What is Amnesic Shellfish Poisoning
Amnesic shellfish poisoning is a rare type of food poisoning caused by eating seafood that contains a poison (toxin) called domoic acid. Domoic acid is produced by a saltwater form of algae, and it is often eaten by shellfish, such as clams, oysters, and mussels.
You can get sick when you eat shellfish or crab that contains domoic acid (is contaminated). Cooking or freezing the shellfish does not kill the toxin.
Domoic acid causes stomach and intestinal problems. It can also cause problems with the brain and spinal cord (nervous system). In severe cases, these problems can be life-threatening.
What are the causes?
This condition is caused by eating seafood that has had contact with domoic acid.
What increases the risk?
The following factors may make you more likely to develop this condition:
- Eating shellfish, such as mussels, clams, and oysters.
- Eating seafood from an area that recently had high levels of algae in the water (red tide).
What are the signs or symptoms?
Symptoms of this condition usually develop within 24 hours after eating contaminated seafood. The first symptoms that develop may include:
- Abdominal cramps.
- Diarrhea.
- Nausea and vomiting.
Severe symptoms may develop within the first 48 hours, including:
- Dizziness.
- Headache.
- Confusion.
- Muscle weakness.
- Heavy sweating.
- Irregular heartbeat (arrhythmia).
- Short-term memory loss that may be permanent.
In the most severe cases, symptoms may include:
- A state of unconsciousness (coma).
- Jerky movements that you cannot control (seizures).
- Loss of the ability to move (paralysis).
- Memory loss that gets worse over time (dementia).
- Kidney failure.
How is this diagnosed?
This condition is diagnosed based on:
- Your symptoms.
- Your medical history.
- Whether you recently ate seafood that could have been contaminated. If possible, the seafood you ate may be tested for domoic acid.
- A physical exam.
How is this treated?
Treatment for this condition is focused on relieving symptoms and keeping you hydrated. Treatment may involve:
- Medicine to help relieve vomiting.
- Medicine to help treat seizures or heart problems, in severe cases.
- Receiving fluids through an IV tube in the hospital, in severe cases.
- Breathing support, if needed.
Follow these instructions at home:
- Drink enough water and fluids to keep your urine clear or pale yellow. Drink small amounts often at first. Gradually drink more as you are able.
- Follow instructions from your health care provider about how to re-hydrate.
- Take over-the-counter and prescription medicines only as told by your health care provider.
- Keep all follow-up visits as told by your health care provider. This is important.
Contact a health care provider if:
- You
have any of the following symptoms that do not go away after 1–2 days:
- Abdominal cramps.
- Nausea.
- Vomiting.
- Diarrhea
- Your symptoms get worse.
Get help right away if:
- You have a seizure.
- You develop paralysis.
- You are urinating less than usual.
- You feel confused or have trouble staying awake.
Summary
- Amnesic shellfish poisoning is a type of food poisoning from certain types of seafood.
- The most common symptoms are stomach cramping, nausea, vomiting, and diarrhea.
- Treatment consists of medicines and fluids to help you recover.
