Power Point Seminar

SEMINAR

HEAVY METAL TOXICITY PRESENTED BY ANUJ M . PANDEY

INTRODUCTION There are 35 metals that concern us because of occupational or residential exposure; 23 of these are “Heavy Metals“. Small amounts of these elements are common in an environment ,diet and are actually necessary for good health, but large amounts of any of them may cause acute or chronic toxicity (poisoning). Heavy metal toxicity can result in damaged or reduced mental and central nervous function damage to blood composition, lungs, kidneys, liver, and other vital organs. Allergies are not uncommon and repeated long-term contact may even cause cancer .

DEFINITION: "Heavy metals" are chemical elements with a specific gravity that is at least 5 times the specific gravity of water.

BENEFICIAL HEAVY METALS In small quantities, certain heavy metals are nutritionally essential for a healthy life. Some of these are commonly found naturally in foodstuffs, in fruits and vegetables, and in commercially available multivitamin products. Heavy metals are also common in industrial applications such as in the manufacture of pesticides, batteries, alloys, electroplated metal parts, textile dyes, steel, and so forth.

TOXIC HEAVY METALS Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissues. Heavy metals enter the human body through food, water, air, or absorption through the skin in agriculture and in manufacturing, pharmaceutical, industrial, or residential settings. Exposure to toxic heavy metals is generally classified as acute, 14 days or less; intermediate, 15-354 days; and chronic, more than 365 days.

COMMONLY ENCOUNTERED TOXIC HEAVY METALS ARSENIC LEAD MERCURY CADMIUM IRON

ARSENIC Most common cause of heavy metal poisoning in adults. Sources for arsenic are paints, red poisoning, smelting process of copper, zinc and lead . Symptoms of acute poisoning are sore throat , red skill , severe abdominal pain , vomiting and diarrhea. Chronic exposure can lead to progressive peripheral and central nervous changes.

PHARMACOLOGICAL AND TOXICOLOGICAL EFFECT ON TARGET ORGANS Cardiovascular system : Small doses of inorganic arsenic induce mild vasodilatation. Larger doses evoke capillary dilation. Gastrointestinal tract : Small doses of inorganic arsenic cause mild splanchnic hyperemia. Tissue damage and bulk cathartic action leads to increase peristalsis and characteristic watery diarrhea. Kidney : Arsenic may cause severe renal damage

Skin : Effects on skin results in necrosis and sloughing. Nervous systems : Both short and long term exposures cause encephalopathy , peripheral neuropathy. Blood : Affects the bone marrow .vascularity of the bone marrow is increased. Liver: Inorganic arsenic causes injury to hepatic parenchyma , produces fatty infiltration , central necrosis and cirrhosis

LABORATORY TESTING AND DIAGNOSIS History of potential exposure Laboratory test – Blood test , Liver function test , Renal function test , Urinalysis , Fecal test X-RAY”S and hair and finger nail analysis.

TREATMENT BAL , DMSA and D- penicillamine are the primary drug used . Supportive care with abundant fluids to increase elimination of arsenic . Decontamination of the gastro intestinal systems with gastric lavage . Chelation therapy shortens the distribution of arsenic in the blood

LEAD Lead accounts for most of the cases of pediatric heavy metal poisoning. Used in pipes, drains, shouldering materials, paint pigments, PVC plastics, X-ray shielding, crystal glass production, pencils & pesticides. Symptoms include abdominal pain, convulsions, hypertension, renal dysfunction, loss of appetite, fatigue, and sleeplessness, hallucination, headache, arthritis & vertigo. Chronic exposure results in birth defects, mental retardation, autism, psychosis, allergies, dyslexia, hyperactivity, weight loss, shaky hands, muscular weakness, and paralysis.

PHARMACOLOGICAL AND TOXICOLOGICAL EFFECT ON TARGET ORGANS Gastrointestinal tract : Affects smooth muscle of the gut, produces vague syndromes like anorexia, malaise, headache & constipation. Neuromuscular effects : Muscle weakness & easy fatigue occurs. muscle group involved are extensors of forearm, wrist, fingers & extraocular muscles. CNS effects : Lead encephalopathy is the most serious manifestation of lead poisoning.

Hematological effects : Hypochromic microcytic anaemia is observed. Renal effects : Renal toxicity occurs in two forms:  A reversible renal tabular disorder (usually seen after acute exposure of children to lead) and  An irreversible interstitial nephropathy (more commonly observed in long-term industrial lead exposure) Other effects: Other signs and symptoms include an ashen color of the face and pallor of the lips; retinal stippling; appearance of “premature aging” with stooped posture, poor muscle tone, and emaciation; and a black, grayish, or blue-black so-called lead line along the gingival margin.

LABORATORY TESTING AND DIAGNOSIS Complete blood count to check on abnormalities on red blood cells (basophylic stippling) Blood lead levels in children higher than 10 mcg/ dL are considered X-rays of long bones reveal “Lead Lines “ in children.

