Tox Exam 2 Metals and Minerals Flashcards
(96 cards)
1
Q
What species are resistant to copper toxicity?
A
swine and poultry
2
Q
Acute copper toxicosis causes what clinical signs?
A
V+, colic, bloody D+, dehydration, shock
3
Q
Tx of acute copper toxicosis?
A
supportive, symptomatic
4
Q
T/F Acute copper toxicosis is more common than chronic copper toxicosis.
A
FALSE
5
Q
Causes of chronic copper toxicosis?
A
excess copper, molybdenum deficiency, or BOTH
also unavailability of sulfate
6
Q
Normal copper:molybdenum ratio?
A
6:1
7
Q
Accumulation of copper requires about ______ weeks exposure in sheep.
A
2-10 weeks
8
Q
Cause of secondary copper toxicosis?
A
liver damage may cause copper accumulation by hepatocytes
9
Q
What causes a sudden loss of copper from liver to blood?
A
stress
10
Q
MOA in chronic copper toxicosis?
A
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.
11
Q
T/F Methemoglobin is unable to efficiently carry oxygen.
A
TRUE
12
Q
Which organ is responsible for removing excess copper from blood?
A
liver
13
Q
Main mechanism that Cu is removed from the body?
A
bile
14
Q
Main mechanism that copper molybdate (CuMoO4) is removed from the body?
A
urine
15
Q
Clinical signs of chronic copper toxicosis?
A
sudden onset of weakness, anorexia, pale MM, icterus, hemoglobinuria, fever, dyspnea, shock.
16
Q
Characteristic lesions of liver due to chronic copper toxicosis?
A
enlarged, yellow, friable
17
Q
Characteristic lesions of kidneys due to chronic copper toxicosis?
A
enlarged, hemorrhagic, bluish-black, friable–“gun metal kidneys”
18
Q
Characteristic lesions of spleen due to chronic copper toxicosis?
A
enlarged, dark brown to black—“blackberry jam spleen”
19
Q
Preferred specimens for chronic copper toxicosis?
A
blood or serum
elevated Cu, liver enzymes AST, LDH (3-6 wks prior to hemolytic crisis)
20
Q
Differential diagnosis for chronic copper toxicosis?
A
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
21
Q
Treatment for chronic copper toxicosis?
A
Ammonium tetrathiomolybate or D-penicillamine
22
Q
Dog breed susceptibilities for chronic copper toxicosis?
A
mainly Bedlington terrier (autosomal recessive) @ 2-6 yrs, West Highlands, Skye terriers, Dobermans
23
Q
Prevention of chronic copper toxicosis?
A
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
24
Q
States where soil is rich in molybdenum?
A
Florida, California, Oregon and Nevada
25
T/F plants accumulate molybdenum from soil
TRUE
26
T/F Molybdenum deficiency causes copper deficiency.
FALSE. EXCESS molybdenum causes copper deficiency. Elevated molybdenum interferes with copper absorption.
27
Sources of molybdenum?
plants, soil, industrial contamination--brick plants and steel mills, molybdenum containing fertilizers
28
T/F Copper deficiency causes molybdenum toxicosis.
TRUE. also copper deficiency can lead to anemia, loss of pigmentation, demyelination, etc.
29
What species is the most susceptible to molybdenum toxicosis?
cattle. toxicosis also seen in sheep.
30
What species are resistant to molybdenum toxicosis?
horses and pigs
31
High levels of dietary _____ increase molybdenum toxicity.
sulfate
32
High levels of dietary _____ decrease molybdenum toxicity.
copper
33
Excretion of molybdenum?
in milk in toxic levels
34
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
35
Main location of depigmentation of hair in molybdenum toxicosis?
around the eyes
36
Best specimen for dx of molybdenum toxicity?
blood. elevated molybdenum, decreased copper, decreased cytochrome oxidase activity.
37
Differential diagnosis for molybdenum toxicity?
selenium toxicity
38
Treatment of molybdenum toxicity?
copper glycinate SC or copper sulfate added to diet
39
MOA of copper deficiency due to molybdenum toxicity?
Cu involved in hematopoeisis, CT metabolism, myelin formation in newborns, pigmentation and bone formation. Cu is a component in essential enzymes such as cytochrome oxidase and aromatic amino acid metabolizing enzymes---tyrosinase, dopamine hydroxylase, MAO. Cu containing proteins (cupreins) in most aerobic cells have superoxide dismutase activity.
40
Other names for selenium deficiency disease?
White muscle disease (WMD) or nutritional muscle dystrophy (NMD) in lambs, calves and foals. Hepatosis dietetica in young pigs, porcine stress syndrome in pigs, exudative diathesis in chicks, nutritional pancreatic atrophy in chickens!
41
Regions with soil deficient in selenium?
northwest, northeast, southeast, great lakes, st kitts
42
States with soil rich in selenium?
