Brain abscess

Brain abscess

    * Introduction
    * Fizioptologie
    * Clinical
    * Diagnostic Laboratory
    * Treatment
Brain abscess is a collection of pus in a cavity contained neoformata, resulting mainly from consecutive tissue necrosis of an area of inflammation. Brain abscesses are considered expansive intracranial processes and are due to the action of bacteria, fungi or parasites. Half of cases are complications of otitis and sinusitis. Brain abscesses can be single or multiple and can be localized in the brain parenchyma at frontal, temporal, parietal, the posterior fossa or brain can be localized adjacent cranio-cerebral trauma. They most often accompany the headache, fever and focal neurological deficits. Conduct disorders occur frequently and depend on the topographic location of abscess. Today we witness a recrudescence of the disease incidence because of increasing microbial resistance to antibiotics. Treatment is combined medical and surgical, surgical excision of the abscess with appropriate antibiotic therapy and treatment is the basis antiedematos in neurosurgery. Early diagnosis by CT and MRI technology and an aggressive medical and surgical approaches are essential for successful treatment.
Brain abscesses are classified in terms of pathogenic in: - Adjacent brain abscesses, with the infectious process starting point is located at the cephalic extremity (sinusitis, otitis). Dissemination of etiologic agents is through continuity. - Metastatic brain abscesses, as a starting point with an infectious outbreak that was not the cephalic extremity. Infectious outbreak is usually located intrathoracic and seeding is done by marrow. - Traumatic brain abscess, with starting point at the initial cranial traumatic injury (wounds or fractures). And in this case, seeding is done by continuity. - Brain abscess imunotarati patients, occurring in patients undergoing chemotherapy or immunosuppressive drugs in patients with AIDS.
Topographic location of brain abscesses in order of frequency: brain abscess is most often localized in the frontal lobe and is in a relationship with chronic sinusitis often. The next most common location is in the temporal lobe. Then comes the fronto-parietal region, parietal region, occipital and cerebellar. Abscesses that develop in the brainstem, basal ganglia intraselar or are rare.
The etiology of brain abscesses
The most frequent etiologic agents are Staphylococcus aureus, streptococci and coliform bacteria. Brain abscesses are mostly mixed infections, caused by several etiologic agents. Most abscesses contain aerobic and one third of them are caused by anaerobic bacteria. Half of aerobic germs that cause brain abscesses are aerobic or microaerophilic streptococci represented. Streptococci the most common are those of the Streptococcus intermedius group: Streptococcus constellatus, Streptococcus anginosus and Streptococcus Miller. In the case of abscesses resulting from neurosurgical or cranio-cerebral trauma, the most frequently isolated etiologic agent is Staphylococcus aureus. Up to one third of brain abscesses are caused by Gram-negative aerobic bacteria as Escherichia coli, Proteus, Klebsiella, Enterobacter, or Pseudomonas aeruginosa. Pneumococii, and Haemophilus influenzae meningococii not produce brain abscesses than imunotarate persons and those infected with HIV. In a small percentage of patients the causative agent of brain abscess is the Haemophilus aerophilus. Abscesses caused by anaerobic bacteria are usually relationship with chronic pulmonary infection or a chronic ear infection. When culture isolates of anaerobic bacteria, they are usually strains of Bacteroides, anaerobic streptococci, Clostridium and Fusobacterium Prevotella.
Etiologic agent of cerebral abscesses may be suggested by their location and their predisposing cause. Thus, in case of frontal lobe abscess that caused by a chronic sinusitis, they are most likely caused by a Streptococcus intermedius tilpina. Brain abscesses are developed after sinus infections mixed aerobic and anaerobic germs. Located in the temporal lobe abscesses occur as a complication of chronic otitis media, and culture are common in Gram-negative aerobes, streptococci and strains of Bacteroides. Abscesses resulting from cranio-cerebral trauma and neurosurgical interventions are most likely etiologic agent as Staphylococcus aureus. In patients imunotarati, brain abscesses may be caused by fungal infections. Patients infected with HIV may develop abscesses following pneumococcal infections, meningococcus or Toxoplasma gondii. In patients with neutropenia, brain abscesses may be caused by Candida, Aspergillus, Gram-negative aerobic bacteria. Brain abscesses occurring after bone marrow transplantation are infections caused by Aspergillus in most cases, the infection is severe with poor prognosis. In patients with defective cell-mediated immunity, brain abscesses are frequently caused by Toxoplasma gondii, Nocardia asteroides, Cryptococus neoformans, Listeria monocytogenes.
Risk for congenital diseases with known risk of brain abscesses are: hereditary hemorrhagic telangiectasia (especially in patients with bone deformities and polycythemia) and cyanogen as tetralogy of Fallot heart disease.