0071643192.pdf

■ Brudzinki sign: Neck flexion results in flexion at hips (neck sign) or

passive flexion of hip on one side results in contralateral hip flexion

(contralateral sign).

■ Look for concomitant infection, such as sinusitis, otitis, pneumonia.

DIFFERENTIAL

The differential diagnosis includes encephalitis, brain abscess, subdural, sub-

arachnoid hemorrhage, intracranial hemorrhage, brain tumor.

DIAGNOSIS

■ Meningitis should be considered in all patients presenting with a

headache or stiff neck and fever.

■ Head CT

■ Required before LP in patients >60 years old, the immunocompro-

mised (eg, HIV), history of CNS disease (including stroke, mass lesions

or recent head trauma), recent seizures within 1 week, the presence of

marked CNS depression, papilledema or focal neurologic deficits.

■ Lumbar puncture (LP)

■ Contraindications

■ Coagulopathy (relative)

■ Infection at skin puncture site (absolute)

■ CSF findings classically vary with viral, bacterial, and fungal etiologies

(see Table 15.6).

■ but—early bacterial infections or partially treated infection may

have a paucity of findings!

■ and—early viral infections may have significant neutrophils!

■ Blood cultures may help isolate causative organism.

NEUROLOGY

Kernig’s = Knee

TABLE 15.6. Analysis of Cerebrospinal Fluid

NORMALLEVELS BACTERIAL VIRAL FUNGAL

Opening pressure 5—20 Elevated Normal or slightly elevated Elevated

(cmH 2 O)

Leukocytes/mm^3 ≤ 5 ≥500, although may be 100—500, although may 10—500

mildly elevated early be mildly elevated early

% Neutrophils 0 (≤1 PMN) >80% <50% <50%

Protein (mg/dL) 20—45 >200 <200 >200

Glucose (mg/dL) 50—80% or ≤40% or <50% of Usually normal <50

60—70% of serum

serum level

Cultures or studies Gram stain, culture, HSV or enterovirus PCR Cryptococcal antigen,

PCR, bacterial yeast

antigen assays