Cerebral toxoplasmosis is an opportunistic infection commonly seen in HIV patients that causes subacute evolving symptoms over 1-2 weeks and may appear on imaging as ring enhancing lesions. Cerebral amebiasis can cause either a rapidly fatal necrotizing encephalitis from Naegleria or a chronic granulomatous meningoencephalitis from Acanthamoeba. Cerebral malaria is a rapidly progressive encephalitis and complication of Plasmodium falciparum infection that results in reduced cerebral blood flow and causes ataxia, seizures, and coma.

1. Prepared by Dr. Amer Shafie
1439

2. By the end of this session the student will be
able to know the main pathological features of
the most important Protozoal diseases which
may involve the CNS
1. Cerebral Toxoplasmosis
2. Cerebral Malaria
3. Cerebral Amebiasis

3.  is an opportunistic infection commonly found
in the setting of HIV-associated
immunosuppression.
 The clinical symptoms of infection of the
brain by Toxoplasma gondii are subacute,
evolving during a 1- or 2-week period, and
may be both focal and diffuse

4.  . Computed tomography and magnetic resonance
imaging studies may show multiple ring
enhancing lesions; however, this radiographic
appearance is not specific, as CNS lymphoma,
tuberculosis, and fungal infections produce
similar findings.
 In non- immunosuppressed hosts, the impact of
toxoplasmosis on the brain is most often seen
when primary maternal infection occurs early in
pregnancy. Such infections often spread to the
brain of the developing fetus and cause severe
damage in the form of multifocal necrotizing
lesions that may calcify.

5.  . A rapidly fatal necrotizing encephalitis results
from infection with Naegleria species, and a
chronic granulomatous meningoencephalitis has
been associated with infection with
Acanthamoeba.
 The amebae may be difficult to distinguish
morphologically from activated macrophages.
Methenamine silver or PAS stains are helpful in
visualizing the organ- isms, although definitive
identification ultimately depends on
immunofluorescence studies, culture, and
molecular methods.

6.  . A rapidly progressive encephalitis, cerebral
malaria is the complication of infection by
Plasmodium falciparum with the highest
mortality. Most likely the result of vascular
dysfunction, cerebral involvement by malaria
is accompanied by reduced cerebral blood
flow and results in ataxia, seizures, and coma
in the acute phase, with long-term cognitive
defi- cits in up to 20% of children after
cerebral malaria