Brain abscess 3840 221940503 2008-06-26T19:58:49Z Colin 381149 [[WP:UNDO|Undid]] revision 219924734 by [[Special:Contributions/Tatterfly|Tatterfly]] ([[User talk:Tatterfly|talk]]) Link to epileptic [[seizure]] article. '''Brain abscess''' (or cerebral abscess) is an [[abscess]] caused by inflammation and collection of infected material coming from local (ear infection, [[dental abscess]], infection of [[paranasal sinus]]es, infection of the [[mastoid]] air cells of the temporal bone, [[epidural abscess]]) or remote ([[lung]], [[heart]], [[kidney]] etc.) infectious sources within the [[human brain|brain]] tissue. The infection may also be introduced through a skull fracture following a [[head trauma]] or surgical procedures. Brain abscess is usually associated with [[congenital heart disease]] in young children. It may occur at any age but is most frequent in the third decade of life. ==Features== The symptoms of brain abscess are caused by a combination of increased [[intracranial pressure]] due to a space-occupying lesion (headache, vomiting, confusion, [[coma]]), infection (fever, fatigue etc.) and focal neurologic brain tissue damage ([[hemiparesis]], [[aphasia]] etc.). The most frequent presenting symptoms are headache, drowsiness, [[mental confusion|confusion]], [[seizure]]s, [[hemiparesis]] or speech difficulties together with fever with a rapidly progressive course. The symptoms and findings depend largely on the specific location of the abscess in the brain. An abscess in the cerebellum, for instance, may cause additional complaints as a result of [[brain stem]] compression and [[hydrocephalus]]. [[Neurological examination]] may reveal a stiff neck in occasional cases (erroneously suggesting meningitis). The famous triad of fever, headache and focal neurologic findings are highly suggestive of brain abscess but are observed only in a minority of the patients. ==Pathophysiology== Brain abscesses are usually polymicrobial in nature. The most common organism recovered from cultures is the [[bacterium]] ''[[Streptococcus]]''. However, a wide variety of other bacteria (''[[Proteus (bacterium)|Proteus]]'', ''[[Pseudomonas]]'', ''[[Pneumococcus]]'', ''[[Meningococcus]]'', ''[[Haemophilus]]''), [[fungus|fungi]] and [[parasite]]s may also cause the disease. Fungi and parasites are especially associated with immunocompromised patients. Organisms that are most frequently-associated with brain abscess in patients with [[AIDS]] are [[Mycobacterium tuberculosis]], [[Toxoplasma gondii]] and [[Cryptococcus neoformans]], though in infection with the latter organism, symptoms of [[meningitis]] generally predominate. Bacterial abscesses rarely (if ever) arise ''de novo'' within the brain, although establishing a causes can be difficult in many cases. There is almost always a primary lesion elsewhere in the body that must be sought assiduously, because failure to treat the primary lesion will result in relapse. In cases of trauma, for example in compound skull fractures where fragments of bone are pushed into the substance of the brain, the cause of the abscess is obvious. Similarly, bullets and other foreign bodies may become sources of infection if left in place. The location of the primary lesion may be suggested by the location of the abscess: infections of the middle ear result in lesions in the [[middle cranial fossa|middle]] and [[posterior cranial fossa|posterior]] cranial fossae;<ref>{{cite book | author=Macewan W | year=1893 | title=Pyogenic Infective Diseases of the Brain and Spinal Cord | location=Glasgow | publisher=James Maclehose and Sons }}</ref> [[congenital heart disease]] with right-to-left shunts often result in abscesses in the distribution of the [[middle cerebral artery]]<ref>{{cite book | author=Ingraham FD, Matson DD | title=Neurosurgery of Infancy andChildhood | location=Springfield, Ill | publisher=Charles C Thomas | year=1954 | paes=377 }}</ref><ref>{{cite journal | author=Raimondi AJ, Matsumoto S, Miller RA | title=Brain abscess in children with congenital heart disease | journal=J Neurosurg | volume=23 | pages=588&ndash;95 | year=1965 }}</ref>; and infection of the [[frontal sinus|frontal]] and [[ethmoid sinus|ethmoid]] sinuses usually results in collection in the subdural sinuses. ==Diagnosis== The diagnosis is established by a [[computed tomography]] (CT) (with contrast) examination. At the initial phase of the inflammation (which is referred to as [[cerebrit]]is), the immature lesion does not have a capsule and it may be difficult to distinguish it from other space-occupying lesions or infarcts of the brain. Within 4-5 days the inflammation and the concomitant dead brain tissue are surrounded with a capsule, which gives the lesion the famous ring-enhancing appearance on CT examination with contrast (since intravenously applied contrast material can not pass through the capsule, it is collected around the lesion and looks as a ring surrounding the relatively dark lesion). [[Lumbar puncture]] procedure, which is performed in many infectious disorders of the central nervous system is contraindicated in this condition (as it is in all space-occupying lesions of the brain) because removing a certain portion of the [[Cerebral Spinal Fluid|cerebrospinal fluid]] may alter the concrete intracranial pressure balances and cause a part of the brain tissue to move out of the skull ([[brain herniation]]). Ring enhancement may also be observed in cerebral hemorrhages (bleeding) and some brain [[tumor]]s. However, in the presence of the rapidly progressive course with fever, focal neurologic findings (hemiparesis, aphasia etc) and signs of increased intracranial pressure, the most likely diagnosis should be the brain abscess. ==Treatment== The treatment includes lowering the increased intracranial pressure and starting intravenous [[antibiotic]]s (and meanwhile identifying the causative organism mainly by blood culture studies). Surgical drainage of the abscess remains part of the standard management of bacterial brain abscesses. The location and treatment of the primary lesion also crucial, as is the removal of any foreign material (bone, dirt, bullets, and so forth). There are a few exceptions to this rule: [[Haemophilus influenzae]] meningitis is often associated with subdural effusions that are mistaken for subdural empyemas. These effusions resolve with antibiotics and require no surgical treatment. [[Tuberculosis]] can produce brain abscesses that look identical to bacterial abscesses on CT imaging and surgical drainage or aspiration is often necessary to make the diagnosis, but once the diagnosis is made no further surgical intervention is necessary. ==Prognosis== Once an almost always fatal disease before the CT era. If the abscess is treated before the person goes into a coma then the death rate has been estimated from 5% to 20% although it is greater in cases of multiple abscesses, when raised intracranial pressure is observed and depending on the level of neurological dysfunction on presentation. Early treatment and the patients overall health has an effect on prognosis. Other factors include: antibiotic resistance or the abscess location. An abscess deep within the brain is more difficult to treat than others. ==References== <references/> [[Category:Neurological disorders]] [[de:Herdenzephalitis]] [[it:Ascesso cerebrale]] [[ja:脳膿瘍]] [[fi:Aivopaise]]