Double Crossed: A Case of La Crosse Encephalitis

Area of Science:

• Neuroscience
• Infectious Diseases
• Pediatrics

Background:

• La Crosse virus (LACv) is a Bunyavirus endemic to the Midwestern and Appalachian regions of the US.
• LACv is transmitted by the eastern tree-hole mosquito, primarily during summer months.
• Pediatric cases constitute the majority of reported LACv infections.

Observation:

• A 10-year-old male with type 1 diabetes presented with fever, vomiting, and headache, initially diagnosed as viral gastroenteritis.
• The patient returned with altered mental status and seizures, exhibiting pleocytosis in cerebrospinal fluid.
• Initial brain MRI was normal, but a follow-up MRI revealed left cerebral cortex enhancement.

Findings:

• Cerebrospinal fluid analysis eventually tested positive for La Crosse virus IgM.
• The patient experienced intermittent seizures and was treated with antiepileptics and IVIG.
• This case represents the first reported instance of La Crosse encephalitis in Rhode Island.

Implications:

• This case underscores the importance of considering LACe in pediatric patients with neurological symptoms, especially after travel to endemic areas.
• Diagnostic delays can occur as early symptoms are non-specific and IgM may be negative initially.
• Prompt diagnosis and supportive care, including seizure management, are crucial for outcomes in LACe.