Myasthenia Gravis (MG) is an autoimmune neuromuscular disorder that affects voluntary muscles. It may be Ocular or Generalised in origin. More types of Myasthenia are being identified. Each type has particular treatment pathways. Common symptoms can include a drooping eyelid, blurred or double vision, slurred speech, difficulty chewing and swallowing, weakness in the arms and legs, chronic muscle fatigue and difficulty breathing. The weakness, which may be intermittent, tends to increase with continued activity and can be improved with periods of rest. Not everyone will display all symptoms, and symptoms can fluctuate.
We can provide you with general information regarding MG, but you should consult with your doctor if you think you have MG. Request an information packet by calling Freecall 1800 802 568 or email info@mgaq.org.au. Visit the "resources" section of this website and view the information booklet.
The Myasthenia Gravis Association of Queensland Inc. (MGAQ) produces and distributes hardcopy information that is available to everyone. This website offers a range of opportunities presented in a variety of formats, to better understand this condition, it’s treatment options and what can be done to live with this condition. These materials describe various aspects of the illness, information on treatment programmes and a number of other topics. You may download and print our materials. If you have difficulty downloading and printing, request a package online and we will send it via mail to people within Australia. Please allow two weeks for delivery.
Raising your questions directly with your Neurologist is also important.
'Developing news' and 'Latest research information' currently in focus with the Association, is best resourced through the Association newsletter and guest speaker presentations. The newsletter can be received by registering on this site and by accessing the newsletter archives contained on the home page. Members are automatically sent the newsletter and can chose to have it delivered in hardcopy. Members only, have access to the guest speaker presentations. Journal Articles resulting from local research can be viewed through the Resources section of this website.
For a more informal source of information, an active Closed Group Facebook Discussion page is offered to Australian residents.
Testing for myasthenia is difficult and involved, mostly because there is no single test to provide an accurate diagnosis. There are a number of tests available, and your Specialist may use several in combination to be as sure of the diagnosis as possible. Not all tests are easy to access or perform.
Acetylcholine Receptor Antibody – A blood test for the abnormal antibodies can be performed to see if they are present. Approximately 80% of MG patients have this antibody and, when detected with an elevated concentration, the AChR antibody test is strongly indicative of MG.
Anti-MuSK Antibody testing – A blood test for the remaining 20% of MG patients who have tested negative for the acetylcholine antibody. These patients have seronegative (SN) MG. About 40% of patients with SNMG test positive for the anti-MuSK antibody. The remaining patients have unidentified antibodies causing their MG.
Anti-lipoprotein-related protein 4 (LPR4) antibody – A further test may be ordered for patients who test negative to both the above tests. The incidence of a positive test varies but it is not high.
CT Scan of the chest – This will look for evidence of thymic tissue.
Muscle Fatigue Test – Your doctor may ask you to perform repetitive exercises during the examination.
Ice Test – Cold can reverse the effects of the myasthenia. Research is underway to formalise a protocol using ice as a reliable marker.
Nerve Conduction Studies - This is the most ‘basic’ type of testing, and involves small electrical pulses to stimulate nerves and measure a response. A small amount of discomfort is common, similar to a TENS machine. This testing is important to exclude other conditions that might mimic myasthenia (eg. peripheral neuropathy). Testing is quick and easy, and leaves no lasting effect.
Repetitive nerve stimulation - This testing uses pulses of electricity, similar to nerve conduction studies. A short train of several in a row are used to observe how the nerve-muscle connection works under pressure. The most common technique uses 10 pulses delivered at 3 Hz (3 per second) , which means the testing is finished in only 3 seconds. However, pulses delivered closely together do feel more uncomfortable than regular nerve conduction studies and mild pain may be experienced briefly. The doctor may choose to modify the technique slightly, and they will explain what is involved at each step. Often several ‘runs’ are performed, with some exercise of the muscle in between, to get a thorough overview o the nerve-muscle connection in all conditions. It is a very specific test, but not very sensitive- that is, a positive test is likely to confirm a diagnosis of myasthenia, but a negative test is common even in people with myasthenia.
Electromyography (EMG) - This testing uses a very find needle, only a little larger than an acupuncture needle (and much smaller than a blood test needle), to sample muscle activity. The needle acts only as a microphone, and does not inject anything or use any pulses. This part of the testing can add extra information about nerve and /or muscle problems, but is commonly ‘normal’ in myasthenia. Side effects are uncommon, and a small amount of bruising is the most common risk. It may sometimes be accompanied by the following testing.
Single Fibre EMG - This is a very specialised form of EMG designed to look directly at the connection between nerve and muscle. It is the most sensitive test for myasthenia (ie. it is almost always abnormal in people with myasthenia, and a negative test can sometimes rule out the disease ) , but specialised training is required and it is not widely available. A very small EMG needle is inserted into a muscle, and the Specialist then acquires a number of readings while a very steady and gentle contraction of the muscle is maintained – very careful cooperation between tester, testee and machine is required! Common muscles tested include the back of the forearm (extensor digitorum communis), the forehead (frontalis) or the muscle that closes the eyelids (orbicularis oculi). The testing takes between 15-45 minutes, depending on complexity. Like EMG, minor bruising and mild discomfort are the most common risks. Because pyridostigmine (Mestinon) can influence the results, the Specialist should specify whether you need to stop your medication. Other medications used in myasthenia can usually continue.
