elevated protein

Tuberculous or fungal

meningitis

Figure 35-1. Meningitis diag nostic algorithm. AMS, altered mental status; CSF, cerebrospinal flu id; IV,

intravenous, LP, lumbar puncture.

general guidelines may be helpful to broadly characterize

CSF findings in many cases, several studies have demon ­

strated that no single laboratory finding can accurately

categorize the cause of CSF pleocytosis in all patients

(Figure 35-1).

CSF studies for patients with encephalitis will lead to

similarly abnormal results, with increased numbers of white

blood cells in the CSF, generally with a lymphocytic predominance. Results may also reveal increased numbers of red blood

cells in the CSF owing to neuronal cell death leading to edema,

hemorrhage, and necrosis when encephalitis is present.

TREATMENT

For patients with suspected bacterial meningitis, empiric IV

antibiotic therapy and admission to the hospital is recommended (Table 35-2). Recommendations for pediatric

patients are based on patient age. For neonates less than

1 month, empiric IV therapy includes ampicillin and cefotaxirne (alternative is ampicillin and gentamicin). Children

1 to 3 months should be given ampicillin and cefotaxirne,

Table 35-2. Recommended empiric therapy for

adu lts with suspected bacterial meningitis.'''

Patient Age IV Empiric Therapy*

Adults <SO years Ceftriaxone or cefotaxime and vancomycin

Adults 2:50 years Ceftriaxone or cefotaxime and vancomycin

and ampicillin

Readers should consult local infectious disease special ists for

recommended empiric antibiotic therapy in your local region.

''Remember to add acyclovir in cases of possible HSV encephal itis.

CHAPTER 35

and for those older than 3 months, empiric therapy includes

ampicillin or ceftriaxone, and vancomycin. Patients with

severe disease may require intensive care unit level care

depending on the clinical circumstances.

The role of adjunctive dexamethasone for patients with

bacterial meningitis remains somewhat uncertain, as

recent work has questioned the value of this treatment that

had previously been strongly recommended to reduce

mortality and poor neurologic outcomes. For patients in

high-income countries, there may be benefit to treatment

with IV dexamethasone that is initiated before or at the

same time as antibiotic treatment.

In patients with suspected bacterial meningitis who

need a CT scan of the brain before LP, blood cultures

should be drawn and empiric antimicrobial therapy administered before CT to avoid additional delays to beginning

treatment.

The treatment for most cases of encephalitis is supportive care. HSV encephalitis is the only cause of this disease

with a specific treatment: N acyclovir.

DISPOSITION

.... Admission

Patients who are diagnosed with bacterial meningitis or

viral encephalitis should be admitted to the hospital for

monitoring, N antimicrobial agents, and other adjunctive

therapies. There may be clinical ambiguity regarding disposition for patients who are clinically well appearing but have

mildly elevated white blood cell levels in the CSF suggestive

of aseptic meningitis. One option for such patients may

include hospital admission for observation with or without

empiric antibiotic therapy, pending CSF culture results.

..... Discharge

In some circumstances, patients with suspected viral meningitis may be appropriate for outpatient management

with close follow-up and strict return precautions. When

considering discharge home for outpatient management of

presumed viral meningitis, it is important to assess the

patient's support system, reliability, availability of close

follow-up, and mechanisms for contacting the patient if

CSF culture results are unexpectedly positive.

SUGGESTED READING

Fitch MT, Abrahamian FM, Moran GJ, Talan DA. Emergency

department management of meningitis and encephalitis.

Infect Dis Clin North Am. 2008;22:33-52, v-vi.

Fitch MT, van de Beek D. Emergency diagnosis and treatment of

adult meningitis. Lancet Infect Dis. 2007;7:19 1-200.

Loring KE, Tintinalli JE. Central nervous system and spinal

infections.