Tox Exam 2 Metals and Minerals Flashcards
What species are resistant to copper toxicity?
swine and poultry
Acute copper toxicosis causes what clinical signs?
V+, colic, bloody D+, dehydration, shock
Tx of acute copper toxicosis?
supportive, symptomatic
T/F Acute copper toxicosis is more common than chronic copper toxicosis.
FALSE
Causes of chronic copper toxicosis?
excess copper, molybdenum deficiency, or BOTH
also unavailability of sulfate
Normal copper:molybdenum ratio?
6:1
Accumulation of copper requires about ______ weeks exposure in sheep.
2-10 weeks
Cause of secondary copper toxicosis?
liver damage may cause copper accumulation by hepatocytes
What causes a sudden loss of copper from liver to blood?
stress
MOA in chronic copper toxicosis?
Cu accumulation in liver causes liver degeneration and necrosis. Release of Cu from liver and excess Cu in blood causes oxidation of erythrocyte membranes, increasing their fragility–hemolytic crisis! Also Cu in blood causes oxidation of hemoglobin to methemoglobin.
T/F Methemoglobin is unable to efficiently carry oxygen.
TRUE
Which organ is responsible for removing excess copper from blood?
liver
Main mechanism that Cu is removed from the body?
bile
Main mechanism that copper molybdate (CuMoO4) is removed from the body?
urine
Clinical signs of chronic copper toxicosis?
sudden onset of weakness, anorexia, pale MM, icterus, hemoglobinuria, fever, dyspnea, shock.
Characteristic lesions of liver due to chronic copper toxicosis?
enlarged, yellow, friable
Characteristic lesions of kidneys due to chronic copper toxicosis?
enlarged, hemorrhagic, bluish-black, friable–“gun metal kidneys”
Characteristic lesions of spleen due to chronic copper toxicosis?
enlarged, dark brown to black—“blackberry jam spleen”
Preferred specimens for chronic copper toxicosis?
blood or serum
elevated Cu, liver enzymes AST, LDH (3-6 wks prior to hemolytic crisis)
Differential diagnosis for chronic copper toxicosis?
hemolytic agents—zinc, naphthalene, DMSO, guaifenesin
poisonous plants—onion, gossypol (cottonseed), red maple (equine only)
infectious dz—lepto, babesia, anaplasma, bacillary hemoglobinuria
certain snake venoms
Treatment for chronic copper toxicosis?
Ammonium tetrathiomolybate or D-penicillamine
Dog breed susceptibilities for chronic copper toxicosis?
mainly Bedlington terrier (autosomal recessive) @ 2-6 yrs, West Highlands, Skye terriers, Dobermans
Prevention of chronic copper toxicosis?
molybdenized copper phosphate sprayed on pastures, supplemental zinc reduces hepatic Cu accumulation, add molybdate to sheep rations, ammonium molybdate and thiosulfate orally daily for individual sheep
States where soil is rich in molybdenum?
Florida, California, Oregon and Nevada
T/F plants accumulate molybdenum from soil
TRUE
T/F Molybdenum deficiency causes copper deficiency.
FALSE. EXCESS molybdenum causes copper deficiency. Elevated molybdenum interferes with copper absorption.
Sources of molybdenum?
plants, soil, industrial contamination–brick plants and steel mills, molybdenum containing fertilizers
T/F Copper deficiency causes molybdenum toxicosis.
TRUE. also copper deficiency can lead to anemia, loss of pigmentation, demyelination, etc.
What species is the most susceptible to molybdenum toxicosis?
cattle. toxicosis also seen in sheep.
What species are resistant to molybdenum toxicosis?
horses and pigs
High levels of dietary _____ increase molybdenum toxicity.
sulfate
High levels of dietary _____ decrease molybdenum toxicity.
copper
Excretion of molybdenum?
in milk in toxic levels
Clinical signs of molybdenum toxicosis?
severe D+ (greenish w/ gas bubbles)–NOT hemorrhagic 8-10 days following exposure, rough hair coat and depigmentation of hair, loss of weight, anemia, osteoporosis, lameness, pica, decreased libido in bulls and infertility in cows
Main location of depigmentation of hair in molybdenum toxicosis?
around the eyes
Best specimen for dx of molybdenum toxicity?
blood. elevated molybdenum, decreased copper, decreased cytochrome oxidase activity.
Differential diagnosis for molybdenum toxicity?
selenium toxicity
Treatment of molybdenum toxicity?
copper glycinate SC or copper sulfate added to diet