Opportunistic Infections Flashcards
Which infections can be prevented by cotrimoxazole
- Pneumocystis pneumonia
- bacterial pneumonia
- bacteraemia
- toxoplasmosis
- isosporiasis
- malaria
Preventative TB therapy in adults
Isoniazid preventative therapy effect in patients on ART (6 months)
- if not on ART, positive Mantoux predicts benefit
- NB, exclude active TB first
TB preventative therapy in children
For children with TB contacts
- all children under 5
- HIV-infected children of all ages
Alternative prophylaxis for pneumocystis jirovecii
- Dapsone
Indications for cotrimoxazole prophylaxis
- WHO stage 3/4
- CD4 <200
Duration of cotrimoxazole prophylaxis inadults
- lifelong, unless CD4 count rises to >200 on ART
Usual organisms causing bcaterial pneumonia
- strep pneumoniae
- h. influenzae
- staph aureus
- klebsiella
- atypicals
Principles of treating serious bacterial infections in HIV/ AIDS
- prompt appropriate empirical antimicrobial
- use a broader spectrum agent
- duration of therpay not well studied
- opportunistic organisms can present like bacterial infection
Management of pneumocystis pneumonia
- high dose cotrimoxazole for 21 days
- adjunctive corticosteroids improve outcome
Adverse effects of cotrimoxazole
- hypersensitivity reactions
- BM suppression
Screening protocol for cryptococcal infection
- screen HIV-infected adults with CD4 <100 (CrAg)
-
MOA of cotrimoxazole
- sequential inhibition of enzymes of the folic acid pathway
Treament of cryptococcal meningitis
- treate with IV ampho B (1mg/kg/day)and fluconazole (800mg/day) for 2 weeks
- then fluconazole 400mg/day for 8 weeks
- the fluconazole 200mg/day for 12 months
AE of amphotericin B
- infusion related fever and rigors (pretreat with paracetamol)
- anaemia and weight loss
- dose-related nephrotoxin (loss of K and Mg) - minimized if well hydrated
Pharmacokinetics of fluconazole
- excellent oral bio-availability
- long half-life
- penetrates well into CSF
- 80% excreted unchanged in uringe
- weak CYP450 inhibitor
Important factors to consider in cryptococcal meningitis
- most patients have raised ICP
- blindness is not uncommon
- defer ART until 4-6 weeks
Treatment of candidiasis
- topical therapy when in oral cavity/ vagina
- fluconazole for refractory cases/ oesophageal involvement
MOA of acyclovir
- purine nucleoside analogue
- inhibitor of Herpes DNA polymerase
Pharmacokinetics of acyclovir
- poor oral bioavailability
- short plasma half life
- excreted unchanged by kidneys
- well tolerated
Important factors in clinical use of acyclovir
- need to be commensed early if immunocomp (<72 hrs for shingles, <24 hrs for recurrent HSV)
Syndromic management for genital ulcers
- Add acyclovir to benzathine penicillin if HIV status positive or unknown
- if no response, add azithromycin
When does shingles usually occur in HIV?
moderate immune suppression (CD4 350)
How does shingles in HIV positive compare to uninfected
- longer duration
- often >1 dermatome
- pain more severe
- higher risk of post-herpetic neuralgia
When does CMV infection occur in HIV positive patients?
CD4 <100
Treatment of CMV
- IV ganciclovir
- maintenance therapy for eye/CNS
Toxicity causes of gancyclovir
BM suppression
