A Fatal Case of Neuroinvasive West Nile Virus Infection in an Immunocompromised Host

The neuroinvasive form of West Nile disease is an uncommon manifestation of the viral infection. To date, documented cases in Michigan of neuroinvasive decompensation from this virus have been rare. Evaluation requires a broad differential diagnosis and treatment options are still quite limited. Objective evaluations entailing physical exam and radiographic and laboratory changes are nonspecific. Serologic testing of cerebrospinal fluid by enzyme immunoassay remains the gold standard for diagnosis. However, IgM antibodies typically do not develop until after the fourth to seventh day of symptom onset. This retrospective case report presents an immunocompromised male patient in his mid-70s in whom neuroinvasive West Nile virus was diagnosed postmortem. All information was obtained from the patient's electronic health record. This patient's immunocompromised state at the time of West Nile exposure made him more susceptible to neuroinvasive disease progression and ultimately influenced the outcome. Prior to withdrawing care, the patient was treated for methicillin sensitive staphylococcus aureus (MSSA) cellulitis and Type 1 Herpes Simplex virus. In this case, neuroinvasive West Nile virus was a less likely diagnosis given the patient's physical exam findings and the context of more likely alternative explanations for his cognitive decline. Treatment options for neuroinvasive forms of West Nile virus are still supportive and would not have altered the patient's hospital course. This case report demonstrates that clinicians must maintain an ongoing index of suspicion for infection in warmer climates where West Nile is becoming more prevalent. Given some patients' obscure physical exam findings and radiographic imaging results, a thorough history with laboratory conformation is required for a more conclusive diagnosis.