Why Is Myasthenia Gravis Difficult to Diagnose?

Medical disclaimer: This content was created for generalized informational purposes only. This is not intended to be a substitute for professional medical advice, diagnosis, or treatment.

Diagnosing myasthenia gravis (MG) can be difficult, especially for doctors not formally trained in neurology. Many symptoms of MG can be nonspecific and mimic other conditions – especially things like weakness and fatigue.

Your doctor will ask detailed questions about your medical history and symptoms. Try to answer to the best of your ability. Remember, it is ok if you do not have all the answers. Since your symptoms may not be present all day, your description of symptoms may be the only piece of information your doctor has to formulate a distinct diagnosis.

Your doctor can try some physical exam maneuvers in the clinic. For example, asking you to flap your arms or look up for a few seconds, to bring out the classic fatigable weakness of MG. But, this is not always reliable. It can take multiple doctor’s visits and additional testing to confirm a diagnosis of MG.

Inconsistent MG symptoms

You should tell your doctor about all of your symptoms, even if they are not present at the time of your appointment. Symptoms of MG are known to wax and wane. Usually, they are worse when you are using and tiring out your muscles, especially at the end of the day.

Your neurologist will be aware of this classic tempo of symptoms. Even if you are not experiencing any symptoms at the time of your appointment, tell your neurologist when you are having symptoms. This will help your doctor adjust your medications and overall treatment plan.

For example, if you are taking pyridostigmine (Mestinon) 2 times per day but still have symptoms throughout the day, your doctor may increase the frequency of the medication to 3 or 4 times per day.

Keep a log of your symptoms

Your doctor's appointments and experience with MG can be overwhelming and stressful. It is easy to forget these details, so it can be helpful to keep a log of your symptoms (on paper or on your phone).

Note the times of the day when you feel the worst and list things that trigger your symptoms - climbing stairs, driving, certain medications, etc. This information can be very helpful to review with your doctor to create the best treatment plan.

Know your MG type

You should know your MG type. At the very least, you should know if you have ocular or generalized MG. Further classification of your MG is based on blood tests (antibody testing, for example, AChR-positive or seronegative disease), thymus gland status, and age of onset.

All of these things can help guide therapy. For example, people with more generalized and severe disease often need to take medications to suppress the immune system in addition to the drug that is used purely for symptom relief (acetylcholinesterase inhibitors like pyridostigmine).

Additionally, some MG types respond better to certain medications. For example, MuSK-positive MG responds well to an immunosuppressant called Rituximab, while other types do not.

What doctor should I see for MG?

Primary care doctors are not formally trained to diagnose or treat conditions like MG. The best doctor to diagnose and treat MG is a neurologist.

If you have a suspicion that you have MG but your primary care doctor has never heard of the condition, you should explain your symptoms and concerns and ask them if a neurology referral seems reasonable.

Delaying diagnosis and treatment of MG is not in your best interest, so when in doubt the safest option is to obtain the expert opinion of a Neurologist.