INTRODUCTION Granulomatous inflammation is a distinctive ...

Aspergillosis is another form of fungal infection that can spread to the CNS either
hematogenously from the lung or by direct invasion from the nasal sinuses. Unlike cryptococcosis,
it is specially prevalent in cases of organ transplantations clinical features vary from diffuse
presentation of meningitis and increased ICT to focal lesions. It characteristically invade cerebral
vessels and adjacent brain parenchyma, causing thrombosis and secondary haemorrhagic
infarcts. It generally has poor prognosis which varies according to patient immunity, in cases of
markedly suppressed immunity it is fatal within few weeks, otherwise it may develop to
granulomas, abscesses evident as ring enhancing lesions in radiological studies (enhancement =
immunity). Definitive diagnosis require brain biopsy. Treatment should be stared as early as
possible, and it includes surgical debridement with adequate safety margin (to avoid postoperative
cerebrovascular complications) and administration of amphotericin B and flucytosine, in addition
to correcting the general condition (immune reconstitution). Recently voriconazole has shown
promising results when combined with surgery (Sepkowitz et al., 1997).
Rhinocerebral Mucormycosis is a life-threatening fungal infection that occurs in
immunocompromised patients, mainly diabetics. These infections are becoming increasingly
common, yet survival remains very poor, as many cases are diagnosed late and treatment
strategies based on available antifungal and surgical debridement with control of risk factors are
not effective (Brad et al., 2005).
Invasive candidal CNS infection is more common in premature infants and neonates, and present
usually by meningitis with insidious vague clinical picture (lethargy, confusion), and it is also
treated with amphotericin B and flucytosine (Burgert et al., 1995).
There has been an increased awareness of the parasitic CNS infection in the last few decades.
Cysticercosis, on of the common parasitic infections, was frequently under diagnosed due to the
lack of adequate diagnostic tools, and even after the advent of modern neuroimaging techniques, it
was frequently misdiagnosed as TB. Viable CNS cysticerci don’t induce an immune reaction and
are frequently asymptomatic, while the immune system is stimulated by the dying organism,
leading to the development of the clinical manifestations of the illness (fits, hydrocephalus). This
has provoked an unsettled debate about the necessity of use of parasiticidal drugs in
asymptomatic patients. Solid diagnosis is difficult except by tissue biopsy, MRI showing cysts with
scolices, or subretinal scolices on fundoscopy. Recently EITB has proved to be 100 % specific
(Carpio et al., 1998).
Toxoplasmosis is another form of parasitic CNS infection. It commonly presents with afebrile
focal cerebral lesions, commonly ganglionic, cerebellar and brain stem. When manifest in an HIV
Patient, it presents with encephalitis, fever and disseminated multi organ affection. Diagnosis is
difficult, serology and PCR are not sensitive. Radiological studies show multiple brain enhancing
lesions which when combined with positive serology empirical treatment (pyrimethamine +
leucoverin) should be started and if there is no response in 2 weeks, a tissue biopsy should be
obtained (Luis, 2006).
In hydatid disease, 5% of cases have CNS affection, in the form of space occupying lesions
presenting clinically as increased ICT, fits of focal cerebral lesions. Imaging studies show a cystic
brain lesion with no enhancement. Diagnosis rests on the evidence of systemic affection, and
ELISA is done in doubtful cases. Treatment is surgical excision under albendazole cover (Eckert
et al., 2001).
Bilharziasis affect the CNS in 1% of cases, through granulomatous inflammation around ova
deposited in brain and spinal cord. It present by myelopathy, meningoencephalitis, optic neuritis
and rarely space occupying lesion. It is diagnosed by demonstrating ova in urine, stool or rectal
biopsy, also ELISA is 99% specific. Brain imaging reveals central linear enhancement surrounded