primary amebic meningoencephalitis

primary amebic meningoencephalitis,

a rare and often fatal acute, febrile, purulent meningoencephalitis caused by usually free-living soil and water amebas of the genera Naegleria and Acanthamoeba. Infection caused by Naegleria is generally seen in young persons who swim or bathe in contaminated freshwater, the pathogens gaining access to the central nervous system by penetrating the nasal mucosa and cribriform plate and then following the olfactory bulbs and nerves to the brain and meninges. By contrast, Acanthamoeba infections tend to be more benign, are more often seen in older or immunocompromised persons, and are sometimes associated with spontaneous recovery; the mode of transmission of these infections is not known, but hematogenous spread from amebic infection at distant sites has been reported.

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primary amebic meningoencephalitis

An intracranial infection by free-living amoebae–eg, Naegleria fowleri, N grubei, Acanthamoeba, Hartmannella, Entamoeba histolytica, etc Clinical Acute, purulent meningoencephalitis–typically by Naegleria spp–in young healthy persons swimming in stagnant, artificial fresh water lakes; inflammation and hemorrhage is most intense along the olfactory tract, inculpating the cribriform plate as the portal of entry via the nose Prognosis Poor; the few Pts who survive are treated with parenteral amphotericin B, miconazole, rifampicin, and have major sequelae; PAM may also be subacute with a granulomatous reaction, a finding more common in immunocompromised hosts