number of other immunosuppressed states.
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|
How does typhlitis present?
|
Typical symptoms include fever, abdominal pain, distension, vomiting and bloody diarrhea. An associated mucositis may involve the oropharynx. Plain films may reveal cecal thumbprinting or pneumatosis. Computer tomography and ultrasound demonstrate bowel wall thickening.
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|
How is typhlitis treated?
|
The primary management is medical, with hydration, broad-specturm antibiotics and nasogastric decompression. Refractory cases may require a right hemicolectomy with mucous fistula.
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|
What is the mortality rate from acute typhlitis?
|
40-50%
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|
What even often precedes the development of acute cholecystitis?
|
Cystic duct obstruction often precedes the development of acute calculous cholecystitis.
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|
What other factors are associated with acute calculous cholecystitis?
|
Supersaturated bile, decreased lecithin and increased lysolecithin in the gallbladder, increased production of prostaglandins (E2), increased fluid secretion within the gallbladder and circulating platelet-activating factor. Ischemia may play a significant role in some patients as a result of decreased blood supply caused by obstruction of the cystic artery as the gallbladder enlarges from inflammatory changes. Underlying atherosclerosis of the cystic artery may also contribute.
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T/F: Bacterial involvement of the gallbladder is a primary event in the development of acute calculous cholecystitis.
|
False. Bacterial inflammation is considered a secondary event and is found in as many as 80% of patients with acute calculous cholecystitis undergoing cholecystectomy.
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|
What is the most common location of a gallbladder perforation?
|
The fundus of the gallbladder due to its larger diameter and thus greater tension.
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|
What % of cholecystectomies are performed for acute calculous cholecystitis?
|
Approx 20%. There are about 500,000 cholecystectomies performed annually in the US.
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T/F: In the elderly, biliary symptoms usually precede the development of acute cholecystitis.
|
False.
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|
T/F: Gallstones are more common in diabetes.
|
False. However, diabetics have a higher incidence of related complications compared to the non-diabetic population.
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|
What % of patients with acute calculous cholecystitis have associated choledocholithiasis?
|
Approx 10%
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T/F: Jaundice commonly occurs in adults with acute calculous cholecystitis.
|
False. Approx 20% of adults with acute calculous cholecystitis develop jaundice. This increases to approx 50% in children.
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|
How specific is laboratory data in patients with acute calculous cholecystitis?
|
Lab data is nonspecific and may, in fact, be normal. Remember that in patients with a rapidly rising bilirubin and no evidence of biliary obstruction, gallbladder perforation with secondary increased absorption of bilirubin through the peritoneal cavity should be considered.
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T/F: An elevated amylase is always indicative of acute pancreatitis in the setting of acute calculous cholecystitis.
|
False. Hyperamylasemia may reflect a gangrenous gallbladder.
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|
What % of gallstones may be visualized on a routine scout film of the abdomen?
|
Only 10% to 20% of patients will have radiolucent gallstones.
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|
What is the diagnostic test of choice for acute calculous cholecystitis?
|
Ultrasound remains the test of choice for diagnosing acute calculous cholecystitis. Suggestive findings include pericholecystic fluid, thickened gallbladder wall, stones or sludge and enlargement of the organ. Murphy's sign is also useful but it may be absent in the presence of gangrenous cholecystitis.
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T/F: Hepatobiliary scanning of the gallbladder is useful in diagnosing acute acalculous cholecystitis.
|
True. A positive test occurs when there is no filling of the gallbladder, usually within 1 hour. However, in some normal patients it may take up to 4 hours for the gallbaldder to fill. Causes of false positives include parental nutrition, prolonger (>24 hours) or limited (<2 hours) fasting, and alcoholism.
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|
What % of patients with acute calculous cholecystitis develop complications?
|
1) Gallbladder empyema 2-12%
2) perforation 3-15% 3) gangrenous cholecystitis < 2% 4) bleeding or hemiperitoneum - very rare 4) emphysematous cholecystitis (usually due to Clostridium species) occurs rarely. The incidence of gangrenous gallbladder in these patients is as high as 75%. 5) Septic metastases - rare |
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|
What % of all cases of acute cholecystitis is due to acalculous disease?
|
Acute acalculous cholecystitis accounts for approx 6-17%.
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|
What factors are involved in the development of acute acalculous cholecystitis?
|
Obstruction fo the cystic duct by sludge, inspissation of bile with associated reduced flow, mechanical obstruction of the cystic duct by other diseases such as tumors or nodes, decreased gallbladder motility, systemic volume depletion, ischemia and possibly infectious organs.
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|
T/F: Infections may cause acute acalculous cholecystitis.
|
True. Infections are particularly important in patients with AIDS, where cytomegalovirus and Cryptosporidium play an important role. Typhoid fever is also associated with acalculous cholecystitis.
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|
What diseases are associated with the development of acute acalculous cholecystitis?
|
Diseases associated with mesenteric vascular compromise (vasculitis), sepsis, prolonger use of total parenteral nutrition, severe burns and intra-abdominal surgery.
