Metals Flashcards
Acute copper syndrome
Uncommon
Excessive exposure
MOA: direct tissue irritant causing coag necrosis
Chronic copper toxicosis
Most common
Sheep most affected
From feed additives, copper soils and plants
Copper MOA
Accumulation in hepatic mitochondria and lysosomes
Excess CU oxidizes RBCs →fragility →hemolysis Hb → methmoglobin
Copper CS
Saliva, nausea, vomiting, colic, diarrhea, dehydration, shock, death
Copper Diagnosis
Hbnemia, Hburia, Brnemia
Elevated AST and SDH
Elevated blood and tissue CU levels
Copper toxic effects
Colic
Icterus, pale mm, dyspnea
Shock and death
Copper lesions
Gun metal kidneys (sheep)
Renal tubular necrosis, Hb casts, fragmented RBCs
Copper treatment
Ammonium tretrathiomolybdate (sheep)
D; penicillamine
Molybenized copper PO4
Chronic hepatic copper accumulation in dogs
In Bedlington terriers, Labs, dobermans, spaniels
Autosomal recessive disorder
Cu retention in liver (lysosomes) –> necrosis
Chronic hepatic copper accumulation CS
Icterus, ascites, hepatic encephalopathy, elevated liver copper, necrotic cirrhosis, hemolytic crisis
Chronic hepatic copper accumulation treatment
Chelation, d-penicillamine
Corticosteroids, Vitamin C
Supplement: Zn
Copper nutritional interactions (Mo and sulfur)
Mo and sulfur antagonists to copper
Prevent gut absorption and ↑ excretion of absorbed copper in liver and tissues
________ is frequently added to sheep diets to help prevent copper toxicity
Molybdenum (too high will lead to copper toxicity)
Monesin and lasalocid supplements
↑ efficacy of copper absorption by sheep
Peracute/ acute injectable exposure to iron
Immediately after injection (anaphylactic rxn)
Dehydration, shock, acidosis, cardio collapse, coma and death
Iron target systems
GIT, liver, CVS and CNS
Iron toxicosis treatment
Decontamination of GIT: milk of magnesia
Chelation therapy: deferoxamine
Vitamin C
Selenium Deficiency
White muscle disease, muscular dystrophy, bleeding disorders, liver necrosis and exudative diathesis
Toxic at low levels
Toxic forms: Selenite (4+) and selenate (+6)
Selenium requiring plants
Require large amounts for growth
Atragalus (locoweed)
OOnoopsis (goldenweed)
Stanleya (prince’s plume)
Xylorrhiza (woody aster)
Industrial/ commercial sources of selenium
Xerography, rectifers
Photoelectric cells
Glass and ceramics
Mechanism of Selenium
Causes glutathione depletion
Secondary lipid peroxidation
Replaces sulfure in aa
Depresses ATP formation
Alters tissues ascorbic acid levels (vasc. damage)
Acute selenium toxicosis
Mis-mixed feeds or seleniferous plants
Lesions on the lung, heart, kidney
Acute selenium toxicosis CS
Rapid cardio collapse (horses and ruminants)
Poliomyelomalasia (swine)
Abnormal behavior, posture, gait
Resp. difficulty, GIT: anorexia, diarrhea, colic
Chronic Selenium: Alkali disease
Source: seleniferous forages and grain
Livestock , esp horses
Damage of the keratin of hair and hoof
Blind staggers
High dietary sullfate
↓ appetite, impaired vision, wandering around circles, paralysis and death
Zinc toxicosis sources
Wire (transport cages), pennies, hardware, ointments, plumbing, galvanized metal
Zinc toxicosis susceptibility
Incidence: dogs and exotics
Sensitivity: ruminants
Cat with zinc poisoning
Competes with other metals
Direct irritation of mucous membranes
Signs: Hburia, icterus, ulcers, cardiac arryth., polyphagia, convulsions and death
Zinc lesions
Hemolytic anemia, renal tubular necrosis, bile cases, centrilobular hepatocytes, etc.