N. and S. Dakota, Wyoming, Montana, Nebraska, Kansas, Utah, Colorado, New Mexico
43
Selenium uses?
Feed supplements for cattle, sheep, swine, poultry. Injectable selenium-vit E preparations. Used in medicated shampoos for treatment of dermatitis. Antioxidant supplements for animals and humans.
44
Selenium sources?
graze seleniferous plants---cattle, sheep, horse
eat grains grown on Se-rich soils--pigs, poultry
Se contaminated water---waterfowl
improper use of Se shampoos (SA) or supplements/preparations
45
T/F Selenium contaminated water is carcinogenic in waterfowl.
FALSE---teratogenic
46
What are the 3 oxidation states of selenium?
selenate (+6), selenite (4+), selenide (-2)
47
Name 2 elements that are irritants to mucous membranes.
selenium and arsenic... many more!
48
T/F Selenium toxicity is increased by a high protein diet and Cu.
FALSE. toxicity is decreased!
49
Ranking of the different selenium states' toxicities.
organic Se in plants > selenate = selenite > selenide > synthetic organoselenium compounds
50
T/F Seleniferous plants have a bad odor and are unpalatable--only eaten when other forage is unavailable.
TRUE!
51
ADME of selenium?
A=readily from SI, soluble organic plant Se more easily abs than selenite, selenate, selenide--elemental Se not absorbed bc insoluble in water
D=throughout body--particularly to liver, kidney, spleen--crosses placenta!
E=in milk, mainly in urine, also bile
52
Chronic exposure of selenium increased concentrations in _____.
hoof and hair
53
T/F Selenium crosses placenta but has no negative effects on the fetus.
FALSE--teratogenic!!
54
What element increases biliary excretion of selenium?
arsenic!
55
Chemical properties of selenium?
Se combines with SH group of glutathione and is a component of glutathione peroxidase. it acts as an antioxidant by prevention of peroxide accumulation through reduction of glutathione. Vit E is synergistic to glutathione peroxidase---Sel/vit E deficiency prevents cellular membrane and cell degeneration in animals.
Se also found in 5-deiodinase (converts T4-T3)
56
MOA of selenium toxicosis?
irritate GI mucosa, dramatic decrease in tissue glutathione and tissue ascorbic acid, decreased ATP.
Se replaces sulfur in amino acids causing abnormal proteins.
57
What are the forms of selenium toxicosis?
acute, subacute, chronic
58
Clinical signs of acute selenium toxicosis?
oral-->
GI: colic, bloat, dark watery D+
Resp: labored resp w/ fluid sounds in lungs, bloody from nares, cyanosis
Other: fever polyuria, mydriasis, uncertain gait
parenteral-->neuro signs including mydriasis and incoordination
death=d/t resp insufficiency from pulmonary edema/hemorrhage
59
Clinical signs of subacute selenium toxicosis?
cattle-->"blind staggers"
stage 1: poor appetite, aimless wandering, circling, walking into objects, normal resp and temp
stage 2: stage 1 signs + depression, incoordination, foreleg weakness, walking on knees, anorexia
stage 3: colic, hypothermia, emaciation, clouded corneas near blindness, paresis, coma, death in hrs
sheep--> similar to cattle but stages not well defined
swine-->"porcine focal symmetrical poliomyelomalacia", incoordiation, lameness, paralysis, alopecia, hoof abnormalities, separation of hoof
death=d/t resp insufficiency from pulmonary edema/hemorrhage
60
Clinical signs of chronic selenium toxicosis?
rough hair coat, loss of hair from mane and tail, hoof deformaties and sloughing, stiffness of joints, lameness, partial blindness, anemia, lethargy, emaciation, infertility, birth defects
death= d/t starvation or thirst from weakness, lameness, blindness
61
Pathology of acute selenium toxicosis?
hemorrhagic gastroenteritis, congestion of organs, hemorrhages, pulmonary edema, hydrothorax
gut contents may smell like rotten garlic/horseradish (hydrogen selenide)
62
Pathology of subacute selenium toxicosis?
swine--focal symmetrical poliomyelomalacia
63
Pathology of chronic selenium toxicosis?
abnormal hooves, cardiac damage, hepatic necrosis
64
Treatment of acute selenium toxicosis?
saline cathartics
symptomatic--> O2, tx pulmonary edema, circulatory shock, gastroenteritis
acetylcysteine
65
Prognosis of selenium toxicosis?
poor in acute toxicosis bc animals die quickly
66
Prevention of selenium toxicosis?
soil/forage should be tested regularly for Se levels, remove animals from seleniferous areas, adding Cu to diet, high protein diet, increased sulfur containing proteins may reduce tox, addition of organic arsenicals to diet to increase biliary excretion
67
Diagnosis of selenium toxicosis?
specimens-->blood, kidney, liver in acute; hair, hoof in chronic
blood-->increased Se, blood/plasma glutathione peroxidase activity correlates w/ blood Se concentrations in cattle, sheep, swine but NOT HORSES!!
