MG BROCHURES

What Causes Autoimmune MG?

The voluntary muscles of the entire body are controlled by nerve impulses that arise in the brain. These nerve impulses travel down the nerves to the place where the nerves meet the muscle fibers. Nerve fibers do not actually connect with muscle fibers. There is a space between the nerve ending and muscle fiber; this space is called the neuromuscular junction.

When the nerve impulse originating in the brain arrives at the nerve ending, it releases a chemical called acetylcholine. Acetylcholine travels across the space to the muscle fiber side of the neuromuscular junction where it attaches to many receptor sites. The muscle contracts when enough of the receptor sites have been activated by the acetylcholine. In MG, there is as much as an 80% reduction in the number of these receptor sites available. The reduction in the number of receptor sites is caused by antibodies that destroy or block the receptor site.

Antibodies are proteins that play an important role in the immune system. They are normally directed at foreign proteins called antigens that attack the body. Such foreign proteins include bacteria and viruses.

Antibodies help the body to protect itself from these foreign proteins. For reasons not well understood, the immune system of the person with MG makes antibodies against the receptor sites of the neuromuscular junction. Abnormal antibodies can be measured in the blood of many people with MG. There are currently three commercially available tests for the abnormal antibodies, the AChR (acetylcholine eceptor), MuSK (muscle specific kinase) and low density lipoprotein related protein 4 (LRP4) antibodies. These antibodies destroy the receptor sites or make them unavailable. Muscle weakness occurs when acetylcholine cannot activate enough receptor sites at the neuromuscular junction.

 

Clinical Features and Symptoms

MG occurs in all races, both genders and at any age. MG is not directly inherited nor is it contagious. It does occasionally occur in more than one member of the same family. MG may affect any muscle that is under voluntary control. Certain muscles are more frequently involved, and these include the ones that control eye movements, eyelids, chewing, swallowing, coughing and facial expression. Muscles that control breathing and movements of the arms and legs may also be affected. Weakness of the muscles needed for breathing may cause shortness of breath, difficulty taking a deep breath and coughing.

 

The muscle weakness of MG increases with continued or repetitive activity and improves after periods of rest. The muscles involved may vary greatly from one person to the next. In some people, weakness may be limited to the muscles controlling eye movements and the eyelids. This form of myasthenia is referred to as ocular MG. Generalized MG refers to those people with MG who have weakness involving muscles outside the eye region. In the most severe form of generalized MG, many of the voluntary muscles of the body are involved, including those needed for breathing. The degree and distribution of muscle weakness for many people falls in between these two extremes. When the weakness is severe and involves breathing, hospitalization is usually necessary.

 

Diagnosis

There are many disorders that cause weakness. In addition to a complete medical and neurological evaluation, a number of tests may be used to establish a diagnosis of MG. Blood tests for the abnormal antibodies can be performed to see if they are present. Electromyography (EMG) studies can provide support for the diagnosis of MG when characteristic patterns are present. The edrophonium chloride (Tensilon®) test is performed by injecting this chemical into a vein. Improvement of strength immediately after the injection provides strong support for the diagnosis of MG. Sometimes all of these tests are negative or equivocal in someone whose story and examination still seem to point to a diagnosis of MG. The positive clinical findings should probably take precedence over negative confirmatory tests.

 

Treatment

There is no known cure for MG, but there are effective treatments that allow many—but not all—people with MG to lead full lives. Common treatments include medications, thymectomy, plasmapheresis (also called total plasma exchange and abbreviated as PLEX or TPE) and intravenous immunoglobulins (IVIg). Spontaneous improvement and even remission may occur without specific therapy.

 

Medications are most frequently used in treatment. Anticholinesterase agents (e.g., Mestinon®) allow acetylcholine to remain at the neuromuscular junction longer than usual so that more receptor sites can be activated. Corticosteroids (e.g., prednisone) and immunosuppressant agents (e.g., Imuran®, CellCept®) may be used to suppress the abnormal action of the immune system that occurs in MG. Intravenous immunoglobulins (IVIg) are also sometimes used to affect the function or production of abnormal antibodies.  Recently, monoclonal antibodies have been investigated for use in MG.   Rituximab has been found to be an effective treatment for MuSK positive patients, and is currently being tried for those positive for AChR.  In 2016, a new treatment for MG called Soliris (eculizimab) was approved to treat people with MG who are AChR positive and have not responded well to other therapies.

 

Thymectomy (surgical removal of the thymus gland) is another treatment used in some people with MG. The thymus gland lies behind the breastbone and is an important part of the immune system. When there is a tumor of the thymus gland (present in 10-15% of patients diagnosed with MG), it is nearly always removed because of the risk of malignancy. Thymectomy frequently lessens the severity of the MG weakness after some months. In some people, the weakness may completely disappear. The degree to which the thymectomy helps varies with each person.

 

Plasmapheresis, or plasma exchange (PLEX), may also be useful in the treatment of MG. This procedure removes the abnormal antibodies from the plasma portion of the blood. The improvement in muscle strength may be striking, but is usually short-lived, since production of the abnormal antibodies continues. When plasmapheresis is used, it may require repeated exchanges. Plasma exchange may be especially useful during severe MG weakness or prior to surgery.

 

Treatment decisions are based on knowledge of the natural history of MG in each patient and the predicted response to a specific form of therapy. Treatment goals are individualized according to the severity of the MG weakness, the person’s age and sex, and the degree of impairment.

 

Prognosis

The current treatments for MG are sufficiently effective that the outlook for most people with MG is bright.  However, some patients do not find current treatments to be effective and these people may face severe difficulties in managing even basic “activities of daily living” such as brushing one’s hair to name just one such activity.

 

Although current treatments will not cure MG, and there is no treatment that is universally effective or tolerated by all people with MG, most  people with MG can expect to have significant improvement in their muscle weakness.  In some cases, MG may go into remission for a time, during which no treatment is necessary. There is much that can be done, but still much to be understood. New drugs with greater efficacy and fewer side effects are needed. Research plays an important role in finding new answers and treatments for MG-and the future of MG research has never been brighter.

Documents to download
MGFA-brochure-Autoimmune.pdf (807.42 KB)

Cautionary Drugs

Certain medications and over the counter preparations may cause worsening of MG symptoms. Remember to tell any doctor or dentist about your MG diagnosis. It is important to check with your doctor before starting any new medication including over the counter medications or preparations.

 

Drugs to avoid or use with caution in MG*

Many different drugs have been associated with worsening myasthenia gravis (MG). However, these drug associations do not necessarily mean that a patient with MG should not be prescribed these medications. In many instances, reports of worsening MG are very rare.  In some instances, there may only be a “chance” association (i.e. not causal).
In addition, some of these drugs may be necessary for a patient’s treatment and should not be deemed “off limits”. It is advisable that patients and physicians recognize and discuss the possibility that a particular drug might worsen the patient’s MG. They should also consider, when appropriate, the pros and cons of an alternate treatment, if available.
It is important that the patient notify his or her physicians if the symptoms of MG worsen after starting any new medication. Only the more common prescription drugs with the strongest evidence suggesting an association with worsening MG are provided in the list below.

