Fatigue in MS can be described as a feeling of extreme mental or physical exhaustion. It is one of the most common symptoms of MS – some studies say up to 90 per cent of people with MS have fatigue – and can affect people with MS for hours, days or even months. Fatigue can affect a person’s ability to work or take part in family or social life. Because fatigue is hidden, people with MS may find that those around them don’t understand fatigue and its impact. Physical fatigue can make a person feel that they need to lie down immediately. Limbs may feel heavy and hard to use. Cognitive fatigue could include difficulty following a conversation or thinking of words or numbers.
Why does fatigue occur in MS?
The cause of fatigue in MS remains unknown. However, the likely causes are a structural abnormality in the brain caused by demyelination and axonal loss, a product of the immune activity in the brain itself, problems of hormone production from the pituitary gland in the brain, or due to problems with control of the heart or chemical changes in the muscles.
How can fatigue be treated or managed?
Unfortunately, there are only a few medications that seem to show some relief for MS fatigue. Amantadine is an antiviral medication, also used in Parkinson’s disease. It has been used in the treatment of MS fatigue since the 1980s but a review of clinical trials has shown it to provide small and inconsistent improvements, from 20 to 40 per cent in the short term. Trials using modafinil in MS fatigue have involved small numbers and have been over a short treatment period (a maximum of 12 weeks), but have mostly shown a positive effect. Further studies are recommended to ascertain the effect of modafinil in the longer term and the appropriate dose. However, many people find they can use techniques such as task prioritisation, taking a regular nap during the day, working part-time, asking for help with daily chores, and doing regular exercise to help minimise the impact of their fatigue.