Within hours of eating shellfish contaminated with toxic levels of saxitoxin, victims develop gastrointestinal distress and neurological symptoms, ranging from benign circumoral paresthesias and tingling of the extremities to ataxia, dysphagia, and changes in mental status. Many patients describe a sensation of “floating” or dissociation.
While most patients recover without treatment, weakness may rapidly progress to respiratory paralysis and asphyxiation.
The diagnosis of paralytic shellfish poisoning is almost always made clinically, but can be confirmed by measurement of saxitoxin levels either in the shellfish meat or the patient’s urine or serum
Currently there are no antidotes to saxitoxin and treatment is supportive..