Exam 3 Flashcards
(93 cards)
Copper
- Essential trace element
- Some areas in PNW are deficient
- Commonly employed feed additive
Dietary Imbalance & Copper
o Cu to Mo (Molybdenum) ratio out of whack (too little Mo & too much Cu)
o Should be 6pt Cu to 1pt Mo
o Molybdenum & sulfur slow absorption of Cu & enhance excretion in bile
o Often comes from feeding sheep feed mineral mixes made for cow, pig, pultry
Sources of Copper Toxicity in Small Animals
Ingestion of coins
o Very very slow absorption into liver
o Recurring bouts of hepatitis
o usually no hepatocellular necrosis
If pre-existing liver issues, Cu can’t get excreted
Animal Effected by Cu Toxicity
Most sensitive:
o Sheep > pre-ruminant calves, goats, llamas, alpacas
Not common
o Young, small, companion animals-exotics
2 Classifications of Cu Toxicity
Primary
• Too much copper not enough Mo
• Group animal
Secondary
• Pre existing liver issue
• 1 animal
Cu Toxicity Mechanism of Action
o Chronic oral exposure o Absorption dependent on form o Excess Cu stored in liver & lysosomes o Cu excreted in bile o Cu/Mo/S excreted in urine o Liver reaches storage capacity + stress -> hepatocellular necrosis -> elevated serum Cu -> hemolysis
Clinical Signs of Cu Toxicity
Clinical Signs o Abrupt onset o Weakness o Abdominal pain o Dysphagia o Teeth grinding o Lethargy o Icterus o Red/brown urine o Production loss
Clinical Pathology & Histopathology of Cu Toxicity
Clin Path o Increased GGT & AST o Anemia o Hemoglobinemia/uria o Hyperbilirubinemia/uria o methemoglobinemia
Histopath
o Hepatic necrosis of varying patterns
o Pigment in hepatocytes & kupffer cells
o Acute renal tubule degeneration & necrosis
o Hemoglobin casts in urine due to hypoxia & hemolysis
o no lesions = NO Cu toxicity
Diagnosis of Cu Toxicity
o Look for GI, liver, hemolysis, & kidney signs
o Check liver enzymes,
o biopsy of liver & kidney for histo**
o NO serum Cu
Treatment for Cu Toxicity
o Guarded/poor prognosis
o Fluids, blood transfusion
o Liver protectants; SAMe, milk thistle, n-acetylcysteine
o Enhance Cu excretion by increasing Mo & S
o Zinc, iron, selenium
o Chelators to decrease burden; D-penicillamine, tetrathiomolybdate
o NO AC
Copper Storage Dz; Baiscs, Diagnosis, Treatment
o Chronic accumulation
o Not excessive in diet
o Autosomal recessive – Bedlington terrier & West Highland white terriers
o Others affected - Dobermans, Skyeterriers, Labradors, mixed, lots others
o Chronic bouts of intermittent hepatitis
Diagnosis
• Antemortem liver biopsy & histology
Treatment
• Penicillamine (chelator–reduces body burden)
• zinc acetate (reduces absorption long term)
• trientine
• tetrathiomolybdate
Mycotoxin
o Produced by fungi/mold
o When mold grows it produces toxin
o Not all moldy feed contains mycotoxins, not all feed w/ mycotoxins are moldy and/or toxic
Aflatoxin Basics & Mechanism
o Aspergillus
o B1 & M1
o Found in corn, cottonseed, grain
o Affects cows, swine, poultry, pets
Mechanism • Acute or chronic HEPATOTOXIC • Immunosuppressive • Nephrotoxic • Mutagenic • Carcinogenic
Aflatoxin Acute & Chronic Clinical Signs
Acute • LIVER • Vomiting • Lethargy • Anorexia • Weakness / abdominal pain • Icterus • Petechiation • Ascites
Chronic • Not common • Drop body weight • Unthriftiness • Drop in production • Poor fertility • Increase incidence of disease • 2° photosensitization
Aflatoxin Clinical Pathology & Diagnosis
Clinical Pathology • LIVER • Increased ALT, AST • Increased bile acids • Hyperbilirubinemia/uria • Decreased cholesterol, albumin, protein C • Increased PT, PTT • Isosthenuria
Diagnosis
• Analyze liver, kidney, lung for aflatoxin (difficult)
• Chromatography of feed
• Need representative sample of feed
Aflatoxin Treatment
• Guarded prognosis
Small Animal
• Liver protectants; SAMe, milk thistle, N-acetylcysteine
• Ursodiol, steroids, transfusion, etc
Large Animal
• Not cost effective to treat
• Use aluminosilicates binders on feed to get rid of contamination
Cyanobacteria Basics & Toxicity
- Blue-green algae
- Target liver & CNS
- Mostly in freshwater w/ decreased O2 & increased Phosphorous, nitrates, sulfates
Toxicity o All species susceptible o Microcystin, nodularin, cylindrospermopsin cause necrosis & hemorrhage of liver o Cylindrospermopsin also affects kidney o Results in DIC
Cyanobacteria Clinical Signs & Pathology
Clinical Signs o LIVER o Acute onset (1-4hrs) o V & D & Abdominal pain o Weakness o Anorexia o Petechiation o Edema o DIC
Clinical Pathology
o Increased ALT, bile acids, bilirubenemia/uria
o Prolonged PT & PTT
o Low albumin, protein, BUN, cholesterol
Cyanobacteria Lesions & Diagnosis
Lesions
o Enlarged & necrotic live
Diagnosis o Exposure to stagnant water o Liver signs o ID of algae o Toxin analysis of water
Cyanobacteria Treatment
Asymptomatic
• Decontaminate if very early
• Cholestyramine
Symptomatic • Corticosteroids • Fuids • Transfusion • Liver protectants, SAMe, milk thistle, n-acetylcysteine • Cholestyramine
Iron Toxicosis Basics
- Poisoning uncommon
- Soluble or ferris iron most important
- Different amounts of elemental iron
- Different bioavailability
- Estimate: 5-15% ingested gets absorbed
- Well documented toxic doses of elemental iron
Sources of Iron
o Iron, vitamin/mineral supplements o Fertilizers o Blood meal o Moss repellants o Molluscicide o Body-hand-feet warmers o Desiccant packs o Birth control pills o Foreign bodies
Mechansims of Action of Iron Toxicity
o Oral
o Absorbed by intestinal cells
o Cells damaged and sloughed off
OR if acute overwhelm of Fe ->
o Fe goes systemically o No efficient way to excrete Fe o Transferrin circulates Fe o Stored as Ferritin or hemosiderin o Systemically affects LIVER, vascular, cardiac
Clinical Signs of Iron Toxicity
o Acute
o No V in 8-12hrs = OK!
o V, D, lethargy, anorexia, abdominal pain
After apparent recovery from initial GI signs
• @ 12-96hrs
• GI signs re-appear
• petechiation, ecchymosis, effusions, tachypnea, shock