Heavy Metals

Question 1

____ Lead is more readily absorbed than ____ lead

Answer 1

Organic lead is more readily absorbed than metallic lead

Question 2

What is the most common source of lead exposure

Answer 2

Lead based paint
Aerial emission from combustion of leaded fuel
Batteries
Insecticide/herbicide

Question 3

Which species is most likely to have lead toxicosis

Answer 3

Birds, water fowl

Question 4

What does lead displace

Answer 4

Calcium and Zinc

Question 5

Why are younger animals more sensitive to lead

Answer 5

Greater GIT absorption

Immature BBB

Question 6

Which species are more resistant to lead

Answer 6

Goat, Swine, Chicken

Question 7

What 3 things decrease lead absorption

Answer 7

Calcium, zinc, protein

Question 8

How is lead absorbed

Answer 8

Active transport using same carrier protein as calcium

Question 9

If patient is deficient in _____ then lead is more readily absorbed

Answer 9

Calcium
Vit D
Zinc
Iron

Question 10

Lead absorption is increased by

Answer 10

GIT acidity

Question 11

How long does lead bind to proteins in soft tissue

Answer 11

4-6 weeks

Question 12

What is Metallothionein

Answer 12

Chelating liver protein

Sequesters metal ions

Question 13

Where can lead be reserved for years

Answer 13

bone matrix

Question 14

Lead targets which tissues

Answer 14

GIT, Blood, CNS

Question 15

Chronic exposure to lead at low doses inhibits ___ leading to ___

Answer 15

Heme Synthesis leading to anemia

Question 16

Lead alters the release of

Answer 16

Neurotransmitters (dopamine, acetylcholine, GABA)

Question 17

Hematologic signs of lead

Answer 17

Anemia, basophilic stippling
Antemortem - whole blood >0.35
Postmortem – Kidney, liver >10ppm

Question 18

CNS signs of lead

Answer 18

Anxiety, vocalization, head pressing, manic behavior, seizures

Question 19

Lead signs in birds

Answer 19

Peripheral neuropathy, chronic wasting

Question 20

Which chelating agent is better

Answer 20

Calcium disodium EDTA

Question 21

What are some concerns with chelating agents

Answer 21

Renal injury (don't treat >5 days)
Binds other minerals (supplement Zinc)

Question 22

What can be used with Ca-EDTA to enhance excretion and why

Answer 22

Dimercaprol - crosses BBB

Question 23

Lead lines do not represent ____

Answer 23

lead deposits in bone

Question 24

What increases zinc release and absorption

Answer 24

Acid - both

Absorption – AAs, peptides, chelating agents

Question 25

What decreases zinc absorption

Answer 25

Dietary fiber, phytate (P), Ca

Question 26

Excess zinc interferes with absorption and use of

Answer 26

Cu and Fe

Question 27

Rapid accumulation of zinc occurs in which organs

Answer 27

Pancreas, liver, kidney, spleen

Question 28

Clinical signs of zinc in GI, Blood and Kidney

Answer 28

GI - vomit, anorexia, lethargy, pain, diarrhea, pica Blood - Hemolytic anemia (hemolysis), icterus, hemoglobinuria Renal - Azotemia (BUN), hypophos

Question 29

What type of tube is used for zinc analysis

Answer 29

Trace elements tube - dark blue top

Question 30

What can chelation therapy cause with zinc

Answer 30

May increase zinc redistribution and absorption ** can use Ca-EDTA after removal of source

Question 31

Which species milk contains no iron

Answer 31

Pig

Question 32

What deficiency in sows increases risk of iron toxicity in piglets

Answer 32

Selenium and Vit E

Question 33

Is organic or inorganic iron more toxic

Answer 33

Organic is less irritant

Question 34

Why is little iron normally excreted

Answer 34

It is bound to transferrin and transported to bone marrow for hemoglobin synthesis

Question 35

Free iron ions are very reactive and cause _____ and direct damage to _____

Answer 35

Cause free radical lipid peroxidation and direct damage to cell membranes

Question 36

The primary effects of iron are on which systems

Answer 36

Cadiovascular, GI and liver -- leads to shock and death

Question 37

Clinical signs for acute iron toxicosis

Answer 37

Severe depression, shock, acidosis and death within hours

Question 38

Stages of acute iron toxicosis

Answer 38

``` Stage 1 (0-6 hr) - GI upset Stage 2 (6-24 hr) - apparent recovery Stage 3 (12-96 hr) - Most severe signs due to metabolic effects Stage 4 (2-6 wks) - GI obstruction due to fibrosis ```

Question 39

How long after ingestion of iron is GI decontamination effective

Answer 39

Within 4 hrs

Question 40

______ is not effective but ____ can be used to precipitate iron

Answer 40

Activated charcoal | Milk of magnesia

Question 41

For iron toxicosis when is chelation therapy warranted and what is used

Answer 41

Has ingested >60 mg/kg, serum iron is >500 mcg/dL | Deferoxamine (rapid injection can cause hypotension and cardiac arrhythmias)