• Telithromycin: antibiotic for community acquired pneumonia. The US FDA has designated a “black box” warning for this drug in MG. Should not be used in MG.
• Fluoroquinolones (e.g., ciprofloxacin, moxifloxacin and levofloxacin): commonly prescribed broadspectrum antibiotics that are associated with worsening MG. The US FDA has designated a “black box” warning for these agents in MG. Use cautiously, if at all.
• Botulinum toxin: avoid.
• D-penicillamine: used for Wilson disease and rarely for rheumatoid arthritis. Strongly associated with causing MG. Avoid
• Chloroquine (Aralen): used for malaria and amoeba infections. May worsen or precipitate MG. Use with caution.
• Hydroxychloroquine (Plaquenil): used for malaria, rheumatoid arthritis, and lupus. May worsen or precipitate MG. Use with caution.
• Quinine: occasionally used for leg cramps. Use prohibited except in malaria in US.
• Magnesium: potentially dangerous if given intravenously, i.e. for eclampsia during late pregnancy or for hypomagnesemia. Use only if absolutely necessary and observe for worsening.
• Macrolide antibiotics (e.g., erythromycin, azithromycin, clarithromycin): commonly prescribed antibiotics for gram-positive bacterial infections. May worsen MG. Use cautiously, if at all.
• Aminoglycoside antibiotics (e.g., gentamycin, neomycin, tobramycin):used for gram-negative bacterial infections.  May worsen MG. Use cautiously if no alternative treatment available.
• Corticosteroids: A standard treatment for MG, but may cause transient worsening within the first two weeks. Monitor carefully for this possibility (see Table 1).
• Procainamide:  used for irregular heart rhythm. May worsen MG. Use with caution.
• Desferrioxamine: Chelating agent used for hemochromatosis. May worsen MG.
• Beta-blockers: commonly prescribed for hypertension, heart disease and migraine but potentially dangerous in MG. May worsen MG. Use cautiously.
• Statins (e.g., atorvastatin, pravastatin, rosuvastatin, simvastatin): used to reduce serum cholesterol. May worsen or precipitate MG.  Use cautiously if indicated and at lowest dose needed.
• Iodinated radiologic contrast agents: older reports document increased MG weakness, but modern contrast agents appear safer.  Use cautiously and observe for worsening.

 

Addendum from MGFA’s Medical and Scientific Advisory Board:

Checkpoint inhibitors: Immunotherapy for cancer is an exciting treatment advance for many types of cancers. However, one newly recognized rare side effect of some of these treatments is myasthenia gravis (MG). MG is recognized as a rare complication of immune checkpoint inhibitors (ICIs) for cancer (immunotherapy). People who did not have MG before beginning immunotherapy have a higher likelihood of developing the disease , although worsening of myasthenic weakness has been reported in people with existing, previously-diagnosed MG. The average onset of MG symptoms is within 6 weeks (range 2–12 weeks) of starting immunotherapy. To date, development or exacerbation of MG has been reported for pembrolizumab, although it has also been seen with nivolumab, ipilimumab and other ICIs. Risk may increase with administration of combinations of ICIs. Patients with MG and cancer considering cancer immunotherapy should talk to their oncologist and neurologist about this possible side effect. Likewise, doctors evaluating new-onset weakness in cancer patients on immunotherapy should consider MG. Additionally, MG with ICIs can be accompanied by inflammation of skeletal and/or heart muscle. MG patients who experience worsening weakness following ICI treatment should contact their neurologist and oncologist immediately.
Examples of immune checkpoint inhibitors (ICIs):

• Pembrolizumab (Keytruda)
• Nivolumab (Opdivo)
• Atezolizumab (Tecentriq)
• Avelumab (Bavencio)
• Durvalumab (Imfinzi)
• Ipilimumab (Yervoy)

Documents to download
MGFA-Cautionary-Drug-List.pdf (383.90 KB)

Every child’s story and course with an illness like myasthenia gravis is different. The general issues outlined below are helpful suggestions but should be considered in the overall context of your own child’s health and daily life. Your child’s neurologist will be a great source of information and help. The Myasthenia Gravis Foundation of America (MGFA) can also provide information and support.

 

Daily Schedule

1.   Regular Sleep: Everyone’s health improves with regular and adequate sleep. However, this is especially important for those with myasthenia gravis.

2.   Scheduled Rest: Planning for quiet rest periods throughout a busy day or week is very helpful for individuals with myasthenia gravis. For example, not scheduling a birthday party on the same day as after-school activities is very helpful.

3.   School Issues: Informal discussions with the school, a Modification Plan under Section 504 of the 1973 Rehabilitation Act or an Individualized Education Plan under Federal Law 108-446 are ways that a child’s daily school schedule can be altered in response to medical needs. For more information on this, please visit our website at myasthenia.org.

 

Many things can be done, as needed, to support the education of children with myasthenia gravis. These include: altering PE requirements (modified PE or temporary or long term exclusion), late starts, use of elevators between floors, transportation to school, allowing additional time between classes, providing a second set of books to be kept at home to prevent heavy backpacks, changing the number of repetitions of math problems, allowing computer access for classroom work or testing, changing nutrition/lunch times, and providing OT/PT/Speech Therapy as necessary. All, or none, of these modifications may be appropriate, depending on your child’s individual needs.

 

 

Medications

1. Dosing and Timing are Important: The medicine schedule that works best for your child depends on their size, type of myasthenia, stage of disease and other health considerations. Once the schedule that works best for your child is identified, it is important that they receive the right dose at the right time. If there are issues relating to after school care, parent’s work schedule and so forth, it is important to discuss these with your child’s doctor so you can develop a schedule for giving medication that can be maintained on a daily basis.

 

2. Refills/Emergency Supply: It is important to know when the current supply of medicines will run out and to have a plan for refilling medications. The amount of medication given to families at once depends on health insurance, which will approve a one-month or three-month supply. In general, it is not recommended that you keep more than a three-month supply as it could expire or decrease in potency if not properly stored. Do not use medicine after the expiration date on the label. You should discuss the issue of emergency medication supply with your child’s doctor: i.e. what phone number to call if the medication is lost or stolen either at home or while travelling. Including a supply of medication in emergency or evacuation plans for threatening weather is important.

3.   New medicines (prescription or over-the-counter): Some medicines (including herbal medicines and ones available at drug stores without prescription) can affect the transmission of the signal between nerve and muscle. This could worsen myasthenia gravis. Therefore, DO NOT give your child a new medication without discussing it with the pharmacist and/or your child’s doctor first. While there are some lists of medications to avoid in myasthenia, the list does not take into account your children’s condition or health issues. For example, some medicines on the list can be used under a doctor’s supervision as needed and there other medicines not on the list that should be avoided completely. Always ASK before starting a new medication.

 

 

Need to Know

Parents have the right to protect the privacy of their children, including who knows about a child’s medical problem. However, as children grow, parents include other adults (family members, teachers, neighbors, group leaders and coaches) in a larger group of responsible adults who supervise their children during the day. Since myasthenia gravis can be unpredictable, it is important that parents create an environment where all responsible adults know that changes in strength or function in a child with myasthenia gravis are paid attention to. If a child develops double vision and complains of “blurry vision”, an adult who doesn’t know about the myasthenia may think the child has dust in their eye. An adult might think that a child who suddenly has garbled speech and drooling is “trying to be funny”. If the supervising adults are aware of the problem and have a plan about who should be contacted, the change in function can be handled safely, quickly and with as much privacy as possible.

