Clipping of news on Brazilian Culture, Law and Citizenship
05/02/2013
This article was translated by an automatic translation system, and was therefore not reviewed by people.
Three killed in Campinas this week after MRI.
Expert explains how the procedure works and contraindications.
The rate of severe reaction to the use of contrast in MRIs is about 0.01% of cases, according to the neuroradiologist Edson Amaro Jr., MD, Albert Einstein Hospital in Sao Paulo, and professor at the School of Medicine USP.
(Correction: to be published, this story was wrong to report that the severe reaction by contrast occurs in 0.1% of cases. Correct number is 0.01%. This information was corrected in 3/2 at 13.30).
On Monday (28), three people died after undergoing an MRI at the Hospital Vera Cruz, in Campinas (SP). The Local Health Surveillance banned the responsible sector and intends to investigate whether the contrast - a chemical compound used in the procedure - has to do with the deaths.
Another case involving this type of substance in Guaratinguetá (SP), a military police officer left hospitalized in the Intensive Care Unit (ICU) of the Hospital Frei Galvão. According to the institution, on the afternoon of Friday (1) the patient's sedation had been cut and he was breathing without the help of machines.
MRI is imaging test that may or may not have the use of contrast (Photo: Mario Barra/G1)
"A severe reaction to gadolinium, a chemical element present in these contrasts, it is extremely rare - not counting deaths, just allergies. And not a joint problem is a known phenomenon, it seems very strange and certainly needs investigation, "highlights.
The contrasts are compounds developed by the pharmaceutical industry to be injected into the veins of patients before imaging tests such as MRI, CT and ultrasound. They help diagnose illness and injury, to become an organ or a change more visible. The need to use them depends on a prior medical evaluation.
"Today's products are more safe and accurate. Besides causing less trouble, have a better ability to show what you want to see progress and that, "Amaro Jr. said.
Other imaging tests such as CT scans and X-rays, can use contrast-based elements such as iodine and barium. Therefore, before making any of these procedures, a person must answer a questionnaire that assesses her susceptibility to allergies.
"Every test has risks and benefits. Allergic individuals may have more contraindications. If the patient is very sensitive, it may even take an oral or intravenous medication a day or hours before the contrast to decrease sensitivity, "says neuroradiologist.
In the opinion of the doctor, stop making the contrast can bring more harm than not using it, because without it a cancer can only be diagnosed, for example.
According to Amaro Jr., the reactions are usually mild contrast and appear within 5 minutes after injection. In the first 24 hours, some change can happen, but they are more common at the beginning - especially if they are serious. What usually happens is a skin rash, with redness and itching in regions such as arm, neck and chest.
"Have moderate allergic reactions include dizziness, nausea and difficulty breathing. In severe cases, the lack of air turns respiratory failure, there is need for action in minutes. But all this can be readily reversed by the injection of substances that nullify the effects of contrast (such as adrenaline) and artificial ventilation, "he explains.
Amaro Jr. also clarifies that the burning in the arm that so many people feel that the contrast is injected is normal because it is the mechanism of flow of the substance in the body, and not an adverse reaction.
What is the resonance
Magnetic resonance imaging (MRI) is a test that helps in the diagnosis of various diseases, such as tumors, headaches, problems with muscles, bones and joints. The procedure uses electromagnetic waves to obtain images of internal organs and structures, and is considered very safe.
"For organs such as liver and brain, the MRI works better than other tests under certain conditions. But choosing the best procedure depends on each case and the patient's symptoms, "says Albert Einstein neuroradiologist.
He points out that this test always need a medical, and most people do to clarify a symptom and a chance to confirm diagnosis. Since the elderly tend to go through the procedure for regular check-ups. Depending on the result, the test should be complemented with other (CT, ultrasound or X-ray) or the patient needs a biopsy or surgery.
Contraindications
The doctor explains that there are over a thousand risk factors for not doing MRI - is one who uses a pacemaker, for example. Other things are more specific, such as some ear prostheses, dental materials or individuals who have had surgery for aneurysm.
People with prostheses and stents (metal object that unclogs arteries) also need to be informed before. The newer stents, according to Amaro Jr., are already well accepted in more resonance.
Who has piercings and tatuagems also must take some care. According to the expert, this is not an absolute contraindication for the exam. People with piercing in general, are indicated to remove the metal accessory before - the tattooed already have plenty to do.
"Tattoos in black and red can heat up and burn because they contain pigments that iron can react with magnetism and cause skin burns. The chances of this happening increase as the greatest tattoo, but that does not mean necessarily that reaction will occur, "he says.
National Alert
The National Health Surveillance Agency (ANVISA) issued a national alert about lots of serum and contrasts used in examinations of patients died in the state of São Paulo.
According to Anvisa, all magnetic resonance equipment in the country must be registered in the agency and be in full working order. Before undergoing the procedure, patients should also be evaluated on the use of metal prostheses, allergy to contrast or other conditions that impair or impede the exam. Cases of allergic reaction are easily diagnosed and usually reversible, according to the note.
Regarding the MRI-related deaths and occurred recently in Campinas, ANVISA states that:
One. Sent technicians to the municipality to monitor and help coordinate investigations by the Local Health Surveillance.
2nd. Samples of the products used during MRI procedures at the hospital where the deaths occurred, were sent for analysis by the Local Health Surveillance Adolfo Lutz Institute in Sao Paulo.
3rd. To date, there is insufficient evidence to justify a ban on the products nationwide.
4th. New information will be relayed to the public as it becomes available.
Source: G1 - News - The Well
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This article was translated by an automatic translation system, and was therefore not reviewed by people.