Fugu Poisoning

Definition

Fugu poisoning occurs when a person eats the flesh of a fugu, also known as a puffer fish, which contains lethal toxins.

Description

Fugu, also known as puffer fish, blowfish, or globefish, has long been a food delicacy in Japan, but has only been introduced in the United States in the last 30-40 years. The fugu and related species may contain a tetrodotoxin, an extremely potent neurotoxin and one of the most toxic substances known, which produces critical illness and often death. Between January 1 and April 1, 2002, at least 10 cases of fugu poisoning were reported in the United States, according to the Centers for Disease Control and Prevention (CDC) in Atlanta. All persons recovered from the poisonings. All of the fish came from the Atlantic Ocean off the coast of Titusville, Florida. Fugu caught in southern U.S. waters, such as the Gulf of Mexico, may also be toxic. Tetrodotoxin has been detected in pufferfish throughout the Pacific Ocean and the Baja California coastal region. Cases of fugu poisoning are sporadically diagnosed, but many more are not recognized or reported. The earliest cases reported to the CDC involved poisonings in Florida during the mid-1970s. Since 1950, only three known fatalities have occurred in the United States, all in Florida.

The dangers of puffer fish consumption have long been recognized. Artifacts recovered from an Egyptian tomb indicate that puffer fish poisoning has been known since approximately 2400–2700 B.C. In journals covering expeditions from 1772–1775, Pacific explorer Captain James Cook provided a vivid description of what some believe to be puffer fish poisoning. Fugu are found in waters throughout the world. Scientists have found that toxic fugu have unique exocrine glands for the secretion of tetrodotoxin. The fish appear to actively produce the toxin, rather than passively acquire it from the environment. For these fish, tetrodotoxin may serve as a natural defense mechanism to repel predators. The flesh of the fugu is generally eaten raw in paper-thin slices, known as sashimi. Part of the reported delight in eating fugu is the tingling oral sensation induced by minute amounts of tetrodotoxin in the flesh. For this reason, eating fugu is considered an "experience," rather than just a meal in Japan. The experience is expensive, however, since a plate of this delicacy can cost as much as $500.

Causes & symptoms

The most common symptoms of fugu poisioning are tingling and burning of the mouth and tongue, numbness, drowsiness, and incoherent speech. These symptoms usually occur 30 minutes to two hours after ingestion of the fish, depending on the amount of toxin ingested. In severe cases, ataxia (the inability to coordinate the movements of muscles), muscle weakness, hypotension (low blood pressure) and cardiac arrhythmias (irregular heartbeat) may develop, followed by muscle twitching and respiratory paralysis, and death can occur. In several cases, people died within 17 minutes after eating pufferfish.

Diagnosis

The initial diagnosis is usually made by observation of early symptoms, including an abnormal or unexplained tingling, pricking, or burning sensation on the skin around the mouth and throat. Definitive diagnosis can only be made in a medical laboratory by examination of the ingested fish and identification of the specific toxins. Ill persons should be advised to proceed to a hospital emergency department and contact their local poison control center.

Treatment

There is no antidote for fugu poisoning, therefore treatment is limited to supportive measures and the removal of the unabsorbed toxin. If spontaneous vomiting does not occur, it should be induced. Gastric lavage (stomach washing) with an alkaline solution has been suggested, as well as endoscopy to remove the poison from the proximal small bowel. Following lavage, activated charcoal is reported to effectively bind the toxin. Other steps include administration of oxygen, assisted breathing, intravenous atropine for bradycardia (slow heartbeat) and intravenous fluids, along with dopamine, to manage hypotension. Since tetrodotoxins and opiates are similar, use of an opiate antagonist may be useful, according to the American Academy of Family Physicians.

Alternative treatment

There is no alternative medicine treatment for fugu poisoning.

KEY TERMS

Ataxia— A lack of muscle control.

Arrhythmia— An irregularity in the normal rhythm or force of the heartbeat.

Atropine— A poisonous alkaloid obtained from belladonna or related plants, used medically to dilate the pupils of the eyes and to stop spasms.

Endoscopy— The use of a medical instrument consisting of a long tube inserted into the body, usually through a small incision, for diagnostic examination and surgical procedures.

Exocrine— Relating to external secretion glands, such as sweat glands or salivary glands that release a secretion through a duct to the surface of an organ.

Hypotension— Low blood pressure.

Lavage— The washing out of a hollow body organ, for example, the stomach, using a flow of water.

Neurotoxin— A substance that damages, destroys, or impairs the functioning of nerve tissue.

Prognosis

The mortality rate may be as high as 60%. Epidemiologic evidence suggests that recovery can be expected if an affected person survives beyond 24 hours. After 24 hours, a person with fugu poisoning usually makes a full recovery.

Prevention

The only prevention is not to eat any of the species of fugu that contain toxins.

Resources

BOOKS

Olson, Kent R. Poisoning & Drug Overdose New York City: McGraw-Hill, 2003.

PERIODICALS

Currie, Bart J. "Marine Antivenoms." Journal of Toxicology: Clinical Toxicology (April 2003): 301-308.

"Fugu Fish Sequenced." Applied Genetics News (August 2002): 0.

Scully, Mary-Louise. "Tingling Away in Titusville, Florida." Infectious Disease Alert (August 1, 2002): 165-167.

ORGANIZATIONS

American Association of Poison Control Centers. 3201 New Mexico Ave., Suite 330, Washington, DC 20016. (292) 362-7217. info@aapcc.org. http://www.aapcc.org.