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MGA News |
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Our grateful thanks go to all those doctors and consultants who took time to attend our medical conference at Oxford on the 13th April 2002.
These are shown below (in alphabetical order) but there were many more unsung heroes of the day that we would like to extend our gratitude to, including the many members of staff of the John Radcliffe Hospital who gave their time and support. You will know who you are, and we are grateful.
| Dr David Beeson | Dr Jacqueline Palace |
| Dr Maria Farrugia | Dr David Shlugman |
| Dr Marguerite Hill | Prof Angela Vincent |
| Dr David Hilton-Jones | Dr Ewan Walters |
| Dr John McConville | Prof Nick Willcox |
Our thanks also go to all those members and supporters who, along with their families and carers, took the time off to attend and make the day an outstanding success.
A great many people were there on the day, and many questions were asked directly. However, some people who were unable to attend also wrote in with some questions. Below we have tried to group these into areas of common interest. One or more of the doctors/consultants have provided the answers. Everybody, regardless of whether they attended or not, will have received an individual response, including questions which were very personal to the individual and which are not shown here.
| NB. Questions are shown in plain font and the Answers are shown in italics. |
Dr Ewan Walters, Vice President of Medical Affairs at ICN Pharmaceuticals, the company that markets Mestinon, summarised queries relating to Mestinon medication.
After being taken orally, levels of Mestinon (pyridostigmine) in the blood can vary greatly between patients, so a dose that is suitable for one patient may not be high enough for another, and too high for yet another. Blood levels can also vary considerably from day to day, even within the same patients taking the same dose of medication at the same time each day.
However, blood levels usually peak after approximately 2 hours. Dr Walters stressed that the key is to maintain adequate blood levels so as to control symptoms. This means taking the medication at regular intervals: frequency of dosing is more important than taking a few high doses, due to the drug’s “half-life”, which is 3 – 4 hours.
(NB – “Half-life” is a measure of the speed of clearance of a drug from the blood, and gives a guide to the duration of action.)
ICN are committed to developing Mestinon further, and research into a number of alternative preparations, such as an “Instant Release” and longer-acting “Slow Release”, is ongoing.
The existing 180mg Mestinon tablet remains unlicensed in the UK.
Q. Do the benefits of Mestinon reduce over the years, making it necessary to keep increasing the dose?
A. In the short term, small changes in Mestinon dose can be useful, but it may be worth considering higher doses of steroids instead for a while to achieve better control, possibly with lower doses of Mestinon. If you are currently on say 15 mg Prednisilone (on alternate days), then you may wish to increase this to ~ 25 mg. Depending on their severity however, it may be sufficient to control your symptoms with Mestinon as and when required, though its benefits do tend to decrease with time.
Q. Mestinon totally upsets my stomach and bowels. It is possible to take it by injection?
A. Mestinon has well known side effects on the stomach and bowels (diarrhoea and cramps). They can be counteracted with other drugs called Probantheline or Atropine, which you can take just before your Mestinon tablets. Alas, alternative preparations given by injection are likely to cause the same side-effects on the gut as the tablet formulations.
Q. From childhood I have been subject to cramp. It has got worse since my MG was diagnosed. I wake with severe cramp several times every night; during the day I get it almost anywhere (jaw, neck, back, hands, thigh, calf, foot). The MGA literature states that quinine, the normal treatment for cramp, should be avoided. Do other myasthenics have similar problems/better solutions?
A. Cramps in MG may be related to the muscle weakness and/or to its treatment with pyridostigmine. If so, treatment with probantheline (15mg tid or qds) may be useful. Unfortunately, the standard treatments for cramps are not recommended for people with MG (quinine, anticonvulsants [eg carbamazepine or gabapentin] and muscle relaxants). BUT Dr Hilton-Jones said that, if the MG is well controlled, cautious test doses might be worth trying. In a very small number of patients, the cramps may be due to the coexistence of neuromyotonia – this can be assessed by electrical tests and blood tests.
Q. Could any of the panel please update me on the availability of the slow release pyridostigmine and in what cases do you envisage this medicine being prescribed?
A. See preamble on Mestinon in MG above. Mestinon (Time Span—180mg) is useful to obtain control of myasthenic symptoms over a long period of time (e.g. overnight) in contrast with the conventional Mestinon, which lasts for four to six hours.
