Question

I have a diagnosis of both ME/CFS and fibromyalgia. For the last couple of months I get a weird thing happening. I can be fine one minute but the next I struggle to keep my eyes open. It’s as though someone has drained all the energy out of my body and I usually end up falling asleep for a few hours. I don’t even have to have done anything but just sitting in my chair. Is this normal for ME/CFS? Or is it something else?

Answer

The simple answer to your question is no. A sudden loss of energy that occurs regularly leading to an inability to keep your eyes open is not normal in ME/CFS – especially if there is no obvious triggering factor (e.g., overactivity) to these episodes. Although people with ME/CFS do occasionally report a sudden deterioration of symptoms for no obvious reason, this should not be regarded as a characteristic or diagnostic feature of ME/CFS.

This is because there are other conditions – that can cause a sudden drop in energy levels with muscle weakness and a need to sleep – which need to be considered and excluded in a situation like this. Two immediate, although rare, examples that come to mind are narcolepsy and myasthenia gravis – both of which are sometimes misdiagnosed as ME/CFS.

By coincidence, I have recently been dealing with someone whose muscle weakness did not really fit with her current diagnosis of ME/CFS. On further investigation, the diagnosis turned out to be myasthenia gravis.

This is something that you really must talk to your doctor about – who can refer you to hospital for further assessment and investigations if necessary.

More information

• The ME Association Clinical and Research Guide (The ‘Purple Book') covers Narcolepsy and Myasthenia Gravis and other conditions in the ‘Differential Diagnosis' section.
• The NHS: Narcolepsy: Symptoms, Cause, Treatments | May 2019
• The NHS: Myasthenia Gravis: Symptoms, Cause, Treatments | January 2020