A man is in a critical condition in a hospital in Hong Kong after consuming puffer fish and suffering suspected tetrodotoxin poisoning.

The 65-year-old man developed facial numbness, general weakness and respiratory failure about two hours after eating cooked puffer fish he caught in local waters for lunch at home earlier this week.

He went to the accident and emergency department of Prince of Wales Hospital (PWH) on the same day as he ate the fish and was then admitted to the intensive care unit of PWH for further management.

Public warning
The Centre for Health Protection (CHP) of the Department of Health is investigating the suspected poisoning case and reminds the public not to consume puffer fish, also known as globefish, fugu, or blowfish.

Puffer fish may contain tetrodotoxin. It is mainly found in the eggs, liver and skin. This fish must be cleaned and prepared properly so that organs containing toxins are removed and do not cross-contaminate the edible flesh of the fish.

A CHP spokesman said consumption of puffer fish is the main cause of food poisoning from tetrodotoxin, a potent water-soluble neurotoxin that can affect the central nervous system.

“Being heat-stable, the toxin does not decompose upon cooking, boiling, drying or freezing. Tetrodotoxin intoxication can cause problems in respiration or circulation and is potentially fatal. There is no known antidote or antitoxin. Members of the public are advised to avoid purchasing and preparing puffer fish or unknown fish for consumption to prevent tetrodotoxin-related food poisoning,” he said.

In Hong Kong, tetrodotoxin intoxication as food poisoning has been a statutory notifiable disease since 1974. From 2004 to June 2014, the Centre for Health Protection recorded 21 cases of tetrodotoxin poisoning affecting 38 people. Twenty-six required hospitalization while six of them needed intensive care but none died.

Rare but serious
In the U.S., a case of tetrodotoxin poisoning related to puffer fish was reported in Virginia in 2014 and two occurred in Minneapolis in the same year. The person in Virginia ate puffer fish imported from South Korea and received by the patient’s relatives. For the brother and sister in Minneapolis the fish was bought in New York. Two people were affected in Chicago in 2007. The fish, bought in Chicago, was labeled as monkfish.

In Japan, puffer fish poisoning is the most common natural marine toxin causing food poisoning.  Puffer fish, also called fugu, is a popular traditional dish. In 2009, there were 50 cases but no deaths.

In Taiwan, from 1992 to 2012, 128 people were affected and 11 died. In China, puffer fish poisoning affected 131 people from 2004 to 2007 and 35 deaths were reported.

Puffer and porcupine fish are common examples of fish containing tetrodotoxin. It has also been isolated from other species including goby, shellfish, California newt, parrotfish, blue-ringed octopus, starfish, angelfish, and xanthid crabs.

Patients with tetrodotoxin poisoning usually develop symptoms within 30 minutes to six hours of ingestion. These may include nausea, diarrhea, and vomiting, abdominal discomfort, numbness in the face, muscle weakness and slurred speech and cardiovascular effects including hypotension, bradycardia and arrhythmia. If the victim survives the first 24 hours, they are expected to fully recover as toxin can be expelled from the body through urination.

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