Ingested seafood toxins

Question 1

histamine (scombroid poisoning)

Answer 1

Source: Spoiled dark-meat fish
such as tuna, mahimahi,
mackerel, and
bonito.
Action: Bacterial histidine
decarboxylase converts
histidine to histamine.
Frequently
misdiagnosed as fish
allergy.
Sxs: Mimics anaphylaxis:
acute burning
sensation of mouth,
flushing of face,
erythema, urticaria,
itching. May progress
to bronchospasm,
angioedema,
hypotension.
Treatment: Antihistamines.
Albuterol and
epinephrine if needed.

Question 2

tetrodotoxin

Answer 2

Source: Pufferfish.
Action: Highly potent toxin;
binds fast voltagegated
Na+ channels
in cardiac/nerve
tissue, preventing
depolarization.
Sxs: Nausea, diarrhea,
paresthesias,
weakness, dizziness,
loss of reflexes.
Treatment: Supportive.

Question 3

ciguatoxin

Answer 3

Source: Reef fish such as
barracuda, snapper,
and moray eel.
Action: Opens Na+
channels, causing
depolarization.
Sxs: Nausea, vomiting,
diarrhea; perioral
numbness;
reversal of hot and
cold sensations;
bradycardia, heart
block, hypotension.
Treatment: Supportive.