Paralytic Shellfish Poisoning
Commonly known as “red tide”, this syndrome is due to ingestion of toxic shellfishes and other aquatic animals.
Saxitoxin is the toxin causing the symptoms and this comes from the algae which are ingested by the shellfishes and other sea fishes during the filter feeding.
It is because of the abnormal proliferation of these algae in sea waters that causes its discoloration which are frequently frequently reddish brown or orange thus the name red tide.
The following factors play a role in the red tide situation:
– pollution of waters
– change in salinity
– ph of the water and
– climactic conditions.
Saxitoxin is a derivative of tetrahydropurine and one of the most lethal poisons known. It is estimated that 0.1 mg is lethal to man.
Clinically, the symptoms occur within 15 minutes up to 12 hours post ingestion of contaminated sea products with an average of 3 hours.
The following symptoms may occur:
– tingling sensation or numbness around the lips and spreading to the face and neck and also the upper and lower extremities
– generalized body weakness manifested in children as inability to get up
– floating sensation
– ataxia and dizziness
– in severe cases there is respiratory paralysis
There is no known specific antidote to red tide poisoning and treatment is purely supportive.
Gastrointestinal decontamination by emesis or gastric lavage with activated charcoal will help eliminate the toxin.
Fats and oily substances can delay absorption of the toxin.
Patients who do not develop severe symptoms within 24 hours post ingestion recover spontaneously.
Patients with respiratory paralysis may need mechanical ventilation.