An 81-year-old female patient presented with acute fever, intense myalgia and a punctual episode of mental confusion. She received an initial diagnosis of pneumonia with prescription of antibiotics. In the subsequent days, there was worsening of polyarthralgia, as well as an evolution to irritability and behavioral changes (patient was found disoriented, with difficulty recognizing relatives and clapping hands without purpose). The patient had cutaneous rash of the trunk and proximal limbs, diffuse arthritis, psychomotor agitation, and fluctuations of the level of consciousness. Considering the clinical picture described, and the epidemiological history of neighbors with Chikungunya virus (CHIKV) infection, the patient was admitted to an intensive care unit with suspicion of CHIKV meningoencephalitis.
Complementary tests demonstrated positive IgM serum serologies for Epstein-Barr virus (EBV), Herpes simplex virus 1 and 2 (HSV) and CHIKV. Cerebrospinal fluid (CSF) analysis seven days after the onset of symptoms revealed lymphocytic pleocytosis, increased proteinorraquia, polimerase chain reactions (PCR) negatives for Zika virus, EBV and HSV, and positive for CHIKV, negative serology for dengue and positive IgM ELISA for CHIKV. Magnetic resonance imaging of the brain with contrast was normal (Figure 1), and the electroencephalogram demonstrated diffuse slowing. The patient evolved with decreased level of consciousness and need for orotracheal intubation. She was treated with human intravenous immunoglobulin for five days, with no evidence of clinical improvement, and evolved to death days later.