Clinical Clues
The patient presents with nausea, vomiting, abdominal pain, diarrhoea, convulsions, and methaemoglobinaemia. This specific combination — corrosive gastrointestinal symptoms plus haemolysis-related and oxidant-type haematological toxicity (methaemoglobinaemia) — is a classic feature of copper sulphate poisoning.
Why Copper Sulphate Poisoning Fits
Copper sulphate (blue vitriol) is a corrosive metallic salt. On ingestion it causes a metallic taste, severe vomiting (often blue-green/bluish vomitus), abdominal pain, and diarrhoea due to its direct corrosive action on the GI mucosa. Systemically absorbed copper causes intravascular haemolysis, and the released haemoglobin is oxidised to methaemoglobin, producing cyanosis unresponsive to oxygen. Haemolysis and copper's direct toxic effects can also cause hepatic and renal damage (hepatorenal failure), and CNS involvement can manifest as convulsions/coma in severe cases. This combination of GI corrosive symptoms + convulsions + methaemoglobinaemia is a well-recognised toxidrome specifically pointing to copper sulphate poisoning, making it the correct answer.
Why the Other Options Are Incorrect
- Aluminium phosphide poisoning: Releases phosphine gas, causing severe refractory hypotension, cardiogenic shock, vomiting, and metabolic acidosis (the classic "garlicky odour" poison). It is not characteristically associated with methaemoglobinaemia; cardiovascular collapse dominates the picture rather than haemolysis-driven methaemoglobin formation.
- Zinc phosphide poisoning: Also releases phosphine on contact with gastric acid, producing GI irritation, vomiting, and CNS/cardiac toxicity similar to aluminium phosphide. Methaemoglobinaemia is not a hallmark feature of zinc phosphide toxicity — the current/old solution incorrectly attributed this finding to zinc phosphide.
- Lead poisoning: Typically a chronic, insidious poisoning presenting with abdominal colic, constipation (not diarrhoea), anaemia with basophilic stippling, peripheral neuropathy (wrist/foot drop), and encephalopathy in children. It does not cause methaemoglobinaemia and does not present acutely in this fashion.
Conclusion
The presence of methaemoglobinaemia together with acute corrosive GI symptoms and CNS involvement (convulsions) is most consistent with copper sulphate poisoning, confirming it as the correct diagnosis.
Important Questions from Chemical Poisoning
Consider the following statements regarding organophosphate-induced delayed polyneuropathy (OPIDN) :
1. It is a rare complication and occurs 2 - 3 weeks after acute exposure.
2. It is a feature of poisoning with certain organophosphorus compounds such as triorthocresyl phosphate.
3. Inhibition of acetylcholinesterase causes motor polyneuropathy with no evidence of sensory loss.
4. There is no specific therapy although regular physiotherapy may limit deformity caused by muscle wasting.
Which of the statements given above are correct?
- The toxic effects of aluminium phosphide is due to the release of:
- Use of calcium carbide for the artificial ripening of fruits is banned but it is often reported to be illegally used. What is/are the likely health hazards of exposure to this chemical?
1. Permanent damage to the eyes
2. Pulmonary edema
3. Irritation of mouth, throat and nose
Select the correct answer using the codes given below: - Which of the following statements is correct regarding Malachite that is used as food adulterant?
Which of the following parts of the human body can be used as a sample/samples for the presence of mercury?
1. Blood
2. Hair
3. Nail
Select the correct answer using the code given below:
