GI Flashcards
Intestinal atresia of the jejunum + wrapping of the ileum around vasculature is caused by =
Vascular occlusion in utero
What is the name of the main SMA and IMA anastamoses?
Marginal artery of Drummond
What is the term for when a pair of alleles from 2 loci are inherited together in the same gamete (haplotype) more or less often than would be expected by random chance alone?
How do you calculate the chance inheritance?
Linkage equilibrium
Chance inheritance is calculated by multiplying freq of A x freq of B
Note: This can also occur if the 2 loci are on different chromosomes
Required supplementation for exclusively breastfed infants? (3)
- Vitamin D: required due to the lack of sun exposure and to prevent rickets. Given at 1 month visit.
- Vitamin K: required due to the lack of gut bacterial colonization that normally produce K. Prevents hemorrhagic disease of the newborn (K required for clotting factors). Given intramuscularly at birth.
- Iron: only required if preterm or low birth weight.
Muscle in charge of esophagus peristalsis
Cricopharyngeus muscle
Most prominent lab finding in acute hepatic failure =
Prolonged PT
due to FVII having the shortest half life of all the proteins made in the liver
Gamma glutamyl transferase (GGT) levels are used to monitor _ injury
biliary injury
Fine, granular, dull, eosinophilic, ground-glass hepatocytes =
Hepatitis B infection - hepatocellular cytoplasm fills with hep B surface antigen
Golden-yellow hemosiderin granules in the cytoplasm of hepatocytes =
Hemochromatosis - iron overload
Lymphoid aggregates in the portal tract + focal areas of macrovesicular steatosis =
Hepatitis C infection
Pain moving to McBurnie’s point is caused by =
Irritation of the parietal peritoneum due to appendicitis
somatic, more localized, sharp pain
5 year old boy + abdominal pain + blind pouch connected to the ileum + fibrous bands attaching the pouch to the umbilicus =
Meckel’s diverticulum
True diverticulum that contains all the layers
Mechanism of H. Pylori duodenal ulceration
H pylori -> inhibits D cells in the stomach antrum -> decreases somatostatin release
No somatostatin -> increased gastrin release from G cells -> increased Histamine secretion and increased direct H secretion
Increased amount of acid released into the stomach -> increased amount of acid enters the duodenum -> normal neutralizing effects are overwhelmed -> ulceration
High pitched, tinkling bowel sounds indicate =
small bowel obstruction
pathogenesis of a Mallory-Weiss tear =
rapid increase in intra-abdominal and intra-luminal gastric pressure
Retroperitoneal Organs (9)
SAD PUCKER
Suprarenal (adrenal) glands Aorta + IVC Duodenum - except for first part Pancreas - except tail Ureters Colon - ascending and descending Kidneys Esophagus - thoracic portion Rectum - partially
WDHA Syndrome
Watery Diarrhea, Hypokalemia, Achlorhydria
Caused by VIPoma (non-alpha, non-beta pancreatic islet cell tumor)
VIP -> increased intestinal water and electrolyte secretion + increased relaxation of intestinal smooth muscle and sphincters
Echogenic = radiolucent or radiopaque
Echogenic = Radiolucent
night blindness is caused by
Vitamin A deficiency
What type of hernia might be found in the scrotum?
Indirect hernia - abdominal contents protrude through the deep inguinal ring all the way through the superficial inguinal ring and into the scrotal sac
Anti-inflammatory cytokines (2) =
IL-10, TGF-beta
99m Tc-Pertechnetate scan is used to diagnose =
Meckle’s diverticulum - the radioisotope used has an affinity for parietal cells (physiologic AND ectopic)
Neutrophil attractants (4)
- IL-8
- LTB4
- C5a
- N-formylated peptides/bacterial products
Where is rRNA made?
nucleolus
2 organisms found most commonly in an intra-abdominal infection/abscess
- B. fragilis
- E. coli
Progressive obstruction of extrahepatic bile ducts leading to jaundice within the first 2 months of life =
biliary atresia
Main immune system defense against mycobacterial infections =
interferon-gamma
What inherited defect can result in disseminated TB early in infancy?