68
Differential diagnosis of selenium toxicosis?
acute, subacute-->pneumonia, infectious hepatitis, enterotoxemia, pasteurellosis
chronic-->molybdenum tox, fluoride tox, freezing, ergotism, laminitis
69
Is lead degraded in the environment?
NOT degraded in environment, also NOT easily metabolized
70
______ conditions favor dissolution of lead.
acidic
71
What percentage of iron is absorbed from the GIT?
only 1-2% bc it forms insoluble compounds
72
What species are most susceptible to lead poisoning?
cattle, horses, pets, waterfowl, wild birds
73
What species are more resistant to lead poisoning?
goats, swine, chickens
74
______ are more frequently poisoned d/t indiscriminate eating habits.
puppies
| more sensitive than adults d/t increased abs and crosses BBB more readily
75
ADME of lead?
A=oral abs poor, using same carrier protein as calcium
D=98-99% bound to RBCs, throughout body, crosses BBB and placenta
E=slowly mainly in urine, small amount bile, in milk at toxic levels
76
T/F Absorption of lead is increased by an acidic environment.
TRUE
77
Absorption is greater in adults or young?
young
78
What factors decrease absorption of lead?
calcium, zinc, protein
79
Deficiency in these factors increases the absorption of lead.
calcium, zinc, iron, vit D
80
Sources of lead toxicosis?
most common source is lead-based paints (before 1977), paint, batteries, plumbing solder, putty, galvanized wire, lead shots, lead weights, fishing sinkers, leaded materials in refuse piles, linoleum, imported ceramics and pottery, contaminated pastures from industry
81
Clinical signs of lead toxicosis?
GI-->anorexia, +/- salivation, V+, lead colic, D+ or constipation, rumen atony, rare megaesophagus in SA
CNS-->anxiety, hyper excitability, vocalize, head pressing, circling, running, maniacal behavior, seizures, tremors, blindness, pharyngeal paralysis, roaring (horses), CNS depression in horses/sheep
Hematologic-->signs related to anemia
82
Onset of clinical signs of lead toxicosis?
few hours, days, wks, months to develop--depends on ant, species, plus other factors
83
What form of lead toxicosis is most common?
subacute
84
Pathology of lead toxicosis?
cerebral cortical necrosis and poliomalacia in cattle. acid-fast eosinophilic intranuclear inclusion bodies in renal tubular epithelium or hepatocytes.
grossly--may see lead in GIT
85
Antemortem specimen of choice in lead toxicosis?
whole blood
| other specimens include liver, kidney, GI contents
86
Hematology in lead toxicosis?
increased nucleated RBCs, basophilic stippling in dogs, increased zinc protoporphyrin esp in dogs, increased blood lead concentration
note: fluoresence of plasma porphyrins under UV light in cattle
87
What can be detected in radiographs of animals with lead toxicosis?
lead objects in GIT, metaphyseal sclerosis in young animals in chronic tox
88
Urinalysis in lead toxicosis?
increased delta-ALA-D levels, increased urinary lead following EDTA admin
89
Differential diagnosis of lead toxicosis?
chlorinated hydrocarbons, urea, OP, carbamates, H2O deprivation/sodium tox, metaldehyde, strychnine, fluoroacetate, nicotine, mercury, PEM in cattle, lupinosis in sheep, hypovitA, hypoMg, bovine ketosis
90
Treatment of lead toxicosis?
decon-->magnesium sulfate (osmotic cathartic), sx removal of lead
supportive/symptomatic-->thiamine, glucocorticoids, mannitol, zinc supplements, diazepam, barbiturates, fluid therapy
chelation--on later card
91
List the chelation drugs used to treat lead toxicosis?
```
calcium disodium EDTA, dimercaprol (given before EDTA), D-penicillamine PO (given after EDTA),
Dimercaptosuccinic acid (DMSA, succimer)
```
92
Prognosis of lead toxicosis?
guarded--better if caught early
93
What is the chelation drug of choice in lead toxicosis?
calcium disodium EDTA
94
What are the negative side effects of calcium disodium EDTA?
anorexia, V+, D+, depression.
prolonged therapy may cause kidney damage. may increase signs of toxicosis d/t mobilization of lead from bone and soft tissues. side effects can be antagonized by zinc supplementation.
95
Chelation drug of choice in pet birds suffering from lead toxicosis?
Dimercaptosuccinic acid (DMSA, succimer)
96
Why is dimercaprol given before administration of calcium disodium EDTA in lead toxicosis?
may improve effect bc crosses BBB and enhances renal and biliary excretion of lead
