Case Presentation: A 64-year-old Caucasian male with hypertension and diabetes mellitus presented to the emergency room with confusion, ataxia, and urinary retention after a 10-day cruise to Aruba. During the cruise, he developed fever, diarrhea, and a rash. After returning home, he visited a local ED and was treated with ciprofloxacin and metronidazole for febrile gastroenteritis. Three days later, his diarrhea had resolved but he developed progressive confusion.
On exam, the patient was febrile to 103, with the remainder of his vital signs within normal limits. Notable neurologic findings included confusion, mild dysarthria, and ataxia. Lower extremity strength was rated 4/5 bilaterally. Patellar reflexes were 2+ on the right and absent on the left. A petechial rash was noted on bilateral lower extremities and dorsum of both hands. Initial laboratory analysis included a WBC of 20 and an unremarkable CMP. CSF analysis demonstrated a WBC count of 299 with 64% polys and 18% lymphs, RBC 0, glucose 60, protein 112, with a negative gram stain. CT head with and without contrast was unremarkable. Further imaging studies included a normal MRI of the brain as well as MRI of the thoracic and lumbar spine which demonstrated abnormal enhancement of the lower thoracic cord and conus medullaris, along with abnormal thickening and enhancement of the nerve roots of the cauda equine.

A viral meningoencephalitis was suspected, but the patient was initially covered for bacterial meningitis, tick-borne illness and HSV due to the equivocal CSF differential. Antibiotics were quickly tapered. Given the finding of myelitis on imaging, the patient was initiated on pulse dose steroids with methylprednisolone 1000mg iv daily for 5 days. Twenty-four hours after receiving steroids, the patient demonstrated resolution of dysarthria, short-term memory improvement, improved word-finding ability, and improved lower extremity strength. By day three, he regained 5/5 strength and was ambulating with minimal assistance. On the fifth day, the patient was ambulating without assistance and had normal mentation. His only residual deficit was continued urinary retention at the time of discharge.

Ultimately, CSF and blood cultures returned negative. Testing for Zika, Chikungunya, Erhlichiosis, and Rocky Mountain Spotted Fever was also negative. West Nile Virus IgM was positive.

Discussion: The causes of meningoencephalitis are numerous. Infectious etiologies such West Nile Virus may be discerned from a thorough history and physical examination, in combination with targeted diagnostic testing. West Nile Neuroinvasive Disease is a rare but life-threatening complication occurring in approximately 1% of Wile Nile Virus infections. Treatment for acute viral meningoencephalitis, for which antiviral therapy does not exist, has traditionally been supportive. However, a small number of reported cases involving closely-related viruses such as Japanese Encephalitis Virus have demonstrated the potential efficacy of pulse-dose steroid treatment in achieving resolution of cognitive and motor deficits.

Conclusions: Neuroinvasive disease is a serious complication of infection secondary to a broad array of viral organisms. Given the significant morbidity and mortality associated with viral meningoencephalitis, physicians should be aware of the potential role for pulse-dose steroids as an evolving treatment modality for viral central nervous system disease.