Page 936 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 72: Encephalomyelitis 667

TABLE 72-2 Less Common Causes of Encephalitis, Diagnosis and Treatment Summary
Etiology Epidemiology Clinical Features Diagnosis Treatment
Lyme disease: Vector—tick CNS involvement in about 15% of untreated CSF—lymphocytic pleocytosis, elevated Ceftriaxone or cefotaxime or penicil-
Borrelia burgdorferi North America patients during early disseminated illness protein, normal glucose concentration lin G
(weeks to months after infection)
Europe, and Asia Serology—blood and CSF ELISA with
Encephalitis is rare confirmatory Western blot
In the United States, highest
incidence in the North Eastern More common are unilateral or bilateral CSF PCR low sensitivity
states as well as Minnesota and cranial nerve palsies (especially facial
Wisconsin in the Upper Midwest nerve), motor or sensory radiculopathy
Late Lyme (months to years after infection)
may develop chronic axonal polyneuropathy
Rocky Mountain Vector—tick Incubation 2-14 days Thrombocytopenia, elevated serum Doxycycline
spotted fever: North and Central America and Fever, headache, myalgia, maculopapular, transaminases If doxycycline is contraindicated,
Rickettsia rickettsii South America—Brazil, Bolivia, petechial rash appearing 3-5 days after CSF—WBC <100 with neutrophil or chloramphenicol is an option
Argentina onset of symptoms. Rash begins typically lymphocytic predominance, elevated
In the United States highest inci- on wrists and ankles and spreads and may protein and normal glucose concentration
dence extends from involve the palms and soles. Serologic testing—indirect fluorescent
N Carolina to Oklahoma Complications include meningitis or antibody assay 95% sensitive
meningoencephalitis with altered mental PCR and direct immunofluorescence of
status and seizures skin biopsy specimen at site of rash
Human Vector—tick Fever, headache, myalgias Leukopenia, mild anemia, Doxycycline
granulocytotrophic Incidence: June-December Rash <10% thrombocytopenia, elevated hepatic
ehrlichiosis (HGE): transaminases
Mid-Atlantic and Northern United Encephalitis is a rare complication,
Anaplasma States and Europe brachial plexopathy and demyelinating Morulae within PMNs in blood smear
phagocytophilum polyneuropathy may be seen may be seen in 20%-80% of cases
Serology—IFA
PCR of whole blood. Serology, PCR of
CSF specimens (low yield)
Human monocyto- Vector—tick Fever, headache, myalgia. Leukopenia, thrombocytopenia, Doxycycline
trophic ehrlichiosis Incidence: May through August Rash in <50%. elevated hepatic transaminases
(HME): CSF—pleocytosis with lymphocytic
US—South central, South eastern, Confusion, stupor, hallucinations, sei-
Ehrlichia chaffeensis Mid-Atlantic, coastal states zures and coma predominance and elevated protein
concentration
Morulae in mononuclear cells of blood
and CSF smears (low sensitivity)
Serology—IFA
PCR of whole blood specimens
PCR of CSF specimens (low yield)
Q fever: Contact with cats, sheep especially Meningoencephalitis rare- <1% Serology—IFA Doxycycline plus a fluoroquinolone
Coxiella burnetii placental tissues Seizures and coma PCR to detect C burnetii DNA in clinical plus rifampin
Occasionally transmitted through samples may be helpful
tick bite, inhalation of infectious
aerosols, and consumption of
unpasteurized milk products
Cryptococcus Inhalation of spores from bird Chronic meningitis is the most common Blood and CSF fungal culture Amphotericin B deoxycholate plus
neoformans droppings presentation Serum and CSF cryptococcal antigen flucytosine followed by fluconazole
Commonly seen in immunocom- Acute presentation as meningoencephalitis CSF Indian ink is the preferred regimen
promised persons, especially AIDS may also be seen Repeated lumbar puncture to reduce
Occasionally in immune increased intracranial pressure
competent persons May need to consider lumbar drain
or VP shunt
Coccidioides species Southwestern United States, Immunosuppression increases the risk of Serum and CSF complement fixing or Fluconazole is preferred.
Mexico, and South America disseminated disease with CNS involve- immunodiffusion antibodies Other options are itraconazole,
Disseminated disease in extremes ment and more common in men CSF culture voriconazole, amphotericin B
of age, pregnancy, and The risk of CNS involvement is very low, (intravenous and intrathecal)
immunosuppression <0.1% of all exposures
Subacute or chronic meningitis is the
usual presentation (Continued)

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