A systematic review was published recently comparing post-treatment Lyme disease (PTLDS) with ME/CFS.
Lyme disease, as discussed in previous articles, is a tick-borne illness caused by the bacteria Borrelia burgdorferi, which can usually be treated with a course of antibiotics. However, the authors of the review cite that 10% to 20% of cases do not resolve following treatment, leading to a collection of symptoms such as debilitating fatigue, muscle and joint pain, headaches, sleep difficulties, cognitive issues, and paresthesia (‘pins and needles’), referred to as PTLDS.
The underlying disease mechanism of PTLDS is unknown, and there is doubt in the medical community about the validity of this diagnosis. Accordingly, the aim of the systematic review was to validate PTLDS as a ‘true chronic disease’ and to draw comparisons with ME/CFS.
The authors evaluated 18 studies related to PTLDS in which patients were reported to have had symptoms for at least 3 months following treatment with antibiotics. Factors such as symptom duration, overlap with ME/CFS symptoms, and percentage of patients reporting specific symptoms were assessed.
These are the key points of the review relating to symptom overlap between PTLDS and ME/CFS:
- 15 out of 18 studies documented PTLDS symptoms as lasting longer than 6 months. The authors highlighted this to parallel with the fact that most ME/CFS-related criteria require symptoms to be present for 6 months.
- Reported in 15 studies, the most common overlapping symptoms were fatigue and brain fog (a non-medical term used to describe cognitive issues such as difficulty concentrating or thinking clearly).
- 11 studies noted arthralgias (joint pain), myalgias (muscle pain) and memory difficulties, which are symptoms also found in ME/CFS.
- Most studies documented at least four out of six major ME/CFS symptoms (including substantial impairment in activity level and fatigue for more than 6 months, post-exertional malaise, and unrefreshing sleep).
- In one study, all of the participants fulfilled the diagnostic criteria for ME/CFS. Note that the systematic review does not directly mention which ME/CFS criteria they are referring to.
Potential overlapping underlying disease mechanisms
Continuing the theme, the review highlighted potential disease mechanisms in PTLDS which overlap with ME/CFS, namely:
- Some studies have demonstrated elevations in markers of inflammation in PTLDS.
- One study noted metabolic differences (differences in chemical processes in the body) in patients with PTLDS in comparison with healthy controls.
Interestingly, the authors also noted that despite there being no evidence of the bacteria Borrelia burgdorferi remaining in human tissue after ‘adequate’ treatment, several studies have shown improvement in fatigue following long-term intravenous antibiotics. In contradiction, two studies did not find any significant differences between those treated with longer-term antibiotics and the placebo group, hence offering additional antibiotics to patients with PTLDS is not standard practice.
It should be noted that the systematic review uses a qualitative approach; i.e. there is an emphasis on non-numerical data. Therefore, the findings are subjective and more likely to be biased in perspective than a quantitative approach (which relies on numerical data). It may be useful to take a more in-depth look at the statistical significance of study findings.
The authors noted several factors which could have skewed the results of the studies, including small sample sizes, homogenous participant populations (participants had similar characteristics), and reliance on participants volunteering for studies or being referred by clinicians.
This systematic review highlights the potential similarities between the symptoms and underlying disease mechanisms of PTLDS and ME/CFS. Further research is needed in order to validate these findings and could provide valuable information about both conditions.