0071643192.pdf

SYMPTOMS/EXAM

■ Often begins with nonspecific acute febrile illness

■ Headache and fever (common)

■ Neurologic abnormalities

■ Altered mental state

■ New psychiatric symptoms

■ Emotional outbursts

■ Cognitive deficits

■ Focal neurologic deficits

■ Seizures

■ Movement disorders

■ Sensorimotor deficits are uncommon.

DIAGNOSIS

■ Suspect diagnosis based on presenting symptoms and exam

■ Lumbar puncture

■ To exclude bacterial meningitis and help identify viral organism via

PCR

■ Cautions and contraindications as with meningitis

■ MRI with contrast

■ Can readily identify areas of involvement (focal edema)

■ Lesions in the temporal lobes = HSV encephalitis.

■ CT with contrast is alternative but is less sensitive.

■ EEG

■ Suggestive EEG abnormalities may be seen.

■ Brain biopsy: Definitive

TREATMENT

■ Empiric treatment for suspected etiologic organisms

■ Acyclovir for HSV and herpes zoster virus

■ Gancyclovir for cytomegalovirus

■ Once herpes and cytomegalovirus infections have been excluded,

there is no benefit from antiviral agents.

Brain Abscess

Brain abscess is an infection that becomes localized to a particular region of

the brain: intraparenchymal, epidural, or subdural locations.

MECHANISMS

Infection reaches the brain via three mechanisms:

■ Contiguous infection of middle ear, sinus, or teeth

■ Neurosurgery or penetrating trauma

■ Hematogenous spread

Common organisms include:

■ Often polymicrobial

■ Streptococci

■ Anaerobic bacteria (esp. Bacteroides)

■ Staphylococcus aureus

■ Fungal and parasitic infections in the immunocompromised

NEUROLOGY

Herpes virus has a

predilection for the temporal

lobes. Patients often present

with “psychiatric symptoms”

or behavioral changes.