15.9 Myasthenia Gravis
15.9.1 Introduction
(i) Myasthenia gravis is characterised by rapid and extreme tiredness of the muscles. Thus, whilst muscle power may initially be strong, it rapidly fades with sustained effort. The disease usually develops in early adult life, but may start in childhood or even late in life. It is twice as common in women as in men.
(ii) The muscles of the face, throat and neck are almost invariably the first and most seriously affected. The condition commonly presents with drooping of the eyelids and double vision. Typically, symptoms first appear in the evening when the person is tired, and disappear after a night's sleep. There may be difficulty swallowing and chewing, complaints that worsen during the course of a meal. Speech may also be affected.
(iii) The muscles around the shoulders are also frequently involved and it is not uncommon for the muscles of the hips and thighs to be affected. The muscles of respiration may also be affected leading to the need for assistance with breathing.
(iv) Although the disease is generally progressive, there tend to be remissions and relapses. In some cases remission is complete and long lasting, and these people will not have significant care and mobility problems. In all but the later more severe stages of the disease, treatment is highly effective and may result in there being neither care needs nor problems with walking.
15.9.2 Care Needs and Mobility Considerations
(i) These will depend on the severity of the disease, the muscle groups affected and response to treatment. In mild cases, particularly those affecting the muscles of the face and throat alone there may be no need for any help of significance. It may be necessary to adapt the lifestyle somewhat to cope with the increased fatiguability at the end of the day but otherwise it should be possible to lead a normal life.
(ii) Those whose shoulder muscles are affected may need help lifting heavy objects. They may later need help at the beginning and end of the day with dressing, washing and bathing. In severe cases they may be able to do very little with their arms and need a considerable amount of help both by day and at night.
(iii) Those whose hip and thigh muscles are affected will have difficulty getting up from a chair or bed, and mobility will be reduced. In most instances the upper limbs will also be affected adding to the difficulty.
(iv) If the muscles of respiration are affected the person may have difficulty breathing, in some instances to a degree sufficient to warrant mechanical assistance. In this situation the care and mobility needs will be considerable.
(v) Insofar as myasthenia gravis does not lead to intellectual impairment, supervisory needs are not normally a feature of the disease. Only in its advanced stages is there likely to be a tendency to fall, by which time attention needs will predominate.
15.9.3 Duration of Need
Most remissions occur in the first five years of the disease. If at any time disability is found to be severe and unresponsive to drug treatment, particularly if the respiratory muscles are involved, there is unlikely to be significant improvement in the future.
15.9.4 Further Evidence
In most cases the level of disability and its duration will be clear. If it is not, a report from the GP or hospital should provide the necessary additional information. Since response to specific treatment with certain drugs is usually good, factual information should be sought on how well the person is managed with appropriate treatments.