Oxalic acid toxicity

Background

• Used in bleach and rust removers
• Also found in some species of plants

Mechanism of Toxicity

• Solution form:
  • Irritative and Corrosive
  • Causes hypocalcemia and formation of calcium oxalate crystals that can deposit in brain, heart, and kidneys.
• Insoluble form:
  • Local mucous membrane irritation

Toxic Dose

• 5-15 g can be lethal

Clinical Features

• Direct contact with skin/eyes
  • Skin and eye irritation and burning
• Inhalation
  • Sore throat, cough, wheezing, pulmonary edema
• Ingestion
  • Weakness, tetany, cardiac arrest

Diagnosis

• Clinical
• No specific levels for oxalic acid

Management

• Protect the airway
• Decontamination
• Calcium chloride or calcium gluconate to reverse hypocalcemia

References

• Olson, K. Poisoning and Drug Overdose, 1999.