Brain abscess – an encapsulated accumulation of pus in the substance of the brain; can occur by contact spread of infection (with purulent otitis media, osteomyelitis, mastoiditis, sinusitis), hematogenous metastasis from a distant source (lungs, oral cavity, skin, bones, rectum, heart) or as a result of direct infection (with traumatic brain injury or neurosurgical intervention). In babies, more than 60% of brain abscesses are associated with congenital heart defects, accompanied by shunting of blood from right to left.
The cause of a brain abscess can be injuries and damage to the skull, as a result of which an infection can develop. Also, numerous cases of brain abscess occur when staphylococci, streptococci and other microorganisms enter the brain tissue. Another reason for the development of an abscess is abscesses that appear with purulent otitis media, rhinitis, and chronic sinusitis. About half of all cases of brain abscess occur due to complications of otitis media. Less commonly, an abscess can be caused by asthma or pneumonia.
A brain abscess is characterized by a triad of symptoms, including headache, fever, and focal neurological symptoms (eg, hemiparesis, aphasia, or hemianopsia). However, the full triad is not found in all patients. So, an increase in body temperature is noted only in half of the cases, as a rule, before the formation of an abscess capsule. After the formation of the capsule (usually by the end of the 2nd week), general infectious manifestations decrease. Less than half of the patients have meningeal symptoms, epileptic seizures, depression of consciousness, congestive optic discs are found.
Diagnosis is primarily based on information about the presence of a purulent focus in the body, in the immediate vicinity of the brain structures. The localization of the abscess is determined by MRI and CT of the brain. The displacement of the median structures of the brain can be detected using echoencephaloscopy. Lumbar puncture for suspected brain abscess is contraindicated. To identify the source of infection, an x-ray of the skull and chest, echocardiography, ultrasound examination of the abdominal organs, and bacteriological examination of blood are performed.
All brain abscesses are subject only to surgical treatment with the integral prescription of broad-spectrum antibiotics. Usually, a combination of a 30% generation cephalosporin (ceftriaxone or cefotaxime) with an antibiotic that acts on staphylococci (for example, vancomycin or oxycillin) and an antibacterial agent that acts on anaerobic bacteria (metronidazole) is used. At an early stage of an abscess or with small (up to 3 cm), multiple or inaccessible abscesses for surgical intervention (for example, in the brain stem), antibiotic therapy may be the only treatment.