Page 937 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

668 PART 5: Infectious Disorders

TABLE 72-2 Less Common Causes of Encephalitis, Diagnosis and Treatment Summary (Continued)
Etiology Epidemiology Clinical Features Diagnosis Treatment
Histoplasma Inhalation of spores May present as chronic meningitis Urine and CSF Histoplasma antigen Parenteral liposomal amphotericin B
capsulatum Throughout Americas (frequent), mass lesion, or cerebritis Special stains for yeast in sputum, followed by oral itraconazole
Africa CNS findings may be isolated or associ- blood, or CSF
ated with systemic findings such as
Endemic in Ohio and Mississippi pneumonia, hepatosplenomegaly
River valleys in the United
States
Also found in Africa, eastern Asia,
and Australia
Infection more common in
immunocompromised persons
Malaria: Vector—mosquito Fever, headache, altered sensorium, Thin and thick blood smears reveal Parenteral quinidine or artesunate
Plasmodium falci- Travel to endemic areas seizures, and focal neurologic deficits. characteristic erythrocytic phase of parasite Corticosteroids not recommended
parum Antigen detection—Binax card test Exchange transfusion with >10%
(FDA approved)—highly specific, may parasitemia or severe cerebral
miss low parasitemias malaria
West African Vector—tsetse fly Slowly progressive illness with CNS Giemsa staining for organism from Eflornithine or melarsoprol
trypanosomiasis: West and Central Africa involvement is late in the disease with chancre (if present), lymph node aspirate,
Trypanosoma brucei Humans are primary reservoirs asymptomatic period for months to years CSF, thin and thick smears of blood or
gambiense Progressive diffuse meningoencephalitis bone marrow specimens.
with headache, irritability, personality Serology—card agglutination test for
changes, psychosis, ataxia, and other trypanosomes (CATT) 96% sensitivity
extrapyramidal signs. Progressive dete- CSF IgM detection is sensitive
rioration resulting in coma and death
East African Vector—tsetse fly Rapid progression of disease with early Giemsa staining for organism from Melarsoprol
trypanosomiasis: East Africa CNS disease Acute febrile illness associ- chancre (if present), lymph node
Trypanosoma brucei Antelope and cattle are primary ated with sleep disturbances, severe aspirate, CSF, thin and thick smears of
rhodesiense reservoir headaches leading to coma and death blood or bone marrow specimens
within weeks to months CSF IgM detection is sensitive
Toxoplasmosis: Reactivation of infection in Focal or nonfocal neurologic signs and A positive serum IgG antibody suggests Pyrimethamine plus either sulfadia-
Toxoplasma gondii immunosuppressed patients symptoms. infection and may define those at risk zine or clindamycin
Intrauterine infection can result in More common presentations are for reactivation.
necrotizing encephalitis seizures, hemiparesis, and cranial nerve CSF PCR not very sensitive
abnormalities MRI/CT brain may show multiple
ring-enhancing lesions
Granulomatous Immunocompromised patients CNS infection is rare Serology (available in specialized Trimethoprim-sulfamethoxazole
amebic meningoen- especially with cell-mediated Subacute manifestation with fever, laboratories) plus rifampin plus ketoconazole
cephalitis: immunodeficiency and chronic altered mental status, seizures, and focal Brain biopsy and culture or
Acanthamoeba alcoholics deficits
species Almost always fatal Fluconazole plus sulfadiazine
plus pyrimethaminecan be considered
Primary amebic Acquired by swimming in lakes CNS infection is rare CSF shows neutrophilic pleocytosis with Intravenous
meningoencephalitis: and brackish water 2-5 days after exposure, change in taste low glucose concentration and intrathecal amphotericin B
Naegleria fowleri or smell followed by meningismus, Motile trophozoites may be seen in wet plus rifampin
nystagmus, and papilledema mount of warm CSF plus one or more of the following
Progression to coma and death can be considered:
azithromycin, sulfisoxazole,
miconazole
Balamuthia Immunocompromised patients CNS infection is rare PCR of brain tissue or CSF Pentamidine
mandrillaris especially with cell-mediated Fever, headache, vomiting, ataxia, Serologic testing available through CDC plus a macrolide
immunodeficiency and immuno- hemiparesis, cranial nerve palsies and California Encephalitis
competent hosts plus flucytosine plus fluconazole
Encephalopathy Project plus sulfadiazine plus a phenothiazine
Almost always fatal Histopathologic examination and may be considered
indirect immunofluorescence of brain
biopsy specimen
Most cases diagnosed postmortem (Continued)

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