Inorganic Arsenic Flashcards
What is the main difference between organic and inorganic arsenic toxicosis?
Inorganic arsenic = corrosive GI disease
Organic arsenic = peripheral neurotoxin (less toxic)
What is inorganic arsenic used for?
insecticides, herbicides, fungicides, and rodenticides
also found in paint, pigments, detergents, and building materials
T/F: Milk from poisoned cows can be toxic to calves
TRUE
What are the 3 oxidative states of inorganic arsenic?
Elemental
Tivalent = arseNITE
Pentavalent = aresenAte
these will react with -SH groups (effects MOA and course treatment)
What is the oral LD for most species and how is inorganic categorized base on the toxicity?
HIGHLY TOXIC
1-25 mg/kg
T/F: Inorganic arsenic toxicosis can be acute, peracute, and chronic
FALSE
**THERE IS NO CHRONIC TOXICITY
acute, peracute, subacute
Which form of inorganic arsenic is poorly absorbed?
Elemental
What animals are most susceptible to inorganic arsenic poisoning?
Herbivores
dogs can be poisoned via ant and roach baits
swine and chickens are rarely poisoned
Which form is more toxic, arsenite or arsenate?
Arsenite (trivalent) is more toxic than Aresenate (pentavalent)
more toxic than organic arsenic
*pentavalent is converted to trivalent in vivo
How is inogranic arsenic absorbed?
absorbed from the GIT, intact skin, and inhalation
What is the distribution of inogranic arsenic?
all over the body but achieves highest concentrations in the KIDNEY, LIVER, and hair, hoof, nail, and skin
(kidney and liver due to high blood flow)
T/F: inogranic arsenic crosses the BBB
False
poorly crosses the BBB
What change occurs to pentavalent inogranic arsenic in the liver?
Changes to MORE TOXIC trivalent arsenic aka arsenite
What is the metabolism and excretion of inogranic arsenic?
Partly metabolized in the liver and kidney by methylation
rapidly excreted in the urine (within 48 hours)
*small amts excreted in feces, milk, saliva, sweat, hair, and exhalation
what is the MOA of inorganic arsenic?
Trivalent (arsenite): binds to 2 -SH groups of lipoic –> SLOWS GLYCOLYSIS and TCA cycle = inhibiting energy production
Pentavalent (arsenate): uncouples oxidative phosphorylation (similar to PCP) and may interfere with B1 and B12 metabolism
both = lack of energy = tissue damage
*locally corrosive
What tissues are the most severely affected from inorganic arsenic poisoning?
Tissues that are rich in oxidative enzymes: intestines liver kidney GI mucosa capillaries -endothelium (hemorrhage)
What clinical signs are associated with PERACUTE inorganic arsenic poisoning?
most severe
sudden death or severe colic, collapse and death hypovolemic shock
What clinical signs are associated with ACUTE inorganic arsenic poisoning?
rapid onset - severe colic, staggering, salivation, vomiting, thirst, watery dhr - hemorrhagic, possible hematuria
death in 1 - 3 days
What clinical signs are associated with SUBACUTE inorganic arsenic poisoning?
Colic, anorexia, depression, dhr with blood or mucosal shreds, dehydration, partial paralysis of the hind limbs, and death in several days
What lesions are associated with inorganic arsenic poisoning?
Hemorrhagic lesions all over the body
GI mucosal edema/hem. with sloughing or perforation, liver and kidney damage, capillary degeneration, skin lesions and blistering (from skin exposure)
What is the BEST antemortem specimen for inorganic arsenic testing?
URINE
What are the best postmortem specimen for inorganic arsenic testing?
Liver and kidney
Other: GI contents, vomitus, feces, milk, suspected source
What is the normal level of inorganic arsenic residues in tissue?
0.5 ppm
***More than 7-10ppm in the liver or kidney = strong indication of inorganic toxicosis
What lab values will be elevated in a patient with inorganic arsenic poisoning?
Increased PCV and BUN
What criteria do you rely on to diagnose inorganic arsenic poisoning?
hx, signs of sudden bloody dhr/watery dhr with mucosal shreds, lesions, and lab values
***there are MANY ddx for this toxicant
What does emergency and supportive treatment for inorganic arsenic poisoning include?
IVF, blood transfusion, tx of acidosis, ABs, Vitamins/antioxidants, analgesics etc
What is the decontamination protocol for inorganic arsenic toxicosis?
Gastric lavage - should only be done if there is NO evidence of damage (so early on in dz)
Mineral oil to coat GIT
Activated charcoal is not very effective
Emetics and strong cathartics are contraindicated**
What specific treatment/therapy is available for inorganic arsenic poisoning?
must have a definitive dx
Chelation therapy: Dimercaprol - not 100% effective
Can have dangerous side effects - should only be used as a last resort
Dimercaptosuccinic acid (DMSA) is a less effective but safer chelator
What is the prognosis inorganic arsenic poisoning?
Grave
unless treated VERY early
