GI Flashcards
What causes a 40yo F to have distended gallbladder with patchy necrosis?
Acute calculous cholecystitis - inflam disease of gallbladder w/o evidence of gallstones or cystic obstruction
After partial pancreatic resection what enzyme are you deficient in? What will be normal?
o Pancreatic digestive enzymes that are secreted into the duodenum to digest polysaccharides
o Trypsin, lipase, trypsinogen
o Normal: D-xylose – monosaccharide whose absorption isn’t affected by exocrine pancreatic insufficiency.
Varices: gastric fundus
o Splenic vein thrombosis.
o Short gastric veins drain blood from gastric fundus into splenic vein
Varices: esophageal and gastric
o Left gastric veins
Gastric bypass surgery can cause small intestinal bacterial overgrowth (SIBO). This results in deficiency of what? It increases production of what?
Deficiency - Vit ADE, B12, Fe
Inc production - folic acid, vit K
Patients that have undergone total gastrectomy require lifelong supplementation of what?
Vit B12 (cant produce intrinsic factor that is normally secreted by parietal cells).
Describe the levels of breath hydrogen content, stool pH and stool osmolality in patients with lactose intolerance
breath hydrogen - increased
stool pH - reduced (inc short-chain FA acidify the stool)
stool osmolality - increased
Manometry - Systemic scleroderma
Dec peristalsis with dec tone at LES
Manometry - Achalasia
dec amplitude of peristalsis in mid esophagus; inc tone and incomplete relaxation at LES
Reduced # of inhib ganglion cells
Hereditary hemochromatosis is caused by a mutation in what protein? What is the function of the protein? patients with this condition have inc risk of what?
HFE protein - interacts with the transferrin receptor to form a complex that senses iron stores. W/o it, there is a falsely low Fe level detected
HCC, CHF, testicular atrophy/hypogonadism
Inhaled-anesthetic hepatotoxicity (esp from halothane) presents with fever, anorexia, nausea, myalgias, arthralgias, and rash. What do labs show?
Elevated LFTs, prolonged PT, leukocytosis, eosinophilia.
PT is prolonged bc liver cant synth factor VII
Where is vit b12 absorbed?
terminal ileum (deficiency with Crohns, surgical resection)
Where is vit b9 (folate) absorbed?
jejunum
where is iron absorbed?
duodenum and proximal jejunum
Adenoma to carcinoma sequence
- normal –> hyperprolif epithelium
- Hyperprolif –> adenoma
- Adenoma –> carcinoma
- APC inactivation, B-catenin accumulation
- K-ras activation
- p53 inactivation
What three receptors are located on parietal cells and increase gastric acid secretion?
Ach, histamine, gastric receptors Act synergistically (potentiation) - disrupt one will disrupt all.
How do you differentiate pseudoachalsia from malignancy from achalasia?
Manometry looks the same
Malignancy - progression is more rapid, asymmetric wall thickening with diff passing endoscope, enlargement of R supraclavicular nodes.
Acute blood loss with no abdominal pain in an elderly patient is indicative of what?
Diverticulosis - incidence inc with age
more fiber in the diet helps prevent
Treatment for mild to moderate extensive UC
Mesalamine, olsalazine, sulfasalazine
Why is an excess of H+ associated with ZE syndrome/gastrinomas?
Gastrin secreted by tumor cells is not subject to normal feedback control.
(Gastrin secretion is normally under neg feedback control by H+)
What drug is a negatively charged agent that forms a physical barrier against acid and pepsin?
Sucralfate (aluminum sucrose sulfate)
Neg charge binds to positively charged proteins at the base of ulcers
Caput medusae, caused by portal HTN is due to dilation of what vein
Paraumbilical v (systemic circ = superficial and inf epigastric v)
Hemorrhoids, caused by portal HTN is due to dilation of what vein
Superior rectal v (systemic circ = middle and inf rectal v)
Dietary lipids are primarily digested where?
After cholecystectomy, where will these lipids be absorbed?
- , Duodenum.
- jejunum (bile salts emulsify lipid breakdown products formign water-soluble micelles, facilitating lipid absorption here).
Rifaximin treats hepatic encephalopathy how?
decreases intraluminal ammonia production
Lactulose treats hepatic encephalopathy how?
Acidification: increases conversion of ammonia to ammonium
What drug is used to tx UC and Crohns disease and has SE of anorexia, reversible oligospermia, and serious skin reactions (SJS, erythema multiforme, TEN)?
Sulfasalazine - sulfa drug
ERCP showing narrowing in distal intrapancreatic common duct and a normal pancreatic duct indicates what? How does primary sclerosing cholangitis or carcinoma of the ampulla of vater differ?
