Encephalitis
Viral meningitis is usually mild and self-limiting. In contrast, viral encephalitis is a medical emergency which warrants prompt intervention. There may be initial diagnostic ambiguity as there is overlap in clinical signs and histopathological features (and the two may exist simultaneous as a meningoencephalitis) - Lorraine Spencer
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HWN Suggests
A Catastrophic Diagnosis You Probably Don't Know
Anti-NMDA-receptor encephalitis may be the most important neurologic disease you've never heard of.
The disease is far more common than one might think. Analysis of data from the California Encephalitis Project found that anti-NMDAR encephalitis was identified more than four times as frequently as encephalitis caused by herpes simplex virus type 1, varicella, or West Nile virus in patients under age 30.
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Episode 39: Encephalitis
Majority of cases are due to infection, of which HSV-1 is the most common in the United States and Japanese encephalitis is the most common global cause.
Articles of Interest
Encephalitis
acyclovir 10mg/kg Q8h IV for 14 days, start prior to definitive imaging, empiric antibiotics to cover for bacterial meningitis is often required.
Altered Mental Status in the Emergency Department – When to Consider Anti-LGI-1 Encephalitis: Case Report
Autoimmune encephalitis is an uncommon cause of acute altered mental status and new-onset seizures in the ED. While there is an exhaustive list of antibody targets implicated in autoimmune encephalitis as a whole (ie, N-methyl-D-aspartate receptor...
Anti-NDMA
The classic presentation is subacute onset psychiatric symptoms with non-specific neurological complaints (e.g. movement abnormalities, speech disorder), often with a preceding viral prodrome. Compared to primary psychiatric diagnoses, the onset tends to be more rapid and there are more mixed symptoms (e.g. rapidly fluctuating agitation/catatonia, mania/depression, pressured speech/mutism).
Anti-NMDA Encephalitis
Should get CSF. Send for oligoclonnal bands. You should also send CSF to test for the anti-NMDA antibody (in addition to HSV, etc).
Anti-NMDA-Receptor Encephalitis
Anti-NMDA-receptor encephalitis is a severe and treatable immune-mediated disorder which presents with a rapid progression of psychiatric and neuropsychiatric symptoms. Although only first reported as a diagnosis in 2007, an exponential number of cases have since been described, suggesting that the disease is not rare but rather under-diagnosed. Emergency physicians play an important role in recognizing this disorder, as prognosis is largely dependent on early treatment with immunotherapy.
Emergency Department Management of Adults With Infectious Meningitis and Encephalitis
Infectious meningitis and encephalitis are often life-threatening illnesses, though prompt workup and targeted treatment can greatly reduce morbidity and mortality. Although presentation of central nervous system infection can sometimes be subtle, this issue focuses on evidence-based strategies for identifying combinations of signs and symptoms to narrow the diagnosis. Identifying meningitis versus encephalitis; bacterial versus viral, fungal, or iatrogenic causes; and providing prompt empiric antimicrobials and appropriate diagnostic testing are key to management.
Japanese encephalitis virus (JEV)
Mosquito-born flaviviral infection present in most parts of Asia extending south to the tip of Australia (Outer Torres Strait Islands)
Management of Infective Encephalitis in Critical Care
Viral meningitis is usually mild and self-limiting. In contrast, viral encephalitis is a medical emergency which warrants prompt intervention. There may be initial diagnostic ambiguity as there is overlap in clinical signs and histopathological features (and the two may exist simultaneous as a meningoencephalitis) but, if there is clinical suspicion, viral encephalitis should be treated with antivirals until the diagnosis is excluded.
Meningitis & Encephalitis
initial empiric therapy prior to LP: 2 grams ceftriaxone IV, 10 mg dexamethasone IV, 10 mg/kg acyclovir IV, (Subsequently adjust antibiotics based on LP results.).
Rapid Review: anti-NMDA receptor encephalitis
Emergency department management is supportive, focusing on control of psychosis, seizures, and autonomic instability. Empiric treatment for meningitis and herpes encephalitis should also be started, as the results of definitive testing will take a while. Ultimately, the patient will require IVIG, steroids, and plasma exchange.
Resources
SAEM
Consider the diagnosis of HSV encephalitis in patients with concerns for CNS infection who have focal neurologic findings, altered mental status, and/or elevated numbers of red blood cells in the CSF. Administer IV acyclovir in addition to the empiric antimicrobial regimen. Initial CSF laboratory findings do not always yield classic results, so consider empiric treatment for possible bacterial meningitis (and/or HSV encephalitis) when CSF results are inconclusive.
