Viral encephalitis and bacterial encephalitis differences

Written by Zhang Hui
Neurology
Updated on September 01, 2024
00:00
00:00

There are significant differences between viral encephalitis and bacterial encephalitis in clinical settings.

Firstly, their clinical symptoms differ; the fever in viral encephalitis is generally lower than that in bacterial encephalitis, where there may be widespread chills and persistent high fever.

From another perspective, laboratory tests also help differentiate the two. In viral encephalitis, a routine blood test shows no increase in white blood cells, mainly an increase in the proportion of lymphocytes. In contrast, bacterial encephalitis is characterized by a significant increase in white blood cells, which aids in distinguishing the two.

Furthermore, an essential diagnostic tool is the lumbar puncture, through which cerebrospinal fluid can be tested. In viral encephalitis, the white blood cell count in the cerebrospinal fluid is slightly increased; in bacterial encephalitis, it is significantly increased. The cerebrospinal fluid in viral encephalitis has a slight increase in protein content with no significant change in chloride levels; however, in bacterial encephalitis, the protein content in the cerebrospinal fluid is notably higher, and there is a significant decrease in chloride levels.

Other Voices

doctor image
home-news-image
Written by Zhang Hui
Neurology
1min 10sec home-news-image

What tests are done for pediatric encephalitis?

Some auxiliary examinations are very necessary for pediatric encephalitis, which help in the diagnosis and differential diagnosis of encephalitis. The main tests generally include the following: First, an electroencephalogram (EEG), which is the most commonly used examination. It is safe, non-invasive, and relatively accurate. Children with encephalitis will show light to moderate abnormalities in the EEG. Combined with the patient's history of fever and headache, it has important clinical significance for the diagnosis of encephalitis. The second important examination is cranial magnetic resonance imaging (MRI). If the encephalitis is severe, pathological changes in the cerebrospinal fluid can be seen on MRI. The third very important examination is lumbar puncture. Lumbar puncture can mainly determine the pressure of the cerebrospinal fluid, the color of the cerebrospinal fluid, and analyze the levels of white blood cells, glucose, and chloride in the cerebrospinal fluid. This is crucial for diagnosing encephalitis and excluding other types of encephalitis.

doctor image
home-news-image
Written by Tang Li Li
Neurology
1min 42sec home-news-image

How is encephalitis diagnosed?

The diagnosis of encephalitis relies on the following aspects. First, it is based on clinical manifestations. If the patient clearly exhibits symptoms such as headache, fever, nausea, vomiting, and signs of increased intracranial pressure, and physical examination shows positive signs of meningeal irritation, then there is a high suspicion of encephalitis. Second, various auxiliary tests can be conducted. Initially non-invasive tests such as electroencephalograms (EEG) and magnetic resonance imaging (MRI) of the skull can be completed. If the MRI reveals significant abnormalities, such as abnormal signals in the frontal and temporal lobes including the hippocampus, then viral encephalitis should be highly suspected. If the EEG shows moderate abnormalities or increased slow waves, it also indicates damage to the cerebral cortex, serving as an indirect indicator of encephalitis. Third, a lumbar puncture can be performed to ascertain any abnormalities in the cerebrospinal fluid (CSF) routine and biochemical tests. If the cell count is elevated beyond ten times the normal value, an inflammatory infection is considered. There is often a minor to moderate increase in protein. The levels of glucose and chloride may decrease in bacterial and tuberculous encephalitis, while they are generally normal in viral encephalitis.

doctor image
home-news-image
Written by Zhang Hui
Neurology
54sec home-news-image

Encephalitis belongs to which department?

Encephalitis is primarily a neurological disorder and is an infectious disease of the central nervous system, mainly diagnosed and treated in neurology. There are many causes of encephalitis, with viral encephalitis being the most common. For example, herpes simplex encephalitis is a typical type seen clinically. Patients may experience fever, even with very high temperatures exceeding 40°C, headaches, nausea, and vomiting. If the condition worsens, seizures, coma, and cognitive impairment may occur. These clinical manifestations require further investigations like electroencephalography, cranial MRI, and lumbar puncture. Additionally, there is a specific type of epidemic, known as Japanese encephalitis, which falls under the category of infectious diseases due to its contagious nature.

doctor image
home-news-image
Written by Zhang Hui
Neurology
53sec home-news-image

What tests are conducted for encephalitis?

First, it is generally necessary to conduct an EEG test. This test is very convenient and non-invasive for patients. If significant slow waves are detected, encephalitis cannot be ruled out. Secondly, an MRI of the brain should be performed. If the viral encephalitis is severe, abnormal signals can be observed in areas such as the frontal lobe, temporal lobe, and hippocampus on the MRI, which are of great diagnostic reference value. Thirdly, lumbar puncture is also very important. It allows for a direct observation of the color of the cerebrospinal fluid, to monitor the pressure of the brain fluid, and to test the cerebrospinal fluid for cell count, protein, sugar, and chloride levels. These tests are very important for the diagnosis and differential diagnosis of encephalitis.

doctor image
home-news-image
Written by Zhang Hui
Neurology
53sec home-news-image

Is encephalitis hereditary?

Encephalitis is mostly caused by viral infections. For instance, Epidemic B encephalitis is caused by the B encephalitis virus, and herpes simplex encephalitis is caused by the herpes simplex virus. Therefore, encephalitis is not related to genetic mutations and is not hereditary, so there is no need for special concern. It is important to note that some cases of encephalitis are not directly related to viral infections and may be related to autoimmune responses. For example, autoimmune encephalitis can occur in patients experiencing immune system disorder, which may be accompanied by some tumors. A disordered immune system can produce antibodies that attack one's own brain tissue, leading to autoimmune encephalitis. This type of encephalitis also has no genetic tendencies.