Fungal infections Flashcards
How are fungi classified?
=> Yeasts:
- Unicellular
- Reproduce by budding
=> Moulds:
- Filamentous fungi
- Grow as filaments (hyphae) which may intertwine to form a mass (mycelium)
=> Dimorphic:
- Grow as moulds in the environment and yeasts in the body
‘Mould in the cold, yeast in the beast’
What are the common fungal pathogens?
=> Yeasts:
- Candida
- Cryptococci
- Pneumocystis
- Malasezzia
=> Moulds:
- Aspergillus
- Dermatophytes
=> Dimorphic:
- Histoplasma
- Coccidioides
What are the different types of fungal infection?
=> Superficial
- Mucus membranes
=> Subcutaneous
- Inocculation into deeper skin tissue
=> Systemic
- Haematogenous spread into any organ
What is the cause of most skin, nail and hair fungal infections?
- Dermatophyte fungi
- Most common species: Trichophyton, Microsproum, Epidermaphyton
- Dermatophytes digest keratin
- Infect dead skin, no living tissue invaded
- Infections with dermatophytes are called ‘tinea’ + the site of infection
What is the name given to nail infections caused by Dermatophytes?
Tinea Unguium often referred to as onychomycosis
What is Pityriasis Versicolor?
- Fungal infection caused by Malassezia
=> Features:
- Well demarcated scaly plaques
- Hypopigmented
- Hyperpigmented
- Erythmatous
How do you diagnose skin and nail infections?
- Microscopy and culture of skin scrapings and toe nail clippings
How do you treat skin and nail fungal ifnections?
=> Self care measures:
- Feet - keep dry and replace footwar
- Avoid scratching
=> Medications:
- TOPICAL Terbinafine, Clotrimazole, Miconazole
- ORAL for severe skin and nail infections. Weekly flucanazole for Pityriasis Versicolor
What Candida species is most prevalent in causing thrush?
Candida Albicans
What are the risk factors of Oral and Candidias?
- Recent antibiotics
- Diabetes
- Malignancy
- HIV
- Steroid use
What is the treatment of Oral and Oesophageal Candidiasis?
=> Oral Candida:
- Treat with Nystatin suspension, oral fluconazole is eevere or in immunocompromised patient
=> Oesophageal Candida:
- PO Fluconazole
What are the risk factors of Vulvovaginal Candida?
- Recent antibiotics
- Pregnancy
- OCP
- Diabetes
- HIV
- Immunosuppressive drugs
What are the treatments for Vulvovaginal Candida?
- Intravaginal antifungal cream or PO Fluconazole
What is Invasive Candidiasis?
Defined as isolation of Candida species from a normally sterile site
What are the investigations in suspected cases of Invasive Candida?
- Blood cultures
- Fungal biomarkers
=> False +ve results for fungal biomarkers can occur with:
- Haemodialysis
- IV immunoglobulin
- IV co-amoxiclav
- Surgical gauze packing
