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Orthostatic intolerance in the chronic fatigue syndrome
R Schondorf1, J Benoit, T Wein
1Department of Neurology, McGill University, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada. cxrs@musica.mcgill.ca
Journal of the Autonomic Nervous System
|April 3, 1999
Summary
Orthostatic intolerance (OI) affects 40% of chronic fatigue syndrome (CFS) patients, presenting as syncope or tachycardia. Identifying this OI subgroup in CFS is crucial for targeted treatment strategies.
Area of Science:
- Cardiology
- Neurology
- Immunology
Background:
- Chronic Fatigue Syndrome (CFS) is a complex condition with diverse symptoms.
- Orthostatic intolerance (OI) is a condition characterized by symptoms that occur when standing up and improve when lying down.
- The prevalence and specific pathophysiology of OI in CFS patients remain incompletely understood.
Purpose of the Study:
- To investigate the prevalence and pathophysiology of orthostatic intolerance (OI) in patients with chronic fatigue syndrome (CFS).
- To determine if OI contributes to the symptoms experienced by CFS patients.
- To identify distinct subgroups within the CFS population based on the presence and type of OI.
Main Methods:
- Seventy-five patients diagnosed with CFS were evaluated for OI.
- Beat-to-beat recordings of heart rate, blood pressure, and stroke volume were taken during supine and head-up tilt (HUT) positions.
- Physiological responses were also assessed during deep breathing and the Valsalva maneuver, with data compared against 48 healthy controls.
Main Results:
- Forty percent of CFS patients exhibited OI during head-up tilt.
- OI presentations included neurally-mediated syncope alone (16 patients), tachycardia (7 patients), or a combination (6 patients).
- Patients with OI had a shorter disease duration, were younger, and had a more subacute symptom onset compared to those without OI.
Conclusions:
- A clinically identifiable subgroup of CFS patients with OI exists.
- This subgroup differs significantly from healthy controls and CFS patients without OI.
- Treatment aimed at improving orthostatic tolerance may be indicated for this specific CFS subgroup.