Diagnosis
Although myasthenia gravis (MG) is a rare disease, doctors in Canada are diagnosing it with increasing frequency. The journey toward an MG diagnosis usually begins when patients report telltale symptoms, such as general muscle weakness that worsens with activity and improves with rest.
Because MG is rare, many in the medical community lack awareness of the disease. This means receiving a proper diagnosis is a long and frustrating process for many patients. For these reasons, two of the goals of MGSC are to support individuals on their unique journeys and to raise awareness about this challenging disease.
The Stages of the Journey
1. Symptom Onset
- Individual first starts to experience symptoms
- Eventually, as the symptoms worsen, the individual is prompted to seek medical care
2. Pre-diagnosis
- Individuals may face medical gaslighting from healthcare practitioners
- Individuals will experience frequent referrals to specialists and testing
3. Diagnosis
- Patients will undergo medical history review, physical examinations, diagnostic testing for specific antibodies, neurophysiological and imaging studies
- On average, it can take an individual 5 years to receive a correct diagnosis for MG, and they will typically experience multiple misdiagnoses
4. Treatment
- Healthcare professionals specializing in MG will prescribe medications
- There is currently no cure for MG and treatments can be slow to take effect – it may take several months or even years before improvements are seen
5. Post-diagnosis
- Muscle weakness can be unstable, fluctuating and unpredictable – emotional and psychological support are important
- Developing coping strategies with family and caregivers for managing fluctuations is key for MG patients’ quality of life
To investigate your symptoms and determine a diagnosis, there are several approaches your doctor or healthcare provider might use. The path to a diagnosis is rarely a straight line, so these tests may be performed in a different order depending on your specific situation.
Some of the things your doctor might do include:
Physical Examinations:
A healthcare professional may use simple physical tests to observe muscle fatigue, a hallmark of MG. This includes checking for drooping eyelids after looking up, arm weakness with repeated movement, or slurred speech that develops during the exam.
Blood Tests:
A blood test may be done to look for specific antibodies known to disrupt nerve-muscle communication. While most people with MG have these antibodies, their absence does not completely rule out the disease.
Nerve and Muscle Response Tests:
Your doctor might recommend specialized tests to see how your muscles respond to signals. This could include a nerve test that uses small electrical impulses or a diagnostic injection of a medication that temporarily boosts muscle strength to see if your symptoms improve.
Electromyography (EMG) & Nerve Conduction Studies (NCS)
An EMG and NCS are diagnostic tests that give your doctor important information about the health of your muscles and nerves. They are often done together to understand the connection between them.
The Patient Experience
- Who performs it? A neurologist or a highly trained specialist.
- How does it work? The NCS uses sensors on the skin to check nerve speed. The EMG uses a very fine needle to record electrical activity in the muscle itself.
- What will I feel? You may feel a slight, temporary discomfort when the needle is placed, but most patients tolerate the test well.
- Your role: You will be asked to relax and then gently tense your muscles so the specialist can record their activity.
- The results: The findings from these tests are a key piece of the puzzle, helping your doctor create an accurate diagnosis and treatment plan.
Medical imaging is frequently done when a patient is diagnosed with MG or if MG is suspected. Because 10-15% of myasthenia gravis patients have a tumour on their thymus gland (called a “thymoma”), physicians recommend a CT scan of your chest to examine your thymus gland. Other medical imaging techniques may be used too.
Most MG sufferers endure a long and complex diagnostic journey. An eventual diagnosis will be based on a combination of findings, though many patients will be presumed to have MG despite never receiving conclusive test results.
These studies help your healthcare provider:
- Pinpoint the cause of muscle weakness, pain, or numbness.
- Evaluate how well nerves are functioning after an injury.
- Diagnose conditions affecting muscles or nerves, including myopathies and neuromuscular disorders.
In some cases, to check for muscle response, a doctor may perform a simple diagnostic check known as the “Ice Pack Test“