Heavy Metal Flashcards
lead distribution
about 99% of lead in the bloodstream binds
to hemoglobin in erythrocytes; only around 1% is available to
the tissues; initially, lead is distributed to soft tissues (tubular
epithelium of the kidney and liver), but in time the lead is
redistributed and deposited mostly in bone but also in teeth
and hair
lead symptoms
a. GI: GI effects are an early warning sign of lead exposure;
anorexia, muscle discomfort, malaise, and headache;
constipation; a persistent metallic taste; lead colic (severe
abdominal pain)
b. neuromuscular: lead palsy or neuromuscular syndrome is
rare in the U.S.; muscle weakness (wrist-drop and foot-drop)
and fatigue occur long before paralysis
c. CNS: lead encephalopathy; is the most serious manifestation
of lead poisoning and more common in children; early signs
are clumsiness, vertigo, ataxia, falling, headache, insomnia,
restlessness, and irritability; later, delirium, tonic-clonic
convulsions, and coma follow; may be a progressive mental
deterioration in children
lead hematological
blood lead concentration of 80 g/dl
causes basophilic stippling (aggregated RNA) but is not
pathognomonic of lead poisoning; hypochromic microcytic
anemia is more common and reflects a decreased life span of
the erythrocytes and an inhibition of heme synthesis
e. renal: less dramatic than the CNS or GI effects
Lead lines: long bones on X-ray
lead- what accumulates in blood
delta-aminolevulinate (delta-ALA)- second step in heme synthesis is blocked by lead
protoporph accumulates in blood
lead chelators
1) Dimercaprol, 2) Succimer
(kids) , 3) EDTA and 4) penicllamine
mercury
dental amalgams & fish (methylmercury)
organic mercury
organic mercurials are more completely absorbed (90%)
from the GI tract than inorganic mercury salts; the primary
concentration is in erythrocytes and hair; t1/2 is 45-105 days
organic can cross BBB & placents
mercury is similar to …
methionine- can go thro aa transporters in the body
mercury symptoms
neurological
mercury treatment
polythiol resin
target for arsenic
sulfhydryol groups- will be found in high levels in hair and nails
arsenic half life
short compared to other metals bc it is metabolized by glutathione
chronic arsenic poisoning
a. early signs are muscle weakness and aching, skin
pigmentation (eyelids, neck, nipples and axillae)
b. less prominent GI effects; garlic odor of the breath and
perspiration
arsenic treatment
dimercaprol
cadmium half life
the half life is 10-30 years
