INTRODUCTION Granulomatous inflammation is a distinctive ...

growth (Geol et al., 1996; Nadkarni et al., 2003).
Prognosis
The prognosis for CNS aspergillosis is poor, with most reported cases being fatal. Fungal
abscesses in patients with cancer are usually fatal (Chernik et al., 1973). An aggressive surgical
approach in nonimmunocompromised patients helped to reduce the mortality form 64 to 39%
(Young et al., 1985). Intracerebral aspergillosis is frequently fatal in immunocompromised
patients, with only 12 reported cases of successful treatment (Camarata et al., 1992).
Cryptococcosis
The HIV pandemic has raised the profile of Cryptococcus neoformans from an obscure yeast to
the most important fungal cause of morbidity and death worldwide. Previously described as a rare
cause of meningitis in the tropics, or inpatients with some form of acquired immunodeficiency
such as haematological malignancy or organ transplantation, cryptococcal meningitis is now a
significant public health burden in developing countries. 20% of all AIDS deaths are due to
cryptococcal meningitis, making it the second most common cause of death in HIV infection after
TB (French et al. 2002).
Pathology
The organism The genus Cryptococcus contains at least 39 species of yeast, but few are able to
cause disease in humans (Casadevall and Perfect 1998). Most human infections are due to C.
neoformans, a dimorphic asexual yeast characterized by oval to spherical cells with a
polysaccharide capsule. It reproduces through budding, which is frequently seen in clinical
specimens. Yeast form is most commonly found in soil with high concentrations seen
predominately in bird droppings, particularly pigeons and chickens (Jeremy, 2004).
The portal of entry into the human body is through inhalation. Once within the pulmonary tree,
the organism forms a polysaccharide capsule, which is resistant to phagocytosis. The capsular
enlargement may be related to the high carbon dioxide tension present. From the lungs, the
cryptococci spread into the intrathoracic lymph nodes and may lie dormant, with reactivation of
infection occurring during lapses in the host's immune defenses. On entering the bloodstream,
dissemination occurs, predominately within the CNS. In one study, 90% of patients at autopsy had
CNS involvement, with the lungs involved in 50% of cases (Karoll and Thomas, 2004). Patients
with weakened cell-mediated immunity are at risk, including patients with AIDS,
reticuloendothelial malignancies, sarcoidosis, organ transplant, and collagen vascular disease and
patients receiving corticosteroid therapy (Perfect and Durack, 1997).
Epidemiology
Incidence Rates of cryptococcosis in non HIV infected individuals approach one case per 100000
population, yet during the AIDS epidemic before highly active antiretroviral therapy in the United
States, several cities were reporting rates of 17 to 66 per 1000 patients with AIDS. In Zimbabwe
45% of all meningitis is caused by Cryptococcus neoformans (Mwaba et al. 2001).
C. neoformans var A, D are distributed worldwide, while var B, C are present in the tropical and
subtropical areas (Jermey, 2004). CNS cryptococcosis is rare in children with AIDS, most cases
occur in the 20–50 years old age group (Lewis and Rabinovich, 1972). In contrast to other fungal
infections of the CNS, most cases (80%) occur in men. This statistic was evident before the AIDS
epidemic and has remained fairly constant and may be related to occupational exposure (Karoll
and Thomas, 2004).