 

 

Accessing Emergency Care

1.   School Emergency Plan: Schools assign responsibility to someone (generally a nurse) to identify children with various health problems (including asthma, serious allergies, immune suppression as well as myasthenia gravis) and to develop emergency action plans. Participation of parents and a child’s doctor allows the school to know what specifically they might expect in terms of symptoms (although they understand that unexpected problems might also occur) and to know what the recommended action should be on their part. While paperwork is always a hassle, this opportunity to make suggestions and requests for action on the part of the school is a very valuable opportunity to protect your child’s health.
2.   Authorization to Treat for Coaches, Group Leaders, Family, Friends: All people will receive emergency medical care under life-threatening circumstances. However, when the situation is less severe, adults providing supervision to your child need may need to contact a parent or legal guardian to get authorization for medical treatment, or to have written, notarized permission from you to consent on your behalf. Since it is generally not possible to guarantee that phone lines might not break down or mobile phone transmission might not fail, it is important to think about this issue and consider providing authorization to selected adults. Sometimes having that authorization at the emergency room or facility that will provide the emergency care until you can be reached is most efficient.
3.   Meet Emergency Medical Service (EMS) Teams: Myasthenia gravis is a relatively uncommon disorder. In small communities, particularly ones that depend on volunteer EMS teams, the initial responders may not be familiar with myasthenia and the possible, urgent health issues that can arise. In that setting, some myasthenic patients have felt that their care was delayed while an extended history or interview was attempted while their shortness of breath or weakness made it difficult to respond. This is an example of why it would be useful to contact the local EMS system and arrange for a scheduled meeting to make certain that first responders and others are familiar with myasthenia gravis. Emergency management brochures and alert cards are available at myasthenia.org or by contacting us.
This information might seem overwhelming at first. However, it is important to recognize that with quality, ongoing healthcare and monitoring, the majority of children with myasthenia gravis can have very normal, active and full lives.

Documents to download
MGFA-brochure-Children-Adolescents.pdf (1.02 MB)

What are congenital myasthenic syndromes?
Congenital myasthenic syndromes (CMS) is the term used for a group of uncommon hereditary disorders of the neuromuscular junction as distinguished from autoimmune myasthenia gravis (MG). There are several different subtypes of CMS, each the result of a specific genetic mutation. The major differences between these syndromes and the more common autoimmune MG include: 1) CMS, as the name implies, usually manifest early in life, often in infancy with variable degrees of fluctuating weakness. 2) CMS is not associated with antibodies against any one of the components of the neuromuscular junction. 3) All of the CMS disorders result from mutations that alter one of the components of the neuromuscular junction. Patients with a CMS disorder tend to have lifelong or relatively stable symptoms of generalized fatigable weakness. These disorders are nonimmunologic in nature and patients do not have acetylcholine receptor antibodies; therefore, patients do not typically respond to immune therapy often used in patients with autoimmune MG (steroids, thymectomy, plasma exchange). Most patients with CMS develop symptoms in infancy or childhood with variable degrees of fluctuating weakness.

Are there different types of congenital myasthenic syndromes?
Yes. Not all forms of congenital myasthenia are the same. A number of different types of congenital myasthenia have been identified with a variety of different structural and functional abnormalities of the neuromuscular junction. Patterns of inheritance, clinical symptoms, electrophysiology, and response to therapy vary depending on the type. Some of the subtypes that one may encounter include “familial infantile myasthenia,” a “congenital absence of acetylcholinesterase” presenting in infancy or childhood with generalized weakness and reduced muscle tone, “the slow channel syndrome,” which often follows an autosomal dominant pattern of inheritance with a variable age of onset and severity of symptoms, and a collection of disorders characterized by defective acetylcholine receptors.

Is there any reason to try to determine the exact type of congenital myasthenic syndrome?
A thorough diagnostic evaluation is worthwhile in patients with suspected congenital myasthenia because of the different types, and somewhat different treatment options. Patients with some subtypes may respond best to Mestinon(r) (pyridostigmine), while patients with other subtypes may respond best to other therapies (some types respond to ephedrine, some to 3, 4 DAP, quinidine or fluoxetine, as well as a variety of other drugs depending on the type of congenital myasthenia).

In general, what is the long-term prognosis for patients with congenital myasthenic syndromes?
Most patients remain fairly stable throughout their lifetime and tend not to have wide fluctuations of symptoms or function nor myasthenic crises. Overall, patients tend to stay about the same on a long-term basis.

What is the difference between congenital myasthenia and transient neonatal myasthenia?
Transient neonatal myasthenia occurs in 10-15% of babies born to mothers with autoimmune myasthenia gravis. Within the first few days after delivery, the infant has a weak cry or suck, appears generally weak and, on occasion, requires mechanical ventilation. Maternal antibodies that cross the placenta late in pregnancy cause transient neonatal myasthenia. As these maternal antibodies are replaced by the infant’s own antibodies, thesymptoms gradually disappear, usually within a few weeks, and the baby is normal thereafter. Infants with severe weakness from transient neonatal myasthenia may be treated with oral pyridostigmine and whatever degree of general support (mechanical respiratory ventilation, for example) is necessary until the condition clears. Infants with transient neonatal myasthenia gravis do not have an increased risk for the long-term or future development of myasthenia gravis.

Should patients with congenital myasthenic syndromes avoid the same medications that may aggravate autoimmune myasthenia gravis?
Yes. It is advisable to be cautious when starting newly prescribed or even some over-the-counter medications

Documents to download
MGFA-brochure-Congenital-Myasthenic-Syndromes.pdf (822.54 KB)

Patients with MG may require special management considerations. These include modifying dental treatment to accommodate altered muscle strength, identifying and managing myasthenic weakness or crisis, avoiding the potential of harmful drug interactions, and monitoring oral side effects of drugs and therapies used to treat MG.

Appointment Scheduling

Oral infections and/or stress of anticipating or undergoing dental treatment may precipitate or worsen myasthenic symptoms. Short-duration morning appointments may minimize fatigue and take advantage of the typically greater muscle strength experienced by most people with MG during the morning hours. Appointments are best scheduled approximately one to two hours following oral anticholinesterase (Mestinon) medication so as to benefit from maximum therapeutic effects and decrease the risk of myasthenic weakness or crisis.

 

Private Office or Hospital

A stable MG patient with limited or mild neuromuscular involvement you may be safely treated in the private dental office setting in most instances. However, if the patient suffers from frequent or significant exacerbations of the pharyngeal and/or respiratory tracts or from generalized weakness, he or she is most safely treated in a hospital dental clinic or other facility with emergency intubation and respiratory support capabilities.

 

Dentures

A patient’s ability to manage complete dentures may be compromised by the inability of the weak muscles to assist in retaining the lower denture and to maintain a peripheral seal for the upper denture. Over extended and over contoured maxillary dentures with thick flanges that impinge upon muscle and frenal attachments can lead to muscle fatigue and altered salivation. Improperly fitting dentures may exacerbate symptoms of difficulty in closing the mouth, tongue fatigue, a tight upper lip, dry mouth, impaired phonation, dysphagia, and masticatory problems.

 

Respiratory Collapse

If respiratory collapse occurs, an open airway and adequate respiratory exchange must be established. Dental staff should be trained in and prepared to do basic life support (CPR) until an ambulance arrives, when needed. Dental suction devices can be used to suction secretions and debris from the oropharynx to prevent aspiration and mechanical blockage of the airway. Manual retraction of the weakened tongue may prevent obstruction of the airway.

 

Oral Findings

• Tongue: Atrophy of the tongue (loss of muscle, replacement with fat) may result in a furrowed and flaccid clinical appearance. In severe cases, it can result in a triple longitudinal furrowing of the tongue.
• Mouth Drop: Lack of muscle strength in the lower jaw muscle, especially following a sustained chewing effort, may cause the mouth to hang open, unless the mandible (lower jaw) is held shut by hand.
• Chewing/Swallowing: Lack of strength of the muscles of chewing strength can inhibit proper eating of food.  Eating can be further inhibited by dysphagia (difficulty swallowing), when the tongue and other muscles used for swallowing are involved; also by aberrant passage of food or liquids from the nasopharynx into the nasal cavity, when the palate and pharynx muscles are affected. The consequences of this may include poor nutrition, dehydration and hypokalemia (reduced potassium levels).

Drug Interactions

Many common drugs used in dentistry may have potential complications for MG patients by exacerbating their muscle weakness or interfering with breathing. The following table may be of help to the myasthenic patient and the treating dentist. Please remember that this list cannot cover all potentially dangerous medications and one should consult with their treating physician if there are any questions.