inherited defect in interferon-gamma signaling
Things above the pectinate line in the rectum travel to which LNs? (1)
-internal iliac LN
Things below the pectinate line in the rectum travel to which LNs? (1)
-superficial inguinal LN
Branches of the splenic artery = (3)
- pancreatic branches
- L gastroepiploic artery
- short gastric branches
epigastric calcifications + alcoholic + diarrhea =
chronic pancreatitis
3 day old + bilious emesis + fibrous bands from cecum and R colon that attach to the retroperitoneum =
malrotation
Odonophagia definition =
painful swallowing
Is vitamin B12 water soluble or fat soluble?
water soluble
Phenobarbital is a treatment for what type of hyperbilirubinemia =
Given in Crigler-Najjar Syndrome type II (less severe form compared to type I). Absent UDP-glucoronosyltransferase -> increased unconjugated BR.
Phenobarbital = Increases synthesis of liver enzymes.
Innervation:
- Above the pectinate line
- Below the pectinate line
Above = inferior hypogastric plexus Below = inferior rectal nerve, a branch off the pudendal nerve
1 month old + persistent jaundice + muscle rigidity + seizures =
Crigler-Najjar Syndrome type I
= absent UDP-glucuronosyltransferase -> elevated UCBR
Patients die within a few years
Increased alkaline phosphatase indicates trouble in what 2 systems/organs
Liver (biliary tract)
Bone
Liver damage is more likely than bone. To check that it is liver/biliary problems, order GGT.
Bioavailability of a non-IV drug
Always will be less than 1 (a fraction due to the fact that IV-drugs have a bioavailability of 1)
Adult acquired diverticula are _ diverticula that have _ pathogenesis
false diverticula = not covered by all the layers
pulsion pathogenesis = increases in intraluminal pressure created during sustained bowel movements pushes the wall outwards, most common pathogenesis in adults/elderly
NK Cell’s main function =
Destroy cells with absent MHC Class I receptors on them
Cells lose their MHC Class I when they are virally infected or when they become tumor cells.
Location of the white-yellow pseudomembranes in C. difficile infection?
Colon!
Pseudomembranous colitis
Liver disease = increased BUN or decreased BUN?
Decreased BUN due to the fact that ammonia (waste) cannot be turned into urea in light of the damaged hepatocytes
Elevated tissue transglutaminase IgA =
gluten insensitivity
Name 4 anti-cholinergic side effects
- dry mouth
- urinary retenton
- blurry vision
- constipation
2 watershed areas of the colon
- L colonic/splenic flexure = between the SMA and IMA
- Rectosigmoid junction = between the sigmoid artery and the superior rectal artery
Treatment of nausea related to GI insults =
5HT3 receptor antagonist
Ondansatron
Small intestine bacterial overgrowth effect on:
Vitamins ADEK, Folate, B12, Iron, Zinc
- Increased vitamin K, folate (due to production by the bacteria)
- Decreased Vitamin ADE, B12, Iron, Zinc (due to malabsorption)
Acid stable = low infecting dose or high infecting dose?
acid stable = low infecting dose
the bugs are resistant to the stomach acid therefore only a few are needed to cause damage
Examples = Shigella dysenteriae, Entameba histolytica, Giardia lambila
Stool = Mucin + Sloughed off epithelial cells + No WBC/RBCs
Rice water stools found in Vibrio
1 year old + colicky abdominal pain + nausea/vomiting + currant jelly stools =
intussusception
Histology: microvesicular steatosis + small fat vacuoles in hepatocyte cytoplasm + no necrosis + child =
Reye syndrome
Histo: periductal granulomatous inflammation of the bile duct =
Primary biliary cirrhosis
Histo: hepatocyte ballooning, hepatocyte apoptosis (councilman bodies) + mononuclear inflammation =
viral hepatitis
carcinoid tumors are often found incidentally when removing what organ?
appendix
CREST Syndrome =
C = calcinosis R = raynaud phenomenon E = esophageal dysmotility (due to fibrous replacement of muscluaris layer) S = sclerodactyly T = telangiectasias
3 GI cancers that can present as “ulcers”
- Esophageal
- Gastric
- Colorectal
What immune cell is responsible for stimulating granuloma growth in Crohn’s disease =
Th1 Helper T cell
Ingesting a solution containing C-13 radiolabeled urea and then 30 minutes later collecting the radiolabled carbon you breathe out, is a test for?
