Background and Clinical Significance: When diverse clinical presentations coincide with complex laboratory findings, particularly in older adults, the diagnostic process can be especially challenging. Case Presentation: We report the case of a geriatric patient who was hospitalized with initial gastrointestinal and respiratory symptoms, followed by progressive chest pain and profound weakness, accompanied by elevated transaminases, troponin elevation, and hyponatremia, initially suggesting multiple competing diagnostic entities. During the clinical course, the patient developed neurological symptoms. Ultimately, careful history-taking, including detailed exposure assessment, raised suspicion for tick-borne encephalitis, which was subsequently confirmed by serological testing. Conclusions: This case highlights the diagnostic complexity of tick-borne encephalitis in older adults, where atypical and multisystem presentations may obscure the underlying etiology and delay recognition of a neuroinfectious disease.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex neuroimmunological disorder characterized by disabling symptoms that are often difficult to manage. More recently, in the context of SARS‐CoV‐2 infection, potential pathophysiological overlaps and disease modulation have been hypothesized. Our successful case highlights the need to investigate novel therapeutic approaches, including plasma exchange.