Topic

Autonomic Nervous System

Domain: Autonomic

PEM-relevant research

3 studies in the atlas

Dysautonomia, orthostatic intolerance, and cerebral blood flow deficits in ME/CFS.

What We Know

Upright tilt table testing and CPET studies show abnormal heart rate response, reduced cerebral blood flow in upright posture, and significant orthostatic intolerance across ME/CFS cohorts. These correlate with cognitive symptoms.

What We Think

Vagal nerve stimulation and beta-blocker trials are underway. Research into small fiber neuropathy as an autonomic driver is expanding.

What We Don't Know

Not all ME/CFS patients show autonomic abnormalities. The relationship between POTS, orthostatic hypotension, and ME/CFS remains complex. Treatment trials targeting autonomic dysfunction have mixed results.

Studies in this Topic

E0 ConsensusPEM ?Moderate confidenceReviewed

Understanding, diagnosing, and treating Myalgic encephalomyelitis/chronic fatigue syndrome - State of the art: Report of the 2nd international meeting at the Charité Fatigue Center.

Steiner, Sophie, Fehrer, Annick, Hoheisel, Friederike et al.·Autoimmunity reviews·2023

Over 100 international researchers gathered in Berlin in May 2023 to discuss what we currently know about ME/CFS, how to diagnose it, and how to treat it. The conference highlighted that ME/CFS involves problems with the immune system, blood vessel function, and nervous system control, and that some cases may be triggered by viruses reactivating in the body. Despite growing interest due to Long COVID, ME/CFS remains under-researched and needs significantly more funding to find better diagnostic tests and targeted treatments.

Autonomic Nervous SystemImmune Dysregulation

E1 ReplicatedPEM ✓Moderate confidenceReviewed

Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia

C. M. C. van Campen, F. C. Visser, P. C. Rowe·Journal of Internal Medicine·2020·n=429

In the largest study of its kind, 429 ME/CFS patients underwent head-up tilt testing with simultaneous cerebral blood flow monitoring. Nearly all ME/CFS patients showed significantly reduced cerebral blood flow when upright, even when blood pressure and heart rate were normal. The reduction correlated with symptom severity.

Autonomic Nervous SystemCognitive Impairment

E3 PreliminaryPEM ✓PreliminaryMachine draft

Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome.

Vøllestad, Nina K, Mengshoel, Anne Marit·Frontiers in physiology·2023

This paper reviews how post-exertional malaise (PEM)—the worsening of symptoms after physical or mental activity—is experienced and studied in ME/CFS patients. Patients describe PEM in many different ways and report that it can start immediately or be delayed by days, lasting anywhere from a few days to months. When researchers use standardized exercise tests in laboratories, they see more immediate symptom worsening, but the duration still varies widely between patients.

Autonomic Nervous SystemPost-Exertional Malaise