ambirnba's version from 2015-04-13 15:03

Section 1

Question Answer
MECKEL DIVERTICULUM occurs whenthe vitelline duct, which connects the gut with the yolk sac, does not completely involute.
Meckel Diverticulum
Rule of 2’s2% of the population; 2 inches long; Found within 2 feet of the ileocecal valve; Males are twice as likely to have; Most patients with Meckel diverticulum are asymptomatic, but if symptoms do occur, they will be present by age 2.
4 types of intestinal obstructionherniation, adhesions, volvulus, intussusception
Reduction in intestinal blood flow can cause Ischemic colitis.
Ischemic colitis presents with ____. affects what age group? Pain after eating >>> weight loss. elderly
Ischemic colitis occursat watershed areas (splenic flexure, distal colon).
Splenic flexure (why is it watershed?)superior and inferior mesenteric arterial circulations terminate
Sigmoid and rectum (why is it watershed?)inferior mesenteric, pudendal and iliac arterial circulations end.
celiac disease is associated with HLA-DQ2 and DQ8
steps in gluten pathogenesists most pathogenic component is gliadin. 1. Once absorbed, gliadin is deamidated by tissue transglutaminase (tTG). 2. Deamidated gliadin is presented by antigen presenting cells via MHC class II. 3. Helper T cells mediate tissue damage.
duodenal biopsy in celiac revealsflattening of villi, hyperplasia of crypts, and increased intraepithelial lymphocytes (
how is tropical sprue similar to celiac?similar histology
lactase deficiency- histologySince the problem is a biochemical defect, the histology is unremarkable
Abetalipoproteinemia is caused byutosomal recessive deficiency of apolipoprotein B-48 and B-100
Abetalipoproteinemia clinical features (2) 1. Malabsorption—due to defective chylomicron formation (requires B-48) 2. Absent plasma VLDL and LDL (require B-100)
stain used to diagnose Whipple diseasePAS (periodic acid–Schiff)
whipple disease isPAS positive foamy macrophages in small bowel lamina propria, which compress lacteals, preenting chylomicrons from going to lymphatics
whipple disease presents as diarrhea, weight loss, and arthalgia
t whippelii organisms hide out inmacrophage lysosomes
crohn disease locationCan occur anywhere in the GI tract; it often involves terminal ileum.
carcinoid tumor. type of cells? most common site? tumor marker?neuroendocrine cells; small intestine; chromogranin
carcinoid syndrome. presentation. trigger. must strongly suspect: characterized by bronchospasm, diarrhea, and flushing of skin; symptoms can be triggered by alcohol or emotional stress, which stimulate serotonin release from the tumor. metastasis

Section 2

Question Answer
pancreas divisum. how common is it? what is it? predisposes to?3% - 10 % of population; ventral and dorsal parts fail to fuse; chronic pancreatitis.
what is pancreatitisAutodigestion of the pancreas by its own enzymes.
acute pancreatitis is most commonly due toalcohol and gallstones
acute pancreatitis- describe the painEpigastric abdominal pain that radiates to the back, nausea + vomiting
Acute pancreatitis labsincreased amylase, lipase (higher specificity)
Acute pancreatitis + calcium levelsHypocalcemia (calcium is consumed during saponification in fat necrosis)
5 complications of acute pancreatitisshock, pancreatic pseudocyst, pancreatic abscess, DIC + ARDS
most common cause of chronic pancreatitisalcoholism
chronic pancreatitis clinical presentation (4)abdominal pain, pancreatic insufficiency, weight loss due to malabsorption, diabetes
chronic pancreatitis: imagingmay show calcifications within the pancreas.
chronic pancreatitis: histologyductal dilatation 'chain of lakes' pattern and intralumenal protein plugs and calcifications.
chronic pancreatitis: cellular response to injury (2)fibrosis and acinar cell loss
pancreatic abnormalities (fibrosis, glandular atrophy, plugged ducts) are found in 90% of patients with cystic fibrosis
pseudocyst: formed by fibrous tissue surrounding liquefactive necrosis and pancreatic enzymes
True cysts are ______; pseudocysts lined by epithelium; have no epithelial lining.
pancreatic adenocarcinomavery aggressive tumor with poor prognosis arising from pancreatic ducts. tumors most common in pancreatic head
Alcohol can cause pancreatitis by: (4) -Being directly toxic to acinar cells. -Causing secretion of protein-rich pancreatic fluid, which forms inspissated plugs that can obstruct small pancreatic ducts. -Increasing contraction of the sphincter of Oddi at the Ampulla of Vater. -Defective intracellular transport.
Telescoping of proximal bowel segment into distal segmentINTUSSUSCEPTION
GI pathology involving granulomacrohn disease