Sappinia is classified as a member of the Thecamoebidae. It can be found in soil and tree bark. It is believed to be acquired by inhaling an aerosol.
Trophozoites measure 40-70 microns in diameter and often engulf RBCs.
Microscopically the amoeba has
(1) 2 closely apposed nuclei
(2) a large contractile vacuole
Patients may be immunocompetent or immunodeficient. CNS invasion may be preceded by sinusitis.
Features of Sappinia amebic encephalitis (SAE):
(1) impaired consciousness
(2) emesis
(3) headache
(4) photophobia
(5) blurred vision
(6) diplopia
(7) seizures
The typical lesion consists of a tumor-like cerebral mass without an abscess wall. There is central necrosis and hemorrhage with acute and chronic inflammation. Granulomas and eosinophils tend to be absent.
PCR can be helpful in establishing the diagnosis, especially in limited samples.