Documents to download
MGFA-brochure-Dental.pdf (724.51 KB)

Background

Dysphonia (voice disorder) is relatively common in the general population, occurring in about a third of all people at some point in their lifetime but occurs in only about 2% of persons with MG. On the other hand, dysarthria (slurred speech) is less common in the general population, but occurs in over 10% of people with myasthenia gravis. Difficulty voicing or speaking can affect job performance and may cause a person to feel socially isolated because they have a hard time being heard or understood.
Human voice production starts by generating air pressure in the lungs. It flows through the vocal folds (vocal cords), causing them to vibrate and produce sound. Symmetric and fluid vibration of the vocal folds creates a pleasing, smooth voice. Human speech is produced by using the muscles of the throat, jaw, palate, tongue, and lips to shape the sound generated by the voice box into consonants and vowels. When the muscles of the lungs, vocal tract, throat or mouth are affected in MG, we may see symptoms of voice, speech, and swallowing problems.
Voice problems seen in MG include vocal fatigue (voice wears out over the day or with prolonged speaking tasks), difficulty controlling pitch, or a monotone voice (lack of ability to change vocal pitch). The voice problem can stem from poor breath support or from weakness causing the vocal folds not to move properly. Speech disturbances include a hypernasal voice or slurred speech (dysarthria). Dysarthria is more frequently seen in younger patients diagnosed with MG, whereas dysphonia is more often seen in elderly men with MG. Typically, the symptoms appear and/or worsen with continuing or extended speech.

 

Diagnosis

The diagnosis of dysphonia or dysarthria is often very apparent to a person with MG because they perceive a change in their voice or speech production. Sometimes, the symptoms may be subtle or intermittent. A speech-language pathologist or a medical doctor makes the diagnosis. Since dysarthria is a common symptom of stroke, any new onset of dysarthria should be immediately evaluated by a medical professional. Any person with vocal disturbance lasting more than 2 weeks should seek medical attention in a timely manner.
If you are experiencing a voice disorder, you may be referred to an ear, nose, and throat (ENT) physician to be sure that the dysphonia is due to MG and not another cause. The ENT physician will usually perform a laryngoscopy. This is a relatively straightforward examination that uses a small flexible camera inserted through the nose to visualize the upper airway. It is done with local anesthesia in the office setting and only takes a few minutes to complete.

 

Treatment

The treatment of speech and voice disorders in MG is individualized and based on the underlying cause and severity of the problem. Pharmacological therapies used for other symptoms of MG are typically utilized. Other treatments may involve therapy with a speech-language pathologist. Strengthening exercises and/or compensatory strategies may be employed to help increase understandability. A strengthening program is not indicated during a myasthenic crisis or exacerbation, but may be implemented during stability or when in remission. Exercises should be performed during peak drug therapy. Always review any plan of care with your MG treating provider.
Improvement and prognosis of voice and speech is often related to the treatment of overall MG disease. Research will continue to play an important role in answering questions and developing new treatments.

Documents to download
MGFA-brochure-Effects-of-MG-on-Voice-and-Speech.pdf (985.03 KB)

Download and complete the Emergency Alert Card in the event of an MG Crisis

I have myasthenia gravis (MG), a disease that can make me so weak that I may have difficulty standing or speaking clearly. In addition, I may have drooping eyelids, double vision, and even difficulty breathing or swallowing. Sometimes these symptoms are mistaken for intoxication. If my breathing and swallowing difficulty is severe, I may be having an “MG crisis” or “MG exacerbation” that warrants emergency treatment.

Documents to download
MGFA-Emergency-Alert-Card-2021.pdf (105.98 KB)

Triggers which may worsen MG muscle weakness include:

• Medications
  • High doses of steroids
  • IV magnesium
  • Some antibiotics
  • Certain heart/blood pressure medications
  • Some general anesthetics and paralytics
  • Botulinum toxin
  • Stopping or reducing medications used to treat MG
• ​Illness or infection
• Heat
• Stress from trauma or surgery

Myasthenic Crisis

• A potentially life-threatening complication of myasthenia gravis. Respiratory failure occurs due to weakness of respiratory muscles and mechanical ventilation is required.
• Repiratory failure may also develop due to weakness of muscle that keep the airway open.  BiPAP may be sufficient or the patient may need endotracheal intubation.
• Careful assessment and monitoring is required as myasthenic crisis presents differently from other forms of respiratory failure.
• Prompt recognition of impending myasthenic crisis may prevent fulminant crisis from developing.

PRE-HOSPITAL RESPIRATORY ASSESSMENT AND MANAGEMENT
Check for tachypnea:

• Rapid shallow breathing is seen in MG patients to compensate for weak respiratory muscles.
• Pulse oximetry is NOT a good indicator of respiratory strength in MG patients as abnormalities often develop only after life-threatening respiratory failure has already occurred. This is distinct from other causes of respiratory failure. Careful observation of respiration and bedside measurements (forced vital capacity, single breath count) are more reliable indicators of respiratory status than pulse oximetry in MG patients.

Inspect for use of accessory muscles of respiration:

• Check for retraction of supraclavicular fossa and intercostal spaces as indicators of respiratory accessory muscle usage. Patients may also use neck and abdominal muscles. Use of accessory respiratory muscle in MG patients is an important sign that respiratory effort may not be sustained. However, generalized muscle weakness in MG patients can at times mask accessory muscle usage.
• Paradoxical breathing and inability to lie supine or speak more than a few words are indicators of diaphragm weakness.
• Weak neck flexion also correlates with diaphragmatic dysfunction. Neck flexion strength can be tested by having the patient lie supine and attempt to lift his/her head off the stretcher and tuck his/her chin.
• Severe slurred speech and difficulty managing secretions are also signs of potential impending MG crisis.

Single breath count test:

• Single breath count test is a good bedside measurement of respiratory function which can be performed quickly and without additional equipment
• To perform, ask patient to count out loud after maximal inspiration. Ability to reach 50 indicates normal respiratory function. Single breath count of less than 15 typically correlates with low forced vital capacity (FVC) and respiratory muscle weakness.

Immediate management:

• Elevate head of the stretcher, keep patient cool and have suction available
• Oxygen usage is helpful but does not alleviate respiratory distress in MG patients. Titrate to keep oxygen saturation at 94-98% on pulse oximetry. If breathing is inadequate, provide assistance with ventilation immediately. Non-invasive ventilation may be given via bag-valve mask (BVM) or BiPAP.
• Invasive ventilation is needed when airway patency cannot be maintained or when noninvasive ventilation is unsuccessful.
• Transport patient immediately. Alert ED to the patient’s history of MG. Bring medical history paperwork if patient has it readily available

In-Hospital Initial Assessment and Management

Measure forced vital capacity (FVC) and negative inspiratory force (NIF) at baseline and trend, typically every 6 hours or more or less frequently, as needed. Trend of numbers over time is more important than individual test results. A declining NIF or NIF worse than 20 cm H2O and FVC less than 10 to 15 mL/kg typically prompts BiPAP or intubation.  However, abnormal PFTs are always interpreted in the context of the patient’s clinical picture. BiPAP may be indicated earlier for FVC less than 20 ml/kg or NIF worse than 30 cm H2O if patient is able to clear his/her secretions and has adequate bulbar strength.

Careful observation (tachypnea and use of accessory muscles) and bedside measurements (forced vital capacity, single breath count) are much more informative than pulse oximetry or ABG results. Measuring FVC upright and supine can sometimes provide insight, as decline in the supine position may indicate neuromuscular weakness.

