Opportunisitic Infections

Opportunistic infections

 = affect patients with compromised immune systems

• HIV(+) with low CD4 count

• Chemotherapy 

• Organ transplant 

• Stem cell transplant 

CD4 Count in HIV… 

• < 200 cells risk of 

  • PJP and oral candidasis 

• < 100 cells risk of 

  • toxoplasmosis, cryptococcal meningitis 

• < 50 cells risk of 

  • Disseminated mycobacteria avium complex

IRIS

- Immune Reconstitution Inflammatory Syndrome…

→ syndrome caused by immune system improvement in ART patients 

• Therefore must wait before starting ART

IRIS Pathogens…

1. Mycobacterium avium 

2. Cryptococcus spp. Infections

3. Cytomegalovirus

Oral Candidasis 

Common in patients with CD4 < 200 cells/mm3

• Primary pathogen = Candida albicans

  • Oropharyngeal candidiasis (confined to oropharynx)

  • Esophageal candidasis

Oropharyngeal Oral Candidiasis Treatment 

→ 7-14 days of fluconazole PO (lower than systemic dose) 

• Not for use in pregnancy 

Alternatives: 

• Clotrimazole troches x 5 days 

• Nystatin solution (topical) x 4 days

• Posaconazole

• Itraconazole

Esophageal Oral Candidiasis Treatment 

→ 14- 21 days days, must use systemic agents 

• Fluconazole PO/IV 

Alternatives:

• Voriconazole 

• Isavuconazole

• Echincocandins

• Amphotericin B

Pneumocystis Pneumonia

(PJP/PCP)

→ human pathogen Pneumocystis jirovecii (human pathogen)

• Ubiquitous fungus

• airborne spread

PJP Primary Prophylaxis…

Should be started in HIV(+) patients with CD4 < 200 cells/mm3

• Should be CONTINUED until CD4 > 200 cells for at least 3 months

Restart primary prophylaxis if patients with CD4 < 100 or CD4 < 200 AND have detectable HIV RNA

• PROPHYLAXIS TX:  Trimethoprim-sulfamethoxazole (TMP-SMX)

  • Alts: 

    • Atovaquone liquid daily 

    • Dapsone 

    • Pentamidine Inhlalation (once monthly)

PJP Severity Grading…drives treatment choice

drives treatment choice

Mild 

• Alveolar arterial gradient < 35 mmHG

• PaO2 > 70 mmHG

Moderate

• Aa-DO2 = 35 - 44 mmHG

• PaO2 < 70 mmHG

Severe

• Aa-DO2 > 45 mmHG

• PaO2 < 70 mmHG

PCP Treatment: 

PCP Treatment: 

MILD

→ preferred: Trimethroprim-sulfamethoxazole (TMP/SMX) x 21 days

Alts: primaquin PO + clindamycin PO x 21 days OR atovaquone PO x 21 days

MODERATE to SEVERE 

→ preferred: TMP/SMX x 21 days

Alts: primaquin + clindamycin IV x 21 days OR pentamidine IV x 21 days

G6PD Deficiency…

Use of dapsone and primaquine can result in hemolysis and methemoglobiemia 

→ patients started on these should be tested if possible

Corticosteroids and PCP treatment?

→ patients who have moderate/severe disease may exhibit paradoxical worsening within 3-5 days of starting therapy

• Increased inflammatory response due to organism lysis 

• Corticosteroids should be started within 3 days of treatment to avoid this

  • Prednisone or methylprednisolone 

Toxoplasmosis Primary Prophylaxis…

1. Should be STARTED in those HIV+ with CD4 < 100 cells AND are toxoplasma IgG positive 

   1. Primary prophylaxis should be continued until CD4 > 200 cells for at least 3 months…

Restart primary prophylaxis in patients with CD4 < 100

PROPHYLAXIS TREATMENT: TMP-SMX PO daily 

Alts: dapsone + pyrimethamine + leucovorin OR atovaquone daily

T. gondii Encephalitis Treatment

→ preferred therapy: 

• Pyrimehtamine + sulfadizaine + leucovorin 

• TMP-SMX

Treated for 6 weeks

T. gondii Chronic Maintenance (Secondary Prophylaxis)...

Preferred

• Pyrimethamine + sulfadiazine + leucovorin

• TMP-SMX daily  

Secondary prophylaxis should be continued until CD4 > 200 for at least 6 months

• Restarted at CD4 < 200 cells