Infectious Disease Compendium

Chronic Fatigue Syndrome


CDC definition: Clinically evaluated, unexplained chronic fatigue greater than 6 months' duration associated with a significant reduction in occupational, educational, social, or personal activities PLUS four or more of the following symptoms: Impaired memory or concentration, sore throat, tender cervical or axillary lymph nodes, muscle pain, multi joint pain, new headaches, unrefreshing sleep, post exertion malaise.

Epidemiologic Risks

Who knows.


Who knows. Fatigue follows many acute infections.

Giardia is associated with a fatigue state that fades over 6 years (PubMed). That is one of many infections, I suspect many infections can lead to a fatigue state that was set off by the infection but not due to ongoing infection. Q fever and EBV can cause it as well. Post parvovirus CFS is associated with preexisting increased stress (PubMed). Unfortunately treating the infection does nothing as it is long gone.

After culture proven Lyme, fatigue is uncommon, perhaps in 3% of patients (PubMed).

"Metabolomics showed that chronic fatigue syndrome is a highly concerted hypometabolic response to environmental stress that traces to mitochondria and was similar to the classically studied developmental state of dauer (form or hybernation or stasis) ((PubMed))."

These patients have other manifestations of hybernation with "impaired efficiency of energy metabolism combined with lactate overproduction" (PubMed).

Maybe a post infectious dysregulation of various genes (PubMed), although this line of investigation may be a nonstarter (PubMed).

Empiric Therapy

There is none or are none.


At least check out the issue of chronic carbon monoxide toxicity due to faulty heaters or increased insulation.


I remain uncertain what causes CFS; a subset appears to clinically have an infectious onset, if it is truly infectious or, more likely, post infectious I cannot say. I suspect it is a common final response to many infections where some metabolic switch was flipped and can't be flipped back.

Last Update: 06/10/18.