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|
What patient group is more commonly associated with acute acalculous cholecystitis?
|
Contrary to calculous disease, acalculous cholecystitis is more common in men, especially the elderly.
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|
What is the main complication that may occur in acute acalculous cholecystitis?
|
Perforation may occur in as many as 60% of these patients.
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|
What is the overall mortality in acute acalculous cholecystitis?
|
Approx 50%
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|
What is the current gold standard test for the diagnosis of choledocholithiasis?
|
Endoscopic retrograde cholangiography (ERC) remains the gold standard in the diagnosis of choledocholithiasis. In expert hands, ERD is successful in completely visualizing the biliary tree in almost 100% of the patients. The stones may also be removed using this technique.
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|
What is the most common cholangiographic pattern of primary sclerosing cholangitis (PSC)?
|
While it may affect both intra- and extra-hepatic ducts, PSC more commonly presents as multiple short strictures found throughout the liver with characteristic beading and pruning and isolated dilations of the intrahepatic ducts.
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|
What other conditions can mimic the cholangiographic appearance of PSC?
|
Cirrhosis and metastatic disease to the liver may give a similar appearance.
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|
T/F: Endobiliary stents are the non-surgical treatment of choice for PSC-related bile duct strictures.
|
False. Unless absolutely necessary, less is more when it comes to endoscopic therapy in PSC.
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|
T/F: Cholangiocarcinoma is usually easily detected in the setting of PSC.
|
False.
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|
What is the most common cause of acute suppurative cholangitis?
|
Intrahepatic or extrahepatic stones are the cause of almost all cases. Patients with a biliary endoprosthesis and/or previous biliary manipulation are also at risk.
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|
What is the classic clinical triad of acute suppurative cholangitis?
|
Charcot's triad consists of right upper quadrant abdominal pain, jaundice and fever. Hypotension and full blown septic shock (Reynold's pentad) may subsequently ensue very quickly.
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|
What is the treatment of choice in acute suppurative cholangitis?
|
Endoscopic decompression along with systemic antibiotics.
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|
|
What biliary tract disease is associated with the acquired immunodeficiency syndrome (AIDS)
|
AIDS can produce cholangitis-like picture associated with upper abdominal pain and elevate liver function tests, especially alkaline phosphatase. The cholangitis may be associated with the AIDS virus alone or with other infections such as CMV, Cryptosporidium, or microsporidia. A causative organism is found in about 60% of cases.
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|
At what T lymphocyte count is AIDS cholangiopathy more likely to occur?
|
When the T-cell count is below 200
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|
What is the most likely diagnosis in a patient with AIDS who complains of severe abdominal pain and has an elevated alkaline phosphatase?
|
Papillary stenosis. AIDS may produce severe abdominal pain associated with elevated alkaline phosphatase due to papillary stenosis. The pain may improve dramatically after endoscopic sphincterotomy.
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|
T/F: AIDS cholangiopathy adversely affects the overall outcome of AIDS patients.
|
False. AIDS cholangiopathy does not appear to have any influence on the progression of the underlying disease.
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|
|
What patient group is at high risk for infections and parasitic cholangiopathies?
|
Patients from SE Asia are particularly at risk for parasite-related bile duct disease.
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|
|
What are the most common parasites implicated in biliary obstruction?
|
Clonorchis sinensis and Ascaris lumbricoides are the most frequently found parasites causing biliary disease. More frequent than stricturing is the presence of undulating and elongated filling defects of the bile ducts.
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|
What is Oriental cholangitis?
|
Oriental cholangitis is characterized by the development of pigmented stones, diffuse biliary strictures and chronic, recurrent episodes of cholangitis. This is particularly common in people from SE Asia.
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|
What is autoimmune cholangitis?
|
The clinical expression of autoimmune cholangitis is very similar to that of primary biliary cirrhosis except it is not associated with antimitochondrial antibodies.
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|
What type of cholangiographic injury has been associated with intra-arterial infusion of 5-flurodeoxyuridine?
|
An intra-hepatic sclerosing cholangitis-type pictures
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|
|
What other conditions are associated with the development of bile duct disease causing stricture formation?
|
1) surgical trauma
2) anastomotic arterial strictures 3) hepatic artery thrombosis |
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|
What autoimmune diseases may have pancreatic involvement?
|
Systemic lupus erythematosus, rheumatoid arthritis, polyarteritis nodosa and Bechet's Syndrome.
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|
|
What etiologic factors have been proposed in systemic autoimmune-related pancreatic inflammation?
|
Presumed causes include vasculitis, systemic steroid use and circulating anti-bodies to acinar cells.
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|
What is the most common hereditary disease involving the exocrine pancreas?
|
Cystic fibrosis (CF), which affect 1 in every 2000 live births
|
|
|
Describe the inheritance pattern of CF.
|
Autosomal recessive with a gene frequency of approx 5% among caucasians.
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|
What are pancreatic manifestations of cystic fibrosis (CF)?
