176 kilometers from Manaus, the city of Itacoatiara has caught the attention of the health authorities of Amazonas in recent days. Since August 22, dozens of local residents have a condition called rhabdomyolysis, marked by the destruction of the fibers that make up the body’s muscles.
In the same period, individuals from five other municipalities in Amazonas (Silves, Manaus, Parintins, Caapiranga and Autazes) were also diagnosed with the same condition.
All 44 cases registered so far are being investigated, but the main suspicion is that these individuals have been affected by Haff’s disease, popularly known as “black urine disease”.
Known since the 1920s, the disease is related to a toxin that is found in fish and shellfish.
It is precisely this substance that causes damage to the muscles and can even seriously damage the kidneys.
But what explains the outbreak in Amazonas? What are the forms of prevention, diagnosis and treatment? Know what is already known and what remains to be known about this disease.
Mystery in the Baltic
According to an article written in 2013 by specialists at Hospital São Lucas Copacabana, in Rio de Janeiro, the name of the disease has to do with its origin.
The first reports of it are from 1924 and come from the coastal region Könisberg Haff, which is close to the Baltic Sea. Currently, this site is part of the city of Kaliningrad, which belongs to Russia and borders Lithuania and Poland.
At the time, the doctors who worked at the site described a condition of sudden onset, with “muscle rigidity, often accompanied by dark urine”.
After the publication of the first reports, new cases were registered at the site for the next nine years. They occurred mainly between summer and autumn and had one factor in common: fish consumption.
“Due to the absence of fever and the rapid onset of symptoms after eating cooked fish, it is believed that Haff’s disease is caused by a toxin,” write the Brazilian authors.
Since then, new outbreaks have been registered in other countries, such as the former Soviet Union, Sweden, the United States and China.
In Brazil, the first cases were identified in 2008 and 2009.
The most serious moment happened in 2017, when Bahia counted 71 patients with the disease, 66 of them in the capital Salvador.
Symptoms and Diagnosis
As it is rare and poorly studied, Haff’s disease does not have a closed list of manifestations.
The main annoyances are muscle pain a few hours after eating fish or shellfish.
“Usually we see this muscle pain concentrated in the trapezius, shoulders and neck region”, says physician Luis Filipe Miranda, from the Nephrology Service of Hospital Português da Bahia, in Salvador.
Some patients also experience chest pain, shortness of breath, numbness, nausea, dizziness, and weakness.
Another characteristic symptom is dark urine (hence its popular name), which resembles the color of coffee.
It is believed that the cause of the disorder is some toxin found in fish species (such as salmon, pacu, eel and several others, both in fresh and salt water) and crustaceans (such as crayfish, crayfish and shrimp).
So far, scientists have not identified the toxin behind the disease.
“Since the first cases in 1924, people have tried to find out what this substance is, but so far nothing specific has been found”, emphasizes Miranda.
“It is also not known how fish acquire this toxin. Changes in the ecosystem are suspected, as well as the presence of cyanobacterial toxins or heavy metals, but so far no toxic levels of these substances have been identified”, completes the nephrologist.
As far as we know, all these repercussions on the body have to do with rhabdomyolysis, a progressive destruction of the fibers that make up the skeletal muscles (those responsible for our contractions and movements).
Over time, the content of these muscle cells is dumped into the blood, which often leads to a second complication: kidney failure.
This is because one of the components of muscle cells is myoglobin, an enzyme that is toxic to the kidneys.
According to the article by Hospital São Lucas Copacabana, the diagnosis of Haff’s disease can be made in the office itself, with the analysis of symptoms and confirmation that the patient has eaten fish in the last 24 hours.
To be 100% sure, it is possible to have blood tests that determine muscle breakdown. They measure the level of enzymes such as myoglobin and creatine phosphokinase.
Treatment and Prevention
In most cases, the condition usually evolves well, but there is a risk of death, especially in people with comorbidities.
It is recommended to seek help soon after the appearance of the first symptoms so that the diagnosis can be made as soon as possible.
When the patient needs to stay in the hospital, one of the main forms of treatment is to make a reinforced hydration.
A good amount of fluids allows “dissolve” and reduces the concentration of impurities in the blood, which facilitates the work of the kidneys.
“We also suspended the use of medications that can further damage the muscles and kidneys, such as statins and anti-inflammatory drugs,” adds Miranda.
When the kidneys are already affected, it is often necessary to resort to hemodialysis (a procedure in which a machine filters the blood for a specific period or for the rest of that person’s life).
If therapeutic resources are already scarce, the prevention of Haff disease is even more uncertain.
There is nothing specific that can be done to prevent the illness.
There are no ways to identify the toxin: it has no smell, taste or color and does not disappear after cooking the meat.
“In general, the orientation is to look for a hospital when symptoms appear in the first 24 hours after consuming the fish or shellfish and not to use medication on their own”, says Miranda.
What is missing about the Amazon outbreak?
According to the last note published on the website of the Foundation for Health Surveillance of Amazonas (FVS-AM), as of August 30, 44 cases of rhabdomyolysis had been identified.
The most affected city is Itacoatiara, with 34 patients and 1 death. Next, appear the municipalities of Silves (4 cases), Manaus (2), Parintins (2), Caapiranga (1) and Autazes (1).
“This Monday (30), 10 people are hospitalized, all from Itacoatiara. The other patients were discharged”, informs the entity.
For now, local authorities are still investigating the problem and have not officially confirmed that the outbreak is actually Haff disease, although that is the main suspicion.
This is because rhabdomyolysis can have other causes, such as trauma, strenuous physical activity, seizures, use of medications and alcohol, heavy metal intake or consumption of foods such as fish.
In another note published on the FVS-AM website, specialists say that the population does not need to stop eating fish, as they form the basis of the Amazonian diet.
“The important thing is to understand that if we are going to compare the level of fish consumption with the number of cases [de rabdomiólise], we see that it is a minimal relationship, however, no less worrying. Any situation that puts people’s health at risk must be carefully evaluated, people must be treated as appropriately as possible and we must also be concerned with the economic and nutritional aspect”, guides infectologist Antonio Magela, from the Foundation in the text. of Tropical Medicine Dr. Heitor Vieira Dourado, in Manaus.
“We’re still working in the field of hypotheses. It could be a bacterium, a virus, or even a toxin. People have a clinical picture suggestive of intoxication, after food intake, and it evolves rapidly. Until today, in all situations that this occurred, with all the analysis of samples and tissues, it has not yet been possible to confirm the real cause of these cases of rhabdomyolysis, which are associated with previous ingestion of fish”, completes the infectologist.
Since 2017, other suspected or confirmed cases of Haff disease have been reported not only in Amazonas, but also in Ceará, Alagoas, Bahia, Pernambuco and Goiás.