Q. A number of questions relating to newer immunosuppressive drugs and vaccines were received.
A. Re newer immunosuppressive drugs and vaccines:-
Dr Hilton-Jones said that cyclosporine, tacrolimus and mycophenolate are powerful drugs with quite significant side effects which are used a lot to stop graft rejection. He keeps them in reserve for problem MG cases who can’t take the standard treatments. There is no hard evidence that there is any improvement on those currently used. Re immune vaccines. There is one USA team who are testing one, but it is not based on convincing science, and remains to be validated. The Oxford team – and some others – are working hard on smart weapons for selectively targeting the damaging autoimmune response against the muscles in MG without clobbering the whole immune system.
Q. Whilst the use of Mestinon and corticosteroids clearly help, they do have serious side-effects. What research is there on possible alternatives, such as various foods, which may have slower but longer term benefits?
A. There is no real evidence that particular foods help in MG.
Yes, steroids and Mestinon are associated with side-effects – steroids with long-term problems of diabetes, high blood pressure, weight gain, stomach ulceration and bleeding, bone-thinning and cataracts and also the risk of infections due to immunosuppression, including fungal infections. Mestinon can give problems with cramps and diarrhoea.
Q. Can myasthenia 'burn itself out'? My first symptoms of MG became apparent early in 1996.
A. Immunosuppression should have prolonged benefits; it is given to achieve remissions and may eventually be tailed down gradually to very low doses. Stopping altogether can be more tricky, and doesn’t work in everyone. They are all different; some relapse earlier and some (lucky ones) never. How we wish we could predict that – but not yet, alas. The disease goes into spontaneous remission (ie – burns itself out) in about 1% of patients per annum.
Q. As I am 56 years old, is a thymectomy appropriate to help me improve my outcome.
A. We think thymectomy is most suitable when the MG starts before age ~ 45. If so, it might still be worth considering, in theory, at age 55, BUT some people think it is best done early if at all. IF the new thymectomy trials get going, we may be on firmer ground.
Q. Having had a thymoma removed in 1994, should I have regular scans as a follow up procedure? Does azathioprine exacerbate this condition?
A. Thymomas rarely recur, but they vary. At one extreme, some seem completely benign under the microscope and follow-up may not be necessary. At the other, if they are already spreading when first operated, then repeat scans (e.g. yearly) are definitely needed, even if the MG is well controlled. In between, it is up to you/your Neurologist.
Q. I was advised that, because of my myasthenia, I should not have a hepatitis related jab. Is that correct and what if any effects would it have?
A. Hepatitis Vaccine is a ‘dead’ vaccine and is therefore safe in patients on immunosuppression. The live ‘attenuated’ ones may pose some risk – eg measles, German measles, mumps, polio etc, but these are usually given in childhood – ie before the MG starts – so the issue rarely arises. However, the vaccine for yellow fever may be recommended for exotic holidays, but should be avoided in patients on immunosuppression. If immunosuppressed patients are living with a child who is getting polio vaccine, and have not been immunized against polio themselves, then the child should get the killed (injectable) form and not the live oral vaccine
Q. Can 'live' vaccines cause a myasthenic attack?
A. No, we don’t believe vaccines provoke MG. We spent a lot of effort looking for signs that viruses in general might do so, but found nothing
Q. Are there any associated problems with MG and hormone replacement therapy? Is HRT recommended? Do MG symptoms worsen during menopause?
A. There are no worries about HRT and certainly it is recommended. Sometimes MG may relapse at the onset of the menopause but can often be controlled with some adjustment of medication, symptomatically. But, during the menopause itself, patients rarely have problems.
Q. Is there anything specific that triggers the onset of MG, ie menopause, birth, stress and foreign travel, childhood, illness etc.
A. It is more likely that menopause, stress and childbirth will make symptoms of MG worse rather than precipitate them. But there have been cases where the MG seemed to start after babies were born or after surgery. There are no childhood illnesses that are known to trigger off myasthenia.
