From the Guidelines
Yes, there is a classic triad associated with encephalitis, which consists of fever, abnormal mental status, and severe headache, nausea, and vomiting. These symptoms are commonly seen in patients with infectious encephalitis, as noted in a study published in the Journal of Infection 1. The clinical features of encephalitis can be diverse, but fever and abnormal mental status, often accompanied by severe headache, nausea, and vomiting, are the most typical presentations.
Some key features of encephalitis include:
- Fever, which is present in the majority of patients, with 85% of adults with HSV-1 encephalitis being febrile on admission 1
- Abnormal mental status, which can range from disorientation, speech disturbances, and behavioral changes to coma
- Seizures, which can be the initial presenting feature in some patients, especially those with cortical involvement
- Alterations in higher mental function, including lethargy, drowsiness, confusion, and disorientation
It's essential to note that the presentation of encephalitis can be subtle, and some patients may not exhibit the classic triad. With the advent of molecular diagnostic methods, more subtle presentations of encephalitis have been recognized, including low-grade pyrexia, speech disturbances, and behavioral changes that can be mistaken for psychiatric illness or other conditions 1. Prompt medical evaluation is crucial when suspecting encephalitis, as early treatment can significantly impact morbidity, mortality, and quality of life.
From the Research
Classic Triad of Encephalitis
- The classic triad associated with encephalitis includes fever, headache, and an altered level of consciousness 2.
- Additional symptoms may include focal or multifocal neurologic deficits, and focal or generalized seizure activity 2.
- In some cases, encephalitis may also present with prominent psychiatric manifestations, such as psychosis, aggression, mutism, memory loss, euphoria, or fear, particularly in autoimmune encephalitis 3.
Diagnostic Criteria
- The International Encephalitis Consortium set criteria for diagnosis of encephalitis based on clinical and laboratory features in 2013 3.
- The World Health Organization coined the term "acute encephalitis syndrome" in 2006, which refers to the acute onset of fever with convulsions or altered consciousness or both 3.
- Diagnosis of encephalitis can be challenging due to the diverse range of causes, including viral and non-viral infections, as well as autoimmune processes 3.
Treatment and Outcome
- Treatment of encephalitis is largely supportive, with specific treatment available for herpesvirus group and non-viral infections 3.
- The optimal treatment regimen for herpes simplex-1 encephalitis is still unclear, but timely administration of antiviral treatment is essential 4.
- Outcome of encephalitis can vary widely, with some patients experiencing severe neurological deficits, while others may make a full recovery 5, 6.