High-Yield Medical Mycology: Top CAT Exam OmpathStudy

Most Repeated CAT Questions — Medical Virology & Mycology Based on analysis of all past papers --- MYCOLOGY — Most Repeated CAT Topics --- 1. Ergosterol as the component of fungal cell membrane Appeared in virtually every single paper. Always comes up as MCQ and sometimes short answer. Know that ergosterol is the fungal cell membrane component (not cholesterol like in humans, not peptidoglycan like in bacteria). --- 2. Paracoccidioidomycosis — the Latin American village question This exact clinical scenario appeared in at least 4 different papers. A physician visits a rural Latin American village, finds many mature males affected but few females and immature males. Answer is always Paracoccidioidomycosis . Know why — testosterone enhances fungal growth while oestrogen inhibits it. --- 3. Histoplasmosis — the Mississippi farmer / macrophages question Appeared in at least 5 papers. A farmer in Mississippi presents with chronic cough, chest radiograph shows opaque mass, biopsy shows macrophages with multiple yeast forms. Answer is always Histoplasmosis . Also paired with the Philadelphia pigeon/air conditioning scenario — same organism. --- 4. Chromoblastomycosis — the West African farmer question Appeared in at least 4 papers. A farmer in tropical West Africa develops persistent scaly papule on leg that progresses to cauliflower-like purplish lesions. Answer is always Chromoblastomycosis . Key fact — in tissue, organisms convert to sclerotic bodies (Medlar/copper-penny cells) that reproduce by fission and have transverse septations. --- 5. Phaeohyphomycosis — the brain lesion question Appeared in at least 4 papers. A 54-year-old man with progressive headache, brain scan shows cerebral lesion, surgery reveals darkly pigmented septate hyphae. Answer is always Cladophialophora (genus). Know the term phaeohyphomycosis means infection by darkly pigmented (melanised) fungi. --- 6. Drug of choice questions — repeated constantly Drug Condition --- --- Itraconazole Sporotrichosis (first line) Amphotericin B Severe systemic mycoses, cryptococcal meningitis Posaconazole Candida glabrata resistant to fluconazole Nystatin Superficial/mucocutaneous candidiasis Griseofulvin Dermatophytosis (older drug) Micafungin/Caspofungin Targets β-1,3-glucan (cell wall) --- 7. Actinomycotic mycetoma — most common cause Appeared in at least 3 papers. Question asks most common cause of actinomycotic mycetoma. Answer is always Nocardia spp. Know the distinction — actinomycetoma is bacterial, eumycetoma is fungal. --- 8. Dermatophyte identification questions Repeated across nearly every paper: Epidermophyton — does NOT have microconidia, does NOT infect hair Microsporum canis — zoophilic, causes acute inflammation, associated with pet cats Trichophyton rubrum — most common cause of tinea pedis and onychomycosis Trichosporon ovoides — causes scalp hair white piedra Tinea imbricate — NOT a superficial mycosis (it is a cutaneous one) — this exact exception appeared 3 times --- 9. Candidiasis epidemiology — repeated MCQ Appeared in at least 4 papers. The correct statement is always: "Patients with AIDS frequently develop mucocutaneous candidiasis such as thrush" The wrong statements that keep appearing as distractors: Pregnancy lowers risk of candidal vaginitis — FALSE , it increases it Patients with diabetes have enhanced resistance — FALSE Bone marrow transplant patients not at risk — FALSE --- 10. Fungal cell wall statement — repeated MCQ Appeared in at least 5 papers. The correct statement is: "Ligands associated with the cell walls of certain fungi mediate attachment to host cells" Wrong statements to watch out for: Cell wall is not essential for fungal viability — FALSE Major components are proteins like chitin, glucans, mannans — FALSE (they are polysaccharides not proteins) Cell wall components rarely stimulate immune response — FALSE --- --- VIROLOGY — Most Repeated CAT Topics --- 1. HSV transmission and pathogenesis The most repeated virology topic across all papers. Key facts tested repeatedly: HSV is readily inactivated by drying and soap and water Most seropositive HSV-2 individuals shed virus intermittently without symptoms A patient with HSV is always at risk for shedding the virus Primary HSV-2: lesions present, symptoms usually severe, HSV-1 and HSV-2 antibodies absent Herpesvirus family replicates in the nucleus (NOT cytoplasm — this is always the wrong statement) --- 2. HSV antiviral therapy Appeared in every single virology paper: Oral medications: Acyclovir, Valacyclovir, Famciclovir — all three together is the correct answer Acyclovir selective toxicity — depends on viral thymidine kinase phosphorylating it first --- 3. Retroviruses / HIV Repeated heavily: Viruses with two copies of positive strand RNA and reverse transcriptase = Retroviruses Positive strand RNA that does not act as mRNA but converts to DNA = Retroviruses HIV transmission growing fastest through = sexual transmission between homosexual or bisexual males (f