GI Ettinger Flashcards
Which cell in the stomach makes intrinsic factor?
Parietal cells
What are the 3 major components of acid secretion?
Histamine, Gastrin, ACh
Which hormone is responsible for decreasing gastrin, histamine, and acid secretion when stomach pH
Somatostatin
What are the components of the gastric mucosal barrier?
§ Tightly opposed epithelial cells § Bicarbonate rich mucous § Abundant mucosal blood supply § Prostaglandins (PGE2) are important in modulating · Blood flow · Bicarbonate secretion · Epithelial cell renewal
What factors slow emptying of stomach?
Carbs, AA, fats
Release of CCK in response to FA and AA
What are the 3 major digestive enzymes in the stomach?
Pepsin (releases as pepsinogen in response to ACh and histamine) Gastric lipase (in response to pentagastrin, histamine, PGE2, and secretin, active in SI) Intrinsic factor (dogs)
Which breeds get hypertrophic gastropathy?
Basenji, small breed dogs (shih Tzu)
Which breed gets atophic gastritis?
Lundehund
What can stoamtocytosis tell you on a CBC?
Stomatocytosis has been described in Drentse Patrijshond dogs with familial stomatocytosis-hypertrophic gastritis
What are causes of metabolic alkalosis?
· Metabolic alkalosis
o Associated with pyloric/duodenal outflow obstruction
o Associated with parvo and pancreatitis
o Gastrinomas
§ Also associated with aciduria
§ hypoCl/K due to gastric acid hypersecretion
Conservation of volume at expense of pH (renal reabsorb HCO3 and exchange Na for H+ = promotes acidic urine (paradoxical aciduria)
What breed when given IV secretin will have a high gastrin level w/o a gastrinoma?
Basenjis (with enteropathies)
What gastric tumors are found in these locations? Pyloric antrum, cardia, diffuse
§ Pyloric antrum · Adenocarcinoma (lesser curvature also) § Cardia · Leiomyoma § Diffuse · LSA
What is the most common site of an adenomatous polyp?
Pyloric antrum
Which breeds are predisposed to PLE?
SCWT, Yorkie, Basenji, Lundehund, Shar-Pei
What AA def can results in high ammonia in cats?
Arginine def
Which coag factor is NOT made by the liver?
Factor VIII
What defines DIC?
Prolonged PT/PTT Decreases fibrinogen thrombocytopenia increased FDPs (all of which can be seen with liver dz too)
What is the most toxic bile acid?
Lithocholic acid
How can diuretics exacerbate HE?
Alkalosis and HypoK!!!
What tropic factors are important for hepatic growth?
Insulin and Glucagon (from portal blood)
What is the toxin in cycad?
Cycasin (converted to MAM (methylazoxymethanol) by GI microbes) and unnamed neuro toxin
What is the MOA of cycad toxin?
Cycasin: MAM results in GI, hepatotoxin, neurotoxin
MAM alkylates DNA/RNA
What are the target organs of cycad toxin?
Cycasin: LIVER, GI, Neuro
What is the clinical presentation of cycad toxin?
Cycasin: within 24 hrs (GI signs and neuro signs)
What are the main clin path signs of cycad toxin?
50-60% increased transaminases
30-50% increased bili
50% increased PT/PTT
30% decreased platelets
What are the histopath features of cycad toxin?
Cycasin: MIXED
Acute: Centrilobular necrosis and neutrophilic inflammation
Chronic: LP inflammation, fibrosis, biliary hyperplasia
What is the definitive test for cycad toxin?
None, hx of eating plant = Look for plant in vomit
What antidotes are recommended for cycad toxin?
Charcoal! Shown to be protective!!!!
What is the prognosis for cycad toxin?
Cycasin: Guarded - 30-50% mortality
What are the known prognostic indicators for cycad toxin?
Higher ALT, T bili, lower albumin (at presentation), prolonged coag = NONSURVIVORS
Early charcoal admin was PROTECTIVE!!
What is the toxin in amanita?
Alpha-amanitin (1 cap can kill!)
What is the MOA of amanita?
Alpha-amanitin: Inhibits RNA polymerase II (no transcription or protein synthesis)
Apoptosis of hepatocytes
Insulin Release
What are the target tissues of amanita?
LIVER
Intestines (crypts)
Kidneys (prox tubules)
What is the onset of CS with amanita?
GI phase: 6-12 hrs - Severe gastroenteritis
Recovery: 12-24 hrs
HEPATIC FAILURE: 36-48 hrs
Fulminate liver and kidney failure
What are the clin path changes with amanita?
