Prognosis and duration

Prior to the development of successful treatments for myasthenia gravis 25% to 30 % died within 3 years of onset. Now the majority of people (up to 90%) are likely to be able to lead a normal life without undue restrictions. Life expectancy is considered to be close to normal. Complete remission is rare, but up to 20% of cases go into remission, and the disease does not reappear for some years.

However for people whose disease does not remit, the need for drug treatment is life long. Standard drug treatments provide good relief of symptoms, and people are able to carry out many normal daily tasks in the absence of disabling muscle weakness,

Thymectomy improves the prognosis and its benefits in improving symptoms may continue for months or up to several years after the operation.

A poor prognosis is more likely when onset of myasthenia occurs after the age of forty years, when disease progression is rapid and if a thymoma is present. Early mortality occurs in the first three years; after that the disease tends to stabilise.

Date of onset 3 years or less – award for 3 years.

Date of onset 3 years or more – Indefinite award.

All information must be taken into account when considering the duration of disabling effects and the duration of disabling effects must be based on the particular circumstances of the individual claimant.

Amended June 2008