The Editors have – together with the Scientific Committee – decided that new EFNS guideline papers will be presented in the Forum of NEUROPENEWS. In the May issue of the European Journal of Neurology the new EFNS/ENS Guidelines for the treatment of ocular myasthenia is published and we highlight this important article by offering you the abstract. We also asked the corresponding author, Professor Kerty, for a short statement.
Background and purpose: The symptoms of acquired autoimmune ocular myasthenia are restricted to the extrinsic eye muscles, causing double vision and drooping eyelids. These guidelines are designed to provide advice about best clinical practice based on the current state of clinical and scientific knowledge and the consensus of an expert panel.
Search strategy: Evidence for these guidelines was collected by searches in the MEDLINE and Cochrane databases. The task force working group reviewed evidence from original articles and systematic reviews. The evidence was classified (I, II, III, IV) and consensus recommendation graded (A, B or C) according to the EFNS guidance. Where there was a lack of evidence but clear consensus, good practice points are provided.
Conclusions: The treatment of ocular myasthenia should initially be started with pyridostigmine (good practice point). If this is not successful in relieving symptoms, oral corticosteroids should be used on an alternate-day regimen (recommendation level C). If steroid treatment does not result in good control of the symptoms or if it is necessary to use high steroid doses, steroid-sparing treatment with azathioprine should be started (recommendation level C). If ocular myasthenia gravis is associated with thymoma, thymectomy is indicated. Otherwise, the role of thymectomy in ocular myasthenia is controversial. Steroids and thymectomy may modify the course of ocular myasthenia and prevent myasthenia gravis generalization (good practice point).
E. Kerty, A. Elsais, Z. Argov, A. Evoli and N. E. Gilhuse; European Journal of Neurology, Vol. 21, Issue 5, pages 687-693, May 2014
Introduction by Emilia Kerty:
Myasthenia gravis is a common autoimmune disease with prevalence of 117-179 per million in different population based studies. Almost all patients will have ocular manifestations at some point during the course of their diseases.
Although ocular symptoms are often the first in myasthenia gravis, most patients progress to generalized myasthenia during the first years and only 15% continue having isolated ocular complaints for the entire course of the disease. In ocular myasthenia the weakened eye muscles cause double vision and uni- or bilateral ptosis. The goal of the treatment is to reduce patients’ symptoms and possibly to prevent or delay the progression to generalized myasthenia gravis.
Controlled randomized and blinded trials in treatment of ocular myasthenia are very rare. Recommendations in this review are based largely on retrospective and observational studies as well as clinical experiences. In case sufficient evidence for recommendations after GRADE criteria was not available, we found it extremely important to follow the recommendation of using “good practice points”, which means that there had to be consensus amongst all members of the task force after several rounds of circulating drafts.
There is general agreement that it is appropriate to initiate the treatment with an acetylcholinesterase inhibitor – usually pyridostigmin. However, the clinical experience shows that pryridostigmin therapy alone seldom achieves resolution of ocular symptoms, especially of diplopia. Based on several retrospective studies corticosteroids have been shown to be very effective in controlling ocular symptoms. Additionally, the rate of generalizing myasthenic weakness is probably also lower in patients treated with corticosteroids than in patients receiving only acetylcholine esterase inhibitors. But this risk-modifying effect of corticosteroids is under debate. Patients, who do not respond to or not tolerate corticosteroids, can receive second-line immunosuppressives. Ocular myasthenia is not a life threatening condition but the symptoms are disabling and interfere with almost all daily activity as work, reading, computer work, driving and watching TV. As with any disease, the risk of therapy must be weighed against the potential benefits, and the ideal treatment is the least harmful therapy that relieves the patient’s symptoms.
Another controversial question is the role of thymectomy in non-thymomatous cases with pure ocular symptoms. Some retrospective studies have suggested benefits to thymectomy in ocular myasthenia, based on the very favourable response and improved rate of remission. Thymectomy in early stage of the disease may also reduce the rate of conversion to generalized myasthenia gravis. Other reports did not show any benefits of surgery, but rather potential risks.
There are several on-going clinical trials on treatment of generalized myasthenia gravis, and hopefully some of the results can be extrapolated in some extent to ocular myasthenia.
Emilia Kerty is neurologist at the Oslo University Hospital and Professor of Neurology at the University of Oslo, Faculty of Medicine in Oslo, Norway.