Toxic Metals

Metal toxicity / Metal poisoning

the toxic effect of certain metals in certain forms and doses in life

• Atomic absorption spectrometry with flame (AAS-F)

• electrothermal

  atomization furnace (AAS-ETA)

• inductively coupled plasma-optical emission spectrometry (ICP-OES)

• inductively coupled plasma-mass spectrometry (ICP-MS)

• high performance liquid chromatography-mass spectrometry (LC-MS).

analytical methods used to measure metals in biological fluids

Beryllium

this metal was once called glucinum because of the sweet taste of its salts

quinalizarin + bromine water

beryllium is differentiated from magnesium by adding:

Be: persistence of blue color

Mg: disappearance of blue color

result when identify wether a metal is Be or Mg by adding quinalizarin + bromine water

Beryllium

regarded as the most toxic metal

• Inhibits carbohydrate metabolic cycle by preventing breakdown of phosphorus compounds

• Disturbs respiration, circulation, and temperature

• No specific antidote is known

why is beryllium regarded as the most toxic metal?

Beryllium

used in the fluorescent lighting industry; metallic, alloys and ceramics of __ are widely used in dental appliances, wheelchairs, nuclear power and neutron modulator

Chronic Beryllium disease (CBD)

a chronic respiratory condition due to chronic beryllium exposure that is characterized by the formation of granulomas resulting from immune reaction to Be in the lungs

Aluminum

It is most abundant metal and the 3rd most abundant element

aluminum

it may constrict the blood vessels when applied topically

• may constrict the blood vessels when applied topically

• astringent (inherent)

• antiseptic

• antiperspirant

• used as inhalation in the treatment of silicosis (aluminum powder)

• Used in burn treatment (aluminum foil)

pharmacological action & uses of aluminum:

Aluminum/ Aluminum powder

used in burn treatment - protects the burn an conserves the fluid and stimulates tissue growth

Aluminum

___ overload may replace calcium in bone disrupting normal osteoid formation and may be reflected diagnostically with low parathyroid hormone (PTH)

Aluminum toxicity

patients with renal failure has high risk of:

Thallium

a soft metal that quickly oxidizes upon exposure to air; it is a minor constituent in a variety of ores

Thallium

used in the manufacture of jewelry, semiconductors, and optical devices

green twig

thallium is derived from the word thallos meaning

Thallium

sign & symptoms of poisoning includes:

• loss of hair

• peripheral neuropathy

• seizures

• renal failure

• may also cause green tongue

Thallium

This can also be a by-product of lead smelting which can be very toxic

Thallium

Primarily use as rodenticide

Thallium

(Mechanism of Toxicity) it appears to affect a variety of enzyme systems, resulting in generalized cellular poisoning

Thallium

(Mechanism of toxicity) Its metabolism has some similarities to that of potassium, and it may inhibit potassium flux across biologic membranes by binding to Na-K ATP transport enzymes

12-14 hours

How many hours after ingestion of thallium does symptoms occur?

• abdominal pain

• nausea

• vomiting

• diarrhea (sometimes with hemorrhage)

• shock may result from massive fluid or blood loss

acute effects of thallium toxicity

• delirium

• seizures

• respiratory failure

• death

what effects of thallium toxicity may occur within 2-3 days?

• painful peripheral neuropathy

• myopathy

• chorea

• stomatitis

• opthalmoplegia

what are the chronic effects of thallium toxicity?

• hair loss

• nail dystrophy (Mee’s lines)

what effects of thallium toxicity may occur after 2-4 weeks?

