Symptoms and signs
The symptoms and signs which, based on the evidence available, are seen more frequently in health care checks may be characterized as the following:
- Exertion intolerance, fatigue
- Flu-like and ‘sickness behavior’ symptoms: fever, feverishness, muscle pain, feeling sick, malaise, sweating, irritability
- Neurological/neurocognitive symptoms: brain fog, impaired concentration or memory, trouble finding words
- Rheumatologic symptoms: chronic or recurrent joint pain
- Trigger-specific symptoms: for example, eye problems post Ebola, IBS post Giardia, anosmia and ageusia post COVID-19, motor disturbances post polio and post West Nile virus
Myalgic encephalomyelitis/chronic fatigue syndrome
Patients with this disorder experience worsening of symptoms following physical, cognitive, or emotional exertion above their (very low) tolerated limit. Other prominent features frequently observed in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are neurocognitive impairments (colloquially referred to as brain fog), unrefreshing sleep, pain, sensory disturbances, gastrointestinal issues, and various forms of dysautonomia. Up to 75% of ME/CFS cases report an infection-like episode preceding the onset of their illness. Postinfectious and postviral fatigue syndromes were originally postulated as subsets of chronic fatigue syndrome. However, there appears to be no clear consensus at present about whether these terms should be considered synonymous to the ME/CFS label or any of its subsets, or include a wider range of postinfectious fatigue conditions.
Practical diagnostic criteria
From a revision of the available criteria, it emerges that the diagnostic criteria for a PAIS should include not only the presence of symptoms, but ideally also the intensity, course, and constellation of symptoms within an individual, as the individual symptoms and symptom trajectories of PAIS vary over time, rendering a mere comparison of symptom presence at a single time point misleading. Furthermore, when a diagnosis of ME/CFS is made, attention should be given to the choice of diagnostic criteria, with preference given to the more conservative criteria, so as not to run the risk of overestimating the syndrome.
Asthenia is the cornerstone symptom for most epidemiological studies on PAIS, but it would be reductive to concentrate only on this rather than the other characteristics, such as the exacerbation of symptoms following exertion, together with other characteristic symptoms and signs that may allow for better identification of the overall, observable clinical picture in these postinfection syndromes, which have significant impacts on a patient’s quality of life.
This article was translated from Univadis Italy. A version of this article appeared on Medscape.com.