Toxicology of Heavy Metals Flashcards
1
Q
mechanism of toxicity of lead poisoning
A
- interferes with heme synthesis, DNA transcription, Ca dependent release of NT and protein kinase C (learning and memory)
2
Q
pathophysiology of lead poisoning
A
- GI tract and respiratory system are major routes of absorption
- may compete with Ca for a common transport system
- an empty stomach also increases absorption
- about 90% of inhaled lead is absorbed
- 99% of absorbed lead binds hemoglobin
3
Q
symptoms of acute lead poisoning
A
- metallic taste and thirst
- milky vomitus
- black stool
- CNS - parasthesia, pain and muscle weakness
- hemolytic crisis
- death usually occurs within 1-2 days
- survivors exhibit chronic symptoms
4
Q
symptoms of chronic lead poisoning
A
- wrist drop and foot drop
- anemia
- decreased creatinine clearance
- no sensory deficit but motor neuron degeneration present
5
Q
diagnosis of lead poisoning
A
- CaNa2EDTA
6
Q
treatment of lead poisoning
A
- stop further intoxication
- chelation therapy indicated at concentrations > 50-60 g/dl
- CaNa2EDTA is 1st line for asymptomatic adult exposure
- symptomatic exposure - CaNa2EDTA with BAL
- D-penicillamine not recommended for adult exposure
7
Q
pharmacokinetics of arsenic
A
- human carcinogen
- hair and nails have the highest arsenic concentration in the body
- readily crosses the placenta and fetal injury can occur
8
Q
skin lesions associated with arsenic poisoning
A
- melanosis, especially on the trunk and extremities
- hyperpigmentation
- conjunctivitis, skin cancer
- hyperkeratosis, palms and soles
- alopecia, brittle nails
- Mee’s lines
9
Q
symptoms of chronic exposure to arsenic
A
- bone marrow depression and impaired folic acid absorption
- folic acid and B12 deficiency, megaloblastic anemia
- muscle weakness
- Mee’s lines
- malignant neoplasms
10
Q
treatment of aresenic poisoning
A
- chelation therapy - charcoal, oral penicillamine,
- dimercaprol (BAL) is CI
- dimercaptopropansulfonate (DMPS) is DOC for chronic exposures
11
Q
pathophysiology of mercury poisoning
A
- bind sulfhydryl groups
- inhibit enzyme systems and disrupt membrane integrity
12
Q
symptoms of mercury vapor poisoning
A
- gingivostomatitis
- tremor
- memory impairment, nervousness, depression, social withdrawal, shyness, timidity, irritability
13
Q
symptoms of chronic exposure to inorganic mercury
A
- long term behavioral impairments - attention deficits, memory, motor performance
14
Q
symptoms of methyl mercury poisoning
A
- gradual onset of ataxia
- constriction of visual field and dysarthria
15
Q
diagnosis of mercury poisoning
A
- 3-4 g/dl
