Neurological Manifestations Associated With a Chikungunya Outbreak: A Case Series During an Emergency in an Area Endemic for Dengue

Neurological manifestations of chikungunya virus infection are rare and underdiagnosed. Clinical recognition is challenging due to the nonspecific spectrum of symptoms, limited availability of specific tests, and similarity to other etiologies. In addition, establishing causality with concomitant acute infection is complicated by the patient profile, which often includes atypical presentations, comorbidities, and advanced age. We present a series of ten cases treated at a tertiary hospital during a chikungunya emergency in the northwest of São Paulo state. Neurological cases were identified among 144 chikungunya infections recorded through an active surveillance system covering all arbovirus-related hospitalizations, enabling early detection of neurological manifestations associated with infection. Diagnosis of chikungunya virus infection was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR) using a multiplex panel in serum and, in some cases, cerebrospinal fluid. The mean age of patients was 75 years; all were adults, with predominance of males. Of the ten cases, eight had relevant comorbidities, most commonly systemic arterial hypertension, diabetes mellitus, and dyslipidemia. Isolated cases had liver cirrhosis, chronic kidney disease, or a history of ischemic stroke. The main neurological syndromes observed were encephalopathy, ischemic stroke, myeloradiculopathy, transient confusional state, status epilepticus, and cranial nerve palsy, with overlap in some patients. In general, CSF analysis showed pleocytosis with predominance of mononuclear cells and elevated protein levels. There were three deaths related to the severity of neurological involvement and associated comorbidities. This series highlights the diversity of neurological presentations associated with chikungunya virus infection. Given population aging and the virus’s urban expansion, it is essential to strengthen surveillance, train health services, and incorporate neurochikungunya diagnosis into routine clinical practice, as early recognition can positively impact outcomes and represents a relevant public health challenge in Brazil.