Paper II — 2024 March (Supplementary) (2010 Scheme) — Q2

Paper II

2024 March (Supplementary) (2010 Scheme) · 40 marks · 120 min

Question

Candidiasis

Q25 marksShort Essays★✓

Answer

Candidiasis is caused most commonly by Candida albicans, part of normal human commensal flora, becoming pathogenic when local or systemic host defences are compromised.

Predisposing factors: broad-spectrum antibiotic use, immunosuppression (HIV/AIDS, corticosteroids), diabetes mellitus, indwelling catheters/devices, pregnancy.

Morphology: dimorphic (yeast and pseudohyphal/hyphal forms), oval, budding yeast.

Clinical spectrum:

• Mucocutaneous — oral thrush, vulvovaginal candidiasis, cutaneous intertrigo.
• Oesophageal candidiasis — an AIDS-defining opportunistic infection at low CD4 counts.
• Invasive/systemic candidiasis — candidaemia and disseminated disease in critically ill/immunocompromised or catheterized patients.

Laboratory diagnosis: direct microscopy (KOH/Gram stain) showing budding yeast with/without pseudohyphae; culture on Sabouraud dextrose agar; germ tube test (rapid identification of C. albicans, germ tube formation in serum at 37°C); chlamydospore formation on cornmeal agar; CHROMagar for rapid speciation; blood culture for invasive disease.

Treatment: topical/oral azoles for mucocutaneous disease; echinocandins or amphotericin B for invasive disease, given rising azole resistance in some non-albicans species (C. glabrata, C. krusei, C. auris).

Related Concepts

1. 1Systemic Candidiasis and Systemic Mycoses

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