Note: the use of “CFS” in this article reflects the nomenclature used in the studies referenced.
New research published in Fatigue: Biomedicine, Health & Behavior found ventricular lactate (lactate present in cerebrospinal fluid) might serve as a biological marker of underlying brain dysfunction for patients with chronic fatigue syndrome (CFS), fibromyalgia (FM), and those with a dual diagnosis. The study, titled “Elevations of ventricular lactate levels occur in both chronic fatigue syndrome and fibromyalgia”, also found evidence for a unitary hypothesis of the pathophysiology of CFS and FM – that is, they are different presentations of the same condition.
The study was authored by Dr. Natelson, of the Pain & Fatigue Study Center at Beth Israel Medical Center, in conjunction with pain specialists, clinicians, and quantitative experts. Dikoma Shungu, PhD, (a project leader on the Cornell ME/CFS Collaborative Research Center) and a team at Weill Cornell Medicine used neuroimaging to measure ventricular lactate in subjects across three diagnostic groups – FM only, CFS only, or CFS plus FM – and compared to healthy controls. A modified version of the 1994 Fukuda (CDC) criteria was used to select CFS patients.
The group found that, relative to healthy controls, ventricular lactate was higher in all illness groups included in the study. Elevations in ventricular lactate suggests a shift to anaerobic processes and a problem with brain-related mitochondrial metabolism across the CFS-FM spectrum. The authors conclude that, while there is evidence that ventricular lactate measured by neuroimaging can be used as a biomarker of syndromes characterized by medically unexplained pain or fatigue, this result does not indicate it can be used to differentiate CFS from FM.
Previous work from 2008 considering the relationship between ventricular lactate and ME/CFS also used a condition with symptomatic overlap as a study comparison group. The researchers looked at ventricular lactate levels in individuals with CFS (diagnosed with the 1994 guidelines) and Generalized Anxiety Disorder (GAD) – a condition that includes fatigue with an unknown origin as a hallmark symptom. However, this study found an abnormal increase in ventricular lactate in CFS relative to the comparison group (GAD). Unlike the connection between FM and CFS supported by Dr. Natelson’s study, this finding suggests distinct neurobiological differences between CFS and GAD.
CFS and FM were found to have statistically indistinguishable levels of lactate in the recent finding detailed in Fatigue, but we don’t have proof this reflects the same underlying cause. Nonetheless, ventricular lactate is indicated as a viable biomarker of underlying brain dysfunction for some patients with either or both diagnoses. The authors note that further research will be needed to further address if CFS and FM are different illnesses or variations of the same condition.
Natelson et al. (2018). Fatigue: Biomedicine, Health & Behavior. “Elevations of ventricular lactate levels occur in both chronic fatigue syndrome and fibromyalgia.” Retrieved from http://www.tandfonline.com/doi/full/10.1080/21641846.2017.1280114
This article has been modified from the original version to include attribution to Dr. Shungu and Weill Cornell Medicine for the neuroimaging.