On average, symptoms begin 3-4 hours after consumption, but can begin anywhere from several minutes to 18 hours afterward. Symptoms typically include neurologic and gastrointestinal issues including:
nauseavomiting
diarrhea
numbness and tingling in the lips, mouth, face, and extremitiesThe latter has been described as “nerves being on fire” or “ants crawling and biting all over”.Other less common symptoms can include:
ataxia
loss of coordination
limb paralysis
reversal of hot and cold sensations
slurred speech
headache
pupil dilation
generalized fatiguePatients may be thought to be disoriented or intoxicated. Rarely, patients may experience respiratory distress requiring ventilatory support. Despite this seemingly severe constellation of symptoms, there have been no documented deaths due to NSP. NSP can present similar to other disorders such as:
common food poisoning
seafood allergy
paralytic shellfish poisoning
ciguatera fish poisoning
pesticide poisoning
alcohol intoxication
certain psychiatric disorders.Due to the extensive list of disorders with similar symptoms, a detailed food history is necessary to make the diagnosis. Management and treatment
Treatment for NSP is mostly supportive with monitoring and symptom management. Intravenous fluids and observation of respiratory function are the mainstay of treatment along with pain control. Activated charcoal can be given if the patient presents within four hours of consumption to decontaminate the gastrointestinal tract. Currently, there is no specific antidote for brevetoxins, however there may be a role for mannitol (the primary treatment for ciguatoxin, a dinoflagellate-produced toxin found in some species of fish) or brevatal, a natural antagonist of brevetoxin produced by K. brevis. Though public health policy differs by state, measures are taken to prevent shellfish poisoning outbreaks.
The Florida Department of Health has added NSP to their list of reportable diseases. Additionally, since the mid-1970s the Florida Department of Environmental Protection has conducted monitoring of dinoflagellate levels and restricted the harvest of shellfish from nearby shellfish beds when levels are dangerously elevated. Shellfish beds are subsequently opened after two weeks with confirmation of safety by mouse bioassay testing (mouse bioassay testing involves the injection of mice with shellfish extract with subsequent observation for mouse death). See also
Amnesic shellfish poisoning
Diarrheal shellfish poisoning
Paralytic shellfish poisoning
Ciguatera fish poisoning


== References ==