Arsenic Toxicity Symptoms Quiz

Heavy Metal Toxicity

• Heavy metal toxicity is a major concern, as metals are not degradable and can form poisonous soluble compounds.
• Sources of heavy metal toxicity include mining, industry, agriculture, and occupation.

Lead (Pb) Toxicity

• Sources of lead toxicity include:
  • Batteries
  • Glass, plastics, and ceramics
  • Lead-based paints
  • Combustion of leaded gasoline
  • Metal alloys
• Environmental effects of lead include:
  • Water pollution
  • Air and soil pollution
• Forms of lead compounds:
  • Inorganic lead
  • Organo-lead compounds
• Toxicokinetics:
  • Inorganic lead: not readily excreted, accumulates in blood, bone, and brain
  • Organic lead: volatile, lipid soluble, and readily absorbed through the respiratory and gastrointestinal tracts
• GIT effects:
  • Moderate exposure: constipation and loss of appetite
  • High exposure: lead colic, characterized by abdominal pain, nausea, and vomiting
• Oral effects:
  • High exposure: gingival lead lines (Burton's lines)
• Bone effects:
  • Chronic exposure: lead replaces calcium and accumulates in bones
• Haematological effects:
  • Moderate exposure: "lead anemia"
• CNS effects:
  • Acute exposure: encephalopathy, neurocognitive deficits, tremors, convulsions, mental retardation, and death
  • Chronic exposure: decreased learning, cognition, and IQ, hearing impairment, poor postural balance, and behavioral symptoms
• Diagnosis:
  • Symptoms: according to age and dose
  • Lab tests: blood lead level, aminolevulinic acid in urine, and reduction of active blood ALAD enzyme
• Management:
  • Supportive care: treatment of seizures, controlling cerebral oedema
  • Antidotes: metal chelators (succimer, disodium calcium EDTA, British Anti-lewisite, and dimercaprol)

Arsenic (As) Toxicity

• Sources:
  • Metal hardening
  • Insecticides, rodenticides, and fungicides
  • Glass industry
  • Pigments industry
  • Water and food pollutant
• Forms:
  • Organic: pentavalent arsenate (As5+)
  • Inorganic: trivalent arsenite (As3+), arsine gas (AsH3), and pentavalent arsenate (As5+)
• Symptoms of acute toxicity:
  • Hematemesis and abdominal pain
  • Rice-water diarrhea
  • Garlic-like breath
  • Thirst and metallic taste
  • Contact dermatitis
  • Arsine gas exposure: acute hemolytic anemia and striking chills
• Symptoms of chronic toxicity:
  • Stomach pain and diarrhea
  • Numbness in hand and feet
  • Partial paralysis and blindness
  • Chronic lung disease
  • Melanosis and keratosis (palms and feet), and black foot disease
• Management:
  • Supportive care: exchange transfusion, vigorous hydration, and hemodialysis (if renal failure occurs)
  • Antidotes: metal chelators (no benefit in chronic toxicities)

Cadmium (Cd) Toxicity

• Sources:
  • Silver mining
  • Industrial effluent
  • Household cleansers
• Acute vs. chronic cadmium toxicity:
  • Acute: GI effects (oral) and local respiratory irritation (inhalation)
  • Chronic:
    • Kidney: most cadmium-sensitive organ (atrophy)
    • Lungs: emphysema
    • CVS: hypertension
    • Bones: osteomalacia (bone softening)
    • Testes: necrosis
    • Itai-Itai disease
• Itai-Itai disease:
  • Cause: contamination of river water by cadmium from silver mining companies
  • Effects: "It hurts-it hurts"