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Medical and Surgical Management of MG Brian A. Crum, MD Department of Neurology Mayo Clinic Rochester, MN MGFA National Meeting, St. Louis May, 2010 Basic Facts Prevalence 20 in 100,000 Women: younger (30’s); Men: older (40’s) The disease looks different in different people The disease is treatable Most patients improve and do well The disease is most active the first few years There are significant costs, side effects, and manifestations of the disease Variables in Treatment Ocular vs. Generalized vs. Crisis Types of antibodies (AchR vs. MuSK) Thymoma or not Age and other medical conditions Men vs Women (esp childbearing) Access to healthcare Not: Levels of antibodies in the blood Ocular vs. Generalized Ocular: Just in the eyes Generalized: Face, arms, legs, neck 80+% of MG starts in the eyes Many will ‘generalize’ in the first monthsyear Most that DON’T generalize at a year will remain ocular Ocular vs. Generalized Treatment is mostly symptomatic If double vision and droopy eyes are a problem, need treatment Treatment with steroids may reduce the chance of ‘generalizing’ Thymectomy generally not recommended for just ocular disease Types of Antibodies MuSK antibody positive MG Affects face, neck, shoulders, breathing Tests (like EMG) may not show as much of the MG changes AchR antibodies are negative Mestinon/pyridostigmine less effective, may make weakness worse Plasma Exchange works Thymectomy probably not Thymoma or Not 10-20% of MG patients have a thymoma Most have no symptoms (other than MG) Found with imaging like CT Surgery is done to remove tumor Usually totally removed If not, chemo or radiation done w/ oncologist MG is more difficult to treat Overview--Treatments Short Term Medium Term Immune-Mediating: Several Longer Term Immune-Mediating: Steroids Long Term Symptomatic: Mestinon Immune-mediating: IVIG, Plasma Exchange Thymectomy Goal: Normalize strength, minimal medications (or none) Mestinon (pyridostigmine) Short-acting 30-60 minutes to start working, lasts a few hours Used ‘as needed’ Patients can experiment with doses ½ to 1 to 2 pills at a time 3-6 times a day Too much can lead to cramps, twitching, diarrhea, sweating, more weakness Also a longer-acting form (at night) NeuroMuscular Transmission Acetylcholine Ach Esterase Ach receptor Muscle Contraction Short-Term: IVIG/Plasma Exchange Usually for severe weakness (ie in the hospital) One not better than the other (in studies on crisis) IVIG shown to be effective in improving weakness and reducing need for steroids in outpatients with MG IVIG 3-5 days in a row Pooled antibodies from blood donors Screened for transmissible disease Thought to reduce the immune attack on muscle Improvement w/in days Requires and IV in the arm Expensive, but typically covered Done more in outpatient setting now Plasma Exchange “Filtering” of blood through a machine Typically done every other day for 5-7 exchanges (10-14 days) May required a larger IV line (central line) placed in neck or chest Risks of infection or blood clotting Improvement in days Usually reserved for hospital patients Medium-Term Prednisone (the ‘love/hate’ drug) Proven to work in MG Takes days to weeks to see improvement Usually given as pills, sometimes IV Doses and frequency (every day or every other day) vary Initial high doses can lead to more weakness Prednisone Inexpensive drug Side Effects many: -Weight gain, puffiness -Facial hair -Bone thinning* -Stomach irritation* -Infections* -Diabetes, high blood pressure, glaucoma *=other medications can be given for these Steroid-Sparing Drugs “Long-Term” General idea is to use these to allow reduction and elimination of Prednisone Or, sometimes to avoid using it altogether Require monitoring of lab tests Blood counts, liver tests Steroid-Sparing Drugs “Long-Term” Imuran (azathioprine) Most commonly used Takes 6-12 months to ‘work’ Cellcept (mycophenolate) Studies have shown it may not ‘work’ Takes months to ‘work’ (> 6) Cyclosporin or Tacrolimus (FK506) Studies show these ‘work’ Steroid-Sparing Drugs “Long-Term” Others: Cyclophosphamide Given by mouth or IV Reserved for severe disease Rituximab (Cytoxan) (Rituxan) Given IV weekly for 4 weeks Reserved for severe disease Longer-Term Thymectomy Done since the 1930’s/1940’s Not proven definitively to help Data: 1.5 to 2 times higher chance that a patient will have remission after thymectomy But: Studies are not controlled or randomized Other factors go into how patients do (for example who gets picked to have surgery) Longer-Term Thymectomy International MGTX study ongoing Patients randomized to getting surgery or not Also controversial what kind of thymectomy to do More minimal invasive surgery Considered in patients with generalized disease, within the first few (2-3) years and all patients with thymoma Doing well Some disease Crises In relation to common medical conditions In relation to common surgical conditions Newly Diagnosed-Clinic Mestinon If not fixing weakness, then… Prednisone IVIG Eventual taper of prednisone with or without a steroid-sparing drug Get disease stabilized Consider thymectomy Newly Diagnosed-Hospital Plasma Exchange or IVIG Prednisone +/- Mestinon Imaging of chest to look for thymoma If none, thymectomy can be considered, but once patient is stabilized (may be months) If yes, then operate when safe medically Doing fine, maintenance Mestinon Tapering Prednisone +/- a steroid-sparing drug Question becomes when to stop the steroid-sparing drug if patient is in remission Exacerbations Treat any medical factor that may contribute Start or increase Prednisone Use IVIG for a course of 3-5 days Sometimes weekly or monthly Difficult to control disease Regular IVIG or plasma exchange A different steroid-sparing drug Thymectomy (if not done) Medications that affect MG Antibiotics Cipro, Gentamicin, Levaquin, Erythromycin, Azithromycin (aka Z-pak) Bo-Tox Less likely: Blood pressure drugs Statin medications Other symptoms in MG Fatigue, fatigue, fatigue Adequate sleep Treatment of pain Treatment of depression Review medications Regular exercise Thanks!! MG is diagnosable MG is treatable Treatment is individualized, but effective in most We need better treatments and answers to treatment questions (like thymectomy)