Cryptococcosis

Cryptococcosis (torulosis) is the most prevalent cerebral mycosis. Cryptococcus neoformans, in yeast form, measures 5 to 12 microns. It is surrounded by a polysac-charide capsule that stains with Alcian blue and mucicarmine; it appears as a halo in sections stained with silver (Fig. 6.21).

The primary infection is commonly a granuloma-tous inflammation in the lungs. The fungi reach the brain by hematogenous dissemination and produce a granulomatous meningoencephalitis with thick, gelatinous exudate, minimal inflammatory reaction, and a few microgranulomas. These are composed of infiltrates of lymphocytes and plasma cells, epithelioid cells, fibro-blasts, and multinucleated giant cells. The yeasts invade the brain along the perivascular spaces, expanding and

TABLE 6.5

Major CNS Mycotic Infections

Fungus

Primary Site

Pathology

Cryptococcus neoformans

Lung

Meningoencephalitis Abscess, granuloma

Aspergillus fumigatus

Lung

Septic necrosis,

Paranasal sinuses

Granuloma, abscess

Mycotic aneurysm, arterial thrombosis

Candida species

Skin, Oral cavity

Meningitis

Gastrointestinal tract, Genitourinary tract

Microabcesses Microgranulomas

Coccidioides immitis

Skin Lung

Acute/chronic granulomatous meningitis

Histoplasma capsulatum

Lung

Meningitis, granulomas

Blastomyces dermatitidis

Epidural abscess

Mucoraceae species

Nasal and oral cavities, nasopharynx

Hemorrhagic necrosis Cavernous sinus thrombosis Carotid artery thrombosis

Alcian Blue Cryptococcus

FIGURE 6.21

Cryptococcus meningoencephalitis. The subarachnoid space is densely packed with cryptococcus yeasts (silver stain).

FIGURE 6.21

Cryptococcus meningoencephalitis. The subarachnoid space is densely packed with cryptococcus yeasts (silver stain).

gradually transforming them into multiloculated gelatinous cysts. Solitary abscesses are rare.

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The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

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