Thallotoxicosis

(Diagnosis) should be considered when gastroenteritis and painful paresthesia are followed by alopecia

• CBC

• electrolytes

• glucose

• BUN

• creatinine

• hepatic transaminases

• plain abdominal x-rays (after acute ingestion)

laboratory studies for the diagnosis of thallotoxicosis includes:

• maintain an open airway and assist ventilation if necessary

• treat seizures and coma (coma & stupor) if they occur

• treat gastroenteritis with aggressive intravenous replacement of fluids (and blood if needed); use pressors only if shock does not respond to fluid therapy (see hypotension)

(treatment) emergency and supportive measure for thallium toxicity:

• Prussian blue (ferric ferrocyanide)

• Activated charcoal

• BAL (Dimercaprol)

drugs and antidotes for thallium toxicity

Prussian blue (ferric ferrocyanide)

This compound has a crystal lattice structure that binds thallium ions and interrupts enterohepatic recycling.

Activated charcoal

• readily available and has been shown to bind thallium in vitro

• multiple-dose __ is recommended because thallium apparently undergoes enterohepatic recirculation

• it was shown to be superior to Prussian blue in eliminating thallium.

Silicon

It is 2nd most abundant element next to oxygen but the most abundant elements in the environment.

1. Colloidal silicon dioxide

2. Amorphous oxide of silicon

3. Methylated polymers of silicon

Compounds of silicon

Colloidal silicon dioxide

a compound of silicon used as adsorbent, desiccant, thickener

Amorphous oxide of silicon

a compound of silicon: inhalation of asbestos-containing dust leads to asbestosis, deposition of asbestos fiber in the pulmonary alveoli

Methylated polymers of silicon

Silicon appears to induce a response from polymorphonuclear cells and macrophages that bind small particles of silicon and transport them to lymph nodes where they can accumulate.

Silicosis

a lung condition resembling chronic tuberculosis, developing after exposure to respirate silica dust

Lead

a soft, malleable metal that is obtained chiefly by the primary smelting and refining of natural ores or by the widespread practice of recycling and secondary smelting of scrap __ products.

Lead

Absorption is slow but action is cumulative; accumulates and stored in bones; it can be ingested, inhaled or through dermal contact.

Lead

Toxicity will result to impaired growth and mental development, decrease vitamin D and hemoglobin synthesis, nephropathy, encephalopathy and death.

• chelation of BAL

• dimercaprol

antidotes for lead toxicity:

Lead

The multisystem toxicity of __ is mediated by several mechanisms, including inactivation or alteration of enzymes and other macromolecules by binding to sulfhydryl, phosphate, or carboxyl ligands and interaction with essential cations, most notably calcium, zinc, and iron. Pathologic alterations in cellular and mitochondrial membranes, neurotransmitter synthesis and function, heme synthesis, cellular redox status, and nucleotide metabolism may occur. Adverse impacts on the nervous, renal, GI, hematopoietic, reproductive, and cardiovascular systems can result.

Lead

Inhalation of __ fume or other fine, soluble particulate results in rapid and extensive pulmonary absorption, the major though not exclusive route of exposure in industry.

45%-50%; 10%-15%

Nonindustrial exposure occurs predominantly by ingestion, particularly in children, who absorb ___ of soluble lead compared with approximately ___ in adults.

• urine

• hair, nails, and sweat

Approximately 70% of lead excretion occurs via the ___ , with smaller amounts eliminated via the feces and scant amounts via the ___, ___, and ___.

skin irritation

Dermal absorption is minimal with inorganic lead but may be substantial with organic lead compounds, which may cause ___

Gastrointestinal lead absorption

It is increased by iron deficiency and low dietary calcium and decreased by co-ingestion with food.

• abdominal pain

• anemia (usually hemolytic)

• toxic hepatitis

• encelopathy

acute ingestion of very large amounts of lead may cause:

• fatigue

• malaise

• irritability

• anorexia

• insomnia

• weight loss

• decreased libido

• arthralgias

• myalgias

constitutional effects of lead poisoning includes:

• acute ingestion

• constitutional effects

• gastrointestinal effects

• CNS

• peripheral motor neuropathy

• hematologic effects

• adverse reproductive outcomes

clinical presentations of lead poisoning

• antaxia

• myoclonic jerking

• hyperflexia

• delirium

• convulsions

repeated, intentional inhalation of leaded gasoline will result to:

hemolysis

may occur after acute or subacute high-dose lead exposure