It is the crayfish season again; the delicious crayfish because popular in China’s hot mid summer nights ever since the late 1990s. However this year over dozens of people in Nanjing were hospitalized with strange symptoms of unbearable muscle pains after eating crayfish since July. The doctor’s diagnosis was rhabdomyolysis (the destruction or degeneration of muscle tissue) serious cases even cause kidney damage. The speculation was that the “shrimp washing powder” (洗虾粉) which was popularly used by the sellers to make the crayfish look spanky fresh and clean could be the root cause. Actually the public has already been suspicious about the powder for causing health issues. There has already been reports as early as July, that “shrimp washing powder” is killing the crayfish season and citizens cry for a public “safe list” so they know where to go to enjoy them safely.
(From Sina and everywhere else) Sore back, back pain, looking deathly pale, not being able to stand up – in the afternoon of August 21, when 27-year-old Ms Chen was transferred from Jiangsu Provincial People’s Hospital emergency room into the renal ward, Chief physician thought it was something more serious. But it turned out the culprit was the crayfish (Chinese people call them “small lobsters”). “This is the third patient being admitted to the ward for this in the recent days” Doctor Liu said. Reporter learned that since this week the Provincial People’s hospital already had over 10 people came in with the same problems after eating crayfish.
The patients at People’s Hospital of Jiangsu Province are not alone. Since July of this year, Nanjing Gulou District Hospital emergency room also saw number of patients after they have eaten crayfish. Different from the ordinary food poisoning, patients did not vomit or have diarrhea and other gastrointestinal symptoms, but felt unbearable muscle pain. Doctor diagnosed it as rhabdomyolysis, in serious cases it could impair renal function and have the symptom of “soy sauce urine”.
In Jiangsu Provincial People’s Hospital renal ward, Xiao Gong was playing video games in bed. “He is fine now, doctor said to keep him in the hospital for observation to see if there is any renal dysfunction.” Xiao Gong is 21 years old. She told the reporter that she had some crayfish on August 20 at 1-2am. “Dad and his friend went out for dinner and took some food home for my mom and me. I probably ate over 10 of them, and also drank some beer.” Around 7 in the morning Xiao Gong’s whole body began to feel sore, and even had trouble breathing. Xiao Gong’s mom had the same symptoms even earlier. Two of them were send to the Provincial People’s Hospital emergency room. “Dad was ok, but my dad’s friend also had problem and went to another hospital.”
Because two of them are in serious condition, both were transferred to the renal ward. Test results showed that both had myoglobin level up to 4000μg / L and 6000μg / L in their blood. “Normal value would not exceed 50, such high level of myoglobin means that the mother and daughter’s muscles are dissolving.” (sarcolysis)
Unlike Xiao Gong and her mother, the 27 year old Ms Cheng bought her crayfish home and processed them by herself. In Just a few hours after eating the crayfish, Ms Cheng appeared to be in pain, “very severe back pain, like being pinched by needles.” Miss Cheng also felt difficult to breath, but did not have general food poisoning symptoms like nausea, vomiting, diarrhea etc.
After Ms Cheng was sent to the Hospital, the doctor got to know here past medical history and initially determined the symptoms had to do with eating crayfish. Tests revealed that Ms Cheng’s myoglobin level was at 1000μg / L, and already had urinary protein, so her kidney function was affected.
Doctors usually treat patients of rhabdomyolysis with alkaline urine processing and blood transfusion, making patients drink more water to help excreting the myoglobin in their bodies. Some not particularly serious kidney damage is reversible.
According to Provincial people’s hospital emergency room records, they have treated more than 10 people this week that had muscle pain and stiffness symptoms after eating crayfish. These people are mainly young, rather scattered in locations, some had crayfish in a restaurant, some bought crayfish home and processed themselves. Other than Nanjing, some patients are transferred from outside of the city.
"In terms of epidemiological investigation methods, we treated patients with same symptoms all after consuming crayfish, the time period between eating crayfish to being sick are about the same, and all with the same symptoms, so we can determine these rhabdomyolysis patients had to do with eating crayfish" director Liu Jia Said.
The cause for sure was the crayfish, but most crayfish food poisoning over the past had gastrointestinal symptoms of vomiting, diarrhea and so on. This time the symptom was sarcolysis, clearly different from the past. Many cases occurring at the same time is also different from the past. “Crayfish’s living environment was polluted? Crayfish was contaminated during shipping, cleaning or cooking process, all of them are likely to lead to such result.”
A Doctor at Gulou Hospital emergency room where the first “crayfish case” was found has been tracking these cases and found that there are still many question unanswered. The cases at Gulou Hospital are mostly from home made cooking, and mostly braised, so it is unlikely that the cause of illness being bacterial food poisoning. “Residual heavy medal” is also unlikely, because the issues caused by heavy metal resided in human body are accumulated from long periods of time, will not show up immediately. So chemical poisoning, organic poisoning are more likely.
Several patients have described to the doctors that the crayfish they had looked especially clean. So the doctors went to a local crayfish seller after work. The seller admitted that his crayfish are washed with some kind of “shrimp washing powder” (洗虾粉), but he had no idea what was in the powder.
According to reports, the crayfish currently sold on the market have all been washed by “shrimp washing powder”, and the powder is a kind of industrial acid – formed with “oxalic acid”, which is a 10,000 times stronger acid than vinegar. Director of First Affiliated Hospital of Tsinghua University, Lu Fangping believes that Oxalic acid and other chemicals or their metabolites can form crystals in renal tubules, and cause tubular blockage, resulting in symptoms such as acute tubular blockage and even lead to acute renal failure. Meanwhile, Director Lu Fangping also reminded us that rhabdomyolysis can cause by many reasons, long-term use of certain drugs, chronic alcoholism and excessive alcohol intake, may also lead to this situation.