A woman who ingested a household cleaning solution develops severe pain in the mouth and throat, haematemesis, and within hours painful carpopedal spasm with a serum calcium of 5.8 mg/dL. Which corrosive was most likely ingested?
- A Sulphuric acid
- B Nitric acid
- C Oxalic acid ✓
- D Carbolic acid
Correct answer: C. Oxalic acid
Explanation
Oxalic acid binds ionised calcium to form insoluble calcium oxalate, producing profound hypocalcaemia with tetany, convulsions and cardiac arrhythmia, along with renal tubular damage from oxalate crystal deposition. Sulphuric and nitric acids cause coagulative necrosis and charring without hypocalcaemia, and phenol causes white cauterised mucosa with dark urine from oxidised phenol products.
Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.
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