LECTURE SLIDES 18 - Fungal Infections of Humans.pdf

FUNGAL INFECTIONS OF HUMANS CHRISTINE JOYCE M. JAVIER, RMT, MLS(ASCPI)CM 2024 Jul 11 – 13 MICRO PARA LEC CONTENTS Introduction How Do Fungi Cause Disease? Classification of Fungal Diseases Fungal Infections of the Skin Fungal Infections...

FUNGAL INFECTIONS OF HUMANS CHRISTINE JOYCE M. JAVIER, RMT, MLS(ASCPI)CM 2024 Jul 11 – 13 MICRO PARA LEC CONTENTS Introduction How Do Fungi Cause Disease? Classification of Fungal Diseases Fungal Infections of the Skin Fungal Infections of the Respiratory System Fungal Infections of the Oral Region Fungal Infections of the Genitourinary System Fungal Infections of the Circulatory System Fungal Infections of the Central Nervous System Recap of Major Fungal Infections of Humans Appropriate Therapy for Fungal Infections How do Fungi Cause Disease? The tissue damage associated with fungal infections results primarily from direct invasion of tissue, with subsequent displacement and destruction of vital structures, coupled with toxic effects of the inflammatory response. Masses of fungal cells can cause obstruction of bronchi in the lungs and tubules and ureters in kidneys, leading to obstruction of the flow of bodily fluids. Some fungi can grow in the walls of arteries and veins, leading to occlusion and tissue necrosis resulting from a lack of oxygen. Fungal Infections of the Skin Fungal infections (mycoses) can be classified into the following four categories: Superficial mycoses—fungal infections of the outermost areas of the body (outer surfaces of hair shafts, the epidermis) Cutaneous, hair, and nail mycoses (tinea or “ringworm” infections) Subcutaneous mycoses Systemic mycoses—the most serious types of fungal infections Subcutaneous Mycoses Fungal Infections of the Skin Types of Tinea Infections Dermatophytosis (Tinea [“Ringworm”] Infections, Dermatomycosis) Caused by various species of filamentous fungi: -Microsporum -Epidermophyton -Trichophyton spp. A. Tinea pedis These fungi are collectively B. Tinea corporis referred to as dermatophytes. C. Tinea capitis Note that ringworm infections D. Tinea cruris have nothing to do with worms. E. Tinea unguium Chromoblastomycosis of the Foot Fungal Infections of the Lower Respiratory Tract Coccidioidomycosis (Valley Fever) Coccidioides immitis, a dimorphic fungus; transmission occurs via inhalation of arthrospores Cryptococcosis Two subspecies of Cryptococcus neoformans, an encapsulated yeast; transmission occurs via inhalation of yeasts Histoplasmosis Histoplasma capsulatum var. capsulatum, a dimorphic fungus; transmission occurs via inhalation of conidia from soil Fungal Infections of the Lower Respiratory Tract (cont.) Pneumocystis Pneumonia (PCP; Interstitial Plasma-Cell Pneumonia) Caused by Pneumocystis jiroveci, which has both protozoal and fungal properties Was once classified as a protozoan, but is now classified as a fungus Mode of transmission is unknown; perhaps direct contact, transfer of pulmonary secretions from infected to susceptible persons, or perhaps airborne Tissue Invasion by an Aspergillus Species, the Cause of Aspergillosis Fungal Infections of the Oral Cavity Oral Candidiasis (Thrush) Thrush A yeast infection of the oral cavity Common in infants, elderly patients, and immunosuppressed individuals White, creamy patches occur on the tongue, mucous membranes, and the corners of the mouth Caused by Candida albicans and related species Yeast Vaginitis Most cases are caused by the yeast, Various Forms of Candida Yeasts Candida albicans Seen in Clinical Specimens and Cultures Can be diagnosed by microscopic examination of a saline wet mount of vaginal discharge material, in which numerous yeasts and hyphae may be observed The mere presence of yeast is not proof of yeast vaginitis, as the vaginal flora of up to 25% of healthy women can contain Candida spp. Cryptococcal Meningitis Can be caused by three subspecies of Gram-Stained Appearance of Cryptococcus neoformans, an Cryptococcus encapsulated yeast Cryptococcosis starts as a lung infection, but spreads via the bloodstream to the brain Cryptococcal meningitis can be presumptively diagnosed by observing encapsulated, budding yeasts in CSF specimens examined by an India ink preparation Recap of Some Major Fungal Infections of Humans Fungal Infections of the Skin Types of Tinea Infections Dermatophytosis (Tinea [“Ringworm”] Infections, Dermatomycosis) Caused by various species of filamentous fungi: 1. 2. -Microsporum 3. -Epidermophyton -Trichophyton spp. These fungi are collectively 4. referred to as dermatophytes. Note that ringworm infections have nothing to do with worms. 5.