Eastern equine encephalitis

This code identifies a severe, mosquito-borne viral infection affecting the central nervous system, caused by the Eastern equine encephalitis virus (EEEV). It typically presents with sudden onset of fever, headache, vomiting, diarrhea, and can rapidly progress to encephalitis, seizures, and coma.

Assign this code when documentation confirms a diagnosis of Eastern equine encephalitis. This typically follows laboratory confirmation of EEEV infection, such as positive serology (IgM or IgG antibodies) or PCR from CSF or tissue samples, in a patient presenting with compatible neurological symptoms.

• Ensure documentation specifies "Eastern" equine encephalitis to differentiate from other forms.
• Sequence this code as the primary diagnosis when it is the reason for the encounter.
• Look for supporting documentation of mosquito exposure or travel to endemic areas.