Lion's mane jellyfish sting

The lion's mane jellyfish (Cyanea capillata) is described as the largest jellyfish in the world, growing up to 2.5 metres in diameter, trailing up to 1000 tentacles each of up to 45 metres in length. Its range is confined to cooler waters of the world's oceans. The toxins released by the lion's mane jellyfish are complex, involving histamines, kinins, peptides, prostaglandins, 5-hydroxytryptmine and other vasoactive compounds.

While there is some ongoing debate around the most appropriate initial treatment for jellyfish stings, it seems probable that hot-water immersion is the most universally beneficial treatment, especially in stings from the lion's mane species. Vinegar also has a potential role in removing adherent tentacles and nematocysts (Doyle et al, 2017).

A 45-year-old female presented to the emergency department following multiple stings from a jellyfish. She was attempting to swim across ‘The Minch’—at the point of her crossing, this is a 25-mile stretch of water separating the Isle of Lewis in the Outer Hebrides from mainland Scotland. Wider than the English Channel and more exposed, this represents a significant challenge to even the most experienced open-water swimmer. During her swim, the sea temperature was recorded as 9–11°C (48-52°F). Departure time from the Isle of Lewis was at approximately 9 pm because of the tide and prevailing currents. Despite the late hour, it was a full moon so light conditions were reasonable. Unfortunately, it is assumed that the full moon increased the likelihood of jellyfish swarms closer to the shore (University of Haifa, 2016). The support crew also postulated the theory that the propeller of their boat may have shredded the jellyfish, thus distributing pieces of tentacles over a larger area.