Encephalitis: Causes and Common Symptoms

Encephalitis is a condition that occurs when the brain and central nervous system become infected by various pathogens. Depending on the type of pathogen and the specific areas of the brain or meninges affected, symptoms can vary significantly. Common infectious agents include viral, bacterial, and parasitic organisms, as well as specific infections such as tuberculous meningitis, fungal infections—most notably cryptococcal meningitis—and other rare pathogens.

Common Symptoms of Encephalitis

One of the primary indicators of encephalitis is the involvement of the brain and meninges, which can lead to symptoms such as neck stiffness and signs of increased intracranial pressure. These signs often include severe headaches, nausea, vomiting, and papilledema (swelling of the optic disc). During a physical examination, patients may exhibit positive Kernig's or Brudzinski's signs, which are clinical indicators of meningeal irritation.

General Infection Symptoms

Many patients initially experience general symptoms of infection, such as fever, headache, dizziness, and a feeling of pressure in the head. These early signs may progress to more severe neurological impairments as the infection affects brain tissue.

Symptoms Related to Brain Tissue Damage

When brain tissue becomes inflamed or damaged, individuals may develop motor impairments such as weakness or numbness in one side of the body. Visual disturbances are also common, including blurred vision, double vision, or loss of vision in certain visual fields. These symptoms are often a direct result of inflammation in specific regions of the brain responsible for sensory and motor functions.

Brainstem Involvement

If the brainstem is affected, patients may experience difficulties with balance, coordination, and swallowing. Symptoms can include dizziness, difficulty walking (such as ataxia resembling cerebellar or sensory ataxia), trouble swallowing, and coughing while drinking fluids. These manifestations are due to the disruption of neural pathways that control essential motor and sensory functions.

Diagnosis and Treatment

The specific symptoms a patient experiences often depend on the location and severity of the inflammation. Prompt diagnosis through imaging studies, lumbar puncture, and laboratory tests is crucial to identify the causative pathogen. Treatment typically involves targeted antimicrobial therapy based on the underlying cause, along with supportive care, symptom management, and neuroprotective strategies to aid recovery and prevent long-term complications.