Question

I sometimes have acute and short lived episodes involving symptoms that are found with low blood sugar:  feeling weak and dizzy, looking pale, sweating, increased pulse rate, blurred vision and confusion.

I’ve read on the internet that one of the symptoms of ME can be episodes of low blood sugar (hypoglycaemia).  However, I cannot find hypoglycaemia being listed in any of the official diagnostic criteria for ME/CFS, or in the symptom list in the MEA purple book.

As my brother is diabetic, I’ve been checking my blood sugar levels at these times and found them to be low.  My GP said he didn’t know if this could be related to ME/CFS and has arranged for me to see an endocrinologist (hormone specialist) for further assessment.

Please could you clarify if there is a link between ME/CFS and low blood sugar.  If so, what is the best form of treatment?  I should add that I have a healthy balanced diet with no food restrictions.

Answer

Blood sugar levels are regulated by the hormone insulin – which is made in the pancreas and reduces the level of blood sugar.  When the pancreas fails, insulin production falls and blood sugar levels rise leading to diabetes.   However, if the pancreas produces too much insulin, or there is a rapid surge in insulin (which can occur when diabetes management with insulin is not under good control, or as a natural response to a heavy meal) then blood sugar levels will fall – and if very low will lead to symptoms of hypoglycaemia.

You don't say what your blood sugar level is during these episodes but hypoglycaemia is normally defined as having a blood glucose level below 4 mmol/L. Below this level, it can cause all the symptoms you list as well as feeling hungry, nausea and tingling of the lips.  If the level is very low it can cause loss of consciousness – which is a real medical emergency.

What I can say in general terms is that although hypoglycaemia has been described in ME/CFS, there is not any sound research evidence to indicate that it is part of the underlying disease process.  So it is not a recognised diagnostic feature and other explanations need to be assessed and investigated if someone with ME/CFS is having what appear to be hypoglycaemic episodes. 

In addition to the link to diabetes, there are a small number of medical conditions that can cause hypoglycaemia.  These include liver and kidney disease. Addison's disease and low thyroid function/hypothyroidism can also do so – as well as causing ME/CFS like symptoms. So your GP is managing this correctly by referring you to a specialist.

If you have symptoms of low blood sugar, eat or drink something that will raise your blood sugar quickly, such as a small glass of fruit juice, a sugary fizzy drink, glucose or dextrose tablets.

You should also ask your GP for some further information about how to keep blood sugar levels stable while you are waiting to see a specialist and what to do/take if you are having more severe hypoglycaemic symptoms 

• NHS information on hypoglycaemia 

https://www.nhs.uk/conditions/low-blood-sugar-hypoglycaemia/

• Please let us know if you have been found to have low blood sugar associated with ME/CFS