What is the most common cause of encephalitis?

The most common cause of encephalitis is herpes simplex virus type 1 (HSV-1). This virus is known for its potential to cause severe neurological complications, including encephalitis, which primarily affects the temporal lobes of the brain. HSV-1 can lead to a range of clinical manifestations, and in its encephalitic form, it typically results in symptoms such as fever, headache, seizures, confusion, and alterations in consciousness.

The pathophysiology of HSV-1 encephalitis involves direct viral invasion of brain tissue, leading to inflammation and necrosis. A prompt diagnosis and initiation of antiviral therapy with acyclovir are critical for improving outcomes in patients with this condition.

While other viruses, such as West Nile virus, enteroviruses, and cytomegalovirus can also cause viral encephalitis, HSV-1 remains the most prevalent cause, particularly in adults and in certain settings. Clinicians must consider the patient's history, symptomatology, and laboratory findings when diagnosing and managing encephalitis to ensure the best possible outcomes.