Hypoglycemia (releases insulin)
Coagulopathy
Azotemia
Increased AST, ALT, ALP, bili
What are the histopath findings with amanita?
Pan-lobular hepatocellular necrosis
Acute tubular necrosis
How do you make a definitive diagnosis of amanita?
LC/MS or ELISA for alpha-amanitin (toxin)
Early in urine or in vomit (also see mushrooms)
Later kidney or liver
What is the antidote for amanita?
Silibinin has helped!!!
Charcoal (if early)
What is the prognosis for amanita in dogs?
Poor
50% mortality in dogs
What is the toxin in cyanobacteria?
Microcysts aeruginosa (blue green algae) = Microcystins
What is the MOA in cyanobacteria toxin?
Microcystins: Inhibit serine-threonine phosphatases = Build up of phosphorylated proteins = Necrosis = Apoptosis = Massive HEMORRHAGE
What are the target organs of cyanobacteria?
Microcystins: Liver, Kidney (prox tub) and Neuro (anabaena)
What is the presentations of cyanobacteria?
Microcystins: ACUTE (hours) - GI, respiratory, liver, tremors, seizures, comas
What are the clin path findings with cyanobacteria?
Increased ALP, GGT, bili
Marked increased in ALT (can be less if microcystoin inhibits tansminase synthesis??)
What is the histopath finding for cyanobacteria?
Hepatic necrosis - MASSIVE hemorrhage
Acute renal tubular necrosis
How is a definitive diagnosis of cyanobacteria made?
ELISA (confirmed with LC/MS) or MMPB method to detect all forms of toxin)
Best in vomit!!!, can check water source too
Liver (toxin level)
What is the antidote for cyanobacteria?
NONE
Rifampin in mice/rats can inhibit uptake
What is the prognosis for cyanobacteria?
GRAVE
What is the toxin with aflatoxin?
Aspergillus = Aflatoxin B1 converted to AFB1 8,9 epoxide
esp dogs and poultry
What is the MOA of aflatoxin?
P450 converts to AFB1 8,9 epoxide
Inhibits RNA polymerase
Bind to mitochondrial DNA
Depletes GSH
What are the target tissues of aflatoxin?
Liver
Kidney (prox tubules) - CASTS before azotemia
What is the CS onset of aflatoxin?
Highly variable, most are chronic (>1 month of eating food)
What are the clin path findings with aflatoxin?
Increased LEs, icterus, low cholesterol, decreased AT and protein C
What are the histopath findings with aflatoxin?
Acute: Centrilobular necrosis Diffuse hepatocyte lipid vacuolization
Chronic: MIXED
How do you make a definitive diagnosis of aflatoxin?
ELISA, HPLC, LC/MS for toxin AFB1 in food source (>60 ppb)
Serum, liver, urine = Alfatoxin M1
What is the antidote for aflatoxin?
Replenish GSH (N-acetylcysteine or SAMe) Sulfhydryl groups may bind AFB1 8,9 epoxide too
What is the prognosis for aflatoxin?
Guarded, 60% mortality
What are the prognostic indicators for aflatoxin?
100% predictive of death = CASTS
Longer PT/PTT, decreased AT, decreased protein C, increased bili, decreased albumin and cholesterol = Risk factors for mortality
What is the MOA of xylitol?
Rapid, severe increased in insulin from Beta cells (6X more than glucose)!!
Hepatic depletion of ALP (from metabolism via pentose phosphate pathway)
What are the target organs of xylitol?
LIVER (>0.5 g/kg) Beta cells (>0.1 g/kg)
What are the clinical presentation with xylitol?
30 min-1 hrs - Hypoglycemia
9-72 hrs = Acute hepatic failure
What are the clin path findings with xylitol?
Marked increased ALT, bili
Hypoglycemia
Coagulopathy
HypoK, HypoPhos
What is the histopath findings with xylitol?
Periacinar-mid zonal necrosis
What is the definitive diagnosis of xylitol?
HX, no tests for it
What is the antidote for xylitol?
Early emesis, SAMe, dextrose
Charcoal DOES NOT bind it
What is the prognosis for xylitol?
Good if early, guarded if prolonged hypoglycemia and LEs increased
What is a prognostic indicator for xylitol?
Hyperphosphatemia - Poor prognosis
What is the MOA of carprofen?
Idiosyncratic cytotoxic hepatocellular reaction (maybe IM) - Labs?