What Is a Brain Abscess?
A purulent infection of the brain tissue caused by purulent bacteria. Pathogens can be classified as otic, nasal, blood, cryptogenic or damaging. The main manifestations are cryptic infection, increased intracranial pressure, and focal symptoms and signs in the brain.
- Western Medicine Name
- Brain abscess
- Affiliated Department
- Surgery-Neurosurgery
- Disease site
- brain
- Main cause
- infection
| Zhao Ruilin | (Deputy Chief Physician) | Department of Neurosurgery, Xuanwu Hospital, Capital Medical University |
| Hong Tao | (Resident) | Department of Neurosurgery, Xuanwu Hospital, Capital Medical University |
- A purulent infection of the brain tissue caused by purulent bacteria. Pathogens can be classified as otic, nasal, blood, cryptogenic or damaging. The main manifestations are cryptic infection, increased intracranial pressure, and focal symptoms and signs in the brain.
Causes of brain abscess and common diseases
- According to the history analysis, the possible causes are: non-infective focal bacteremia, brain trauma and postoperative, abscess formation related to craniocerebral surgery (abscess formation after cerebral hemorrhage, abscess after brain tumor surgery), otitis media, rhinitis, endocarditis, Congenital heart disease, respiratory infections, skin infections, etc.
Differential diagnosis of brain abscess
- DWI is a method that can measure the diffusion of water molecules in living tissues today. Based on the different properties of cyst fluid in brain abscesses and cystic tumors, it can detect the degree of diffusion restriction of water molecules in cyst fluid and distinguish between the two. The brain abscess cavity is an inflammatory viscous fluid with limited diffusion of water molecules. Generally, it shows a high signal on DWI, the apparent diffusion coefficient (ADC) value is low, and the ADC picture shows a low signal. Mainly, water molecules diffuse relatively freely, showing a low signal on DWI, the ADC value increases, and the ADC graph shows a high signal.
- According to the pathological properties of brain abscess and cystic tumor, MRS can identify brain abscess and cyst by detecting cyst fluid, cyst wall and surrounding tissue. Cytosolic amino acid and lactic acid (LAC) levels were elevated in the necrotic center of the enveloped brain abscess in MRS, with or without elevated acetic acid and succinic acid. Because lactic acid signals can also be detected in brain tumors without AA, AA (valine, leucine, and isoleucine) is a key marker for the diagnosis of brain abscess. However, if the brain abscess or tumor has a small cyst space, the cyst wall is not thick, and the surrounding tumor tissue infiltration is not obvious, the MRS test will be limited. Therefore, MRS can be helpful for identification only when the capsule cavity is relatively large, the capsule wall is irregular and thick.
Brain abscess examination
- CT and MRI have become the most important imaging methods for diagnosing brain abscesses. The more typical manifestation is a smooth, ring-shaped enhanced space with a smooth cyst wall surrounded by edema of varying degrees. However, there are also ring-shaped intensive spaces after tumor necrosis, which is difficult to distinguish from brain abscess. In addition, brain abscesses may also have atypical radiological manifestations, such as irregular abscess walls and smaller abscess cavity, and the clinical symptoms of patients are atypical, resulting in misdiagnosis and mistreatment of brain abscesses. In recent years, the clinical application of DWI and MRS has provided assistance in the diagnosis, differential diagnosis and treatment of cerebral abscess.
Brain abscess treatment principles
- The treatment of brain abscess is very mature. Antibacterial drugs, puncture of abscess cavity, and craniotomy are the main treatment methods. However, the treatment of brain abscess cannot be based on uniform standards, and patients need to be flexible and individualized. Abdominal puncture due to small trauma has become the mainstream treatment method, especially deep brain or functional area abscess is particularly applicable. However, for patients with significant intracranial pressure or thick-walled multi-room abscesses, craniotomy should still be the first choice. For traumatic abscesses, craniotomy can remove possible foreign bodies and close possible fistulas.
- Abscess puncture is a very effective treatment. Nowadays, stereotactic techniques and even frameless neuronavigation techniques have been widely popularized. Abscess puncture is more and more popular. Most abscesses can be cured by puncture aspiration assisted antibacterial drugs, and a few cases require multiple punctures. The main reasons may be the thickness of the pus cavity wall, incomplete aspiration of the pus, and unclean pus cavity irrigation. Reasonable antibacterial treatment is necessary. Generally speaking, a broad-spectrum antiperspirant with good blood-permeable brain barrier should be selected. Conventional choices include ceftriaxone and meropenem. If there are culture results, antibacterial drugs can be selected according to the drug sensitivity results. If necessary, it is necessary to consider mixed infection and anaerobic infection and choose antibacterial drugs.