Cholangiocarcinoma
Primary sclerosing cholangitis - everything would be dilated on ERCP
Carcinoma of ampulla of vater - ERCP would not be able to be completed (probe passes through ampulla of vater first)
Treatment for Wilson disease?
Penicillamine or trientine - copper chelator
note - penicillamine can cause lupus-like syndrome, fever and lymphadenopathy
H pylori affects what histological location of the stomach?
in the mucus layer above the mucosa
Differentiate cholecystitis vs choledocholithiasis symptoms
Cholecystitis (stone in cystic duct) - constant pain
Choledocholithaisis (stone in common bile duct) - colicky pain esp postprandially
HNPCC (Lynch syndrome) is due to problem with mismatch repair. What part of the cell cycle does this normally occur in?
G2 phase (gap 2 phase)
Colicky upper quad abd pain, inc bruising, bone pain, xanthomas, scleral icterus, hypercholesterolemia indicates what?
Obstruction of extra hepatic bile ducts –> conjugated hyperbilirubinemia.
Impairs bile flow –> dec fat sol vit like vit K and D3. Dec use of cholesterol in bile acids –> hypercholesterolemia
Poor healing of perianal fistulas and sinus tracts should make you consider what?
Crohns
Inflammation of the full thickness of the intestinal wall –> poor healing and sinus/fistual development
Where are bile acids normally reabsorbed?
Terminal ileum
Damage (crohns) or resection, can cause fat malabsorption –> ADEK vit def
What is the mechanism behind Zenker (false) diverticulum?
Diminished relaxation of cricopharyngeal muscles during swallowing –> inc intraluminal pressure in oropharynx –> herniation of mucosa through the zone of mm weakness
What factors increase and decrease risk of cholesterol stone formation?
increase - inc cholesterol
decrease - high levels of bile salts and phosphatidylcholine (inc cholesterol solubility)
Differentiate the cause of duodenal vs jejunum/ileum atresias?
Duodenal - failure of recanalization at 8-10wk (double bubble) - assoc w/Down synd
Jejunum/ileum - vascular injury (bilious emesis seen bc below 2nd part of duodenum) - assoc w/Gastroschisis
Elevation in Gamma-glutamyl transpeptidase (GGT) suggests what?
Suggests that alkaline phosphatase elevation is due to LIVER (not bone) pathology
hyperplasia of submucosal glands is a result of what? What are they called and what do they excrete?
Chronic overproduction of gastric acid (eg H pylori)
Brunner glands - bicarb
Diarrhea caused by celiac disease can lead to what vitamin deficiency?
Vit D def –> dec serum phosphorus, inc PTH, low serum ca
secondary hyperparathyroidism
Decreased # of somatostatin-producing cells in the gastric antrum is associated with formation of what?
DUODENAL ulcers - due to inc gastric acidity from H pylori.
Note: Gastric ulcers are not a result of dec somatostatin producing cells
Patient with inflammatory (eg celiac) or infectious (eg giardiasis) processes damage microvilli of the small intestines, which can cause what deficiency?
Secondary lactase deficiency (cant convert lactose into galactose)
Main mechanism of copper removal in healthy human?
Hepatic excretion into bile
(60% Cu absorbed into stomach and duodenum bound to albumin –> liver. Forms ceruloplasmin in the liver. Senescent ceruloplasmin and unabsorbed copper secreted into bile and excreted in stool).
Wilson’s disease = AR toxic accum of copper in liver, brain (basal ganglia), eye
AR d/o with defective hepatic excretion of conjugated bilirubin glucuronides due to mutation in canalicular membrane transport protein. Sx - jaundice episodes, black liver. Dx? Why black liver?
Dubin-johnson
Impaired excretion of epinephrine metabolites (histo: dense pigments within lysosomes)
Patient with hx of UC with abd distension and tenderness w/o rebound or guarding, bloddy diarrhea, signs of shock is what?
Toxic megacolon (common complication of UC) Dx - plain xray
Ulcer where in the GI tract is NOT at inc risk of carcinoma?
Duodenal ulcers
Note: esophageal, gastric, and colorectal ulcers can lead to cancer
Air in the gallbladder and biliary tree indicates what?
Gallstone ileus (gallstone has fistulalized into the small bowel, obstructing the ileum) Sx similar to small bowel obstruction but xray shows air in gallbladder and biliary tree
Barrett esophagus increases the risk of what type of cancer?
Adenocarcinoma
note: major RF for SCC of esophagus are smoking and ETOH
What liver pathology is associated with exposure to carcinogens such as arsenic, thorotrast, and polyvinyl chloride .What cell marker does it express?
