# West Nile virus neuroinvasive disease and cardiac involvement in critically ill patients in central Italy: a case series

## TL;DR

This study examines critically ill West Nile virus patients in Italy, highlighting the link between severe neurological disease and cardiac complications.

## Contribution

The study provides new insights into the frequency and impact of cardiac involvement in critically ill West Nile neuroinvasive disease patients.

## Key findings

- Cardiac involvement, including suspected myocarditis and Takotsubo syndrome, was observed in 4 out of 12 critically ill WNND patients.
- Non-survivors were older and had more comorbidities, with 41.7% of patients dying within 30 days of ICU admission.
- Brain MRI showed thalamic and brainstem abnormalities in most patients, while cerebrospinal fluid showed lymphocytic pleocytosis and elevated protein.

## Abstract

West Nile virus (WNV) infection represents an emerging health concern in Southern Europe. Although most infections are asymptomatic, a small proportion progress to WNV neuroinvasive disease (WNND), occasionally complicated by cardiac involvement. Data describing critically ill patients with WNND and cardiac involvement requiring intensive care (ICU) are limited.

We conducted a two-month observational case-series of consecutive adult patients with confirmed WNND admitted to the ICUs of two tertiary hospitals in Lazio region, Italy from July 1 to September 1, 2025. Clinical, laboratory, imaging, and outcome data were collected, with particular focus on neurological and cardiac manifestations.

Among 197 patients with confirmed WNV infection, 64 (32%) had WNND, of whom 12 (6.1%) required ICU admission. These 12 patients were subsequently enrolled in the study. The median age was 76.5 years (IQR 70–83), and 75% were male. The most common symptoms were fever, myalgia, and gastrointestinal complaints, followed by confusion, limb weakness, and psychomotor slowing. Cerebrospinal fluid analysis showed lymphocytic pleocytosis (median 135 cells/mm3), elevated protein (median 126 mg/dL), and normal glucose. Brain MRI revealed T2/FLAIR hyperintensities in the thalami and brainstem in most cases, 2 patients had normal imaging. Four patients had cardiac involvement; two fulfilled criteria for suspected myocarditis and one was diagnosed with Takotsubo syndrome, based on new left ventricular dysfunction, elevated troponin, and diffuse hypokinesis not confined to a coronary territory. Five patients (41.7%) died within 30 days of admission. Non-survivors were older (median 83 years) and had more comorbidities. Survivors showed higher inflammatory markers.

WNND remains a life-threatening condition requiring multi-disciplinary critical care. Cardiac involvement, including suspected myocarditis, was observed in a substantial proportion of critically ill WNND patients and occurred more frequently among non-survivors in this cohort. Although descriptive, these findings highlight the importance of early neuro-cardiac assessment and comprehensive supportive management to optimize outcomes in severe WNND.