5. Lead poisoning

Question 1

What is lead?

Answer 1

Lead is a heavy metal.

Question 2

What could be the sources of lead poisoning?

Answer 2

Major environmental hazard because it is present in the air and water throughout the world. Found in storage batteries, ammunition, metal alloys, gasoline, small amount found in cigarettes etc.

Question 3

What is Acute lead poisoning and it’s accompanying symptoms?

Answer 3

1. No longer common (ban from products: gasoline).
2. The primary signs: acute abdominal colic, CNS changes - acute encephalopathy.

Question 4

What is organic lead poisoning?

Answer 4

1. Tetraethyl lead or tetramethyl lead gasoline additives –> no longer used.
2. Absorbed through the skin and lungs.

Question 5

What is Chronic lead poisoning (Plumbism)?

Answer 5

​Chronic lead poisoning or Plumbism is a term for chronic exposure of lead over time and this usually happens to people working in an occuption where lead is used or present. Its common among workers like painters, typesetter etc.

(Plumbism- Plumbers?)

Question 6

What are the therapy options for Lead poisoning?

Answer 6

Chelation therapy:

1. Oral succimer in outpatients,
2. Parenteral agents (eg, EDTA with or without dimercaprol) in more severe cases
3. Disodium calcium edetate/ CaNa2EDTA is able to remove lead from the bones, but enhances brain concentration.

Question 7

In general why are heavy metals (like lead) toxic for the body?

Answer 7

1. Most of their effects appear to result from interaction with sulfhydryl groups of enzymes and regulatory proteins. They cause alterations of enzymatic activity.

Question 8

What are the effects of lead poisoning on the body?

Answer 8

Question 9

How does lead enter the body?

Answer 9

Mostly via ingestion than inhalation and lastly skin absorption.

Question 10

What is the MOA of lead?

Answer 10

1. The primary cause of its toxicity is its predilection for interfering with the proper functioning of enzymes. It does so by binding to the sulfhydryl groups found on many enzymes, or mimicking and displacing other metals which act as cofactors in many enzymatic reactions.
2. Among the essential metals that lead interacts with are calcium, iron, and zinc. High levels of calcium and iron tend to provide some protection from lead poisoning; low levels cause increased susceptibility.

Question 11

What are the symptoms and signs of Chronic lead poisoning (Plumbism)?

Answer 11

1. Peripheral neuropathy (Tremor??)
2. GIT symptoms (loss of appetite, constipation in higher dose – bouts of abdominal pain „lead colic”). Anorexia, Weight loss
3. (Microcytic) Anemia (interferes with heme synthesis- lead inhibits porphobilinogen synthase and ferrochelatase, preventing both porphobilinogen formation and the incorporation of iron into protoporphyrin IX, the final step in heme synthesis.)
4. Interstitial fibrosis and nephrosclerosis (even after years)
5. Uric acid excretion decreases – symptoms of gout

Question 12

Which organs are affected by heavy metal intoxication/poisoning?

Answer 12

Nearly all organ systems are involved, however, the most commonly involved organ systems: CNS, PNS, GI, hematopoietic, renal, and cardiovascular.