H. Pylori infection
The bug makes urease. Urease turns urea into CO2 + NH3. The radiolabeled CO2 gets breathed out and can be measured.
Diphenoxylate
Mu opioid receptor agonist
Slows GI motility
Used as an anti-diarrheal agent
Treatments of C Difficile (3) and their indications
- Oral metronidazole - moderate cases
- Oral vancomycin - severe cases
- Oral fidaxomicin - recurrent cases, part of the macrolide family
Pleuroperitoneal membrane
Malformation of the development of the diaphragm
Presents with respiratory distress, absence of bowel sounds in the abdomen, hemithorax
Hyperplastic colonic polys are located mainly _
Rectosigmoid (Left) colon
Purple-red hemorrhagic findings inside of small intestine + severe acute abdominal pain
Acute mesenteric thrombosis -> acute mesenteric ischemia
Treatment for a woman with crampy abdominal pain + intermittent bloody diarrhea with mucous + diffuse ulcers seen on colonoscopy =
Sulfasalazine
Combination drug of sulfapyridine (antibacterial) + 5-aminosalicylic acid (anti-inflammatory)
First line for ulcerative colitis
3 week old infant + straw colored discharge from umbilicus =
persistent allantois (patent urachus)
Allantois VS Urachus VS Vitelline duct
Yolk sac becomes the ALLANTOIS which extends into the urogenital sinus.
ALLANTOIS becomes the URACHUS which acts as a duct between the fetal bladder and yolk sac.
VITELLINE DUCT is also known as the omphalo-mesenteric duct which connects the yolk sac to the midgut lumen
Onion skin bile duct + positive p-ANCA =
Primary sclerosing cholangitis
Removal of head and neck of pancreas + proximal duodenum + gallbladder =
Whipple procedure
CA 19-9 is a tumor marker for?
pancreatic carcinoma
marker for hepatocellular carcinoma =
increased alpha-fetoprotein (strikingly elevated)
only moderately elevated in chronic viral hepatitis
micronodular fatty change around the central vein =
alcoholic cirrhosis
lipase is specific for _ damage
pancreatic
IBD: granulomas
Crohn’s
IBD: neutrophils
UC
IBD: fistulas
Crohn’s
IBD: toxic megacolon
UC
IBD: Th1 mediated damage
Crohn’s
IBD: Th2 mediated damage
UC
IBD: Calcium oxalate stones
Crohn’s
IBD: +pANCA
UC
IBD: Transmural inflammation
Crohn’s
IBD: Mucosal inflammation
UC
IBD: Bloody diarrhea
UC
Thickened and leathery stomach wall =
Linitis plastica (Desmoplasia)
occurs in diffuse type stomach cancer
What cancer spreads to the left supraclavicular LN?
Gastric cancer (Adenocarcinoma)
Chronic H Pylori location =
antrum
Chronic autoimmune gastritis location =
body or fundus
Esophageal carcinoma/adenocarcinoma lymph node mets:
Upper 1/3 -> 1
Mid 1/3 -> 2
Lower 1/3 -> 2
Upper ⅓ -> cervical LN
Middle ⅓ -> mediastinal or tracheobronchial LN
Lower ⅓ -> celiac or gastric LN
mutation in the HFE gene leading to hemochromatosis mechanism =
- Reduced hepatocyte iron uptake - makes the liver thing there is an iron shortage
- Increases enterocyte iron uptake from the GI
- Decreases hepcidin synthesis (from the liver) to subsequently increase ferroportin
Parietal cells are found where?
Body of the stomach in the superficial gastric glands
Chief cells are found where?
