Internal Medicine

0521779407-B01 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 20:52

248 Brain Abscess

BRAIN ABSCESS

MICHAEL J. AMINOFF, MD, DSc

history & physical

■Primary infection often present either adjacent to cranial infection

(eg, ears, teeth, nasal sinuses) or at distant site (eg, lungs); may relate

to cyanotic congenital heart disease

■Symptoms of expanding intracranial mass–eg, headache, somno-

lence, lethargy, obtundation, focal deficits, seizures

■Fever may be absent (40% of cases)

■Signs depend on location of abscess & on ICP

■Common signs include fever, confusion, somnolence, obtundation,

papilledema, extraocular palsies, neck stiffness, weakness, visual dis-

turbances, dysphasia, dysarthria

■May be signs of primary infection or of congenital heart disease

tests

■Blood studies: leukocytosis (absent in 25% cases)

■Cranial CT or MRI: one or more rim-enhancing lesions, w/ perile-

sional edema; shift of midline structures

■CSF is at increased pressure; may show pleocytosis, increased protein

concentration; cultures usually negative

■Blood cultures & culture of specimens from likely sites of primary

infection to identify causal organism

differential diagnosis

■Other expanding focal lesions usually excluded by imaging appear-

ance, but metastatic disease may be simulated

■If abscess suspected clinically, perform imaging studies first; do not

perform LP as herniation & clinical deterioration may result

management

■Control cerebral edema w/ steroids (eg, dexamethasone); mannitol

is also effective in short term

■Control infection w/ antibiotics

■Needle aspiration to identify organism if poor response to antibiotics

■Consider surgical drainage (excision or aspiration) if significant mass

effect; periventricular location; poor response to antibiotics

specific therapy

■Antibiotics