Central sensitization syndrome worsens Lyme disease symptoms?

Central sensitization syndrome (CSS) involves changes in the central nervous system, particularly the brain and spinal cord. This syndrome “is thought to involve hyperactivation of central neurons, leading to various synaptic and neurotransmitter/neuromodulator changes,” writes Batheja.

There are several potential causes of central sensitization, which include:

• Genetic factors
• Increase in neurotransmitters that facilitate pain
• Decrease in neurotransmitters that inhibit the pain pathways

“The appropriate balance of these neurotransmitters is essential because they serve as a ‘volume control’ for pain and sensory processing.”

• Changes in the brain from repetitive nociceptive and infections

“Notably, in relation to Lyme disease, infections, in general, are known to activate central sensitization in some patients, possibly through the release of inflammatory cytokines,” Batheja points out.

In fact, patients with persistent Lyme disease symptoms “have many of the same symptoms experienced by other patients thought to have central sensitivity syndrome.”

And since post-treatment Lyme disease Syndrome (PTLS) patients typically experience pain to non-noxious stimuli, such as light and sound, they would meet the criteria for central sensitization syndrome, explains Yunus. [2]

The primary symptoms of central sensitization include pain, fatigue, and sensory hyperarousal.

Pain

There are 3 types of pain:

1. Peripheral (or nociceptive) pain is caused by inflammation or tissue damage in the periphery.
2. Neuropathic pain is the result of dysfunction or injury of peripheral nerves (e.g., diabetic neuropathic pain).
3. Central (or non-nociceptive) pain is characterized by atypical central nervous system (CNS) sensory processing of pain. (e.g., fibromyalgia).

According to Batheja, central pain due to “central sensitization or the augmentation of CNS pain-processing may account for the persistent experience of widespread pain.”

Central pain leads to diffuse hyperalgesia and allodynia. “Allodynia (pain due to a stimulus that does not usually provoke pain) and hyperalgesia (increased pain from a stimulus that usually provokes pain) are prominent symptoms in patients with neuropathic pain,” writes Jensen. [3]

READ MORE: Case Report: Persistent pain and fatigue after treatment for Lyme disease

“In the case of Lyme disease, it is likely that all three types of pain are involved to a different extent in any particular patient,” Batheja writes.

Fatigue and cognitive impairment

Fatigue and cognitive impairments are prominent features of central sensitization syndrome. Patients with post-treatment Lyme disease syndrome or chronic Lyme disease often have persistent insomnia and fatigue.

And while fatigue can have a central or peripheral origin, the authors explain that “Central fatigue often has the significant correlate of cognitive impairment.”

For example, studies of patients with post-treatment Lyme disease syndrome “have shown that problems with memory, working memory, processing speed, and verbal fluency are common,” Batheja writes.

Central sensitization syndrome has been described in a number of illnesses characterized by fatigue and with similar presentations to Lyme disease including fibromyalgia and chronic fatigue syndrome.

Sensory Hyperarousal

Sensory hyperarousal to lights and sound is a defining feature of central sensitization. And while it may seem that these sensitivities are mere annoyances to the individual, they can, in fact, be quite disturbing.

“The individuals’ life may be quite altered by this hypersensitivity: wearing sunglasses indoors and avoidance of being outside during daylight, which, in turn, limits the ability to sustain a normal work and social life.”

[bctt tweet=”Do some Lyme disease patients with persistent pain, fatigue and sensory issues suffer from central sensitization syndrome?” username=”DrDanielCameron”]

In patients with post-treatment Lyme disease syndrome, “sensory hyperarousal was reported by a majority of patients after acquiring Lyme disease, most often affecting hearing and/or vision,” the authors write.

In fact, one study found that out of 85 patients with Lyme disease, 70% reported hypersensitivity to light. And, 48% reported heightened sensitivity to sound.

“The auditory hyperacusis seen in Lyme disease patients can be intense and incapacitating,” the authors point out, adding “in some individuals, even the volume fluctuations in a normal conversation can be noxious.”

Conclusion

“Because many individuals with post-treatment Lyme syndrome (PTLS) [or chronic Lyme disease] have a similar symptom cluster, central sensitization may be a process mediating or exacerbating their sensory processing,” the authors conclude.

Therefore, they recommend further research as “it would be extremely valuable to conduct studies exploring whether patients with PTLS have heightened sensitivity to noxious and non-noxious stimuli and neural activation patterns similar to that found among patients with other CSS [central sensitization syndrome] disorders.”

Editor’s note: Many of my patients appear to suffer from central sensitization syndrome. For transparency, I am an author of the International Lyme and Associated Diseases Society (ILADS) guidelines which do not dismiss the persistent infection hypothesis.