L34: AIDS and headache Flashcards
AIDS and headache
- Brain abscess due to toxoplasma gondii
- Cryptococcus neoformans (fungi) a cause of meningitis in immunocompromised patients
- Usually appears later than candida
AIDS and dsyphagia
- Oral candidiasis with colonies on soft and hard palates
- Candida albicans (fungi) will grow on blood agar plates
- Oral candidiasis can appear relatively early, oesophageal slightly later
Fungal infections
Can be common, minor skin and mucosal infections OR rare, serious, deep tissue infections
Yeasts = round or oval, single cell, reproduce by budding
- Candida albicans and other candida
- Cryptococcus neoformans
Moulds = tubular hyphae, multi-cell, reproduce by budding spores
- Dermatophytes (skin)
- Aspergillus species
- Zygomycetes
Candida albicans
- Commensal of mouth, gut or vagina
- Overgrowth related to antibacterial therapy, immune suppression, hormonal effects, foreign bodies
Causes:
- Oral (hard and soft palate) or vaginal thrush
- Cutaneous or nail candidiasis
- Urinary catheter-related bladder infection
- Rare systemic infection (usually IV cannula)
Diagnosis of candida albicans
- Swab from area of infection
- Seen as black yeasts with pseudo-hyphae on gram stain
- Grows well on blood agar (produces colonies)
Treatment of candida albicans
Infection usually on mucosal surface: treatment usually topical, sometimes oral
- Nystatin suspension or pastilles
- Amphotericin B pastilles
- Azole pessaries (vaginal tablets) or cream
Cryptococcus neoformans
- Rare yeast
- Pigeon faeces, eucalyptus trees
- Environmental contamination common
C. neoformans disease
Pulmonary infection:
- Inhalation of aerolised fungus
- Controlled in people with normal immune system
- Usually asymptomatic
Spread via blood to CSF: only in people with severe immunodeficiency
Meningitis in immunodeficient people (e.g. AIDS, high dose prolonged corticosteroid treatment)
Chronic lymphocytic meningitis: slow deterioration in mental state with headache and fever
Diagnosis of cryptococcal meningitis
- Lumbar puncture: WBCs in CSF (lymphocytes predominate), protein raised, glucose low
- India ink stain: encapsulated yeasts seen
- Agar: C. neoformans grown (e.g. brown colonies on bird seed agar)
- ELISA: antigen positive in CSF and serum (quantitative colour change)
Treatment of cryptococcal meningitis
Need antifungal drug to enter CSF (long duration)
- IV amphotericin B
- IV or oral fluconazole
- 6wks total therapy
Dermatophytes
Cause "ringworm" - Tinea capatis (head) - Tinea corporis (body) - Tinea cruris (groin) - Tinea pedis (feet) Never invasive Human or animal hosts Easily recognised and treatment with antifungal cream Diagnosis: microscopy or culture
Treatment of dermatophytes
For skin: topical azole e.g. clotrimazole, econazole, ketoconazole, miconazole
For nails: oral agent e.g. terbinafine, itraconazole
Two other common skin fungal infections
Pityriasis (tinea) versicolor:
- Caused by Malassezia furfur
- Hypopigmented macules on trunk (raindrops)
- Treatment with 2wks topical or oral azole
Seborrheic dermatitis:
- Caused by pityrosporum species
- Red, greasy, itchy, facial rash in nasolabial folds, above eyebrows, behind ears
- Dandruff
- Treatment with topical azole
Aspergillus fumigatus
- Rare cause of severe disease in neutropenic patients
- Spore bearing branching mould, widespread in rotting vegetation
- Enters lungs and can cause necrotising pneumonia
- Can also cause allergic bronchopulmonary aspergillosis
- Diagnosis: microscopy or culture
- Treatment: amphotericin B IV for weeks, liposomal amphotericin B, voriconazole (other azoles), surgery
Amphotericin B
- Binds to ergosterol -> disrupts cytoplasmic membrane
- IV 0.5-1 g/kg
- Infusion related anaphylactic reactions
- Nephrotoxicity with K+ loss
- Lipid formulations less toxic
