Chapter 25. ID IV: Opportunistic Infections

What constitutes an immunocompromised state?

• HIV CD4 count <200 cells/mm^3

• systemic steroids for 14 days or longer at a prednisone equivalent dose of ≥20 mg/day or ≥2mg/kg/day

• Asplenia

• use of immunosuppressants

• use of cancer chemotherapy / severe neutropenia (ANC <500 cells/mm^3)

• Also another population at risk of infx are Transplant recipients

What infections are transplant patients at risk of?

• [should get recommended vaccines before initiating immunosuppressives]

• Viral infections, especially CMV

  • Use CMV PPX with Letermovir (for kidney and bone marrow transplant) or Valganciclovir (for any solid ogan transplant recipient)

• PJP (Pneumocystis Jirovecii Pneumonia) - similar tx options for those with HIV

What infection is common in the immunocompromised but prophylaxis is usually not recommended?

Candida infections

Viral infection prophylaxis (especially CMV) TOC for transplant patients

kidney/bone marrow: letermovir

solid organ: valganciclovir

Criteria for starting Pneumocystis jirovecii pneumonia (PCP/PJP) primary prophylaxis

CD4 count < 100 cells/mm³

OR

CD4 count < 100-200 cells/mm³ if HIV RNA level detectable

Criteria for discontinuing PJP primary prophylaxis

• CD4 count ≥200 cells/mm³ for ≥ 3 months AND

• Remains on ART

Alternative Tx for PJP/PCP primary prophylaxis in sulfa allergy

• atovaquone

• dapsone

• pentamidine

Alternative tx for PCP primary prophylaxis in G6PD deficiency

• atovaquone

• pentamidine

What medicine is added to all pyrimethamine containing regimens and why?

Leucovorin (rescue therapy)

• Prevent its induction of myelosuppression

PJP Primary Prophylaxis Regimens

• Preferred: SMX/TMP DS daily (or SS)

• Alternatives: Dapsone + pyrimethamine + leucovorin OR

OR Atovaquone alone

OR Dapsone alone

Toxoplasma gondii encephalitis criteria for starting primary prophylaxis

Toxoplasma IgG positive and CD4 count <100 cells/mm^3

Toxoplasma gondii encephalitis preferred primary prophylaxis regimens

• Preferred: SMX/TMP DS daily

• Alternatives: Dapsone + leucovorin + pyrimethamine OR atovaquone alone

Criteria for starting mycobacterium avium complex (MAC) prophylaxis

Initiate if:

• NOT taking ART

• CD4 count <50 cells/mm³

• No active Mac Infection

• FYI: not recommended if ART is started immediately

Preferred MAC primary prophylaxis treatment regimen

Azithromycin 1,200mg weekly

Criteria for discontinuing MAC primary prophylaxis

Taking fully suppressive ART

Candidiasis treatment ("thrush"); appears as white film in mouth/throat

Preferred: Fluconazole

Alternative: Itraconazole

Secondary prophylaxis of candidiasis

Not recommended

Cryptococcal meningitis treatment

preferred: amphotericin B + flucytosine

alternative: Fluconazole

CMV treatment

Preferred: valganciclovir or ganciclovir

Alternative: foscarnet, cidofovir [if resistant to valganciclovir or ganciclovir]

MAC treatment

preferred: (clarithromycin or azithromycin) + ethambutol

PJP treatment

Preferred: SMX/TMP (high dose) x 21 days

Alternative: Pentamidine IV

Toxoplasmosis gondii encephalitis treatment

Preferred: Pyrimethamine + Leucovorin + Sulfadiazine

Risk factors for toxoplasmosis gondii infection

• Exposure via ingestion of undercooked/raw meat

• Contact with cat feces/litter

How should we treat thrush in a patient with HIV?

Systemic treatment preferred over localized, even if mild