Brain abscesses are rare. The abscesses can occur from contiguous structures like sinuses or from distant sources. Thus, the brain abscesses can broadly be divided into two categories: contiguous abscesses and hematogenous abscesses (i.e. distant sources). The cases of contiguous foci-based abscesses are more common than that of from the distant sources.
The contiguous abscesses include abscess that originate within nose, throat and ear. These abscesses affect the cortical area. Infection spreads directly or indirectly. If infection source is known, organisms causing the abscess can generally be predicted. For instance, frontal abscess due to sinusitis usually occurs because of streptococcus milleri. A wide range of antibiotics is administered up to six months for treating the abscess. Complete removal of the affected body part is also necessary.
A brain abscess affecting the fontal lobe (cortical area) is generally secondary to the frontal sinuses’ symptoms(sinusitis). About 15% of brain abscesses are due to sinusitis. However, in developed nations, incidences of sinusitis related brain abscess have declined. Since the frontal lobe is generally neurologically silent, there may not be any signs indicating the abscess. Frontoethmoidal disorder is the main cause of the sinugenic brain abscesses, i.e. sinuses’ symptoms-induced abscess.
A brain abscess may grow slowly or rapidly. If the abscess forms gradually, minimal constitutional signs appear. Especially in case of frontal abscesses, only subtle changes in the behavior or mood are seen. However, if surrounding part of the brain has notable edema, intracranial pressure may increase. And if the abscess breaks within the ventricular system, patient dies quickly. The abscess may also grow rapidly and the edema may lead to herniation of the uncus.
A sinuses symptoms-induced brain abscess usually occurs in boys and men who are in their 20s and 30s. The infection may spread directly or indirectly. In case of direct source, the infection may spread via meninges, intervening bone and tissues. The indirect source of the infection is diploic veins’ retrograde thrombophlebitis. The brain abscess location depends on predisposing causes. For instance, sinusitis related abscesses occur in the brain’s cortical area.
Common brain abscess symptoms
Patients having brain abscess may have the following symptoms:
Lack of attention (inattention)
Generalized hemicranial headache
Minor changes in behavior or mood
Changes in mental status and reduced mental function
Seizures may occur before abscess’ surgical draining.
Increase in the intracranial pressure may cause vomiting and nausea.