Heavy metal toxicity Flashcards Preview

DPPT Unit 2 > Heavy metal toxicity > Flashcards

Flashcards in Heavy metal toxicity Deck (10):
1

What are the three forms of heavy metals and which is *most toxic?

(1) Elemental - Pb
(2) *Inorganic salts - PbCl2
(3) Organic salts - (C2H5)4Pb

2

What are three mechanisms of heavy metal toxicity?

(1) Displacement of essential elements (ex. zinc, a cofactor for many enzymes)
(2) Formation of covalent bonds with sulfhydryl and hydroxyl groups (-SH and -OH)
(3) Carcinogenicity - arsenic, chromium, nickel, cadmium

3

Which heavy metals are carcinogenic?

CANCer
(1) Chromium
(2) Arsenic
(3) Nickel
(4) Cadmium

4

What are two modes of treatment for heavy metal intoxication?

(1) Removal of source of exposure
(2) Chelation therapy - only when levels high due to side effects

5

At what level of lead in blood do you get cognitive impairment?

5 mg/dl blood

6

What are the effects of lead poisoning?

(1) CNS - (a) impaired mental function in children and (b) lead encephalopathy (hyperactivity, ataxia, neuro deficits, seizures, coma, death)
(2) PNS effects - lead palsy, wrist drop, motor nerve dysfunction
(3) GI effects - abdominal cramps (primary symptom that brings adults to hospital), constipation
(4) Sterility
(5) Hypochromic, microcytic anemia with coproporphyrinogen and aminolevulinic acid (heme synthesis intermediates) in urine
(6) Hypertension

7

How can lead exposure be monitored?

(1) Coproporphyrinogen and aminolevulinic acid in urine
(2) Blood lead levels
(3) X-ray fluorescence - lead in bone with fluoresce

8

How can short-term lead exposure be diagnosed? Long term?

Short-term - blood lead levels
Long-term - x-ray fluorescence

9

What are four lead chelators?

(1) Succimer (most popular) - can be given orally, may cause severe skin rashes and diarrhea
(2) Dimercaprol - can cause hypertension/tachycardia
(3) CaEDTA - Ca exchanged with Pb, can cause kidney toxicity
(4) Penicillamine - can cause bone marrow suppression and allergic reactions to those who are allergic to penicillin

10

At what lead level should chelators be used for lead toxicity?

45 mg/dl