Chromium toxicity

Background

• Blue white metal
• Essential in glucose and fat metabolism
• The predominant forms are trivalent (Cr³⁺) and hexavalent (Cr⁶⁺)
• Cr⁶⁺ is a carcinogen
• Uses
  • Chrome platting
  • Component of making stainless steel
  • Used to make cement
  • Welding
  • Joint arthroplasty
  • Coronary artery stents
  • Tanned leather products

Toxicokinetics

Form	Toxicity	Absorption	Distribution	Elimination
Cr3+	Rarely develops toxicity	Limited oral absorption with 98% recovered in feces		Urinary excretion
Cr6+	Main cause of toxicity Oxidative agent producing oxidative DNA damage	Modestly absorbed 10% orally 50-85% inhalational	50% total body burden is localized to the kidney and liver With additional stores in bone marrow, lymph nodes, spleen, and testes	Cr6+ is rapidly converted to Cr3+ in the blood

Clinical Features

• Acute
  • Similar to corrosive metal ingestions
  • GI hemorrhage
  • Vomiting
  • Bowel perforation
  • Intravascular hemolysis with DIC
  • Acute tubular necrosis and Renal failure
  • Metabolic acidosis
  • Hyperkalemia
  • Acute lung injury
  • Skin inflammation and ulcerations
    • Dermal chromic acid (H₂CrO₄) can lead to systemic toxicity with as little as 10% BSA
• Chronic
  • Most are occupational inhalation exposures
  • Chrome holes
    • Nasal septal perforation
    • Skin ulcerations
  • Chronic cough
  • Dyspnea and bronchospasm
  • Anaphylactoid-like reactions
  • Pneumoconicosis
  • Increase risk of lung cancer
    • Small cell lung cancer, however all types are associated with Cr⁶⁺ exposure
  • Contact dermatitis and Type IV hypersensitivity reaction

Differential Diagnosis

Heavy metal toxicity

• Aluminum toxicity
• Antimony toxicity
• Arsenic toxicity
• Barium toxicity
• Bismuth toxicity
• Cadmium toxicity
• Chromium toxicity
• Cobalt toxicity
• Copper toxicity
• Gold toxicity
• Iron toxicity
• Lead toxicity
• Lithium toxicity
• Manganese toxicity
• Mercury toxicity
• Nickel toxicity
• Phosphorous toxicity
• Platinum toxicity
• Selenium toxicity
• Silver toxicity
• Thallium toxicity
• Tin toxicity
• Zinc toxicity

Evaluation

• BMP
• LFTs
• CBC
• CPK
• EKG
• If toxicity present add coagulation factors
• Chromium levels
  • Whole blood: 20-30 μg/L (380-580 nmol/L)
  • Serum: 0.05-2.86 μg/L (1-56 nmol/L)
  • Urine: < 1μg/g creatinine (<19.2 nmol/g creatinine)
    • Can reflect acute absorption of chromium over the past 1-2 days, however wide variation in metabolism and total body burden
  • Baseline levels have varied over the past 50 years by 5000-fold, additionally it is difficult to establish standard reference range, use caution when interpreting these levels
  • Phlebotomy needles and blood containers for storage contain chromium

Management

• Decontamination
  • Activated charcoal not indicated
  • Consider NG lavage if Cr⁶⁺ ingestion and presenting within 1-2 hours without signs of vomiting
  • Consider oral N-acetylcysteine
    • Shown to increases renal elimination of chromium in rats
• Supportive care
• Chelation
  • Not effective in reducing chromium levels
• Dialysis
  • Not effective in those with normal renal function
  • Consider in those on chronic dialysis

Disposition

• Acute toxicity likely requires intensive care unit
• Consult Toxicology or Poison Control Center

References

Bird, S. Chromium. In: Goldfrank's Toxicologic Emergencies. 9th Ed. New York: McGraw-Hill; 2011: 1243-1247