Heavy Metals Flashcards
Mode of action for Lead
Altered GABA transmission, Displaced Calcium from binding sites, altered nerve and muscle transmission, decreased smooth muscle contraction and interference with mineral absorption.
Lead Clinical sings in a dog
Primarily GI signs- V, D, anorexia, tender abdomen
Secondarily: Neurologic signs- lethargy, ataxia, convulsions
Lead Clinical signs in a cow
NEurologic signs predominate (blindness, increased vocalization, ataxia, circling, aimless wandering)
GI signs are secondary- Rumen stasis, Gaunt, anorexia
Lead Clinical signs in horse
Paralysis of recurrent laryngeal nerve -> Roaring
Birds clinical signs with lead
Neurologic, muscle wasting
What Diagnostic samples do you want with Lead. Both post-moretem and ante-moretem
Antemortem- Whole blood in a purple tp tube, Milk
Post mortem- Liver, Kidney, Bone, Brain
Treatment methods for Lead
NO LEGAL ANTEDOTE IN FOOD ANIMALS**
CaEDTA given IV or SQ- must remove any foreign body to prevent continued absorption
Succimer- oral but is extremely expensive
Arsenic Mode of action
3+ binds to Lipoic Acid & blocks cellular respiration -> decreased ATP, capillary dilation -> Edema
5+ substitutes for P, uncouples oxidative phosphorylation -> Decreased ATP
Clinical signs associated with Arsenic
Gastrointesstinal, bloody diarrhea
Swine Clinical signs associated with Arsenic
Goose stepping, lack of proptioception, blindness
Appropriate samples for Arsenic
Sciatic and optic nerve- demyelination of the nerve
Gross lesions seen with Arsenic
Necrohemorrhagic gastroenteritis, ulcerations
Microscopic lesions associated with arsenic
GI and renal necrosis, peripheral neuromuscular degeneration, submucosal edema
Treatment for Arsenic
Decontamination: cathartics, gastric lavage, emesis
Supportive care: correct dehydration and acidosis
Chelators:
Succimer- Extremely expensive
Dimercaprol: must be given before clinical signs are present- expensive
Thiotic ACid- not for food animals - increases antioxidants
Mercury Toxicity
Organic > Inorganic > Elemental
Mercury Mode of action
Organic- inhibition of protein synthesis decreasing proteins, and funciton, resulting in necrosis
Inorganic- binds to sulfhydryl groups -> inhibits sulfhydryl enzymes, decreasing energy and funciton, resulting in necrosis
Clinical signs associated with Mercury
ORganic- stomatitis, conjunctivitis, blindness, ataxia, paresis, abnormal posture, paralysis, coma, death
Inorganic- vomiting, diarrhea, stomatitis, oliguria, death
What samples are appropriate for Mercury
Liver, kidney, Brain for Hg testing
Whole blood and urine in acute cases
Lesions associated with Mercury
Ulcerative/necrotic gastroenteritis, renal tubular necrosis, demyelination of peripheral nerves in swine
Cerebellar hypoplasia in cats
Treatment of Mercury
Oral decontamination: Egg whites, D-penicillamine, Na Thiosulfate, Saline cathartic
Succimer- expensive and not practical in LA
Organic= damage is generally extensive and too late
environmental concerns associated with Mercury
Contaminated livestock should not be used for consumption
Mode of Action for Zinc
Unknown, but causes hemolysis, GI irritation and erosion
Clinical sign of dogs with Zinc
Hemolytic anemia, GI irritation , anorexia, V, D
Clinical signs of ruminants associated with Zinc
Decreased growth and efficiency
Clinical signs associated with equine and Zinc
Lameness, and Laryngeal paralysis
Swine clinical signs associated with Zinc
Lameness