Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome.
Rowe, P C, Barron, D F, Calkins, H et al. · The Journal of pediatrics · 1999 · DOI
Quick Summary
This study looked at 12 teenagers who had both ME/CFS and a connective tissue condition called Ehlers-Danlos syndrome (EDS). All of them also experienced problems with blood pressure and heart rate when standing up (orthostatic intolerance). The researchers found that abnormal connective tissue in blood vessels may cause blood to pool in the legs when standing, which could explain why these conditions often occur together.
Why It Matters
This study is important because it identifies a potential subgroup of ME/CFS patients who also have EDS and suggests a specific physiological mechanism—abnormal blood vessel function—that could explain symptoms in these individuals. It recommends that doctors evaluating ME/CFS patients routinely screen for connective tissue disorders and orthostatic intolerance, which could lead to better diagnosis and targeted treatment strategies.
Observed Findings
All 12 patients (100%) met diagnostic criteria for both CFS and EDS
All 12 patients (100%) exhibited orthostatic intolerance with either postural tachycardia or neurally mediated hypotension
Equal representation of classical-type EDS (n=6) and hypermobile-type EDS (n=6)
Patient population was predominantly female (11 of 12) and adolescent (median age 15.5 years)
Echocardiography and ophthalmological evaluation were performed without apparent structural cardiac abnormalities reported
Inferred Conclusions
Abnormal connective tissue in blood vessels of EDS patients may cause excessive venous distension, leading to increased blood pooling in dependent areas and resulting orthostatic intolerance
A clinically relevant subset of CFS patients also have undiagnosed EDS and orthostatic dysfunction
Screening for hypermobility and connective tissue abnormalities should be incorporated into the evaluation of CFS patients with orthostatic intolerance symptoms
Remaining Questions
What is the actual prevalence of EDS in the broader ME/CFS population, and how many ME/CFS patients have undiagnosed connective tissue disorders?
Does the presence of EDS and orthostatic intolerance define a distinct ME/CFS subtype with specific treatment implications?
What This Study Does Not Prove
This small case series cannot establish how common the combination of ME/CFS, EDS, and orthostatic intolerance actually is in the broader ME/CFS population. It does not prove that EDS causes ME/CFS or orthostatic intolerance, only that these conditions may co-occur in some patients. The study cannot determine whether the proposed mechanism (venous pooling from connective tissue abnormalities) is the actual cause of symptoms.
Tags
Symptom:Orthostatic IntoleranceFatigue
Biomarker:Blood Biomarker
Phenotype:Pediatric
Method Flag:PEM Not DefinedNo ControlsSmall SampleExploratory Only