Background: Symptoms of nausea, feeling faint, malaise and mild anxiety are common in young people with CFS and popularly attributed to ‘hypoglycemia’ resulting in various dietary interventions with little reported improvement.
Objectives: To determine whether the symptoms are associated with measured hypoglycaemia using continuous tissue glucose monitoring or whether these symptoms are associated with documented orthostatic intolerance.
Methods: Nine young people with CFS (mean age 20 years) and mean duration of 4.5 years with persistently troublesome symptoms were compared with 10 healthy adult controls without diabetes. Each subject agreed to 3 days Continuous Glucose Monitoring System (Medtronic CGMS). This is routinely used in adolescent diabetics to document food intake, tissue glucose levels and activity levels to monitor control.
Subsequently 8 of these had formal cardiac tilt table testing where heart rate and blood pressure are measured supine and during 70 degree head-up tilt for up to 10 minutes to assess the presence orthostatic intolerance (either postural orthostatic tachycardia (POTS) or neurocardiogenic hypotensive syndrome). If positive, appropriate medical management of increasing salt and fluids, gentle improvement of muscle tone and blood pressure support medications, was implemented.
Results: The tissue glucose was calibrated with the blood glucose and all fell within acceptable normal range. There was statistical (but not clinical) significance in average tissue glucose in CFS subjects. 6% of time in controls and 16.8% in CFS was spent in the range <4mmol/L glucose (95% CI -23% to +2%, p=0.1) suggesting weak evidence for a difference given the variability and small sample size. The reported presence of symptoms throughout the day was not associated with significant reduction in tissue glucose levels.
Six had confirmed evidence for POTS, one for neurocardiogenic syndrome and one for a combination of both. All 8 reported improvement in all symptoms especially nausea, dizziness and malaise with active treatment of their orthostatic intolerance.
Conclusion: This study could not confirm a link between putative symptoms of ‘hypoglycemia’ and documented hypoglycemia. This suggests that symptoms frequently attributed to ‘hypoglycemia’ may be due to orthostatic intolerance and further investigation and management of this condition provides more reported relief for these troublesome symptoms.
Dr Kathy Rowe, Senior Consultant Paediatrician, Department of General Medicine, Royal Children’s Hospital, Melbourne, Victoria, Australia 3052
kathy.rowe@rch.org.au No conflicts of interest to declare. RCH internally funded.
Source: Katherine Rowe, Rebecca Gebert, Susan Donath, Angas Hamer & Fergus Cameron. Are symptoms of ‘hypoglycemia’ in Chronic Fatigue Syndrome (CFS) associated with hypoglycemia or orthostatic intolerance in young people? From: The IACFS/ME 2016 Conference Syllabus.