Central sensitization entails several top-down and bottom-up mechanisms, all contributing to the hyper-responsiveness of the central nervous system to a variety of inputs.
In the late nineties, it was first hypothesized that chronic fatigue syndrome (CFS) is characterized by hypersensitivity of the central nervous system (i.e. central sensitization). Since then, several studies have examined central sensitization in patients with CFS. The present paper provides an overview of such studies.
Various studies showed generalized hyperalgesia in CFS for a variety of sensory stimuli, including electrical stimulation, mechanical pressure, heat and histamine.
Various tissues are affected by generalized hyperalgesia: the skin, muscle tissue, and the lungs.
Generalized hyperalgesia in CFS is augmented, rather than decreased, following various types of stressors like exercise and noxious heat pain.
Endogenous inhibition is not activated in response to exercise and activation of diffuse noxious inhibitory controls following noxious heat application to the skin is delayed.
The observation of central sensitization in CFS is in line with our current understanding of CFS. The presence of central sensitization in CFS corroborates with:
• The presence of several psychological influences on the illness,
• The presence of infectious agents and immune dysfunctions,
• And the dysfunctional hypothalamus pituitary adrenal-axis as seen in these severely debilitated patients.
Source: European Journal of Clinical Investigation, July 2011. DOI: 10.1111/j.1365-2362.2011.02575.x, by Nijs J, Meeus M, Van Oosterwijck J, Ickmans K, Moorkens G, Hans G, De Clerck LS. Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel; Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Belgium. [Email: Jo.Nijs@vub.ac.be]