A fatal and deceiving case of copper sulphate poisoning
The present case has been published in the Indian Journal of Anaesthesia.

A 26-year-old male, painter by occupation, was brought to the casualty with alleged suicidal intake of copper sulphate crystals of unknown amount 2 h back. He complained of abdominal pain and had three episodes of vomiting. He was conscious and oriented with stable vital parameters. He was started on intravenous (IV) injection (inj.) penicillamine, inj. ondansetron and IV pantoprazole infusion. On arrival in the intensive care unit (ICU), he had pulse rate of 82 beats/min, blood pressure 116/70 mmHg and SpO2 90% on room air and 96% on ventimask.

Routine haematological investigations and chest X-ray were found to be insignificant. However, after 6 h, patient developed breathlessness and SpO2 decreased to 75%. Arterial blood gas (ABG) analysis at that time showed pH 7.46, PO2 330 mmHg, pCO2 25.3 mmHg, HCO3 17.9 and SpO2 98%. Based on disparity between SpO2 on the pulse oximeter and ABG, methaemoglobinemia (methHb) was suspected.

High flow of warm humidified oxygen through nasal cannula at flow rate of 55 l/min and FiO2 of 70% was given. The methHb level was 11.4%. Methylene blue 100 mg was administered IV over 15 min and tablet vitamin C 500 mg 12 hourly was given. Inj. methylene blue was repeated after 1 h. After second dose, breathlessness was relieved. However, SpO2 on monitor remained 84–85%.

From next day onwards, patient started having cola-coloured urine with decreased urine output. Kidney function tests also started deteriorating.

Urine routine microscopy and peripheral smear revealed signs of haemolysis and blood investigations showed raised serum lactate dehydrogenase and total creatinine phosphokinase levels. Urine output did not improve with fluid bolus challenge and as blood pressure of the patient began to fall; dopamine IV infusion was started.
Read more here: http://www.ijaweb.org/article.asp?issn=0019-5049;year=2018;volume=62;issue=10;spage=819;epage=820;aulast=Gupta;type=3
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