Term
| Where is atresia and stenosis of the GI tract most common? |
|
Definition
|
|
Term
| What are the different types of intestinal atresia? |
|
Definition
| diaphragm, cord, gap, and multiple gaps |
|
|
Term
| Where is duplication of the GI tract most common? |
|
Definition
|
|
Term
| What are the different kinds of small intestinal duplication? |
|
Definition
closed (enterogenous cyst)= 75%
open: at one end= giant diverticulum
at both ends: jejunum duplex, ileum duplex |
|
|
Term
| What is nonrotation/malrotation? |
|
Definition
| when the cecum remains in the left upper quadrant |
|
|
Term
| What is incomplete rotation? |
|
Definition
| when the cecum stops in the right upper quadrant (subhepatic) |
|
|
Term
| Malrotation predisposes you to obstruction by... |
|
Definition
| ladd bands and midgut vovulus |
|
|
Term
|
Definition
| herniation into the base of the umbilical cord where organs are covered by amnion and peritoneum. Frequently associated with other serious congenital defects |
|
|
Term
|
Definition
| abdominal wall defect adjascent but not involving the umbilicus (almost always to the right). Organs are NOT covered and it is NOT frequently associated with other congenital anomalies |
|
|
Term
| What causes a meckel's diverticulum? |
|
Definition
| an imcomplete involution of the vitelline duct |
|
|
Term
| Where are meckel's diverticuli located? |
|
Definition
| within 60-100cm of the ileocecal valve, antimesenteric |
|
|
Term
| What type of tissue is found in meckel's diverticulum? |
|
Definition
| heterotopic gastric mucosa or pancreatic tissue in about half |
|
|
Term
| What are complications of Meckel's diverticulum? |
|
Definition
| bleeding is the most common and it predisposes you to volvulus but most are asymptomatic |
|
|
Term
| What population presents with bleeding from a Meckel's diverticulum? |
|
Definition
|
|
Term
| What is Hirschsprung's disease? |
|
Definition
| absence of ganglion cells (aganglionosis) in myenteric and submucosal plexuses. Ganglion cells migrate from the neural crest in a proximal to distal direction |
|
|
Term
| What is short-segment hirschprung's? |
|
Definition
| clasical, involves the rectum and sigmoid and is more common in boys |
|
|
Term
| What is long-segment Hirschsprung disease? |
|
Definition
| aganglionosis beyond the sigmoid. more evenly distributed among boys and girls |
|
|
Term
| Is Hirschsprung's a familial disorder? |
|
Definition
| most cases are sporadic but there are some familial forms (defects in genes regulating neurogenesis, particularly the RET oncogene) |
|
|
Term
| What are the signs/symptoms/complications of Hirschsprungs? |
|
Definition
| failure to pass meconium, obstipation, massive distention of the colon (megacolon) proximal to the aganglionic segment, enterocolitis, perforation |
|
|
Term
| What's another name for gastroenteritis and what is it? |
|
Definition
| enterocolitis, inflammation of the GI tract that mostly manifests as diarrhea |
|
|
Term
|
Definition
| increase in stool mass and frequency and a decrease in consistency |
|
|
Term
| What is secretory diarrhea? |
|
Definition
|
|
Term
| What is exudative diarrhea? |
|
Definition
|
|
Term
|
Definition
| diarrhea with blood, mucus, and fever |
|
|
Term
| What is osmotic diarrhea? |
|
Definition
| hyperosmolar and voluminous (usually due to laxatives) |
|
|
Term
| What is malabsorption diarrhea? |
|
Definition
| deffective absorption of ingested food items (qualifies as osmotic) |
|
|
Term
| Secretory, noninfectious diarrhea is most commonly due to... |
|
Definition
|
|
Term
| Exudatie non-infectious diarrhea is due to... |
|
Definition
|
|
Term
| Osmotic noninfectious diarrhea can be due to... |
|
Definition
| antacids (magnesium sulfate), sugar/fat substitutes (sorbitol, olestra), and laxatives |
|
|
Term
| What causes malabsorption, non-infectious diarrhea... |
|
Definition
| disaccharidase (lactase) deficiency, abetalipoproteinemia, pancreatic insufficiency, biliary obstruction, sprue, crohn's disease, short bowel syndrome |
|
|
Term
| What causes a functional, noninfectious diarrhea? |
|
Definition
|
|
Term
| What viruses cause infectious, secretory diarrhea? |
|
Definition
| rotavirus (infants) and norovirus (older children and adults) |
|
|
Term
| What toxigenic bacteria cause secretory diarrhea? |
|
Definition
| E coli (enterotoxigenic, traveler's diarrhea) and cholera |
|
|
Term
| What parasites cause secretory diarrhea? |
|
Definition
| giardia (also causes malabsorption) and cryptosporidium |
|
|
Term
| Which invasive bacteria can cause exudative diarrhea? |
|
Definition
| campylobacter (most common in US), E coli (enteroinvasive), shigella, salmonella, yersinia |
|
|
Term
| What toxigenic bacteria cause infectious diarrhea? |
|
Definition
| E coli (enterohemorrhagic), shigella, and clostridium difficile |
|
|
Term
| What parasites cause exudative diarrhea? |
|
Definition
|
|
Term
| Name two salmonella organisms that cause dysentery? |
|
Definition
| salmonella enteritidis, S. typhimurium |
|
|
Term
| What is the major source of salmnonella infection? |
|
Definition
| poultry contaminated with feces |
|
|
Term
| What diseas does salmonella typhi cause? |
|
Definition
| typhoid fever, a disseminated condition (fever, malaise, abdoinal pain, constipation), chronic infection (gallbladder), and asymptomatic carrier state |
|
|
Term
| T/F Salmonella typhi can be found in poutry and uncooked eggs. |
|
Definition
| false, there are no significant animal reservoirs |
|
|
Term
| Where does giardia lamblia live and what type of diarrhea does it cause? |
|
Definition
| small intestine, secretory or malabsorptive diarrhea |
|
|
Term
| What individuals are affected by cyrptosporidium, where in the GI tract does it live, and what type of diarrhea does it cause? |
|
Definition
| immunosuprresed, small intestine, chronic secretory diarrhea |
|
|
Term
| Where does entamoeba histolytica live and what symptoms/disease states does it cause? |
|
Definition
| colon, flask-shaped ulcers, exudative diarrhea, dysentery, and liver abscesses |
|
|
Term
| What is hemolytic uremic syndrome? |
|
Definition
| endothelial cell injury, microangiopathic hemolytic anemia, thrombocytopenia, renal failure |
|
|
Term
| What causes hemolytic uremic syndrome? |
|
Definition
verocytotoxin produced by escherichia coli (type 0157:H7)
shiga-like toxins produced by shigella and other toxigenic bacteria |
|
|
Term
|
Definition
| AI disease with reactive arthritis, urethritis and conjuctivitis due to shigella, salmonella, campylobacter and other bacterial antigens. Susceptible individuals have HLA-B27 |
|
|
Term
| What bacteria is associated with guillain barre syndrome? |
|
Definition
|
|
Term
| Name the four specific types of enterocolitis. |
|
Definition
| necrotizing enterocolitis, pseuomembranous colitis, microscopic colitis, and inflammatory bowel disease (crohns or ulcerative colitis) |
|
|
Term
| What is necrotizing enterocolitis? |
|
Definition
| full-thickness gangrenous necrosis that mostly involves the terminal ileum of the proximal colon |
|
|
Term
| What population is most susceptible to necrotizing enterocolitis and what causes it? |
|
Definition
| neonates (premature or low birth weight) upon initiation of oral foods; possibly due to abnormal response to bacteria and toxins on onset of oral feeding with immature gut immune system leading to deranged intestinal blood flow |
|
|
Term
| What is pseudomembranous colitis? |
|
Definition
| disruption of the normal flora by broad spectrum antibiotics (clindamycin, cephalosporins, others) causes toxin-forming bacteria to flourish. |
|
|
Term
| Which bacteria cause pseudomembranous colitis? |
|
Definition
| clostridium difficile with exotoxins A and B |
|
|
Term
| How do you diagnose and treat pseudomembranous colitis? |
|
Definition
| detection of exotoxins A and B in stool and tx with antibiotics (vancomycin) |
|
|
Term
| What are the symptoms of microscopic colitis? |
|
Definition
| chronic watery diarrhea of unknown etiology. |
|
|
Term
| What is microscopic colitis/what is its appearance? |
|
Definition
| nmal gross appearance but positiv emicroscopic findings. Bandlike collagen deposit under surface epithelium (collagenous colitis) and prominent intraepithelial infiltrate of lymphocytes (lymphocytic colitis) |
|
|
Term
| What population is affected by microscopic colitis? |
|
Definition
| collagenous is much more common in women. lymphocytic affects men and women equally |
|
|
Term
| What is inflammatory bowel disease? |
|
Definition
| chronic, idiopathic, inflammatory conditions causing intermittent attacks of diarrhea |
|
|
Term
| What are the different types of inflammatory bowel disease? |
|
Definition
| crohn's, ulcerative colitis, and about 10% are classified as indeterminate colitis |
|
|
Term
| What are the postulated mechanisms for IBD? |
|
Definition
| exaggerated immune response to normal flora, failure to down-regulate the immune response, questionable autoimmune mechanisms, defects in the epithelial barrier function, genetic predisposition |
|
|
Term
| What is the distribution of Crohns among locations in the GI tract? |
|
Definition
sharply delineated involved segments, separated by unaffected (skip) areas.
