Paralytic shellfish poisoning

Paralytic shellfish poisoning, often shortened to PSP, is one of four recognised shellfish poisoning syndromes and is linked mainly to bivalve molluscs such as mussels, clams, oysters and scallops. These filter feeders accumulate neurotoxins, chiefly saxitoxin, made by microscopic algae including dinoflagellates, diatoms and cyanobacteria, and the toxins survive ordinary cooking because they are stable to heat and acid. Symptoms usually begin ten to thirty minutes after eating and can include nausea, tingling or burning of the lips and face, slurred speech and loss of coordination. By blocking sodium channels the toxins stop signals passing between neurons, which can cause partial or complete paralysis, and in rare severe cases death. There is no antidote, so care is supportive, with oxygen or mechanical ventilation if breathing is affected.