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78 Cards in this Set
- Front
- Back
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What is the first organ to receive a toxin after its absorbed from the GI tract?
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Liver
-Has enzymes to activate toxins |
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What are the 3 sources of blood supply to the liver?
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1) Portal
2) Hepatic artery 3) Umbilical in fetus |
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What are the 2 general steps of diagnosing hepatic toxicity?
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1) Determine that liver disease or failure is present
-Liver disease may be present w/o clinical signs until some liver functions fail 2) Look for toxins or other causes of liver damage |
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True or false. The liver is not essential for life.
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False, if remove the liver your dead in a few hours
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What are the 7 functions of the liver?
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1) Anabolism
-Gluconeogenesis -Protein 2) Catabolism -heme, fatty acid 3) Storage -Glycogen, fat, vitamins 4) Toxin removal 5) NH4---> urea (only in liver) 6) Compartmentalize enzymes 7) Secretion, BILE |
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What are 4 primary signs of liver disease in cattle?
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1) Weight loss
2) Ascites 3) Diarrhea 4) Tenesmus w/ prolapse |
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What are the 3 primary signs of liver disease in horses?
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1) Weight loss
2) Icterus 3) Behavioral change -Hepatic encephalopathy |
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Why can horses with liver disease have inspiratory dyspnea?
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From pharyngeal/laryngeal paralysis
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Why can horses with liver disease have dermatitis?
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-Bile acid in skin
-Photosensitization (don't excrete phylloerythrin) |
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How reliable are non-specific blood biochemical tests?
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Not reliable
-NOT CONSISTENT |
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What are 5 biochemical parameters that can be altered w/ liver disease?
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1) Low blood glucose
2) Elevated ammonia 3) Low BUN 4) Clotting time 5) Low serum albumin |
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What stage of liver disease do you see abnormal clotting times?
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LATE IN DISEASE
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What is the reserve capacity of the liver?
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80% reserve
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True or false. Liver disease results in low total proteins.
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False, low serum albumin but NOT low total protein
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What are the 4 types of liver derived enzymes that are measured for diagnostic tests?
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1) Gamma glutamyl transfersase (GGT)
2) Alkaline phosphatase 3) Dehydrogenases -LDH -SDH -GLDH 4) Aspartate amino transferase |
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What are 3 liver parameters measured to diagnose liver disease?
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1) Liver derived enzymes
2) Serum total bile acids 3) Excretion tests -Bilirubin -Sulfobromopthalene BSP |
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What information can you get from a liver biopsy?
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May suggest a specific cause of the liver damage
-could provide prognosis -could analyze tissue for toxin |
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True or false. Liver biopsies are a pretty risky procedure.
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False, not difficult, relatively safe
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When is the prognosis of liver disease poor? (4)
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1) Problems in clotting
2) Albumin low 3) GGT elevated but dehydrogenase low 4) BRIDGING FIBROSIS |
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What are 3 types of plants that are hepatic toxins?
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1) Pyrrolizidine alkaloid containing
2) Cocklebur, horserush, Kochia?? 3) Gossypol, blue green algae |
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What are 2 mycotoxins that are hepatic toxins?
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Aflatoxin & rubritoxin
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What are 3 chemicals that are hepatic toxins?
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1) CCl4
2) CS2 3) Iron in young |
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What is the toxin in cocklebur?
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A glycoside: carboxyatractyloside
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What part of the cocklebur plant contains the hepatic toxin?
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Seeds & cotyledons
-Toxic after dry |
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What is the lethal dose of cocklebur?
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1% of BW is lethal
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What are the signs of cocklebur toxicity? (3)
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1) Liver failure
2) Depression, ataxia, recumbence 3) Could die in 24-48 hours |
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What are the 3 postmortem lesions associated with cocklebur toxicity?
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1) Centrilobular hemorrhage & necrosis
2) Gastroenteritis 3) Hemorrhages |
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What is the source of gossypol?
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From cotton seed
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What is the toxin in gossypol?
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A polyphenolic pigment
-in pigment gland -Bound & free, free form is toxic |
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What is the horsebrush toxin?
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Tetradymol
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What does the horsebrush toxin cause? What animal is mostly affected?
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Causes liver damage
-sheep |
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What is the Lantana toxin?
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Polycyclic triterpene
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What animals are affected by the Lantana toxin?
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Ruminants
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What does the lantana toxin cause?
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Causes intra-hepatic cholestasis
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What is blue-green algae?
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A one celled algae
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Where do you find blue green algae? How does it grow?
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Rapid growth on surface of ponds & lakes
-"bloom" rises to surface -concentrated by wind |
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What are the 5 chemical toxins that cause hepatic toxicity in large animals?
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1) CCl4
-used by mad-scientists to produce liver damage 2) CS2 -Used in past to treat bots in horse 3) Coal tar pitch -swine eat 4) Iron in neonates 5) Cu, but more likely hemolytic crisis |
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What are the 4 components to treating chemical toxins that cause liver toxicosis?