Prof Angela Vincent (Oxford) has long had a special interest in these typical myasthenics who don’t have the normal antibodies to the muscle ‘ignition lock’ (ACh receptor). It was always known that they must have some damaging antibodies, because they clearly get better with plasma exchange and/or steroids. Her team has recently found that over half of them have other antibodies against a new target nearby on the muscle called MuSK. They are now developing a commercial diagnostic test for these, which should be a big help in diagnosing a lot of tricky cases. Her lab already does this test (free of charge) on blood samples as they ( increasingly) arrive. She is also keen to look for subtle differences in their MG and/or responses to treatments, and for clues to how this form gets started. BUT there is still an obstinate core with other unknown target(s) which are still under study...
Q. My antibody-negative MG was diagnosed in June 2000. I have low levels of antibodies against the MusK target. (a) is that because I am newly diagnosed, (b) is it likely to remain at that level, (c) or is research into MuSK at too early a stage to be given a definitive answer yet?
A, Yes, you guessed right; it is too early to say about the likely course of your MG, but your ‘MuSKy’ ones seems to start worse and respond better to treatment in Angela’s preliminary survey. On the other hand, some of you seem particularly reluctant to come under control.
Q. I am an antibody-negative myasthenic with the usual weakness and positive tensilon test. My nerve conduction has improved but I keep on relapsing! Is there any other test that can be done to prove beyond all doubt that I do have MG and not say, ME?
A. Seronegative MG is always rather challenging. See premable above. Among nerve conduction tests (EMG), single fibre EMG is the final court of appeal. It is not completely specific for MG, but usually is a very reliable pointer. A response to treatment - eg with Mestinon - can, in itself, point to a problem with muscle triggering, and a response to steroids, to an immune disease
Q. How soon do the blood tests for inherited myasthenia yield results? If we hear nothing, are further samples needed?
A. Dr David Beeson’s work is on inherited faults in muscle triggering. His new diagnostic service in Oxford is now doing the most straightforward genetic testing routinely. Alas, there can be faults in around 12 different genes, so they can’t handle all the rare ones as soon as they would like. It is useful to check each patient’s subgroup, because some need different treatments; in some, Mestinon can even make them worse. In any patients where it clearly helps, there is no hard evidence that Mestinon causes long-term effects on the nerve?muscle junction, so it is best to keep taking it. Even if previously suspected effects were to be confirmed, they should be reversible.
Q. I have been told that my MG is not hereditary, however my mother started with MG when she was about 72 years old. What are the odds of MG showing up again in my family line in the future?
A. There are inherited risk factors in the immune myasthenias, but it is very rare to find more than one case of immune MG in the same family. However, other immune diseases (e.g. of thyroid, diabetes or rheumatoid arthritis) are more common than among the national average
Q. My wife is currently in hospital with recurrent MG, unsteady walking, floppy mouth and swallowing; steroids have again been prescribed. She also has Alzheimer’s (or dementia). Do other myasthenics have this problem and how they are affected?
A. There is no association between MG and Alzheimer’s, they are two separate pathologies. One expects a common condition like Alzheimer’s to crop up purely by bad luck in the occasional myasthenic.
Q. Has any research been carried out on the effects of alternative/complementary medicine in the treatment of MG?
A. There is good hard evidence that the conventional treatments work in MG, ie Mestinon, immunosuppression and plasmapheresis or intravenous immunoglobulin (IvIg); it is not so hard for thymectomy yet (watch this space).
There is no evidence that diet in itself or alternative/complementary treatments affect MG. However, from experience in other autoimmune diseases, it is probably reasonable to:
Q. I find that two or three 'squares' of a high quality (dark) chocolate (70% cocoa solids) can often produce an almost instant 'lift' (ie. within less than 2-3 minutes) from both the mental and physical effects of a myasthenic 'down'. Does anyone else find the same?
A. It is quite plausible that chocolate produces an almost instant lift both psychologically and physically. It is made from the seeds of the tropical tree Theobroma cacao. In Greek, theobroma means food of the gods, and chocolate contains several drugs in small amounts. A study in Harvard has shown that chocaholics tend to live longer. Possibly, its polyphenols may protect against heart disease.
Chocolate also contains tiny quantities of anandamide, a natural brain counterpart of cannabis; also N-oleolethanolamine and N-linoleoylethanolamine, which may both prolong the effects of anandamide.
Chocolate also contains caffeine in modest amounts as well as the precursor [tryptophan] of serotonin, a natural LSD counterpart. Chocolate also releases endorphins, the brain’s natural painkillers.
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