Family Gets Extremely Rare Muscle-Wasting Disease after Eating Toxic Fish

Three members of a family in Australia have all contracted a rare disease after eating recently thawed and cooked queen snapper fish.

Haff disease, also known as rhabdomyolysis, is a rare condition that is often associated with eating cooked seafood. The disease causes muscle tissue to break down and release muscle fiber contents into the blood, leading to unexplained muscular rigidity and elevated levels of serum creatine kinase.

According to the authors of a recent case report in the BMJ, Haff disease was first described in 1924, with occasional occurrences in the U.S. and in China, usually linked to consumption of buffalo fish, crayfish, and salmon. This family was the first recorded case in Australia, according to the case report.

Around 10 hours after eating the snapper fish, the family went to the hospital, as they were all experiencing severe muscle pains in their limbs. The son also reported passing dark brown urine. All members of the family were found to have rhabdomyolysis, but the son, who is in his 20s, also had an acute kidney injury. The authors suggest that this might be because he had two portions of the fish. The family was rehydrated via IV drip.

Scientists don't really know what causes rhabdomyolysis after eating seafood, speculating that perhaps there is "an unidentified and unisolated toxin that can directly induce rhabdomyolysis" present in the fish.

According to the authors, one suggested mechanism is a palytoxin-like compound. Palytoxin is a cytotoxin that acts on sodium–potassium, hydrogen and calcium ion channels, and has been isolated in Palythoa toxica, a species of sea anemone, as well as other animals including corals.

42-hydroxy-palytoxin has been shown to induce damage to mouse skeletal muscles, but there is no current evidence of it causing rhabdomyolysis in humans. Additionally, there have been reported cases of Haff disease in people who have only been exposed to non-Palythoa fish species, like parrotfish.

The authors discuss the fact that the fish that have been involved in cases of Haff disease are often omnivorous and higher in the food chain. This may mean that the causal toxin is bioaccumulated, becoming more concentrated as each predator eats its prey.

"In this particular case, the queen snapper has a diet including cephalopods, which have been reported to accumulate several toxins such as palytoxin," the authors said in the paper.

"However, the presumption that this toxin is involved in the pathogenesis of this disease remains debatable, as it has only been detected in marine fish and not freshwater fish (i.e. buffalo fish) that has also been implicated in Haff disease."

The case of the son is of particular interest to the authors, as the disease was worse in him than in his parents, and he had eaten twice as much snapper fish as they had.

"The presence of similar presentations of varying severity in a family cluster had alerted the attending medical team to the possibility of Haff disease as the cause of the common presentations. Clinicians should be cognisant of the importance of a detailed medical history, including the potential exposure to dietary and environmental toxins when encountering cases of rhabdomyolysis," they said.