Table of ContentsView AllTable of ContentsPurposeTestProcedureResultsWhy the Test Was DiscontinuedAlternative Testing
Table of ContentsView All
View All
Table of Contents
Purpose
Test
Procedure
Results
Why the Test Was Discontinued
Alternative Testing
Read on to learn more about how the test worked and what is currently being used to diagnose myasthenia gravis.
Verywell / Alexandra Gordon
Purpose of the Tensilon Test
The most common reason to have a Tensilon test was to differentiate between myasthenia gravis and other conditions that caused weakness. The weakness of MG typically worsens after physical activity and improves after resting.
The most common symptoms of MG include double vision, droopy eyelids, slurred speech, and weakness and tiredness of the arms or legs. The symptoms are generally worse late in the day, and the weakness can affect the muscles that control your ability to breathe as well, which means that you have to exert effort to breathe.
The condition usually starts in adulthood and can affect both men and women, but may occur as a childhood form during infancy as well. If you have myasthenia gravis and are not diagnosed and treated, you will continue to experience symptoms.
Other Similar Conditions
How the Tensilon Test Worked
The reason a Tensilon test was used to help in the diagnosis of myasthenia gravis is that Tensilon biochemically counteracts the effects of the disease. The disease is anautoimmunecondition, which means that the body attacks itself.
In myasthenia gravis, your immune system attacks the acetylcholine binding sites on your muscles, which prevents them from responding to acetylcholine. This prevents your muscles from working as they normally should, which manifests as muscle weakness.
Because you still have some intact acetylcholine receptors even if you have MG, the disease does not make you completely paralyzed, Instead, it causes you to become weak after you have used your muscles for a while.
How Was the Tensilon Test Performed?
This was an interventional test that required an intravenous (IV) injection of the medication. The person being tested needed to participate in some repetitive physical actions and describe their symptoms to a healthcare provider, usually a neurologist, to assess the results of a Tensilon test.
The steps of the test included:
Results of a Tensilon Test
Other conditions such asblepharospasmandcervical dystoniaare expected to worsen with a Tensilon test. If Lambert-Eaton syndrome or a cholinergic crisis is suspected, then symptoms might also worsen with a Tesilon test.
Next Steps
If a Tensilon Test was diagnostic of myasthenia gravis, a healthcare provider would likely prescribe medication.
Treatments for myasthenia gravis include steroids to suppress the immune system,plasmapheresisto counteract the autoimmune process, Mestinon, Regonol (pyridostigmine), which is an anticholinesterase inhibitor, or thymectomy (removal of thethymus), a surgery to reduce autoimmune activity.
If the Tensilong test was not diagnostic, then further evaluation to identify the cause of weakness would be used.
Why Was the Tensilon Test Discontinued?
Because the Tensilon test resulted in a high number of false positives, the U.S. Food and Drug Administration discontinued the use of the drug (edrophonium) in 2018.
More reliable tests are now used to get an accurate diagnosis of myasthenia gravis. MG can be hard to diagnose because muscle weakness can be a symptom of many disorders. So, a healthcare provider may order more than one type of MG test to make a diagnosis. These tests include:
Neurological exam:Medical history is taken and a physical exam is performed including checking:
Ice pack test:An ice pack is used to help diagnose MG if one or both eyelids are observed to droop.
Antibody test:This blood test looks for certain types of antibodies that are found in people with MG.
Electromyography (EMG):This measures the electrical signals muscles make at rest and during use.
Nerve conduction study:This measures how fast and how well the body’s electrical signals travel down nerves.
Imaging tests:Problems with the thymus gland can be a sign of MG. A CT scan (computed tomography) or an MRI (magnetic resonance imaging) may be ordered to check for an enlarged thymus or a thymus tumor.
Edrophonium test:Edrophonium is a drug that briefly relieves muscle weakness (especially in the eye muscles) in people with MG.
Lung function tests:There are several kinds of lung function tests that measure breathing and how well the lungs are working. In some tests, medicine or a type of gas may be inhaled.
Summary
During a Tensilon test, a drug was administered, physical activities were required, and changes in symptoms were noted. Positive and negative changes were both possibilities. Negative changes were not a concern as the effects of the medication only lasted for about 10 minutes and adverse effects could be reversed rapidly. Use of the Tensilon test was discontinued in the U.S. in 2018, but other diagnostic tests are available.
What Is Myasthenia Gravis?
2 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Naji A, Owens ML.Edrophonium. StatPearls [Internet]. 2023.MedlinePlus.Myasthenia gravis.Additional ReadingIm S, Suntrup-Krueger S, Colbow S, et al.Reliability and main findings of the FEES-Tensilon test in patients with myasthenia gravis and dysphagia.Eur J Neurol.2018 May 26. doi:10.1111/ene.13688.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Evaluation of the edrophonium challenge test for cervical dystonia.Intern Med.2017 Sep 15;56(18):2415-2421. doi:10.2169/internalmedicine.8555-16.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Edrophonium challenge test for blepharospasm.Front Neurosci.2016 Jun 6;10:226. doi10.3389/fnins.2016.00226.
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Naji A, Owens ML.Edrophonium. StatPearls [Internet]. 2023.MedlinePlus.Myasthenia gravis.Additional ReadingIm S, Suntrup-Krueger S, Colbow S, et al.Reliability and main findings of the FEES-Tensilon test in patients with myasthenia gravis and dysphagia.Eur J Neurol.2018 May 26. doi:10.1111/ene.13688.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Evaluation of the edrophonium challenge test for cervical dystonia.Intern Med.2017 Sep 15;56(18):2415-2421. doi:10.2169/internalmedicine.8555-16.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Edrophonium challenge test for blepharospasm.Front Neurosci.2016 Jun 6;10:226. doi10.3389/fnins.2016.00226.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Naji A, Owens ML.Edrophonium. StatPearls [Internet]. 2023.MedlinePlus.Myasthenia gravis.
Naji A, Owens ML.Edrophonium. StatPearls [Internet]. 2023.
MedlinePlus.Myasthenia gravis.
Im S, Suntrup-Krueger S, Colbow S, et al.Reliability and main findings of the FEES-Tensilon test in patients with myasthenia gravis and dysphagia.Eur J Neurol.2018 May 26. doi:10.1111/ene.13688.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Evaluation of the edrophonium challenge test for cervical dystonia.Intern Med.2017 Sep 15;56(18):2415-2421. doi:10.2169/internalmedicine.8555-16.Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Edrophonium challenge test for blepharospasm.Front Neurosci.2016 Jun 6;10:226. doi10.3389/fnins.2016.00226.
Im S, Suntrup-Krueger S, Colbow S, et al.Reliability and main findings of the FEES-Tensilon test in patients with myasthenia gravis and dysphagia.Eur J Neurol.2018 May 26. doi:10.1111/ene.13688.
Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Evaluation of the edrophonium challenge test for cervical dystonia.Intern Med.2017 Sep 15;56(18):2415-2421. doi:10.2169/internalmedicine.8555-16.
Matsumoto S, Murakami N, Koizumi H, Takahashi M, Izumi Y, Kaji R.Edrophonium challenge test for blepharospasm.Front Neurosci.2016 Jun 6;10:226. doi10.3389/fnins.2016.00226.
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