Iwata, Kentaro, Shimada, Tomoe, Kawabata, Hiroki · Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases · 2013 · DOI
This case report describes a 42-year-old woman who had fever and vague symptoms for years but was initially diagnosed with chronic fatigue syndrome. After 14 months, she developed facial paralysis, which prompted testing that revealed she actually had Lyme disease—an infection spread by tick bites. A month of antibiotics improved her symptoms. The report highlights that Lyme disease is rare in Japan but may be underdiagnosed and should be considered in patients with unexplained fevers.
This case is relevant to ME/CFS research because it demonstrates how infectious diseases like Lyme disease can mimic or be confused with ME/CFS, presenting with chronic fatigue and nonspecific symptoms over extended periods. For patients, it underscores the importance of thorough infectious disease investigation before accepting a ME/CFS diagnosis, particularly if atypical neurological symptoms develop. The case also illustrates how missed or delayed diagnoses of treatable infections can occur when initial presumptive diagnoses anchor clinical thinking.
This single case report does not establish the prevalence of misdiagnosed Lyme disease among ME/CFS patients, nor does it prove that Lyme disease commonly masquerades as ME/CFS. It does not demonstrate a causal relationship between Lyme disease and ME/CFS or provide evidence about diagnostic criteria that reliably distinguish the two conditions. The findings are specific to one patient in a low-prevalence region and cannot be generalized to other populations or countries.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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