Pyogenic Brain Abscess

Review of literature

Pyogenic brain abscess:

Introduction: A brain abscess is defined as a focal sup¬purative infection of the brain parenchyma comprising of immune cells, pus and other materials of the brain. It may be bacterial or pyogenic, fungal or parasitic. Pyogenic brain abscess are the most frequently encountered in the clinical practice (1). It is one of the most serious and potentially a life threatening condition. In the developing countries, incidence of brain abscess is approximately 8% of the intracranial masses where as it comprises 1-2% in the western countries (2). Though now it is relatively uncommon, it still remains a fatal disease (3, 4) and is still a significant health care problem in the developing countries which

It is higher in developing countries (14). Male population seems to be predominantly affected than the female population independent of the geography which is reported consistently in the literature till date (2, 5, 8,11,13,15,16 17). and the etiology is still unclear. The male to female ratio varied from 1.5:1 to 4.5:1 in the literature (10,13,16,18,19). The patients ranged from infancy to elderly ages. Majority of the cases occurred in the second and fourth decades of life. Recent study series demonstrated mean age ranging from 24 to 57 years (9,16,18,19). This relationship has not been formally investigated though. It may reflect the greater proportion of older immunosuppressed individuals, greater life expectancy and lower rates of traumatic brain injury in younger individuals (13). Study carried out by (2) observed occurance of brain abscess mostly in the first two decades of life, when intra-cranial complications of paranasal sinuses and odontogenic infections were more evident. Roche et al. (20) found the incidence of brain abscess in children to be lower than they had expected from earlier reports. The incidence in patients > brain abscess overview. In some patients, there is no recognized source of infection and are identified as ‘‘cryptic’’ brain abscess and this accounts for 4.6 % -43.4% (13). In the last two decades, studies show changing trend in the epidemiology showing a decrease

(table) >>>> BRAIN ABSCESS OVERVIEW. Studies show most common location is supratentorial of which ,the most common is frontal but may occur in any location (10, 11, 13, 15, 19) parietal, temporal, cerebellum (26), temporo-pareital, occipital, fronto-parietal, parieto-occipital, brain stem thalamus, basal ganglia, and multiple sites. Blood-borne infection can occur anywhere in the brain, but has a predilection for the territory of the middle cerebral arteries, particularly the fronto-parietal region (32). Abscesses are frequently sub-cortical or periventricular. A thorough search for a predisposing factor should be made. A cardiac cause is frequently overlooked (occult endocarditis and septal defects). In a recent case report, the authors described the rare case of a patient with an echocardiographically proven patent foramen ovale who developed a brain abscess (8) and brain abscess in an adult with atrial septal defect (ASD) (28). Perhaps such intracardiac lesions (with occult bacteremia from an abdominal source) account for some of the cryptic cases identified in previous reports, although larger studies would be needed to identify the frequency and clinical relevance of such