Severe Encephalitis: Recognizing Critical Symptoms and Complications

Severe encephalitis can lead to life-threatening symptoms, with the most extreme cases resulting in a deep coma. In such conditions, vital signs often become unstable. Patients may experience abnormal heart rates—either too fast or too slow—along with drops in blood oxygen levels and fluctuating blood pressure. Intracranial hypertension can trigger persistent high blood pressure that is difficult to manage with medication. Additionally, the patient's level of consciousness deteriorates significantly, often leading to the loss of essential reflexes such as pupillary light response and tendon reflexes in the limbs. Even pathological reflexes may become unresponsive, signaling a critical stage of the illness.

Neurological Deterioration and Seizures

Another alarming feature of severe encephalitis is the occurrence of status epilepticus—an ongoing seizure state that resists treatment. This creates a dangerous cycle: brain inflammation triggers intractable seizures, and the continuous electrical activity in the brain worsens cerebral edema. Electroencephalogram (EEG) monitoring typically reveals excessive spike waves, sharp waves, and other abnormal electrical discharges, indicating significant neurological dysfunction.

Brain Herniation and Its Consequences

Types of Herniation and Their Effects

In severe cases, widespread brain swelling can lead to herniation, most commonly temporal lobe herniation (uncal herniation) and herniation through the foramen magnum (tonsillar herniation). When the latter occurs, the brainstem and vital centers controlling respiration and circulation may become compromised. This can cause erratic breathing patterns, severe oxygen desaturation, bradycardia (slow heart rate), and even brain-heart syndrome.

Brain-heart syndrome refers to cardiac complications arising from severe neurological injury. Patients may develop myocardial ischemia or heart failure due to the systemic stress and neural dysregulation caused by the brain inflammation. These cardiovascular complications can further complicate the clinical picture and worsen prognosis.

Common Complications in Severe Encephalitis

Besides the direct neurological and cardiovascular impacts, patients with severe encephalitis often face secondary complications due to prolonged immobility. These include hospital-acquired conditions such as aspiration pneumonia, pressure ulcers (bedsores), and deep vein thrombosis (DVT) in the lower extremities. Such complications are not only common but also represent significant contributors to mortality in severe encephalitis cases.