Body of the stomach in the deep gastric glands
Medical therapy to manage cholesterol stones
Give the patient hydrophilic bile acids to solubilize the high concentration of cholesterol
High or Low infecting dose needed
Shigella
Campylobacter jejuni
Entamoeba histolytica
Giardia
LOW
These are all acid stable so only a small dose is needed to cause symptoms
High or Low infecting dose needed
Salmonella
Vibrio
C. perfringens
E. coli
HIGH
These are all acid labile therefore a high dose is needed to overcome the stomach acid and cause symptoms
“air in the billiary tree and high pitched bowel sounds”
gallstone ileus
What is found to be elevated in astrocytes during hepatic encephalopathy?
Glutamine
Hepatic encephalopathy -> hyperammonemia due to the liver being unable to break down nitrogen waste products
High levels of NH4+ travel through the BBB into the astrocytes -> turned into glutamine (NH4 + glutamate)
Very high levels of NH4+ make the cells swell and thus the glutamine is stuck inside
Perforation of a posterior duodenal ulcer results in the penetration _ artery
Gastroduodenal artery
Infant with drooling, choking, coughing with cyanosis when trying to feed =
Tracheo-esophageal fistula
the drooling is an important indicator.
Celiac artery is located at what vertebral level?
T12/L1
SMA is located at what vertebral level?
L1
IMA is located at what vertebral level?
L3
Increased concentration of CYP450 enzymes are located in which region of the liver?
Region III = peri-cenral vein/centri-lobular
gene mutation in Hirschsprung disease
RET oncogene mutation
Portal-Systemic Shunt - esophageal varices
L gastric vein -> Esophageal vein
Portal-Systemic Shunt - caput medusae
Paraumbilical vein -> Superficial and Inferior epigastric veins
Portal-Systemic Shunt - hemorrhoids/anorectal varices
Superior rectal vein -> Middle and Inferior rectal veins
How to distinguish between mucosal and pancreatic causes of malabsorption?
D-xylulose test
D-xylose is a monosaccharide therefore it does not need to be broken down any further by pancreatic enzymes
Absorbed = mucosa ok, must be a pancreatic problem causing malabsorption
Not absorbed = mucosa not ok, must be what is causing the malabsorption
Tubular or Villous adenoma polyp? Large, sessile, causes secretory diarrhea and bleeding
Villous - secrete a large amount of water mucus
Tubular = smaller, pedunculated
Gene mutation in systemic mastocytosis
KIT receptor tyrosine kinase -> clonal mast cell proliferation
Pathogenesis of alcohol-related hepatic steatosis
Decreased FFA oxidation therefore FFA build up in the hepatocytes
Caused by an increase in NADH/decrease in NAD
Pathogenesis of T. Cruzi causing megacolon, secondary achalasia and megaureter
Destruction of myenteric plexus therefore constriction and proximal dilation
What 3 structures are found in the hepatoduodenal ligament?
- Common bile duct
- Hepatic artery
- Hepatic portal vein
Where in the colon can this be found? Exophytic mass + iron deficiency anemia symptoms (fatigue) + weight loss + guaiac positive stool test
Right - ascending
Where in the colon can this be found? Infiltrating mass + colicky pain + abdominal distension + constipation
Left - descending
Colon cancer metastases to (2)
- liver
- lungs
Dietary _ exposure is associated with a transversion mutation (G:C -> T:A) in P53 gene
Aflatoxins from Aspergillus
Increases risk for hepatocellular carcinoma
Brown stones indicate an increase in A caused by B
A = increased unconjugated BR
B = infection with bacteria (E Coli) or helminth (Ascaris lumbricoides, Clonorchis sinensis)
Black stones indicate an increase in A caused by B
A = increased unconjugated BR B = chronic hemolytic anemia (sickle cell) or an increased production of UCBR caused by decreased bile salt recycling (Crohn's)
38 yo male with a new colonic mass + dad died of colon cancer at 40 yo + sister has endometrial cancer =
Lynch Syndrome
Mutation in mismatch repair genes MSH2, MLH1, MSH6, PMS2 (tumor suppressor genes)
Lipids are absorbed where in the GI tract?