- hepatic angiosarcoma
2. CD31 (PECAM1) = vascular endothelial cell tumor
Primary biliary cholangitis is a chronic autoimmune liver disease that classically has elevated levels of what antibodies?
Histopathological findings of LYMPHOCYTIC INFILTRATION on bx are also seen in what disease?
- antimitochondrial antibodies
2. Graft vs host disease
Palpable, but nontender gallbladder, wt loss and obstructive jaundice are indicative of what?
Strongest environ RF?
Adenocarcinoma at the head of the pancreas
Smoking (>50, chronic pancreatitis, DM and genetics also inc risk)
Neoplastic polyps vs non-neoplastic polyps
Neoplastic: serrated, adenomatous (tubular, villous, tubulovillious). Villous adenomas are more likely to undergo malig transformation than tubular adenomas
Non-neoplastic (hyperplastic, submucosal, inflam, mucosal)
dX? A chronic liver disease characterized by autoimmune destruction of intrahepatic bile ducts and cholestasis
Primary biliary cirrhosis
MC in middle-aged women - pruritus, elevated alk phos
What medication can be taken to reduce risk of colon adenoma polyps?
COX-2 inhibitors Regular aspirin (COX-1 and COX-2 inhibitor) use dec adenomatous polyp formation bc inc activity of COX-2 has been found in many forms of colon adenocarcinoma (between APC and K-ras mutations)
Diarrhea, weight loss, and epigastric calcifications in a patient with chronic alcoholism is a sign of chronic pancreatitis. This can result in what?
Pancreatic exocrine insufficiency and malabsorption
ETOH-related chronic pancreatitis develops in part d/t ETOH-induced secretion of protein-rich fluid –> ductal plugs –> calcification –> exocrine insufficiency d/t atrophy of pancreatic acinar cells and pancreatic fibrosis.
Porcelain gallbladder can be due to chronic cholecystitis and is assoc with inc risk of what?
Adenocarcinoma of the gallbladder.
Critically ill patients can develop what problem with their gallbladder?
Acute acalculous cholecystitis.
Acute inflam of gallbladder w/o gallstones d/t gallbladder stasis and ischemia.
What part of the large bowel is susceptible to ischemic colitis during hypotensive states (esp in patients with underlying arterial insufficiency)?
Splenic flexure and rectosigmoid junction. Watershed areas
What enzyme converts trypsinogen to trypsin
Enteropeptidase (found in jejunal brush border)
Deficiency –> impaired protein and fat absorption –> diarrhea, failure to thrive, and hypoproteinemia
Crohn disease is assoc with NOD2 mutations (encodes intracellular microbial receptor) –> dec activity of what?
NF-kB Cytokine production (impairs innate barrier function of the intestinal mucosa)
How does cirrhosis cause hyperestrinism? SE?
Impaired estrogen metabolism by the liver –> dec free testosterone/estrogen ratio –> gynecomastia, testicular atrophy, dec body hair, spidar angiomata
ERCP of what duct would help relieve jaundice caused by pancreatic head cancer?
Stent in common bile duct
Since the head of the pancreas is anatomically located next to the second and third parts of the duodenum, it obstructs the bile flow in the common bile duct.
Stomach innervation: what increases Ach stimulation to parietal cells –> inc Acid output and stimulation of G cells via GRP to stimulate ECL cells and increase acid px.
parasympathetic via Vagus nerve
How does liver disease cause erectile dysfunction?
Liver disease is a/w hyperstrenism
(arises from dec catabolism of estrogen, inc SHBP globulin –> dec free testosterone/estrogen ratio –> hypogonadism –> dec testosterone
What is a physiologic risk factor for Crohn’s disease
Barrier dysfunction is present in patients with Crohn’s disease as well as some of their healthy first degree relatives. It has therefore been suggested that increased TIGHT JUNCTION PERMEABILITY (reduced barrier function) is a risk factor for development of Crohn’s disease.
Severe abdominal pain after meals relieved by decreasing amount of food. PMH - atherosclerosis. Abdominal bruit and diminished pedal pulses. Stenosis of what artery is causing this?
SMA - mesenteric ischemia
What causes nausea, intermittent bloating, and diarrhea after gastric bypass?
DUMPING syndrome
Rapid emptying of hyperosmolar chyme into the small bowel –> intraluminal fluid sequestration –> dec blood volume and bloating
Inherited autoimmune disease that attacks parietal cells, resulting in hypochlorhydria and decreased production of intrinsic factor. Dx? What GI hormone is likely to be increased?
Autoimmune metaplastic atrophic gastritis
Inc Gastric acid in response to hypochlorhydria
