Seastroke: a new entity?

Three previously healthy young male patients had brain stem infarction (stroke) after swimming or wading in shallow water along the southeastern North Carolina coastline. Each patient remembered an unusual encounter with something in the water. None sustained any obvious local envenomation. Although these cases may be a highly unusual coincidence, I believe they represent a previously unidentified entity--"seastroke." I speculate that the injuries could be caused by contact with a toxic marine animal.