Tensilon Test - Tensilon, or ‘edrophonium’ is a very short-acting drug similar to pyridostigmine (Mestinon) . It increases the amount of signal transmission between the nerve and muscle for a very short period and so can dramatically improve strength in weak muscles. Tensilon is injected into a vein while an involved muscle is observed for improvement (eg. droopy eyelid, arm strength etc ) . To avoid bias, the Tensilon is usually alternated with an injection of water not containing medication, and the person assessing for a response after each injection should not know which is which. Tensilon can be dangerous in excess, so this procedure is usually performed in a hospital with very close supervision. Side effects include excess saliva, abdominal cramping, and slowed heart rate. Because the test relies on an observer detecting ‘improvement’, which is prone to bias and subjectivity, Tensilon testing is not always easy to interpret and can be falsely negative or positive. It can be helpful if other tests are negative or equivocal and your Specialist still thinks Myasthenia is likely, provided it is interpreted cautiously.
Please refer to the Information Booklet page 9 for more information.
MG results from abnormal immune system activity. Individuals with other auto-immune diseases or an abnormal thymus gland are more likely to have MG. Physicians suspect there may be a combination of factors that trigger the onset of MG symptoms in a susceptible individual such as an infection, other illness, extreme stress.
A genetic predisposition to autoimmune diseases can run in families, but MG is not thought to be directly hereditary. Researchers do not believe that it is contagious.
There is a 12% to 20% incidence of neonatal myasthenia in infants born to mothers with MG. Neonatal myasthenia is a temporary condition of general weakness in a baby and usually occurs within the first 24 to 48 hours after birth and may last days or weeks. It is usually self-limited, lasting three to five weeks, but occasionally lasts longer.
A less common form of Myasthenia gravis is Congenital Myasthenia. This inherited fault makes the junction weak but it is not an auto-immune issue. People are born with this condition though presentation may occur as late as adulthood.
Further details about these treatments can be found in the Information booklet, pages 11, 12 and 13.
In some cases, MG may go into remission for a time, during which no treatment is necessary. Remission is considered to have occurred if treatment levels cause a patient to be symptom-free.
It is not generally thought that MG can be cured, but it can be treated. Many people with MG can live satisfying lives and experience normal life spans. The first one to three years, when various symptoms appear, are often the most difficult. It can take time to work through various treatments to find what works best for you.
MG is called the ‘snowflake disease’ because its symptoms differ for every patient. Symptoms come and go, and periods of remission, when you are symptom-free, are possible. However, there is no way to predict if you’ll achieve remission or how long it will last.
(Information selected from the Hope Foundation website)
Only 20% of sufferers will ever have a crisis – the most common cause is a chest infection. A myasthenia crisis occurs when the muscles that control breathing weaken to the point that breathing is inadequate, creating a medical emergency and requiring a ventilator for assistance. In individuals whose respiratory muscles are weak, crises – which require medical attention – may be triggered by infection, fever, or an adverse reaction to medication.
If a crisis is occurring, a most critical piece of information is the need to appropriately determine if your symptoms are due to a Myasthenia Gravis exacerbation or a Cholinergic crisis.
A Myasthenia Gravis exacerbation crisis is disease induced. It is a by-product of the disease itself and can be exacerbated by underlying infection, uncontrolled/undiagnosed diseases that are flying under the radar or lack of appropriate medication regimen that allows the disease process to flare. (Please read on for additional details about a myasthenia crisis.)
Cholinergic crisis is a whole other animal that looks and acts VERY similarly to a Myasthenia crisis. The key difference here is that a Cholinergic crisis is induced ONLY by too much Mestinon. The best way to determine if you are having a Cholinergic crisis is to monitor your medication regimen. 30-60 minutes after taking your Mestinon, do you notice that you are experiencing:
A Cholinergic crisis can quickly escalate into respiratory failure or compromise. Often, Cholinergic reactions begin with more mild symptoms. The more you take of the Mestinon in failure to recognize what is happening, the more you will build up and create a serious problem for yourself. If you are experiencing any of these symptoms, it is important to get prompt medical attention.
A Myasthenia crisis is presented as a worsening of symptoms by an exacerbation of the disease itself whether it is from insufficient medication, an underlying infection or uncontrolled/untreated/undiagnosed medical condition that is playing a secondary role or trigger. Other triggers can include stress, lack of hydration and nutritional support, heat and contraindicated medications/therapies both synthetic and natural.
A Myasthenia Gravis Exacerbation crisis MAY require additional Mestinon or an adjustment of your current dose as well as additional tertiary therapies until you return to baseline neurological function again.