Jejunum
Mechanism by which fibrates cause cholesterol stones?
Inhibit cholesterol 7-alpha hydroxylase -> decrease the synthesis of new bile acids
Two locations that secrete bicarbonate in the GI tract?
- Brunner glands - beginning of the duodenum, submucosal
- Pancreatic duct cells - secrete a bicarbonate rich, Cl poor fluid
Ultrasound shows signs of GB wall thickening + Radionuclide biliary scan showing no GB is diagnostic for =
Acute cholecystitis
Finding echogenic structures in the GB on ultrasound is suggestive but not diagnostic
Inciting event of appendicitis =
Obstruction of appendix lumen
Councilman bodies
Apoptotic hepatocytes seen in viral hepatits (HAV, HCV) and yellow fever
“Eosinophilic globule”
“Acidophilic bodies”
Sudan III stain finds _
Stains for fat in the stool
Normally there should be none
If there is a positive stain, it indicates fat malabsorption
Dilation of sinusoids and periventricular hemorrhage =
Budd Chiari Syndrome
Fibrosis and nodular parenchymal regeneration =
Cirrhosis
Can occur due to HBV/HCV hepatitis, chronic alcohol, hemochromatosis, non-alcoholic fatty liver disease
Patient with self-resolving jaundice every so often. Liver biopsy shows abundant pigment inclusions in the lysosomes of hepatocytes (polymers of epinephrine metabolites).
Dubin-Johnson Syndrome
- defective liver secretion of CBR
- grossly black liver due to pigment inclusions in lysosomes
- benign - only becomes evident in the context of a trigger/stressor
3 week old preterm infant + abdominal distension + blood streaked stools + on X ray shows curvilinear areas of lucency that parallel bowel wall lumen
Necrotizing enterocolitis
- Necrosis of bowel wall
- Pneumatosis intestinalis = free air in abdomen
- Poor prognosis
Liver tumor common with OCP that may regress if OCP are discontinued
Hepatic adenoma - epithelial tumor
Also seen with anabolic steroid use
Colonic biopsy of someone with untreated HIV: spindle shaped cells with surrounding blood vessel proliferation
Kaposi sarcoma
3 week old male + projectile nonbilious vomiting after every meal + visible peristalsis + olive-sized mass in the abdomen
Congenital pyloric stenosis
- Multifactorial inheritance
- Mass develops secondary to pyloric muscularis hypertrophy
Night time cough + elongation of lamina propria + symptoms resolve with PPI
GERD
Sexually transmitted hepatitis virus?
HBV
Rarely HCV, HDV
Primary biliary cirrhosis presenting symptoms
- Middle aged woman
- Fatigue
- Pruritis (at night)
- Jaundice
- Pale stools
- Xanthelasma
Pathophysiology of a direct inguinal hernia?
Weakness of the transversalis fascia
Administration of exogenous secretin can tell you what?
If gastrin levels increase/no change - then the elevated gastrin is coming from a gastrinoma
If gastrin levels decrease (normal physiologic response) - then the gastrin is coming from normal G cells
Crohn’s disease is associated with a mutation in A that results in decreased activity of B transcription factor causing C
A = NOD2 B = NF-kB C = reduced cytokine production
Erosions end in what layer?
Ulcers end in what layer?
Erosions - within the mucosal layer only
Ulcers - can extend to/through the submucosa or muscularis layer
Inciting event in hepatic encephalopathy?
Increased load of nitrogenous substances absorbed by the gut
Then, due to the fact that the damaged liver cannot metabolize them to harmless urea, the ammonia builds up and eventually makes it to the brain
Complication of acute pancreatitis?
Pancreatic pseudocyst - lined by granulation tissue and fibrosis
Indicators of poor prognosis of cirrhosis (3)
- Hypoalbuminemia
- Increased PT
- Increased BR
Shows a decrease in liver function, not just liver injury (increased transaminases)
Postprandial epigastric pain + food aversion + decreased bowel sounds + weight loss + history of atherosclerosis
Chronic mesenteric ischemia
