An edrophonium test, also called Tensilon® test, is a pharmacological test. It consists of injecting edrophonium bromide or edrophonium chloride, that are substances that react with the transmission of nerve impulses on the muscular level.
The target’s to check a patient’s muscular fatigue. Subsequently, doctors prescribe it to diagnose and assess the response to treatment in myasthenia gravis.
This test is taken into account effective and is essentially the most commonly used test for this disease. Nonetheless, it have to be performed with several precautions. In this text, we’ll explain what the edrophonium test is and what it involves.
What’s the edrophonium test?
The edrophonium test, along with being called the Tensilon® test, can also be called the Anticude® test. These names vary because they consult with the brand name of the drug.
Tensilon® is edrophonium chloride, while Anticude® is edrophonium bromide, as a publication of the Agència Valenciana de Salut explains. These drugs act on the neuromuscular level and forestall the breakdown of acetylcholine, which is a neurotransmitter that acts within the neuromuscular plate.
That’s, in the realm where neurons bind to muscle fibers to stimulate them. By inhibiting the breakdown of acetylcholine, what happens is that a more marked muscle stimulation occurs.
Subsequently, the edrophonium test consists of observing what response takes place on the muscular level. There are diseases, corresponding to myasthenia graviswherein there are changes within the muscle fibers as a result of acetylcholine. Subsequently, it’s useful in diagnosing and monitoring this disease.
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When is the edrophonium test needed?
Doctors often order the edrophonium test when there’s suspicion that the patient has myasthenia gravis. Additionally they use it to manage the dose of anticholinesterase drugs when a diagnosis of the disease has already taken place and the patients taking these drugs as treatment.
As explained within the previous section, the neuromuscular plate is the location where nerves and muscle fibers communicate. On this area, the nerve secretes a neurotransmitter called acetylcholine, which binds to muscle receptors.
In myasthenia gravisthe immune system produces antibodies that block or destroy the acetylcholine receptors. Consequently, the muscle receives less stimulation. Subsequently, there’s weakness and rapid muscle fatigue.
In myasthenia gravisthe weakness worsens with using the affected muscle. In keeping with Mayo Clinic specialistssymptoms improve with rest.
Because the years go by, symptoms progress, and periods of rest now not compensate for the weakness. Greater than half of the patients begin with signs in the attention muscles. Subsequently, two very typical symptoms are drooping of the eyelid and double vision.
What does edrophonium do for myasthenia gravis?
The edrophonium test causes no breakdown of acetylcholine. An enzyme called acetylcholinesterase is answerable for this breakdown. Because it’s not broken down, there’s more concentration. Subsequently, muscle stimulation is larger.
When a patient with myasthenia gravis undergoes the edrophonium test, the muscles are more powerful. As well as, this test also makes it possible to judge which is essentially the most suitable treatment when it comes to dosage.
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Previous preparation
Before performing the edrophonium test, it’s necessary to take certain features into consideration. The physician must know what medications the patient is taking, including supplements or other herbal remedies.
The explanation is that a lot of these substances can interfere with the result. For instance, those that the majority often alter the edrophonium test are acetylcholinesterase inhibitors. These are drugs used to treat dementia, corresponding to donepezil and rivastigmine.
The concept is that the physician will advise whether or not the patient must discontinue their use before undergoing the test. It’s also possible that the doctor may impose some dietary restrictions throughout the days leading as much as the test.
How is the edrophonium test performed?
A physician performs the edrophonium test and it often takes place in a specialized neurology office. First, a specialist places an intravenous needle into the patient’s arm or hand.
Then, they inject a small amount of edrophonium through the needle. To start to check whether myasthenia gravis is present, the physician asks the person to make repetitive movements.
As an article by Galician Health Service explains, the movements could be with different parts of the body. For instance, getting up from a chair, crossing and uncrossing the legs, and keeping the arms raised. The test also studies the voice, asking the patient to count backward from 100.
Through the edrophonium test, several doses of the drug are injected. This tests whether the muscle regains strength after each injection. If it does, then the doctor will make a diagnosis of myasthenia gravis.
What does the result mean?
The outcomes of the edrophonium test are often immediate. As we explained within the previous section, the patient receives a diagnosis of myasthenia gravis if, after each edrophonium injection, the muscle regains some strength.
Nonetheless, in some cases, other tests are needed to verify the diagnosis. On this case, if edrophonium produces a transient stimulation, it implies that the disease has worsened. Alternatively, if injecting the drug weakens the muscle, the test points to an overdose of anticholinesterases.
Risks and suggestions
Experts consider the edrophonium test to be effective and secure. Nonetheless, there are several unwanted effects that occur regularly. Nonetheless, they’re temporary and don’t often last greater than just a few minutes.
Nausea and stomach pain are two of essentially the most common effects. Shortness of breath, sweating, dizziness, and blurred vision may occur. Other patients experience eyelid twitching, increased salivation, and even fainting.
As with all injection, the location of the injection may bruise. Ideally, the patient should apply pressure or ice throughout the first 24 hours to scale back swelling.
There are few cases wherein the edrophonium test has serious repercussions. Subsequently, experts don’t recommend it for individuals with baseline arrhythmias, low heart rate, or arterial hypotension.
The identical is true for patients with sleep apnea and asthma. Although there are indeed limited unwanted effects, in cases where discomfort persists, a specialist can administer an atropine injection to reverse the consequences.
Myasthenia gravis is the important reason for this test
An edrophonium test is a useful test to diagnose myasthenia gravis. It’s also useful for monitoring the treatment of this condition.
Problems with drug dosage are common. It’s necessary to check these patients repeatedly to avoid serious complications. As well as, experts consider this test to be secure and effective, so long as it takes place in a controlled environment.
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