Ciobanu, et al.
Early summer meningoencephalitis: unusual yet usual diagnostic challenge in a geriatric patient—a case report. Reports. 2026;9:205. doi:10.3390/reports9030205
Tick-borne encephalitis (TBE) virus infection typically begins with non-specific influenza-like symptoms, followed by an asymptomatic interval and subsequently a second phase characterized by neurological involvement. In older adults, atypical disease courses may complicate the diagnostic process.
Such a case has recently been reported and is discussed here in detail. A 71-year-old woman was referred to a tertiary care hospital with a three-day history of cough, interscapular pain, and intermittent diarrhea. She was afebrile on presentation, and physical examination revealed no significant abnormalities. Her medical history was notable for arterial hypertension, mild cognitive impairment, and an unclear neurological condition of uncertain etiology. She was discharged because her symptoms were considered consistent with a non-specific viral infection.
Subsequently, the patient developed progressive weakness, nausea, vomiting, and upper abdominal pain, prompting readmission. Based on the clinical presentation and laboratory abnormalities, an extensive differential diagnostic work-up was initiated. During hospitalization, she developed fever, symptomatic orthostatic hypotension accompanied by vertigo and headache, and worsening cognitive impairment with a noticeable decline in memory and concentration.
The diagnosis became apparent only after the patient reported a recent hiking trip in the Black Forest, a TBE-endemic region in southern Germany. Tick-borne encephalitis was therefore suspected, and serological testing confirmed the diagnosis by demonstrating positive TBE virus-specific IgM and IgG antibodies.
Diagnostic algorithms for TBE are not yet fully standardized. A broad differential diagnosis is essential, particularly in patients presenting with diffuse clinical manifestations and non-specific laboratory abnormalities suggestive of conditions such as hepatitis, myocarditis, or gastroenteritis. This case highlights the diagnostic complexity of TBE in older adults, in whom atypical and multisystem manifestations may obscure the underlying etiology and delay recognition of this neuroinfectious disease.