Encefalitt

Encefalitt, also known as encephalitis, is an inflammation of the brain parenchyma. It can result from infections, autoimmune processes, or less commonly metabolic or paraneoplastic conditions. The condition typically presents with acute or subacute fever, headache, and altered mental status, and may be accompanied by seizures, focal neurological deficits, or coma.

Causes are diverse. Viral infections are the most common cause worldwide, with herpes simplex virus type 1 being a leading cause of sporadic encephalitis in adults and requiring urgent treatment. Other viruses include West Nile, enteroviruses, varicella-zoster, and cytomegalovirus. Bacterial, fungal, and parasitic infections can also cause encephalitis. Autoimmune encephalitis, due to antibodies against neuronal surface or synaptic proteins (such as NMDAR or LGI1), is an important non-infectious cause. In many cases no organism is identified.

Pathophysiology often involves inflammation that leads to edema and neuronal injury, sometimes necrosis. Clinically, symptoms develop over hours to days and commonly include confusion or altered behavior, speech or movement abnormalities, seizures, and sometimes coma. Pediatric and elderly patients may have different presentations with fewer focal signs.

Diagnosis relies on clinical assessment and targeted investigations. Magnetic resonance imaging frequently shows abnormalities in affected brain regions (for example, temporal lobes in HSV encephalitis). Lumbar puncture with cerebrospinal fluid analysis often reveals lymphocytic pleocytosis and elevated protein, with normal or mildly low glucose. Polymerase chain reaction testing in CSF helps identify pathogens, and autoimmune panels may be pursued.

Treatment and prognosis vary by cause. Empiric antiviral therapy with acyclovir is started promptly when HSV encephalitis is suspected. Management includes treating the underlying infection or providing immunotherapy for autoimmune encephalitis, controlling seizures, and monitoring intracranial pressure. Prognosis depends on etiology and treatment timing; some patients recover fully, others have lasting neurologic or cognitive deficits.