SOME signs and symptoms of Myasthenia crisis include the following:
Also included is difficulty chewing or swallowing/choking on saliva, difficulty holding your head and neck up or opening your hand fully (palm up), raspy, soft or nasal speech, liquids being swallowed and being pushed back up into your nasal cavity and/or difficulty sitting/standing in brief spurts.
(Response provided by Dr. Angelo Contarino – Clinical Psychologist)
Fatigue is a complex phenomenon and includes both physiological and psychological factors. In recent years a distinction has been made between fatigue as a subjective feeling of tiredness, lack of energy, and difficulty concentrating, and muscle fatigability defined as the difficulty initiating or sustaining muscle activities. Chronic fatigue is commonly defined as fatigue above a certain level lasting for 6 months or more. Persistent fatigue of this type has been studied extensively in the Chronic Fatigue Syndrome (CFS) and in some other chronic diseases. Chronic fatigue in some individuals with MG has been demonstrated to be comparable in intensity and duration to individuals with CFS. Fatigue has generally been under-recognised in MG patients. In the absence of an objective evaluation of disease severity, assessment of fatigue has often been based on the individual’s perspective of their symptoms and a clinical examination. Autonomic (1) symptoms, especially thermoregulatory (2), sleep disorders and fatigue should be taken more seriously than they usually are in people with MG. Fatigue could be misinterpreted as myasthenia weakness and trigger a negative spiral, (i.e., overmedication, which could in turn aggravate more fatigue). Fatigue is a considerable problem in MG even with individuals who are in full remission and not taking medication. MG severity is highly suggestive to be associated with symptoms of autonomic disturbance, which in turn are associated with total fatigue level and functional disability.
(1) Autonomic definition: Involuntary, often refers to Autonomic nervous system which regulates involuntary functions of the body.
(2) Thermoregulatory definition: the ability to regulate temperature. The ability of the body to maintain a constant temperature independent of the environmental temperature.
(Response provided by Dr. Angelo Contarino – Clinical Psychologist)
Decreased cholinergic (3) activity in MG can result in short-term memory loss, cognitive fog (confusion/lack of clarity in thinking), generally reduced cognitive performance, linguistic and comprehension changes. In fact, individuals with MG can often perform worse on delayed recall, memory and verbal learning tasks. This can alarm many individuals who are not sure if this is because of their MG or something else (e.g., dementia). Certain treatments for MG can also cause similar symptoms. It is important for individuals with MG, their carers and medical/therapy service providers to look at the constellation of symptoms in order to determine if the symptoms are MG related or something else. Brain fog and short-term memory loss in MG comes and goes, is worse during periods of flares and can have a sudden appearance in contrast to other conditions. These reactions vary from one individual to another and clearly fluctuate depending upon their mental and physical health.
(3) Cholinergic definition: Activates by or involves Acetylcholine or mimics the action of Acetylcholine.
(Response provided by Dr. Angelo Contarino – Clinical Psychologist)
MG is a neuromuscular condition that deteriorates the communication between nerve cells and muscles. Some studies have indicated that up to 54.3% of those diagnosed with MG experience muscle cramps and pain. Current understanding suggests that MG itself does not directly cause the pain, but the weakness and fatigue associated with MG may lead to secondary non-specific aches and pains. For instance, neck pain may occur because of weakness in the neck muscles. A combination therapy of high-dose cholinesterase inhibitors (7), such as Mestinon can also increase the chances of muscle cramps (particularly in the stomach) of those with MG, thereby reducing their quality of life. Seek medical advice and/or psychological therapy if experiencing cramps or pain. Complimentary therapies such as remedial massage might also prove useful.
(7) Cholinesterase inhibitors definition: An agent that inhibits the breakdown of Acetylcholine.
(Response provided by Dr. Angelo Contarino – Clinical Psychologist)
Individuals with Myasthenia Gravis (MG) commonly experience a broad spectrum of emotional symptoms from appropriate emotional reactions (e.g., grief including associated sadness, irritability/anger) to mental health (MH) disorders. These occur secondary to their chronic autoimmune disease. The most common include – Adjustment disorder, Mood disorders such as Depression, Panic and Generalised Anxiety disorders. In fact, MG often results in a large amount of stress, which can increase the risk of developing these MH problems. There is evidence in the literature about higher doses of corticosteroids affecting certain individuals in a variety of ways that may impact on their mental health such as depression, anxiety and racing thoughts. However as corticosteroids are an essential cornerstone to the treatment of Myasthenia, there is a reason your physician has prescribed it so be sure to have an open discussion with them before reducing the dose or stopping the tablets. Fortunately for the majority of patients, the higher doses are temporary. (See FAQ Treatments for more details.)
If those with MG or their Carers recognise they are experiencing difficult emotional symptoms or MH problems, it is recommended they attend their GP for a referral to obtain treatment with appropriately qualified medical specialists and/or MH professionals (e.g., psychiatrists and psychologists). Remember certain medications commonly used in the treatment of MH disorders cannot be used with those diagnosed with MG (due to adverse reactions). However, effective medical consultations and engagement in therapy are likely to improve the overall wellbeing of those with MG.
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