‘Mad honey’ poisoning not cholinergic
MedWire News: Research suggests that grayanotoxin or "mad honey" poisoning should not be regarded as a form of cholinergic poisoning, despite triggering similar symptoms in affected individuals.
Mad honey poisoning has been reported around the world, but a large number of reported cases have been attributed to consumption of honey produced along the Black Sea coast in Turkey.
The cause of the poisoning is due to bees taking up pollen from Rhododendron and Kalmia species of plants that contain grayanotoxin in their leaves and nectar.
The symptoms of mad honey poisoning, which include bradycardia, hypotension, syncope, vertigo, and nausea, resemble those of cholinergic poisoning.
To assess whether levels of pseudocholinesterase are altered in these patients, Suha Turkmen (Karadeniz Technical University, Trabzon, Turkey) and colleagues measured levels of pseudocholinesterase in a group of 30 patients with suspected mad honey poisoning admitted to an emergency medicine department in Turkey between 2008 and 2009.
The patients all had a combination of bradycardia, hypotension, syncope, dizziness, nausea, or vertigo and had a history of recent honey consumption.
Mean levels of pseudocholinesterase were 7139.30 U/L in these patients. As this is within the normal range for healthy adults of 5400-13,200 U/L, the team says that mad honey poisoning should not be regarded as a form of cholinergic poisoning.
Indeed, only three of the 30 patients had low levels of pseudocholinesterase.
"In contrast to cholinergic poisoning, serum pseudocholinesterase levels do not show a decrease in patients with mad honey poisoning, even though the two types of poisonings have similarities in symptoms and findings," write Turkmen et al in the Journal of Emergency Medicine.
The researchers concede that their study is small and therefore "an answer to the question of whether mad honey poisoning can be regarded as cholinergic poisoning should be sought with wider, more comprehensive analytical studies."
However, they conclude that "the fact that serum pseudocholinesterase levels were within normal limits in 90% of patients in this study does not support the idea that mad honey poisoning is a cholinergic poisoning."
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By Helen Albert