Toxic metals

What are toxic metals?

metals are naturally-occurring, and are always present in the environment

What is important in determining metal toxicity?

exposure, timing, and dosage (diagnosis is difficult)

What must be present in order to diagnose metal toxicity?

-evident source of metal
-characteristic signs related to the metal
-abnormal metal concentration in the appropriate tissue

What is arsenic found in?

pesticides, paints, weed killers, rodenticides, and pressure treated wood

What does arsenic do in the body?

-no ATP produced
-inhibits pyruvate conversion (no gluconeogenesis)
-loss of enzyme activity

symptoms of arsenic poisoning

-explosive gastroenteritis
-Mees lines (keratin binding)
-skin lesions
-CNS damage
-chronic exposure: cancer

Arsenic antidote

BAL (british anti-lewisite, dimercaprol)

Where is Cadmium commonly found?

brightly colored paint/pigment, tobacco products, and rechargeable batteries

Over-exposure to cadmium can cause what?

-nasal epithelium deterioration
-denature protein in alveoli and renal tubules
-lung issues and kidney (chronic proteinuria)

In what instances would someone be exposed to chromium?

-occupational hazard (steel manufacturing)
-orthopedic implant alloys (ARMD)

What container is used to measure chromium in the blood?

navy blue top w/ K2EDTA

What does inhalation of chromium cause?

-nasal epithelium deterioration
-small-cell lung carcinoma

Where is lead commonly found?

paint, earthenware glaze, copper distiller solders, coal burning, toys, batteries

What mechanism does lead use in vivo?

-interacts w/ zinc cofactors inhibiting ALA and ferrochelatase
-deposited in RBCs/bone marrow when present in toxic amounts

Symptoms of lead poisoning

-anemia (heme synthesis impairment)
-coarse basophilic stippling in RBCs
-GI irritation, kidney/CNS damage, weight loss
-mental impairment in kids

Lead antidote

chelation w/ EDTA penicillamine, or BAL

Where is mercury found?

chemical photo reagents, antiseptics, pesticides, batteries, fish, thermometers, earth's crust

What does mercury do to the body?

changes in protein structure (immuno-reactants or loss of function)

Symptoms of mercury toxicity

GI irritation, kidney damage, neurological symptoms (binds myelin)

Mercury antidote

chelation w/ BAL or penicillamine

What methods are used in the lab to analyze heavy metals?

-ICP-MS
-optical emission spectroscopy
-HPLC-MS
-atomic absorption

What specimens are used?

-urine
-whole blood, serum, plasma
-hair, skin, nails