TREATMENT Chelation therapy with DMSA for children with blood lead levels of greater than 45 mcg/ dL. Whole bowel irrigation is used if X-rays indicate the presence of lead . Follow up blood testing for stored lead in bones.

MERCURY Mercury exists in three forms:  Organic mercury  Elemental mercury  Inorganic mercury Used in thermometer, thermostats, dental amalgam & medicines like mercurochrome. Inhalation is the most frequent cause of exposure to mercury. Symptoms of acute exposure are cough, sore throat, and shortness of breath;, abdominal pain, nausea, vomiting and diarrhea; headaches, visual disturbances, tachycardia, and hypertension. Chronic exposure to mercury may result in permanent damage to the central nervous system and kidneys

LABORATORY TESTING AND DIAGNOSIS 24 hrs urine specimen Chest X-ray, abdominal X-ray Liver and Kidney function test

TREATMENT Chelation therapy using BAL, DMSA or D – Pennicillamine Activated charcoal for gastrointestinal decontamination Supportive measures.

CADMIUM Cadmium is used in nickel – cadmium batteries, pvc plastics and paint pigments. Symptoms of cute exposure are nausea, vomiting , abdominal pain , breathing difficulty Chronic exposure results in chronic obstructive lung disease, renal disease fragile bones, arthritis , osteoporosis and cardiovascular diseases.

PHARMACOLOGICAL AND TOXICOLOGICAL EFFECT ON TARGET ORGANS kidney: damages the kidney cell resulting in proximal tubular injury and proteinuria . Lungs: excessive inhalation of cadmium fumes and dust results in loss of ventilatory capacity. Bones: body store of calcium have been found to be decreased in subject exposed to cadmium.

LABORATORY TESTING AND DIAGNOSIS 24- HOURS urine specimen . CBC . Hair and finger nail clippings.

TREATMENT No known medical chelating method is effective. Prevention or elimination of exposure is all that is required for cadmium toxicity .

IRON ingesting dietary iron supplements may acutely poison young children . sources of iron are drinking water, iron pipes, and cookware . Target organs are the liver, cardiovascular system and kidneys. Symptoms of iron toxicity are pain in the stomach , nausea , vomiting . Damages internal organs, particularly the brain and the liver, and metabolic acidosis develops. The body goes into shock and death from liver failure can result.

TREATMENT Chelation with deferoxamine is commonly used with blood serum levels greater than 500 mg/dL. Supportive care with special attention to fluid balance and cardiovascular stabilization are essential in iron poisoning . BAL chelation is contraindicated for iron toxicity, because BAL can combine with medicinal iron to become very toxic.

THERAPEUTIC OVERVIEW Therapies to remove heavy metals from human includes chelation and decontamination procedures as well as supportive measures

Chelation Therapy : It is defined as the process by which a molecule encircles and binds to the metal and removes it from tissue

CHELATING AGENTS Chelating Agent

Toxin

Dimercaprol (BAL)

Arsenic Lead Mercury (inorganic)

Dimercaptosiccinic acid Arsenic (DMSA) Lead (Succimer) Mercury Dimercaptopropanesulfonate (DMPS)

Arsenic

Route

Drug

i.m.

Dimercaptol Injection B.P. BAL in Oil

p.o.

p.o. i.m.

Chemet

Bulk form (for compounding by

)

pharmacists D-pencillamine

Arsenic Mercury Lead

p.o.

Metalcaptase Pencillamine Cuprimine Depen

Ethylenediamintetraacetic acid (EDTA) (Edetate disodium)

Lead

IV

Chealamide Versenate

GASTROINTESTINAL DECONTAMINATION Gastric lavage Whole bowel irrigation Charcoal Cathartics Supportive measures

NATURAL THERAPIES TO PROMOTE CHELATION DETOXIFICATION AND PROTECTION There is no substitute for prompt professional medical attention in cases of heavy metal toxicity. There are numbers of things of dietary nature that are beneficial , protective and supportive of good health. Importance supplements are anti-oxidents , detoxifying agents and dietry fiber.

PREVENTING HEAVY METAL TOXICITY No smoking, eating, or drinking in work areas. Provide appropriate protective clothing that will remain at the facility. Provide showering facilities as needed. Work clothes and street clothes will not be kept in the same area,

CONCLUSION For most people, acute heavy metal toxicity will rarely be a concern or pose a problem. However, certain groups are at a higher risk: Those who live in homes that contain lead pipes and lead-based paint or in areas having high environmental levels of elemental mercury, iron, or aluminum Those who work in industries that manufacture batteries, pesticides, and fertilizers or who are members of their households Those who work in industries that are involved in metal finishing Those who handle chemicals in scientific or laboratory settings Unrecognized or untreated toxicity will likely result in illness and reduced quality of life. Testing is essential if Heavy metal toxicity is suspected & initiation of appropriate & natural medical procedure is required.