Heavy Metals Flashcards
Describe the mechanism by which heavy metals produce toxicity in humans.
Metals form stable coordination complexes with a variety of ligands thereby: disrupting enzymatic and transport processes, causing a loss of energy production and ion regulation and causing potnetial carcinogenesis.
Discuss the symptoms of arsenic poisoning
dermatological effects (rosy complexion, no wrinkles), vasodilation (edema), GI effects (vomiting–>fluid loss and CV collapse), CNS (headache, coma), “garlic breath”, teratogenic, carcinogenic
What is dimercaprol (aka BAL, dithoglycerol) used for?
Treatment of heavy metal poisoning (arsenic and antimony) poisoning: it has a sulfhydral group that combines with ions of various heavy metals to form relatively stable, nontoxic, soluble chelates which are excreted in urine.
What antidotes may be used for gold toxicity?
dimercaprol or penicillamine
Discuss the symptoms of gold toxicity
Dermatitis, metallic taste, proteinuria, GI symptoms, aplastic anemia
What are some key symptoms of mercury poisoning from chronic and acute exposure?
(chronic exposure) tremors, impaired cognitive skills, sleep disturbances; (acute exposure) chest pain, dyspnea, cough, hemoptysis, impairment of pulmonary function, profound CNS effects and evidence of interstitial pneumonia
What are some symptoms of mercury exposure associated with continuing occuaptional exposure?
developing fine tremor beginning in the hands, later spreading to the eyelids, lips and tongue
What is the mechanism by which lead and cadmium cause toxicity in humans?
Lead is an enzyme inhibitor in the production of heme (it inhibits protoporphyrin IX resulting in the diagnostic accumulation of aminolevulonic acid)
What are two antidotes for lead and cadmium poisoning?
calcium EDTA and dimercaprol
What are some symptoms of long-term exposure to lead?
nephropathy, abdominal pain, delayed puberty in girls, reduced congitive capacity and schizophrenia
Describe the mechanism of action of antidotes used to treat heavy metal poisoning.
dimercaprol has a sulfhydral group that combines with ions of various heavy metals to form relatively stable, nontoxic, soluble chelates which are excreted in urine.
What antidote may be used for iron and aluminum toxicity?
deferoxamine: complexes with trivalent ions (Ferric ions) to form ferrioxamine, which is removed by the kidneys
Dimercaprol is an antidote for which heavy metals?
arsenic, antimony, gold, mercury
Calcium disodium edetate (EDTA) is an antidote for which heavy metals?
lead, cadmium
Penicillamine is an antidote for which heavy metals?
gold, mercury, (used long term to clear bone, skin and keratinized tissues of arsenic and antimony)
