Introduction: Most cases of West Nile Virus are asymptomatic but a small percentage of infections can result in severe neurological disease. West Nile Neuroinvasive Disease is characterized by meningitis and encephalitis, accompanied by flaccid paralysis. Encephalitis additionally requires the presence of sustained altered mental status, seizures, or other focal neurologic findings. When WNV overlaps with suspected delirium tremens it becomes significant due to its diagnostic challenge and the need to have greater medical awareness.
Description: A 69-year-old male with a history of alcohol abuse presented to the ED with fever, confusion, nausea, vomiting, and tremors. Vital signs:103°F, tachycardic, tachypneic, and hypoxic on examination. On exam, he had coarse breath sounds bilaterally, and neurological examination showed a GCS of 8, which required intubation for airway protection. CT head and MRI showed no acute changes. The initial working diagnosis was delirium tremens treated with benzodiazepine with no improvement in mental status. An EEG indicated slowing of cerebral activity. A lumbar puncture revealed elevated WBCs and protein. CSF serology for WNV IgM was positive. The patient was administered empiric IVIG for 5 days along with supportive care. The patient was extubated, mentation improved, and transferred from the ICU to the floor.
Discussion: West Nile Virus encephalitis occurring in the geographical region where it was reported makes this case unique. According to the CDC, the reported cases occurred from July to September and neuroinvasive cases had a median age of 60 and were majority males. For neuroinvasive WNV, the case-fatality rate rises as the patient's age increases. This case had overlapping features with alcohol withdrawal; altered mental status, tremors, nausea, and vomiting, and no changes seen after treatment. A lumbar puncture helped narrow down a correct diagnosis and treatment. This case report emphasizes the importance of being mindful of anchoring bias and considering WNV encephalitis as a part of differential during the summer months in patients who have present with altered mental status. This case highlights the crucial role of monitoring for WNV and seasonal outbreaks in patients who are susceptible to severe illness.