• Pulse oximetry and arterial blood gas (ABG) measurements are NOT good indicators of respiratory strength in MG patients as abnormalities often develop only after potentially life-threatening respiratory failure has already occurred.
• Do not wait for ABGs to show hypoxemia or hypercapnia.
• These are late developing signs that appear only immediately prior to respiratory arrest in MG patients. Weak respiratory muscles may suddenly fatigue, producing precipitous respiratory collapse.

BiPAP is an alternative to intubation in MG patients without hypercapnia who are able to clear secretions. Patients may have their own BiPAP or NIV equipment.  Depending on local guidelines, patients may be able to use this if it remains medically appropriate for the presenting clinical scenario.

 

Next Steps

MG patients with impending or actual MG crisis should be admitted to an intensive care unit. Signs of impending crisis with need for ICU admission include: FVC less than 2 ml/kg, NIF less than 30, serial reductions in these numbers, significant bulbar dysfunction, orthopnea and/or rapid shallow breathing.

• Consult neurology for specific treatment options (e.g. plasma exchange, IVIG, corticosteroids etc). Consult with neurology regarding continuation of pyridostigmine if patient is intubated. Due to possibility of increased secretions, continued use may predispose patient to aspiration and ventilator associated pneumonia and is typically avoided.
• Contact the patient’s outpatient neurologist for input regarding care of worsening myasthenia.
• Review medication list and minimize medications which can worsen MG
• Identify and address triggers that may have exacerbated myasthenia (see above).

Documents to download
MGFA-brochure-Emergency-Mgt-First-Responders.pdf (928.68 KB)

Information and Guidance for People with MG, Families and Caregivers

• MG Crisis vs. MG Flare
• How to tell if an MG Crisis is developing
• Respiratory assessment tools for people with MG
• Emergency Assistance and Care

Documents to download
MGFA-brochure-Emergency-Mgt-People-with-MG-Caregivers.pdf (1.03 MB)

We are MG Strong

The Myasthenia Gravis Foundation of America–Your MGFA

Striving for a World without Myasthenia Gravis

 

If you or someone you know is experiencing sudden or gradually increasing symptoms of muscle weakness, it could be a sign of MG or another serious condition.
Talk to your doctor if you are short of breath, have difficulty smiling, talking or swallowing, or cannot walk any distance without having to rest.

 

What is Myasthenia Gravis (MG)?

Myasthenia gravis (pronounced My-as-theen-ee-a Grav-us) comes from the Greek and Latin words meaning “grave muscular weakness.” The most common form of MG is a chronic autoimmune neuromuscular disorder that is characterized by fluctuating weakness of the voluntary muscle groups.  Affecting both men, women, and children, MG can be diagnosed at any age.  Symptoms can be mild or severe, and may vary considerably from one person to another.  The disease can be ocular (causing double vision and drooping eyelids) or generalized, affecting the ability to speak, smile, use arms and legs, and at its worst, even to breathe.  Today, there are treatments, but presently no known cure.

 

The Myasthenia Gravis Foundation of America (MGFA)

The Myasthenia Gravis Foundation of America is the only national voluntary health organization dedicated solely to myasthenia gravis and related disorders.  The mission of MGFA is to facilitate the timely diagnosis and optimal care of individuals affected by myasthenia gravis and closely related disorders and to improve their lives through programs of patient services, public information, medical research, professional education, advocacy and patient care.  Our vision is a world without myasthenia gravis.

History:  It All Began With a Little Girl Named Patricia

When her daughter, Patricia, showed symptoms of myasthenia gravis, Jane Dewey Ellsworth was determined to find out everything she could about this strange disease. She found very little information and few resources for help. In 1952, determined to change this, she founded the Myasthenia Gravis Foundation of America, Inc. (MGFA).

 

Today, the Foundation touches the lives of hundreds of thousands of patients, families, friends, and medical professionals across the country and around the world. Through scientific research, educational literature, website and social media, awareness campaigns, support groups, conferences, and more,  MGFA is moving closer to our vision: A World Without Myasthenia Gravis.

 

Fulfilling the Mission—MGFA Programming

 

Driving Research to Find the Cause, Better Treatments, and a Cure for MG:

• Funding transformational research grants that may lead to new treatment pathways
• Funding post-doctoral fellowships to bring the brightest and best to the field of MG
• Bringing top researchers together to exchange ideas at national and international scientific seminars
• Advocating to legislators and the pharmaceutical industry for more MG research
• Advancing understanding of the disease and promoting clinical trials by managing and growing the MG Patient Registry, http://mgregistry.org/ .

 

The MG Patient Registry is owned and funded by MGFA.  It is the only scientifically based longitudinal database on MG in the country.  Launched in 2014, with new MG patients registering every month, the MG Registry is already yielding greater understanding of the patient experience, and has been used to support clinical trials.  WE URGE EVERY PERSON WITH MG TO JOIN!  To get started go to http://mgregistry.org/.  For more information see the MG Registry Brochure at www.myasthenia.org then go to Living with MG /Informational Materials.

Privacy Policy: The MGFA, MGFA Patient Registry Committee, and the University of Alabama at Birmingham’s Institutional Review Board for research all provide oversight for operation of the MG Patient Registry.  These work in parallel to ensure that the purposes and objectives of the registry are supported and to ensure that the rights and welfare of those enrolled in the registry are protected.  For a full text of the Privacy & Security Statement, visit the Registry Website at http://www.mgregistry.org and choose the Become a Participant tab.

 

Serving People with MG and Their Families:

• Providing accurate and timely information – through print, web, and social media.
• Connecting people living with MG to each other– through a growing network of support groups, trained peer support volunteers, and social media.
• Delivering educational programming – through webcasts, podcasts, and videos.
• Answering questions and connecting people to community resources and MG specialty care through a telephone help line service.
• Bringing together more than 200 members of the MG Community at an annual educational conference.
• Providing a mobile app to enhance doctor/patient communication.

 

The myMG app is a tool that patients can use to help track their MG symptoms and employ when visiting their physician. Use this tool regularly, then, when visiting your doctor, print a tracking report from your computer and discuss with your doctor. http://mymg.myasthenia.org/home

Educating Health Care Professionals and Scientists

 

• Providing information and resources for professionals who treat people with MG, including a handbook: Myasthenia Gravis – A Manual for the Health Care Provider
• Raising awareness of MG in the larger medical community, targeting primary care physicians, ophthalmologist and optometrists, and emergency care providers.
• Hosting medical and scientific meetings and conferences:
  • The MGFA Scientific Session, held in conjunction with the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM). This half day program brings together as many as 200 clinicians and scientists to learn about current research and treatment pathways in MG.
  • The International Conference on Myasthenia Gravis and Related Disorders, held once every 5 years in collaboration with the New York Academy of Sciences.  This three day meeting is the largest gathering in the world of clinicians and scientists focused on MG, drawing more than 300 participants from around the globe who connect to focus on the latest and most important scientific discoveries in MG.
  • Educational Dinner Meetings for Nurses, held annually in conjunction with the MGFA National Conference

 

Raising Awareness and Advocating for Change

• Informing the public about MG through an annual MG Awareness Campaign

• Communicating news and information important to the MG Community through press releases, frequent e-blasts, social media, our website: www.myasthenia.org and the semi-annual newsletter Focus on MG .
• Connecting and empowering grassroots volunteers who are the heart of the MG Community to raise their voices on issues important to those living with the disease.
• Advocating for key issues important to those affected by MG, such as increased funding for MG research, patients’ rights and access to care, disability rights, and family and caregiver support.  Partners include: NORD –The National Organization for Rare Diseases, The National Health Council, Research!America and the American Autoimmune Related Diseases Association (AARDA).

 

YOU Can Help MGFA Support People with MG and Their Families! 

