Case Presentation:

Estimates indicate that West Nile virus (WNV) infects approximately one and one–half million people in the United States of America. West Nile virus neuroinvasive disease is a very rare presentation, occurring in less than 1% of affected patients infected with WNV. Patients may develop any combination of meningitis, encephalitis, and acute paralysis. We present a unique case of West Nile virus neuroinvasive (WNND) disease presenting as flaccid paralysis.

Discussion:

30–year–old man presents with fever, chills, and diffuse weakness for 2 days. Denies ill contact, travels. He works nightshift at a local weaving mill and is occasionally exposed to mosquitoes. Temperature is 103°F, blood pressure 135/60, pulse 104, respiratory rate 22. Physical examination was notable for confusion and flaccid paralysis. He was started on Vancomycin, Cefepime and Ceftriaxone and intubated for airway protection. Laboratory values were normal except for WBC 11.2 K/uL. CSF analysis showed total white blood counts of 94/mm3 with 8% neutrophils, 90% lymphocytes, 77 mg/dl protein, and 67 mg/dl glucose. CSF Gram staining, acid–fast bacilli staining, bacterial meningitis screen, VDRL, HIV, HSV, were all negative. Serum West Nile IGM 3.49 (Normal <1.0) and CSF West Nile IgM 2.80u (normal <.90u) were both elevated. CT head was unrevealing. MRI brain revealed leptomeningeal inflammation in the posterior fossa. He did well post–discharge in rehabilitation.

Conclusions:

We report a unique case of WNV disease presenting as flaccid paralysis. The most reliable diagnostic modality for WNV is the serum IgM antibody to WNV in serum and CSF. WNV is a challenging diagnosis as diseases such as Japanese encephalitis virus, St Louis encephalitis and Guillain–Barre syndrome may have similar findings. It is crucial to elicit a good history and diagnostic investigation, including geographic location, recent travels, exposure to mosquitoes, and time of year to establish an early diagnosis and treatment for this rare complication.