small intestine alone= 40%; small intestine and colon = 30% and colon alone = 30% |
|
|
Term
| What antibody is associated with Crohn's? |
|
Definition
| anti-saccharomyces cerevesiae antibody (ASCA) |
|
|
Term
| What are the histological features of Crohns? |
|
Definition
| transmural involvement; lymphoid aggregates at all levels of the bowel wall. Non caseating granulomas, cryptitis and crypt abscesses less prominent than in ulcerative colitis. Ulcers, narrow, slit-like, deeply penetrating, fistulous, dysplasia/carcinoma |
|
|
Term
| What are the histological features of Crohns? |
|
Definition
| transmural involvement; lymphoid aggregates at all levels of the bowel wall. Non caseating granulomas, cryptitis and crypt abscesses less prominent than in ulcerative colitis. Ulcers, narrow, slit-like, deeply penetrating, fistulous, dysplasia/carcinoma |
|
|
Term
| What are the gross characteristics of Crohn's disease? |
|
Definition
| long, linear ulcers; fistulas, rubbery and thick intestinal wall; narrow lumne; mesenteric fat wraps around involved segments (creeping fat) |
|
|
Term
| What are the demographics of Crohn's disease? |
|
Definition
| western populations, white, Jewish; females slightly more often than males; peak in teens and twenties; smoking is a strong risk factor |
|
|
Term
| What are some associated conditions of Crohn's disease? |
|
Definition
| malabsorption of vitamin B 12 (pernicious anemia), malabsorption of bile salts (steatorrhea), polyarthritis/ankylosing spondylitis, erythema nodosum, uveitis, primary sclerosing cholangitis (PSC), gastrointestinal cancer |
|
|
Term
| Where in the intestines does ulcerative colitis occur? |
|
Definition
| limited to the colon; begins at the rectum and extends in a continuous fashion proximally; the rectum is always involved, there are no skip areas |
|
|
Term
| What antibody is associated with ulcerative colitis? |
|
Definition
| perinuclear anti-neutrophil cytoplasmic antibody (PANCA) |
|
|
Term
| What is the microscopic appearance of ulcerative colitis? |
|
Definition
| affects only the mucosa and submucosa with architectural disarray, granulomas are rare, acute cryptitis and crypt abscesses. Also, extensive ulceration and dysplasia/carcinoma |
|
|
Term
| What is the gross appearance of ulcerative colitis? |
|
Definition
| no skip lesions, begins/more severe in rectum and extends proximally for variable distances (proctitis, protosigmoiditis, pancolitis), wall isn't thickened, serosa is univolved, broad-based shallow ulcerations, exuberant mucosal regeneration results in pseudopolyps |
|
|
Term
| What do you call it when ulcerative colitis causes the colon to swell and become gangrenous? |
|
Definition
|
|
Term
| What are the demographics for ulcerative colitis? |
|
Definition
| white, women, smoking may improve symptoms, onset peaks between 20 and 25 years old |
|
|
Term
| What are the associated conditions of ulcerative colitis? |
|
Definition
| polyarthritis (ankylosing spondylitis), erythema nodosum, uveitis, primary sclerosing cholangitis, high risk of cancer |
|
|
Term
| Which ulcerative colitis patients are at the highest risk for cancer? |
|
Definition
| patients with pancolitis for 10 or more years duration has a 20-30 fold risk |
|
|
Term
| Name some examples of malabsorption syndromes. |
|
Definition
| whipple disease, disaccharidase (lactase) deficiency, abetalipoproteinemia, celiac sprue, and tropical sprue |
|
|
Term
| What is whipple diseae caused by? |
|
Definition
| small intestinal mucosa macrophages loaded with rod-shaped bacilli (tropheryma whippelii) |
|
|
Term
| What are the symptoms of whipple diseas? |
|
Definition
| malabsorption, diarrhea, and weight loss; bacilli laden macrophages also found in LN (LAD), synovial membranes (polyarthritis), and the brain (CNS symptoms) |
|
|
Term
| What are the demographics of whipple disease patients? |
|
Definition
| white men in their 30 to 40s |
|
|
Term
| How do you treat whipple disease? |
|
Definition
|
|
Term
| T/F Congenital lactase dificiency is relatively common. |
|
Definition
|
|
Term
| What demographics are at higher risk for acquired lactase (disaccharidase) deficiency? |
|
Definition
| asian, african-american, native american |
|
|
Term
| What's another name for abetalipoproteinemia? |
|
Definition
|
|
Term
| What is the inheritance pattern of abetalipoproteinemia? |
|
Definition
|
|
Term
| What mutation causes abetalipoproteinemia? |
|
Definition
| microsomal triglyceride transfer protein (MTP) |
|
|
Term
| What is the pathogenesis of abetalipoproteinemia? |