 

Educate, Share & Raise Awareness

 

• Educate others about MG and the challenges it brings, and how MGFA can help.

• Visit local physicians’ offices and ask permission to put out brochures or promote your local support group.
• Staff an information table at a health fair or other venue.  MGFA can provide materials, banner, etc.
• Participate in June is MG Awareness Month. Contact the MGFA office for a toolkit.
• Spread information about MG and the support MGFA can provide via the Internet and social media.  Use Facebook, Twitter, Instagram or start a blog.
  • Become a peer support volunteer.  Organize an MG Support Group in your area, volunteer to help with an existing group, or provide telephone support to others as part of the MG Friends program. Call the MGFA office to learn more.
  • Join our growing network of MG advocates. Write or call your legislative representatives about issues that are important to people with chronic illnesses.
  • Volunteer at an MG Walk or other special event,

 

Donate & Raise Funds

• Make a tax-deductible donation.  Also encourage your employer, family, and friends to make matching contributions. For more information go to http://myasthenia.org/HowcanIhelp/Donations.aspx.
• Join your local MG Walk!  People with MG, families, professionals and others connected to myasthenia gravis can help by becoming MG Walk team captains, walkers and fundraisers in your local market.
• Become a Do It Yourself (DIY) fundraiser.  Host an event inviting friends, family, colleagues, and neighbors to participate and provide the proceeds to MGFA. Call the MGFA office at 1-800-541-5454 to talk about your idea and get a toolkit.
• Make a bequest to MGFA in your will.  For more information go to http://www.legacy.vg/myasthenia.

 

MG Walk Campaign

Why WALK?

The MG Walk Campaign is the flagship national awareness and fundraising campaign for the Myasthenia Gravis Foundation of America (MGFA). Since it started in 2011, the MG Walk has now raised a remarkable $5 million to help fund research for better treatments, much needed programs and services, education and unprecedented awareness to the public and an increase in advocacy efforts. The success of the MG Walks can be directly attributed to the tireless efforts and dedication of the amazing team captains, walkers, support groups, medical community representatives and businesses that support their local MG Walk events.

The MG Walk Campaign continues to bring together those in the MG Community to talk about their experience – many for the first time – and grow the resources and awareness desperately needed. While there are treatments, there is currently no cure for MG…and THAT is why we walk together toward the ultimate finish line…a world without myasthenia gravis!

If you are local MG constituent, member of the medical community or a business that would be interested in supporting the MG Walk Campaign, please contact Info@MGWalk.org or 1-855-MGWalks (649-2557). For a listing of all local MG Walks throughout the country and to learn many more exciting details about the Campaign, please visit www.MGWalk.org. Together, we will be stronger!

 

Financial Information and Stewardship

The MGFA meets all of the standards of BBB Wise Giving Alliance, Community Health Charities, and the National Health Council, and is a careful steward of donations received. In 2018, seventy-two percent (72%) of every dollar donated went to support MGFA programs.

The MGFA is generously supported by donations from individuals, Walkers and Walk Teams, charitable organizations and others. For more detailed financial information, please see the MGFA’s latest annual report, audit and Form 990, on our website at www.myasthenia.org.

 

Information You Can Trust

There is much information available today on the Internet on nearly every subject, but it is often hard to sort out truth from fiction.  Information published by MGFA has been reviewed (and often written) by top experts in MG.  The organization’s Medical/Scientific Advisory Board is a collective of more than 150 of the top MG clinicians and scientists in MG in the world.   Twenty nurses also serve on the MGFA Nurses Advisory Board.  Members of these groups volunteer their time unselfishly, writing and reviewing articles and brochures, organizing curricula and speaking at programs and conferences, and advising on research funding decisions.  They are on call to help MGFA staff respond to complex questions from the MG Community.  It is reassuring to know that information you get from MGFA is supported by the knowledge and expertise of these clinicians and scientists.

 

© Myasthenia Gravis Foundation of America, Inc.

Revised October 2019

Myasthenia Gravis Foundation of America

355 Lexington Avenue

15^th Floor

New York, NY 10017

1-800-541-5454

mgfa@Myasthenia.org

www.Myasthenia.org

Documents to download
MGFA-brochure-MG-Foundation-2023-digital.pdf (1.09 MB)

What is ocular myasthenia gravis?

Ocular myasthenia gravis is a form of myasthenia gravis (MG) in which the muscles that move the eyes and con­trol the eyelids are easily fatigued and weakened.

 

What are the common symptoms of ocular myasthenia gravis?

People with ocular MG have trouble with sight due to double vision and/or drooping eyelids. Their eyes do not move together in balanced alignment, causing them to see “double” images. One or both eyelids may droop to cover all or part of the pupil of the eye, blocking vision.

 

These symptoms may be mild to severe. Eye weakness often changes from day to day and over the course of a day. Eye problems often worsen at the end of the day or after a pro­longed period of use. If you have ocular MG, you may find that eye problems temporarily improve after several minutes of rest.

 

People with ocular MG do not have difficulty swallow­ing, speaking or breathing, nor do they have weakness of the arms or legs. Descriptions of the symptoms that people with ocular MG may have include:

• Double vision – Seeing two images rather than one. This results from weak­ness of the muscles that move the eyes together in alignment. The medical term for double vision is diplopia. If you have diplopia, you may experience blurred vision rather than double vision.
• Drooping eyelids – The eyes do not appear to be opened fully. If the eyelid covers the pupil of the eye, then the vision of that eye will be obstructed. The medical term for drooping eyelids is ptosis (pronounced “toe-sis”).

 

Who gets ocular myasthenia gravis?

Problems with double vision and drooping eyelids are often the first symptoms of MG. Although most people have eye problems at the onset of MG, they may have other muscle weakness or develop other muscle weakness in the first two years after MG symptoms begin. About 15% of people with MG will have only ocular problems (ocular MG). If weakness of other muscles develops over time, the MG changes from ocular MG to generalized MG. About half of all people with ocular issues related to MG in the first year will develop generalized MG. People that have had only ocular MG symptoms for five years or more will most likely not develop generalized MG.

 

People with ocular MG are slightly more likely to have seronegative MG (no measurable autoantibodies like AChR and MuSK) compared with people with generalized MG.

 

Why are the eye muscles frequently involved in myasthenia gravis?

There may be several reasons why eye muscles are more frequently involved. However, this is not completely understood.

 

One hypothesis is that people with MG may simply notice eye weakness more often than mild weakness in other muscle groups in the body. Another hypothesis is that the eye and eyelid muscles are structurally different from muscles in the trunk and limbs. For example, these parts of the body have fewer acetylcholine (AChR) receptors, which is where the defect occurs in autoimmune MG. Eye muscles contract much more rapidly than other muscles and may be more likely to fatigue.

 

Perhaps the most important difference between eye and eyelid muscles compared with other muscles of the body is that eye muscles respond differently to immune attack. The differences in the response of eye muscles to immune attack may explain why eye muscles are also targeted in other autoimmune conditions, such as auto­immune thyroid disease.

 

How is ocular myasthenia gravis treated?

It is important to talk with your physician about the best treatment regimen for you—balancing the   severity of the symptoms and impact on quality of life with the risks and benefits of treatment. People who have primarily cosmetic problems due to ptosis or diplopia may con­sider nonpharmacological treatment, such as:

• Wearing dark glasses in bright light, which some people find helpful.
• Using eyelid tape (a special type of tape used to hold the eyelids open without injuring the eyelids). This can be used for ptosis and may be preferable to drug therapy that alters the immune system: using agents such as glucocor­ticoids (prednisone or similar agents), azathio­prine (Imuran®), cyclosporine or mycophenolate mofetil (CellCept®).
• Applying a patch to one eye. This permits people with double vision to see one image. If the same eye is consistently patched, vision in that eye might decrease. Therefore, it is important to alternate the patch from one eye to the other to avoid permanent vision loss.
• Using eyelid crutches (clever devices attached to glasses to hold the eyelids open) for ptosis.
• Using eyeglass prisms for diplopia.

