Inorganic Arsenic

Question 1

What is the main difference between organic and inorganic arsenic toxicosis?

Answer 1

Inorganic arsenic = corrosive GI disease

Organic arsenic = peripheral neurotoxin (less toxic)

Question 2

What is inorganic arsenic used for?

Answer 2

insecticides, herbicides, fungicides, and rodenticides

also found in paint, pigments, detergents, and building materials

Question 3

T/F: Milk from poisoned cows can be toxic to calves

Answer 3

TRUE

Question 4

What are the 3 oxidative states of inorganic arsenic?

Answer 4

Elemental
Tivalent = arseNITE
Pentavalent = aresenAte

these will react with -SH groups (effects MOA and course treatment)

Question 5

What is the oral LD for most species and how is inorganic categorized base on the toxicity?

Answer 5

HIGHLY TOXIC

1-25 mg/kg

Question 6

T/F: Inorganic arsenic toxicosis can be acute, peracute, and chronic

Answer 6

FALSE

**THERE IS NO CHRONIC TOXICITY

acute, peracute, subacute

Question 7

Which form of inorganic arsenic is poorly absorbed?

Answer 7

Elemental

Question 8

What animals are most susceptible to inorganic arsenic poisoning?

Answer 8

Herbivores

dogs can be poisoned via ant and roach baits

swine and chickens are rarely poisoned

Question 9

Which form is more toxic, arsenite or arsenate?

Answer 9

Arsenite (trivalent) is more toxic than Aresenate (pentavalent)

more toxic than organic arsenic

*pentavalent is converted to trivalent in vivo

Question 10

How is inogranic arsenic absorbed?

Answer 10

absorbed from the GIT, intact skin, and inhalation

Question 11

What is the distribution of inogranic arsenic?

Answer 11

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)

Question 12

T/F: inogranic arsenic crosses the BBB

Answer 12

False

poorly crosses the BBB

Question 13

What change occurs to pentavalent inogranic arsenic in the liver?

Answer 13

Changes to MORE TOXIC trivalent arsenic aka arsenite

Question 14

What is the metabolism and excretion of inogranic arsenic?

Answer 14

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

Question 15

what is the MOA of inorganic arsenic?

Answer 15

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

Question 16

What tissues are the most severely affected from inorganic arsenic poisoning?

Answer 16

Tissues that are rich in oxidative enzymes:
intestines
liver
kidney
GI mucosa
capillaries -endothelium (hemorrhage)

Question 17

What clinical signs are associated with PERACUTE inorganic arsenic poisoning?

Answer 17

most severe

sudden death or severe colic, collapse and death hypovolemic shock

Question 18

What clinical signs are associated with ACUTE inorganic arsenic poisoning?

Answer 18

rapid onset - severe colic, staggering, salivation, vomiting, thirst, watery dhr - hemorrhagic, possible hematuria

death in 1 - 3 days

Question 19

What clinical signs are associated with SUBACUTE inorganic arsenic poisoning?

Answer 19

Colic, anorexia, depression, dhr with blood or mucosal shreds, dehydration, partial paralysis of the hind limbs, and death in several days

Question 20

What lesions are associated with inorganic arsenic poisoning?

Answer 20

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)

Question 21

What is the BEST antemortem specimen for inorganic arsenic testing?

Answer 21

URINE

Question 22

What are the best postmortem specimen for inorganic arsenic testing?

Answer 22

Liver and kidney

Other: GI contents, vomitus, feces, milk, suspected source

Question 23

What is the normal level of inorganic arsenic residues in tissue?

Answer 23

0.5 ppm

***More than 7-10ppm in the liver or kidney = strong indication of inorganic toxicosis

Question 24

What lab values will be elevated in a patient with inorganic arsenic poisoning?

Answer 24

Increased PCV and BUN

Question 25

What criteria do you rely on to diagnose inorganic arsenic poisoning?

Answer 25

hx, signs of sudden bloody dhr/watery dhr with mucosal shreds, lesions, and lab values

***there are MANY ddx for this toxicant

Question 26

What does emergency and supportive treatment for inorganic arsenic poisoning include?

Answer 26

IVF, blood transfusion, tx of acidosis, ABs, Vitamins/antioxidants, analgesics etc

Question 27

What is the decontamination protocol for inorganic arsenic toxicosis?

Answer 27

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**

Question 28

What specific treatment/therapy is available for inorganic arsenic poisoning?

Answer 28

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

Question 29

What is the prognosis inorganic arsenic poisoning?

Answer 29

Grave

unless treated VERY early