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1) Remove toxin
2) Diet -BC amino acids -adequate energy 3) Control behavior 4) Maintain blood glucose |
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What is the source of iron toxicity in young animal?
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Available in many supplements
-Paste given to foals -injectable iron for baby pigs -injectable iron given off label to adults |
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What form of iron is more absorbed?
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Ferrous more than ferric
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What are the 5 circumstances of iron toxicity?
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1) Foals given supplement containing:
-"probiotic" -Iron 2) injected iron IM 3) Iron given IV to race horses 4) Children given excess iron supplement 5) ORAL IRON UNLIKELY TOXIC TO ADULTS -horses won't eat feed if iron content too high |
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Where is iron a absorbed?
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By intestine
-Rapid phase in duodenum, slow in ileum |
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What controls iron hemostasis?
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INTESTINAL ABSORPTION
-If deficiencies, absorption is 15 X base line |
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How is iron excreted?
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No effective method for excretion of Fe
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Where is absorbed iron stored?
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Stored as ferritin in enterocyte
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How is absorbed iron lost in the system?
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Lost as enterocyte is sloughed
-Prevents further absorption |
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Iron circulates bound to _______ in the plasma.
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Transferrin
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Iron is stored in the body as ______ or _______.
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Ferritin or hemosiderin
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70% of iron in the body is in __________.
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Hemoglobin
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5% of iron is in ________.
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Myoglobin
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____% of iron is stored as ferritin & hemosiderin.
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25%
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<0.5% of iron in tissue _____ and plasma.
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enzymes
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When is the toxic dose of iron low?
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When given to animals before gut closure
-iron absorbed w/ other large molecules |
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What type of a toxin is iron?
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A protoplasmic toxin
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What is the mode of action of iron toxicity?
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-Iron induced lipid peroxidation---> organelle dysfunction & mitochondrial death
-free radical production |
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What are the 4 types of liver damage caused by iron toxicity?
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1) Periportal necrosis
2) Fibrosis 3) Inflammatory cell infiltration 4) Cholestasis |
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What are the 4 clinical signs of iron toxicity?
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1) Depression
2) Failure to gain 3) Icterus 4) Behavioral change |
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What clinical sign is specific for iron toxicity from oral intake?
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Necrosis of GI mucosa--> diarrhea, hemorrhagic
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What causes death if animals intake a massive single dose of iron?
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Cardio-vascular collapse
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What 3 diagnostic tests are available to diagnose iron toxicity?
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1) Serum ferritin
2) Saturation of total iron binding capacity i.e. % of transferrin bound w/ iron |
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Why do we test for serum ferritin instead of serum iron?
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Serum iron= <.5%=not good indicator for total Fe
-most serum ion in transferrin, mot free |
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What are the 4 components of treating iron toxicity?
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1) Precipitate iron in GI tract
-sulfates, e.g. MgSO4, Mg2+ 2) Control acidosis, fluids 3) Chelation -Deferoxamine -ascorbic acid 4) Bleeding |
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What produces aflatoxin and rubratoxin?
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Mycotoxins produced by Aspergillus flavus & A. parasiticus
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What does aspergillus species grow in?
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Feed grain
-corn, milo, cottonseed, peanuts |
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What conditions promote aspergillus growth?
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78-90 F
High humidity |
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What are the 4 types of aflatoxin?
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B1, B2, B3, B4
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Where are aflatoxins metabolized?
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Liver
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What are the signs of aflatoxicosis present in all animals?
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Liver failure
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What are the 4 clinical signs of aflatoxicosis specific to swine?
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1) Anorexia
2) Slow growth 3) Icterus 4) Ascites |
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What are the 3 clinical signs specific to cattle aflatoxicosis?
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1) Rumen atony
2) Anorexia 3) Decreased milk -unless very high dose |
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What is the pathophysiology of aflatoxicosis? (3)
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1) Metabolized by liver, MFOs convert to 7+ metabolites
-1= reactive epoxide -Combines w/ DNA, RNA & protein 2) Inhibits protein synthesis -binding w/ guanine in DNA -Prevents mRNA from being formed 3) Interferes w/ transcription |
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Compare the susceptibility of ruminants, monogastric or poultry to aflatoxicosis.
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Ruminants less susceptible than monogastric & poultry
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Are young or old animals more susceptible to aflatoxicosis?
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Young
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What is the toxic dose of aflatoxins?
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100-750 ppb
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What are 3 diagnostic tests for aflatoxins?
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1) In milk & urine for several days
2) Some retained in liver 3) UV light on grain for fungus |
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What are the 4 post mortem findings of aflatoxicosis?
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1) Pale soft liver, icterus
2) Centrilobular hemorrhage 3) Hepatic necrosis 4) Bile duct proliferation |
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What are the 3 components of treating aflatoxicosis?
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1) Detoxify before absorbed
-hydrated Na, Ca aluminosilicate 2) Support -vit E, Se?? 3) Diet for liver |
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What are 3 ways to prevent aflatoxicosis?
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1) Mold inhibitors
2) Lower moisture on grain 3) Anhydrous ammonia on grain -not approved by FDA in US |