The last two treatments are uncommon, older treatment methods for ocular MG.

 

When ocular symptoms are severe or disabling, treatment with immune system modulating therapy may be considered.

Agents that improve neuromuscular transmission, such as Mestinon®, may be helpful for ptosis, but are generally not very useful for diplopia.

Thymectomy is usually not considered for people with ocular MG unless the manifestations are severe or disabling.

Eyelid or eye muscle surgery is generally not recommended for people with MG

Documents to download
MGFA-brochure-Ocular.pdf (594.71 KB)

Myasthenia Gravis in Pregnancy

If you are a woman with myasthenia gravis (MG) and are considering  pregnancy, you will want to discuss your plans with  your MG treating provider well in advance. This will permit adequate time for you and your provider to make any adjustments to your MG treatment plan, allowing for the best outcomes with the least risks for you and your baby. You and your health care providers will also want to discuss  the safety of your current treatment plan during a pregnancy and the avoidance or discontinuation of any therapies that might have unwanted effects on the growing fetus. The impact of changes in your treatment plan on your own health is also an important consideration.

 

Treatment During Pregnancy

The treatment of MG in pregnancy is similar to treatment in non-pregnant patients. The majority of patients under good control prior to pregnancy will remain stable throughout the pregnancy. When there is worsening, it is more likely to occur in the weeks after the delivery of your baby.

Oral pyridostigmine (Mestinon®) is the standard first-line treatment during pregnancy. Intravenous anticholinesterase inhibitors (like pyridostigmine) should not be used during pregnancy as they may produce uterine contractions. However, these should be administered during labor in place of oral dosing.

Prednisone is the immunosuppressant agent of choice during pregnancy. When prednisone is insufficient or poorly tolerated, azathioprine or cyclosporine are considered relatively safe by a consensus of MG experts. However, some MG experts are  opposed to using azathioprine in pregnancy.

Either lasmapheresis (PLEX) or IVIg may be used when a prompt temporary response is needed during pregnancy.

Thymectomy should be postponed until after pregnancy.

 

Planning the Delivery

You should carefully consider where you will give birth. Whenever possible, most pregnant women want the obstetric team who has cared for them throughout the pregnancy to deliver the baby and care for them in the postpartum period. During the course of the pregnancy, the MG provider and the obstetrics team must be in communication about the treatment plans, the progress of the pregnancy, and plans for delivery.  There may be advantages to choosing an obstetric team that performs deliveries at the same medical center where you are treated for MG. Home births and deliveries at birthing centers outside of large hospital centers are typically not recommended for patients with complex medical issues.   Maternal MG presents with special considerations for the infant as well as the mother.  Babies whose mothers have MG may need special care immediately upon delivery (see “Transient Neonatal MG” below).

 

Labor & Delivery

As a pregnant woman with MG, you can expect to have a typical labor and a spontaneous vaginal delivery. Consultation with an anesthesiologist before labor commences is advised. Regional anesthesia is recommended when vaginal delivery is expected. Magnesium sulfate, frequently used for preeclampsia and eclampsia is not recommended in patients with myasthenia as it can precipitate a myasthenic crisis.

 

Transient Neonatal MG

Infants born to mothers with autoimmune MG typically will need to be examined immediately  after birth and observed by skilled neonatal doctors and nurses for the first 3 to 4 days for any signs of transient myasthenic weakness, even if the mother’s myasthenia is well-controlled. A small number will require some very short-term support of breathing and feeding. Infants with transient neonatal myasthenia do not continue to have myasthenia once auto-antibodies passed from mother to baby through the placenta have been removed or spontaneously broken-down.

 

Reference

Sanders, DB, et al. (2016). International consensus guidance for management of myasthenia gravis: Executive Summary Neurology: 87(4), 419-425.

Documents to download
MGFA-brochure-Pregnancy-MG.pdf (455.37 KB)

The following are answers to some of the most common questions asked when a thymectomy is being considered for adult and younger patients with autoimmune myasthenia gravis (MG).

 

The answers supplied below are presented in general terms as background information only and should not be used to make specific decisions. Since each patient’s situation is unique and the types of thymectomy being performed vary, it is essential that you discuss in detail these and all other questions about the surgery with your MG specialist and surgeon.

 

What is a thymectomy and why is it performed?

A thymectomy is the surgical removal of the thymus gland. The thymus has been demonstrated to play a role in the development of MG. It is removed in an effort to improve the weakness caused by MG, and to remove a thymoma if present. About 10% of MG patients have a tumor of the thymus called a thymoma. Most of these tumors are benign and tend to grow very slowly, however occasionally, a tumor is malignant (cancerous).  Every person diagnosed with MG should have a CT scan of the chest to check for a tumor.

 

What is the function of the thymus? Is its removal harmful?

The thymus gland plays a major role in the development of the body’s immune system. Its job is to train immature T-cells to develop into mature T-cells which are then are circulated in the body to help activate the immune system’s B-cells to fight infections. The thymus gland enlarges throughout childhood and starts shrinking during puberty. By the time adulthood is reached, the thymus gland’s function is no longer needed. Removal of the thymus in the treatment of MG in adulthood does not affect the immune system thereafter.

 

Exactly where is the thymus located?

The thymus is located in the front portion of the chest (anterior mediastinum) with “finger-like” extensions into the neck and consists of multiple lobes (two to five or more). In addition, varying amounts of thymic tissue may be present in the fat surrounding the lobes, both in the neck and chest.

Who should have a thymectomy?

A thymectomy is frequently recommended for patients under the age of 60 with moderate to severe MG weakness. However, it is recommended for patients of any age who present with a thymoma or thymic tumor. It is sometimes recommended for patients with relatively mild weakness, especially if there is weakness of the respiratory (breathing) or oropharyngeal (swallowing) muscles. A thymectomy is usually not recommended for patients with weakness limited to the eye muscles (ocular myasthenia gravis).

In a recently completed randomized trial of extended transsternal thymectomy in patients without thymoma, patients aged 18 to 45 and who had a positive AchR blood test and who had presented with generalized symptoms within the last 5 years prior to the surgery were found to have the greatest benefit from thymectomy. These patients had reduced hospitalizations due to MG exacerbations, and reduced requirements for prednisone and other immunotherapies.  Older patients were also randomized in the study, but their numbers were too small to make definitive statements about the benefits of thymectomy above age 45.  [See New England Journal of Medicine, August 11, 2016, Volume 375, No. 6, Randomized Trial of Thymectomy in Myasthenia Gravis, G.I. Wolfe; H.J. Kaminski, et al.]

 

What should I expect as I consider a thymectomy?

When a thymectomy is being considered, you will be referred to a surgeon. It is important to choose a surgeon experienced in performing thymectomies for patients with MG. The surgeon will review your clinical records, examine you, discuss your surgical options  and make a recommendation. The surgeon also explains the anticipated pre- and post-operative courses, possible complications, and the anticipated results. You, in consultation with the neurologist and surgeon, will then make a decision:  whether or not to proceed with a thymectomy and if yes, the type of surgery to be used.

 

What are the goals of a thymectomy?

The neurological goals of a thymectomy are significant improvement in the patient’s weakness, reduction in the medications being employed, and ideally a permanent remission (complete elimination of all weakness and off all medications). A thymectomy is usually not used to treat active disease but rather it is believed to improve long-term outcome. Results may not be seen for one to two years or more after the thymectomy.

 

How is the surgery performed?

