Diagnostic clues in viral encephalitis

Q: Tremors of the eyelids, tongue, lips, and extremities suggest which encephalitis? (select one)

A) St. Louis encephalitis

B) mumps encephalitis 

C) encephalitic rabies

D) varicella-zoster virus (VZV) encephalitis

Answer: A

The objective of this question is to emphasize the important diagnostic clues in the differential diagnosis of suspected viral encephalitis. A few major specific findings of different viral encephalitis are:

• Parotitis - mumps encephalitis
• Flaccid paralysis, a polio-like presentation - West Nile virus infection (frequently misdiagnosed as Guillain-Barré syndrome). A maculopapular rash with the above symptom almost confirms the West Nile virus.
• Tremors of the eyelids, tongue, lips, and extremities - St. Louis encephalitis or West Nile encephalitis (geographic location of known epidemiology is a major determinant.)
• Hydrophobia, aerophobia, pharyngeal spasms, and hyperactivity - encephalitic rabies. It may also present as seizures, cranial nerve palsies, and myoclonus.
• Grouped vesicles in a dermatomal pattern - varicella-zoster virus (VZV).

#neurology

#ID

References:

1. Steiner I, Budka H, Chaudhuri A, Koskiniemi M, Sainio K, Salonen O, Kennedy PG. Viral encephalitis: a review of diagnostic methods and guidelines for management. Eur J Neurol. 2005 May;12(5):331-43. doi: 10.1111/j.1468-1331.2005.01126.x. PMID: 15804262.

2. Esang M, Goldstein S, Dhami R. The Role of Physical Examinations in Psychiatry as Illustrated in a Case of Neuroleptic Malignant Syndrome Versus Viral Encephalitis: A Case Report and Literature Review. Cureus. 2019 Jun 5;11(6):e4840. doi: 10.7759/cureus.4840. PMID: 31410323; PMCID: PMC6684120.

3. Stephen J Gluckman - https://www.uptodate.com/contents/viral-encephalitis-in-adults - © 2023 UpToDate, Inc