Brain and spinal cord abscesses

An abscess of the brain or spinal cord is a limited accumulation of pus in the cranial cavity or spinal canal. Depending on the location, abscesses can be intracerebral (accumulation of pus in the brain matter), subdural (located under the dura mater) or epidural (located above the dura mater). Brain abscesses occur with a frequency of about 0.7 per 100,000 population per year.

Causes of Brain and Spinal Cord Abscesses

It is not always possible to isolate the infectious agent from the contents of a brain abscess. In approximately 25% of cases, abscess contents cultures are sterile. Among the isolated pathogens of hematogenous abscesses, streptococci (aerobic and anaerobic) predominate, often in association with bacteroides (Bacteroides spp.). In hematogenous abscesses due to lung abscess,Enterobacteriaceae (in particular, Proteus vulgaris) are often encountered . The same pathogens are characteristic of otogenic abscesses.

Pathogenesis of brain and spinal cord abscesses

The main routes of infection penetration into the cranial cavity and spinal canal are the following:

• hematogenous;
• open penetrating craniocerebral trauma or spinal trauma;
• purulent-inflammatory processes in the paranasal sinuses;
• wound infection after neurosurgical interventions.

The conditions for the formation of an abscess when an infection penetrates are the nature of the pathogen (virulence of the pathogen) and a decrease in the patient's immunity. In developed countries, hematogenous abscesses are most typical. In developing countries, brain abscesses most often form against the background of chronic inflammatory processes in adjacent tissues, which is associated with inadequate treatment of the latter. In approximately 25% of cases, it is not possible to establish the source that led to the formation of a brain abscess.

Brain and Spinal Cord Abscesses - Causes and Pathogenesis

Symptoms of Brain and Spinal Cord Abscesses

The clinical picture of brain and spinal cord abscesses corresponds to the clinical picture of a space-occupying lesion. There are no pathognomonic symptoms of a brain abscess. As with other space-occupying lesion, clinical symptoms can vary widely - from headache to the development of severe general cerebral symptoms with depression of consciousness and pronounced focal symptoms of brain damage.

Diagnosis of brain and spinal cord abscesses

When making a diagnosis, a thorough anamnesis is of great importance. The appearance and increase of neurological symptoms in a patient with a diagnosed inflammatory process is a reason for conducting a neuroimaging examination.

Computer tomography. The accuracy of the diagnosis of a brain abscess in CT depends on the stage of the process. In case of encapsulated abscesses, the accuracy of the diagnosis approaches 100%. The abscess looks like a rounded volumetric formation with clear, smooth, thin contours of increased density (fibrous capsule) and a zone of decreased density in the center.

Brain and Spinal Cord Abscesses - Symptoms and Diagnosis

Treatment of brain and spinal cord abscesses

Treatment of brain abscesses can be conservative and surgical. The method of treatment depends primarily on the stage of development of the abscess, its size and localization.

At the stage of formation of the encephalitic focus (the duration of the anamnesis is up to 2 weeks), as well as in case of small (<3 cm in diameter) abscesses, conservative treatment is indicated. Empirical antibacterial therapy becomes the usual tactic. Some surgeons prefer to perform stereotactic biopsy for final verification of the diagnosis and isolation of the pathogen.

Forecast

The prognosis for brain abscesses depends on many factors. Of great importance is the ability to determine the pathogen and its sensitivity to antibacterial drugs, which allows for targeted pathogenetic therapy. An important role in the outcome of the disease is played by the reactivity of the body, the number of abscesses, the timeliness and adequacy of treatment measures.

Brain and Spinal Cord Abscesses - Treatment and Prognosis

Mortality from brain abscesses is about 10%, disability is about 50%. Almost a third of surviving patients develop epileptic syndrome.

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