|
Definition
| FFAs and monoglycerides enter the enterocytes and are re-esterified but cannot be assembled into apoliprotein B resulting in vacuolation of enterocytes |
|
|
Term
| How does abetalipoproteinemia present? |
|
Definition
|
|
Term
|
Definition
| acanthocytic erythrocytes due to lipid membrane abnormalities due to lack of apolipoprotein B and FFA absorption |
|
|
Term
|
Definition
| gluten intolerance (wheat rye and barley) specifically gliadin. Villi become atrophic and crypts are elongated/hyperplastic. Results in malabsorption and reverts after gluten is removed from diet |
|
|
Term
| What type of immune response causes celiac's? |
|
Definition
| cell-mediated and antibody immune responses |
|
|
Term
| Where does celiac sprue occur in the GI tract? |
|
Definition
|
|
Term
| What can genetically predispose you to celiac sprue? |
|
Definition
| being white, DQ2 and DQ8 HLAs |
|
|
Term
| What pathogen is associated with celiac's? |
|
Definition
| adenovirus (cross-reactivity of gliadin and type 12 adenovirus E1b protein) |
|
|
Term
| Which circulating antibodies are used for diagnoses of celiac's? |
|
Definition
| antigliadin, antiendomysial, and anti-tissue transglutaminase |
|
|
Term
| What are associated disorders of celiac's disease? |
|
Definition
| dermatitis herpetiformis, AI diseases, long-term risk of malignant disease (lymphomas, particularly T-cell lymphomas) |
|
|
Term
|
Definition
| malaborption (folate aor vitamin B12 deficiency) within days of acute diarrhea where injury is seen at level of the small intestine. No specific causal agent but enterotoxigenic organisms implicated. |
|
|
Term
| What's the treatment for tropical sprue? |
|
Definition
| broad-spectrum antibiotics, folate, and vitamin B 12 |
|
|
Term
| Name some vascular disorders of the GI tract. |
|
Definition
| ischemic bowel disease, angiodysplasia, and hemorrhoids |
|
|
Term
| What are the two types of ischemic bowel diseaes? |
|
Definition
| occlusive (arterial/venous) and non occlusive (shock) |
|
|
Term
| Characterize transmural ischemic bowel disease. |
|
Definition
| gangrenous; acute, total occlusion of large vessels |
|
|
Term
| Characterized non transmural ischemic bowel diseaes |
|
Definition
| non-gangrenous; insidious or incomplete occlusion of large vessels, or occlusion of small vessels |
|
|
Term
| What is the pathogenesis of ACUTE ischemic bowel disease? |
|
Definition
| sudden complete occlusion with transmural infarction |
|
|
Term
| What are the symptoms of acute ischemic bowel disease? |
|
Definition
| sudden, severe, abdominal pain, sudden bowel evacuation of bloody stools, rapid shock and vascular collapse |
|
|
Term
| What is the pathogensis of chronic ischemic bowel disease? |
|
Definition
| insidious, partial occlusion with no visible effect, or infarction limited to mucosa and submucosa |
|
|
Term
| What are teh symptoms of chronic ischemic bowel disease? |
|
Definition
| intermittent episodes of bloody diarrhea, mimicking inflammatory bowel disease |
|
|
Term
| Ischemic bowel disease occurs more commonly in the___ because... |
|
Definition
| colon... fewer collaterols, less arterial blood supply, greater intraluminal pressure |
|
|
Term
| What two areas does the colon have very few collaterals? |
|
Definition
| splenic flexure (whatershed of SMA and IMA) and cecum |
|
|
Term
|
Definition
| dilated submucosal and mucosal vessels in the cecum or right colon (ectatic veins, venules, and capillaries) |
|
|
Term
| What causes angiodysplasia? |
|
Definition
| vascular degenerative changes related to aging (occurs after 50s), and mechanical factors (cecum has the largest diameter and hte greatest wall tension |
|
|
Term
| What are the symptoms of angiodysplasia? |
|
Definition
| common cause of significant lower intestinal bleeding which may be chronic/intermittent or acute/massive |
|
|
Term
| Varices of the anorectal venous plexuses are called ______. |
|
Definition
|
|
Term
| What are the two different types of hemorrhoids? |
|
Definition
external: inferior hemorrhoidal plexus, below the anorectal (dentate) line
internal: superior hemorrhoidal plexus |
|
|
Term
| What conditions/circumstances predispose you to hemorrhoids? |
|
Definition
| low fiber diet, constipation, long periods sitting, obesity, pregnancy portal hypertension |
|
|
Term
| What are the complications of internal and external hemorrhoids? |
|
Definition
internal: no pain, bleeding, prolapse
external: pain, no bleeding, painful thrombosis |
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