Acute methaemoglobinaemia initially treated as organophosphate poisoning leading to atropine toxicity

Methylene blue: a controversial diagnostic acid and medication?

A narrative review of the literature was conducted to determine if the administration of methylene blue (MB) in humans has potential risks. Studies were identified from MEDLINE, Web of Science, Scopus, and Cochrane. MB is a diagnostic substance used during some diagnostic procedures and also a part of the treatment of several diseases including methemoglobinemia, vasoplegic syndrome, fosfamide-induced encephalopathy, and cyanide intoxication, and the detection of leaks or position of parathyroid corpuscles during surgery. Although the use of MB is historically justified, and it ought to be safe, because it originated as a diagnostic material, the basic toxicological characteristics of this substance are unknown. Despite reports of severe adverse effects of MB, which could significantly exceed any possible benefits evaluated for the given indication. Therefore, the clinical use of MB currently represents a controversial problem given the heterogeneity of available data and the lack of preclinical data. This is in conflict with standards of safe use of such substances in human medicinal practice. The toxic effects of the application of MB are dose-dependent and include serious symptoms such as hemolysis, methemoglobinemia, nausea and vomitus, chest pain, dyspnoea, and hypertension. Some countries regard MB as harmful because of the resulting skin irritation and triggering of an adverse inflammatory response. MB induced serotoninergic toxicity clinically manifests as neuromuscular hyperactivity. This review aims to summarize the current understanding concerning the indications for MB administration and define the potential adverse effects of MB.

Reasons for under-reporting of paraquat poisoning in India

Background Paraquat is an inexpensive herbicide used in agriculture because it is easily available and the cost of labour for manual clearance of weeds is prohibitive. Paraquat is toxic to human beings and is also used for committing suicide. We studied the reasons for under-reporting of paraquat poisoning including those related to the training of doctors. Methods In this mixed-methods study, we describe a series of patients with paraquat poisoning. We recorded their demographic data, clinical features, treatment and outcome with an intention to explore the reason for an initial misdiagnosis. We also explored whether deficiencies in curricula contributed to the misdiagnosis. Results The patients of paraquat poisoning (n=28) were mostly young illiterate men driven by impulsive behaviour rather than chronic depression. Paraquat was consumed by patients from non-agricultural background as well, implying easy access to the poison. Many patients could not name the agent and so initial treatment was directed at organophosphorus poisoning. The diagnostic signs included paraquat tongue, renal failure and jaundice. Most of the casualty medical officers and residents were unfamiliar with the symptoms and signs of paraquat poisoning as was evident by their answers to the questionnaire. Knowledge of medical students about paraquat poisoning was not assessed in the theory examinations and viva. Conclusion Factors contributing to the limitation in establishing the diagnosis are illiteracy and ignorance of the patients, lack of specific signs and lack of training of medical officers in treating patients with paraquat poisoning.