GI Flashcards
Where does iron absorption predominantly occur?
Duodenum and proximal jejunum
Malabsorption of which substances can occur after gastrojejunostomy?
Iron, Vit B12, folate, fat soluble vitamins, and calcium
Brown pigment stones
Associated with billiary tract infections
Black pigment stones
Chronic hemolysis (sickle cell, beta thalassemia, hereditary spherocytosis)
Cause of pigment stones
Conditions that increase the amount of unconjugated bilirubin in bile, which promotes calcium bilirubinate precipitation
What time of patients typically get acute acalculous cholecystitis?
Critically ill patients (sepsis, severe burns, trauma, immunosuppression)
Describe right sided colon adenocarcinoma
More likely to bleed and cause iron deficiency anemia
Describe left sided colon adenocarcinoma
Present with obstructing symptoms such as altered bowel habits, constipation, abdominal distension, nausea and vomiting
Describe the mechanism of the Shiga-like toxin in EHEC
Inactivates the 60s ribosomal subunit in human cells, leading to inhibition of protein synthesis and eventual cell death
Lynch syndrome
Autosomal dominant disease caused by abnormal nucleotide mismatch repair, including genes MSHS and MLH1
Derivatives of the dorsal pancreatic bud
Pancreatic tail, body, most of the head, and the small accessory pancreatic duct
Derivatives of the ventral pancreatic bud
Uncinate process, a portion of the pancreatic head, and the proximal portion of the main pancreatic duct
Pathophysiology of pancreatic divisum
Dorsal and ventral pancreatic buds fail to fuse
Polyethylene glycol
Osmotic laxative
Describe the cause of Hirschsprung diease
A result of abnormal migration of neural crest cells during embryogenesis
IL-8
Chemokine produced by macrophages that induces chemotaxis and phagocytosis in neutrophila
What are the 3 main causes of HIV-associated esophagitis?
Candida, CMV, HSV
How is CMV esophagitis characterized endoscopically?
Large, shallow linear ulcerations with intranuclear and cytoplasmic inclusions seen microscopically
List the retroperitoneal abdominal organs
Suprarenal (adrenal) glands, aorta and inferior vena cava, duodenum (except 1st part), pancreas (head and body), ureters and bladder, kidneys, esophagus, rectum (mid-distal)
What is the adenoma to carcinoma sequence is most cases of sporadic colon adenocarcinoma arising from a preexisting polyp?
Mutation of the APC tumor suppressor gene allows for the initial appearance of small adenomatous polyps.
Mutation of the KRAS protoocogene facilitates that increase in size of the adenoma
Malignant transformation requires TP53 mutation
Systemic mastocytosis
Abnormal proliferation of mast cells and increased histamine release. Histamine causes hypersecretion of gastric acid by parietal cells in the stomach as well as hypotension, flushing, pruritus, etc.
“Watershed areas”
In the left colon at the splenic flexure and rectosigmoid junction
Periodic, simultaneous, and non-peristaltic contractions of the esophagus
Diffuse esophageal spasm
What causes diffuse esophageal spasm?
Impaired inhibitory innervation within the esophageal myenteric plexus
How does diffuse esophageal spasm present?
Liquid/solid dysphagia and chest pain due to inefficient propulsion of food into the stomach
What are 3 well known risk factors for gallbladder disease?
“40, fat, female”
Which hormone is responsible for gallbladder contraction? Where is it made?
Cholecystokinin. Made in the duodenum and jejunum in response to fatty acids and amino acids
What is the most important characteristic that correlates with malignancy risk in colonic polyps?
Increasing polyp size
Are villous adenomas or tubular adenomas more likely to undergo malignant transformation?
Villous
Common findings with a gallstoneileus
Pneumobilia = air in the biliary tract
Describe diffuse gastric adenocarcinoma
Infiltrates the stomach wall and displays signet-ring cells on light microscopy
Describe intestinal type of gastric adenocarcinoma
Forms a solid mass that projects into the stomach lumen and is composed of glandular-forming cuboidal or columnar cells
What is a manifestation of galactokinase deficiency?
Cataracts
What is accumulating and causing cataracts with a galactokinase deficiency?
Lenticular accumulation of galactitol
What is the cause of pernicious anemia?
Autoimmune disorder caused by the cell-mediated destruction of parietal cells in the superficial upper glandular layer of the gastric body and fundus
What is the difference in immune responses between the live attenuated oral (Sabin) poliovirus vaccine and the inactivated poliovirus (Salk) vaccine?
Live attenuated oral vaccine produces a stronger mucosal secretory IgA immune response
What can prolonged cholestatic liver disease cause?
Malabsorption and nutritional deficiencies of fat-soluble vitamins (A, D, E, and K)
What kind of kidney stones are seen in Crohn disease?
Oxalate kidney stones
Mechanism of gallstones in Crohn disease
Decreased bile acid reabsorption by the inflamed terminal ileum promotes cholesterol supersaturation of the bile
Meckel diverticulum
Results from failed obliteration of the vitelline duct. Presents with spontaneous but painless lower GI bleeding
Where does iron absorption predominantly occur?
In the duodenum and proximal jejunum
What kind of kidney stones are associated with Crohn disease?
Oxalate kidney stones