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In the early stages, the pancreas may appear normal or there may be a deposition of eosinophilic concretions within ductules. Larger ductular involvement may lead to dilation and acinar disruption. Later on, the pancreas may appear indistinguishable from chronic pancreatitis as cyst development may occur and fat and scar replace pancreatic lobules.
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What % of patients with CF do not have clinically evident pancreatic exocrine insufficiency?
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15%
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What % of patients with CF have diabetes mellitus?
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1% of children and 13% of adults
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T/F: Gallstones are more common in CF and can lead to acute inflammatory exacerbations.
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True. Gallstones develop in 10% to 15% of CF patients.
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T/F: Laparoscopic cholecystectomy should be considered for CF patients with asymptomatic gallstones detected during screening radiography.
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False
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Describe the pathophysiology of pancreatic endocrine insufficiency that may occur in CF.
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Replacement of pancreatic tissue with fibrosis and fat in severe disease leads to disruption of normal islets by autodigestion and dimunition of the number of islets.
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T/F: Microscopic pancreatic involvement is seen in the majority of patients with sarcoidosis.
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False. Pancreatic involvement occurs in only 1% to 6% of all affected individuals and is rarely seen before the diagnosis is made from the upper aerodigestive tract
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T/F: Microscopic gastrointestinal involvement is seen in the majority of patients with sarcoidosis.
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True. Granulomas are seen in nearly 100% of patients with known sarcoidosis, although symptoms are described in less than 1%.
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Briefly describe the pathophysiology of sarcoidosis.
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Non-caseating granulomas occur in sarcoidosis. Enlarged lymph nodes may cause pressure-related symptoms and granulomas infiltration may cause dysfunction or dysmotility in the GI tract.
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T/F: Involvement of the pancreas in Crohn's disease is not seen in the absence of duodenal involvement.
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False.
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What are the suggested mechanisms of Crohn's disease involvement of the pancreas?
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There are four suggested mechanisms; ampullary involvement, cholelithiasis secondary to ileal disease, immunologic injury and drug therapy.
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Describe the usual, albeit rare, manifestations of Wegener's granulomatosis involving the pancreas.
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Pancreatic mass.
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What is the classic triad of Wegener's granulamtosis?
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Focal glomerulonephritis, vasculitis and necrotizing granulomas.
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Classically, Wegener's granulomatosis affects what part of the alimentary tract?
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The intestine. The associated vasculitis can lead to intestinal or colonic bleeding, ischemia or perforation.
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What is the most common cause of pancreatitis in childhood?
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Trauma (child abuse must be considered). In one recent study, 42% of cases resulted from bicycle accidents. Drugs and infections are the other two major causes in children.
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What is Shwachman's Syndrome?
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A disorder of pancreatic exocrine insufficiency and hematologic abnormalities with normal sweat electrolytes. This autosomal recessive disorder is the second most common cause of pancreatic insufficiency in children.
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A patient recovering from gallstone pancreatitis develops multiple painful, erythematous subcutaneous nodules. What is the diagnosis?
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Pancreatic panniculitis. Subcutaneous fat necrosis occurs in 2% to 3% of patients with acute pancreatitis or pancreatic cancer. The lesions may resemble erythema nodosum.
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What are the effects of end-stage renal disease on the pancreas?
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Morphologically, multiple abnormalities (acinar dilation, interlobular fibrosis) may be seen. Functionally, an elevated trypsin wtih a normal output of lipase and impaired bicarbonate secretion may be seen. Clinically, the frequency of acute pancreatitis may be increased in these patients but the mechanisms are unclear.
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What is Shwachman's Syndrome?
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A disorder of pancreatic exocrine insufficiency and hematologic abnormalities with normal sweat electrolytes. This autosomal recessive disorder is the second most common cause of pancreatic insufficiency in children.
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A patient recovering from gallstone pancreatitis develops multiple painful, erythematous subcutaneous nodules. What is the diagnosis?
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Pancreatic panniculitis. Subcutaneous fat necrosis occurs in 2% to 3% of patients with acute pancreatitis or pancreatic cancer. The lesions may resemble erythema nodosum.
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What are the effects of end-stage renal disease on the pancreas?
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Morphologically, multiple abnormalities (acinar dilation, interlobular fibrosis) may be seen. Functionally, an elevated trypsin with a normal output of lipase and impaired bicarbonate secretion may be seen. Clinically, the frequency of acute pancreatitis may be increased in these patients but the mechanisms are unclear.
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What are the pancreatic effects of hereditary hemochromatosis?
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Selective accumulation of excess iron in islet beta-cells results in a loss of endocrine granules and subsequent glucose intolerance or frank diabetes.
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T/F: Diabetics have an increased risk of exocrine pancreatic insufficiency.
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True. Nearly 30% of diabetics will have impaired pancreatic secretion. This is thought to be due to the inhibitory effects of excess glucagon and lack of stimulatory effects of insulin on the pancreas, vagal neuropathy, and nutritional wasting.
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