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Metal Toxicities
| Question | Answer |
|---|---|
| Lead poisoning chelating agents | CaNa2EDTA, BAL, penicillamine, succimer. (EDTA can remove Pb from storage faster than bind it so some acute signs of toxicity may appear) |
| Iron poisoning chelating agent | Deforoxamine |
| Copper poisoning chelating agent | penacillamine |
| Arsenic and gold poisoning chelating agents | Succimer, BAL |
| Mercury poisoning chelating agents | Acute - BAL (won't reverse neuronal damage). Chronic - penicillamine, succimer |
| Thallium poisoning chelating agents | prussian blue, dithizone |
| Calcium poisoning chelating agents | EDTA |
| Cadmium poisoning chelating agents | NONE - contraindicated |
| Inorganic & trivalent Arsenic toxicity | GI hemorrhage, capillary damage; inhibit enzymes by blocking -SH groups (reversed by BAL) |
| pentavalent arsenic toxicity | CNS signs (demyelinate), uncouple oxidative phosphorylation |
| Arsenic toxicity lesions | GI irritation/hemorrhage, capillary damage, soft yellow liver |
| Arsenic toxicity treatment | Early (<4 hours)- emetics, purgative, demulcents. Late (>4 hours) - Dimercaprol (BAL), sodium thiosulfate |
| Arsine (AH3)clinical signs | GI effects, intravascular hemolysis, edema, cyanosis, liver dz, delirium, coma |
| Lead toxicity distribution | bound to RBCs, deposited in liver and KIDNEY cortex. Redistributed 95% to bone. Excreted via bile in animals |
| Lead toxicity signs | GI signs, CNS signs, erythrocytic and renal signs take longer to develop. Death in 3-4 days. |
| Lead toxicity lesions | Cadaver odor, dirty red-grey muscle, GI hemorrhage, *acid fast intranuclear bodies in ascending renal tubules*, petichiation on heart, excessive CSF accumulation, congested lungs. Lead line on gingiva, roaring, metaphyseal lead lines in immature dogs |
| Copper toxicity signs | chronic accumulation in liver - released in stress causing hemolysis, necorsis, kidney injury |
| Copper toxicity lesions | gun metal kidneys, blackberry jam spleen, yellow friable liver |
| Molybdenum toxicity signs | poor-doers, diarrhea, hypoproteinemic, achromotrichia, wool problems |
| Mercury toxicity lesions | Elemental mercury accumulates in kidneys (proximal tubules) but primarily neuronal degeneration |
| Fluoride acceptable levels | water: 2ppm, food: 40-50ppm |
| Flouride toxicity signs | Brown, mottled or crumbling teeth, hyperostosis |
| Iron toxicity MOA | injure gut wall, CV collapse, incr. capillary permeability, inactivates oxidative enzymes, metabolic acidosis, shock. LIVER damage! |
| Cadmium toxicity | young more susceptible, stored in liver and kidney as metallothionine. 90% circulating Cd in RBCs! |
| Cadmium toxicity signs | vomiting, pulmonary edema, CNS effects, hyperchromic anemia, bone marrow hyperplasia, hypertension, kidney dz, yellow teeth, chronic pain |
| Cobalt toxicity | "Beer drinkers cardiomyopathy" |
| Chromium toxicity | hexavalent causes nephritis, dermatitis, lung cancer, ulcers on nasal septum (like coke) |
| Barium toxicity | Alone stimulates all muscle types! Use barium sulfate for GI contrast! |
| Magnesium toxicity | CNS depression, curare-like action on NMJ. Treat with Calcium! |
| Iodine toxicity | Increased respiratory tract secretions, cough, lacrimation, ceased egg production, scaly skin over back, neck, eyes, loss of tracheal cilia |
| Silver toxicity | severe gastroenteritis (denatures proteins), treat with NaCl! |
| Selenium toxicity signs | Acute - emesis, diarrhea, fever, depression, spasms, prostration (calves die in 12 hours). Chronic - hair loss, sloughing of hooves, anemia, paralysis in swine |
| Selenium toxicity lesions | Acute -hemorrhagic GI, congestion of liver/kidneys up to focal necrosis. Chronic - emaciation, hair loss, neuronal degeneration (similar to flouride poisoning) |
| Sulfur toxicity | Elemental sulfur is mostly non-toxic, hydrogen sulfide is as toxic as cyanide. |
| Sulfur toxicity signs | Polioencephalomalacia, purgation, colic, depression. No treatment! |
| Zinc toxicity signs | GI distress, emesis, pica, reduced growth, Heinz bodies, pancreatic damage, arthritis, white muscle dz, hemorrhagic kidneys/liver. Icterus if they live long enough... |
| Chronic zinc toxicity lesions in horses | lesions at growth plates, enlarged joints, stiff gait. Treat with EDTA |