Opportunistic Infections

Question 1

Which infections can be prevented by cotrimoxazole

Answer 1

• Pneumocystis pneumonia
• bacterial pneumonia
• bacteraemia
• toxoplasmosis
• isosporiasis
• malaria

Question 2

Preventative TB therapy in adults

Answer 2

Isoniazid preventative therapy effect in patients on ART (6 months)

• if not on ART, positive Mantoux predicts benefit
• NB, exclude active TB first

Question 3

TB preventative therapy in children

Answer 3

For children with TB contacts

• all children under 5
• HIV-infected children of all ages

Question 4

Alternative prophylaxis for pneumocystis jirovecii

Answer 4

• Dapsone

Question 5

Indications for cotrimoxazole prophylaxis

Answer 5

• WHO stage 3/4

- CD4 <200

Question 6

Duration of cotrimoxazole prophylaxis inadults

Answer 6

• lifelong, unless CD4 count rises to >200 on ART

Question 7

Usual organisms causing bcaterial pneumonia

Answer 7

• strep pneumoniae
• h. influenzae
• staph aureus
• klebsiella
• atypicals

Question 8

Principles of treating serious bacterial infections in HIV/ AIDS

Answer 8

• prompt appropriate empirical antimicrobial
• use a broader spectrum agent
• duration of therpay not well studied
• opportunistic organisms can present like bacterial infection

Question 9

Management of pneumocystis pneumonia

Answer 9

• high dose cotrimoxazole for 21 days

- adjunctive corticosteroids improve outcome

Question 10

Adverse effects of cotrimoxazole

Answer 10

• hypersensitivity reactions

- BM suppression

Question 11

Screening protocol for cryptococcal infection

Answer 11

• screen HIV-infected adults with CD4 <100 (CrAg)

-

Question 12

MOA of cotrimoxazole

Answer 12

• sequential inhibition of enzymes of the folic acid pathway

Question 13

Treament of cryptococcal meningitis

Answer 13

• 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

Question 14

AE of amphotericin B

Answer 14

• infusion related fever and rigors (pretreat with paracetamol)
• anaemia and weight loss
• dose-related nephrotoxin (loss of K and Mg) - minimized if well hydrated

Question 15

Pharmacokinetics of fluconazole

Answer 15

• excellent oral bio-availability
• long half-life
• penetrates well into CSF
• 80% excreted unchanged in uringe
• weak CYP450 inhibitor

Question 16

Important factors to consider in cryptococcal meningitis

Answer 16

• most patients have raised ICP
• blindness is not uncommon
• defer ART until 4-6 weeks

Question 17

Treatment of candidiasis

Answer 17

• topical therapy when in oral cavity/ vagina

- fluconazole for refractory cases/ oesophageal involvement

Question 18

MOA of acyclovir

Answer 18

• purine nucleoside analogue

- inhibitor of Herpes DNA polymerase

Question 19

Pharmacokinetics of acyclovir

Answer 19

• poor oral bioavailability
• short plasma half life
• excreted unchanged by kidneys
• well tolerated

Question 20

Important factors in clinical use of acyclovir

Answer 20

• need to be commensed early if immunocomp (<72 hrs for shingles, <24 hrs for recurrent HSV)

Question 21

Syndromic management for genital ulcers

Answer 21

• Add acyclovir to benzathine penicillin if HIV status positive or unknown
• if no response, add azithromycin

Question 22

When does shingles usually occur in HIV?

Answer 22

moderate immune suppression (CD4 350)

Question 23

How does shingles in HIV positive compare to uninfected

Answer 23

• longer duration
• often >1 dermatome
• pain more severe
• higher risk of post-herpetic neuralgia

Question 24

When does CMV infection occur in HIV positive patients?

Answer 24

CD4 <100

Question 25

Treatment of CMV

Answer 25

• IV ganciclovir

- maintenance therapy for eye/CNS

Question 26

Toxicity causes of gancyclovir

Answer 26

BM suppression