Arsenic Flashcards
Arsenic
-previously used in agriculture and industry (medications, pesticides, food additives)
2 forms of arsenic
- organic
- inorganic (arsenates, arsenites)
Organic form of arsenic
-low mortality/less toxic, no GI signs, but CNS signs present
Inorganic arsenic forms
-nearly 100% mortality
-severe GI signs
-CNS signs present
Sources of arsenic
-dips, sprays for ectoparasite control
-herbicides
-heart worm meds (thiacetarsamide)
-feed additives- arsanilic acid
Toxokinetics of arsenic
- absorption: through skin and GI
- Distribution: energy rich tissues (liver, kidney, GIT). Hair and hoof if chronic.
- Metabolism: inorganic forms are methylated
- Excretion: bile or urine depending on form of arsenic
Mechanism of action of arsenic
-Inorganic forms cause chemical irritation and tissue degeneration
-arsenic will cause impaired cellular respiration and uncoupling of oxidative phosphorylation
Inorganic arsenic toxicity clinical manifestations
- Acute syndrome
- Subacute syndrome
Acute syndrome (inorganic form)
-high mortality
-sudden onset
-vomiting, abdominal pain, weakness, ataxia, recumbency, shock, diarrhea, death within 3-4hrs
-terminal convulsions may be observed
Subacute syndrome (inorganic form)
Longer duration ranging from 2-7days
-GIT: colic, vomiting, diarrhea, salivation, grinding teeth, anorexia, thirst
-CNS: muscle tremors, incoordination, clonic convulsions, hind end paralysis
Chronic inorganic arsenic toxicity
Also effects GI and CNS but will also see unthrifty animals, poor growth, indigestion, reduced milk production, abortion, buccal cavity ulceration
Diagnosis of inorganic arsenic
-clinical signs
-analysis of liver, kidney, hair or food samples
Treatment of inorganic arsenic poisoning
-high levels of exposure= death
-Can try sodium thiosulfate
-fluid therapy
Differential Dx for inorganic arsenic
-CNS: lead, mercury, salt, blue green algae, cyanide
-GIT: urea, mycotoxins, herbicides, OP/carbamates
Where do animals often encounter organic arsenic?
Much less toxic form that historically was used in feed additives therefore improper feed formulation is most likely cause,
Why is it hard to detect organic arsenic issues?
Often quickly eliminated which limits food residue concerns but also makes it hard to detect in tissues
Acute organic arsenic poisoning
Within 1 week, see incoordination, ataxia, paralysis, blindness
*no GI or anorexic signs!!
Chronic organic arsenic poisoning
-similar to acute, but to a lesser degree
-animals remain alert but they fail to gain weight
Diagnosis of organic arsenic poisoning
-history and clinical signs
-feed analysis
-tissue analysis- but be aware of rapid elimination
**often an uneventful recovery, if feed is issue and removed than will be fine.
Treat acute arsenic toxicity
-Selenium