There are three basic surgical approaches explained in the paragraphs below, each with several variations. Regardless of the technique employed, the surgical goal is to remove the entire thymus. Many believe this should include removal of the adjacent fat; others are less sure.

Transsternal Thymectomy

• Incision: Vertical (lengthwise) on the anterior chest; the sternum (breastbone) is “split” vertically.
• Thymus Removal: The chest and neck portion of the thymus are removed through this incision.
• Extended Form: The fat located in the front part of the chest next to the thymus, as well as the thymus, is removed. Complete removal of all tissue containing thymus is believed ensured.  This is the approach that was used in the randomized trial mentioned above.
• Combined Chest and Neck: A few MG Centers add a formal neck dissection to the sternal technique to also ensure the removal of all the thymus in the neck.
• Thymoma: Most recommend the transsternal approach for removal of a thymoma.

 

Transcervical Thymectomy

• Incision: Transverse (horizontal) across the lower neck.
• Thymus Removal: The chest portion of the thymus is removed through this incision.
• Extended Form: The “extended” form allows improved exposure of the thymus in the chest with more complete removal of the thymus. Although the adjacent fat is also removed, less is removed than in the extended transsternal thymectomy.

 

Videoscopic (VATS) Thymectomy

• Incision: Several small incisions on the right or left side of the chest.
• Thymus Removal: Fiber-optic instruments are used. These are small flexible tubes with a light at the end through which small instruments can be passed. The amount of thymus and fat removed is variable.
• Extended Form: In the “VATET” form, incisions are made on both sides of the chest, as well as in the neck, for “more complete” removal of the thymus.

 

What are the results of a thymectomy?

Many neurologists experienced in the treatment of MG are convinced that a thymectomy plays an important role in the therapy of MG, although the benefit is variable. The randomized trial of thymectomy mentioned above has provided evidence to back up this conviction, at least in AchR positive patients with generalized MG.

 

In general, most patients begin to improve within one year following a thymectomy and a variable number eventually develop a permanent remission (no weakness and no medication). Some physicians believe the remission rates after surgery are in the 20-40% range regardless of the type of thymectomy performed. Others believe that the remission rates following the more extensive procedures are in the 40-60% range five or more years after the surgery.

 

It is important to note that rigorous scientific studies are needed to resolve the debate concerning the best method of performing a thymectomy in the treatment of MG patients.

 

What type of thymectomy should I have?

Since there is no universal agreement, or unequivocal proof, as to which type of thymectomy is best, it is difficult for patients to decide what is best for them. There is, however, general agreement that the entire thymus should be removed and that the patient should select the procedure that ensures as much as possible that this is accomplished. Some surgeons believe that all the surrounding fat should be removed as well, because it frequently contains microscopic (very small) amounts of thymus; others believe this may not be necessary.

 

There is growing evidence that “minimally invasive” procedures (transcervical and videoscopic) are as effective as more invasive approaches.  The evidence for this is mainly through retrospective comparisons of patients who underwent different types of surgery during different eras in the last two to three decades.  As of yet, there are no prospective, randomized studies comparing different surgical techniques which would provide a higher level of evidence.

 

Since there is no absolute proof as to which type of thymectomy is the procedure of choice, it is up to you to become fully informed, review the evidence presented by the neurologist and surgeon caring for you, and perhaps obtain additional consultation (second or even third opinion). Again, the key to the optimal outcome is to remove as much thymic tissue as possible in the safest way possible for a particular patient.  It is important that you have your questions answered, and confidence in your medical team and the decisions about your plan.

 

What can the MG patient expect in the pre-operative, anesthesia and post-operative periods?

In general, MG Centers have developed protocols for the care of MG patients and have a team of neurologists, surgeons, pulmonologists, intensive care and respiratory care specialists, nurses and anesthesiologists caring for MG patients undergoing a thymectomy.  To ensure that you are fully prepared, ask for time to discuss all aspects of the pre-and post-operative care and anesthesia with the surgeon, anesthesiologist and neurologist.

 

To reduce the risks of post-operative respiratory complications or the post-operative need for prolonged respiratory support with a ventilator (breathing machine), your doctor may require pre-operative plasma exchange (PLEX) or intravenous immunoglobulin (IVIg), and some require immunosuppressive therapy as well. If you are taking pyridostigmine (Mestinon) your medical team will advise on what to do both in the weeks before, and the day of and the days after surgery.  The surgical team will also advise on all medications you may be taking—not just for MG, but for other conditions such as blood pressure, pain (like aspirin, NSAIDs, etc.).  Be sure to have these discussions.

 

The anesthesia for patients with MG is similar to the anesthesia given to other patients. An endotracheal tube (tube in the windpipe) is inserted after you are asleep. Muscle relaxing drugs, however, are usually avoided. You may or may not be extubated (removal of the endotracheal tube) upon awakening, depending on your strength. If the endotracheal tube is not removed on awakening, the tube will be attached to a ventilator.

Ordinarily after the surgery, you will go to a Recovery Room, Respiratory Care Unit, or Intensive Care Unit depending on each hospital’s method of taking care of MG patients following surgery. A ventilator may be required depending on the type of operation and the severity of your weakness. As soon as the breathing tube has been removed, you will be asked and helped to deep breath and cough frequently to keep the lungs clear of secretions. One or two chest tubes (small tubes exiting the chest and attached to drainage bottles) are usually used after the transsternal and videoscopic operations, and removed soon after surgery.

 

Medications used to manage MG before surgery are usually continued after surgery. The neurologist will decide how to taper your medications after surgery in subsequent follow-up appointments.

 

Pain is minimal following transcervical thymectomy and usually mild following videoscopic thymectomy, although some patients have reported late pain. The pain associated with transsternal thymectomy is temporary and well controlled with medication and gradually resolves within 3-5 days. Patients typically require minimal pain medication on hospital discharge. If your pain is not well-controlled, talk with your doctors about options.

 

The length of time in the hospital will vary depending on the type of surgery and your overall weakness. In most cases you will be ready to go home in a few days to a week. Your preoperative medications, immunosuppression and other forms of therapy are usually resumed after surgery for variable periods of time depending on the MG symptoms and the neurologist’s recommendations.

 

When can I return to my usual activities?

It is hard to predict the recovery time for any individual patient.  And the return to work, school and other responsibilities and activities will also vary—as certainly some jobs and life responsibilities are more physically demanding than others.  It may be best to plan for the worst (when working with both health and disability insurance) and still hope for the best. Your physician can provide an estimate, based on your expected responsibilities, as well as your normal level of weakness and the surgical plan—but no one really knows how any given person will react to and recover from surgery—especially someone with MG.

 

A patient who does heavy lifting or construction work, or is a school teacher or hospital nurse on his/her feet all day, may need to be off work longer than someone who has a desk  job. And the mom or dad whose day job is taking care of a toddler may need extra help until he/she is able to safely lift 25-30 pounds.  It is also hard to predict the fatigue factor with MG.  It is better for those who are employed and planning to return to work to ask your physician to write for a longer time off for your short-term disability.  If you feel great and are ready to go back, no one will argue if your doctor reduces the needed time off.    It is encouraging to note that most patients have very few problems after the surgery and are able to return to their usual pre-operative activities.

 

Will my insurance pay for the surgery?

Health insurance companies do pay for thymectomies. Since there may be questions concerning insurance coverage with specific surgeons and specific institutions, it is a good idea to check with your insurance company as soon as a thymectomy is being considered to make sure that the coverage is in order. Some insurance companies may require additional consultation and some type of prior authorization. In some instances, letters from the neurologist and surgeon will be required to defend the procedure selected.

Documents to download
MGFA-brochure-Thymectomy.pdf (7.18 MB)