Infectious Diseases IV

Question 1

What do opportunistic infections occur?

Answer 1

Immunocompromised patients are predisposed to opportunistic infections, which occur when the immune system is weak and unable to respond normally to invading bacteria, fungi, viruses and protozoa

Question 2

What do immunocompromised states include?

Answer 2

• Diseases that destroy key components of the immune response, primarily HIV with a CD4 T lymphocyte count < 200 cells/mm3 (which is a defining criteria for AIDS)
• Use of systemic steroids for 14 days or longer at a prednisone dose (or prednisone equivalent dose (> 20 mg/day) or > 2 mg/kg/day
• Asplenia (lack of a functioning spleen), as with sickle cell disease or following a splenectomy
• Use of immunosuppressants for autoimmune conditions or transplant
• Use of cancer chemotherapy agents that destroy white blood cells, particularly with severe neutropenia (ANC < 500 cells/mm3

Question 3

What are some common opportunistic infections requiring primary prophylaxis?

Answer 3

Pneumocystis jirovecci pneumonia (PJP or PCP), Toxoplasmosis gondii encephalitis, Mycobacterium avium complex (MAC)

Question 4

What is an opportunistic infection that does not required prophylaxis?

Answer 4

Candida infections in the mouth/esophagus (e.g. thrush) are a higher risk in immunocompromised states, but prophylaxis is not usually recommended

Question 5

How can opportunistic infections be prevented?

Answer 5

OIs can be prevented with antibodies, antifungals and/or antivirals which is referred to as chemoprophylaxis or simply prophylaxis

Question 6

What is the selection of alternatives based on?

Answer 6

Selection of primary or alternative regimens (for prophylaxis or treatment) depends on patient-specific factors

Question 7

What are some examples of alternative regimens and why they are used?

Answer 7

• Atovaquone, dapsone and pentamidine are options for PCP in the setting of a sulfa allergy
• Atovaquone and pentamidine are options in the setting of a G6PD deficiency
• Leucovorin is added to all pyrimethamine-containing regimens as rescue therapy to reduce the risk of pyrimethamine-induced myelosuppression

Question 8

What is the criteria for starting prophylaxis treatment of Pneumocystis jiroveccii?

Answer 8

CD4 count < 200 cells/mm or AIDS-defining illness

Question 9

What is the preferred prophylaxis regimen for pneumocystis jiroveccii?

Answer 9

SMX/TMP or SS daily

Question 10

What is an alternative prophylaxis regimen for pneumocystis jiroveccii?

Answer 10

SMX/TMP DS 3x/week or Dapsone or Dapsone + pyrimethamine + leucovorin or Atovaquone or inhaled pentamidine

Question 11

What is the criteria for discontinuing prophylaxis regimen for pneumocystis jiroveccii?

Answer 11

• CD4 count > 200 cells/mm3 for > 3 months on ART

- Can consider when CD4 count is 100-200 cells/mm3 and viral load has been undetectable for > 3-6 months

Question 12

What is the criteria for starting a prophylaxis regimen for Toxoplasma gondii encephalitis?

Answer 12

Toxoplasma IgG positive and CD4 count < 100 cells/mm3

Question 13

What is the preferred primary prophylaxis regimen for Toxopasma gondii encephalitis?

Answer 13

SMX/TMP DS tab PO daily

Question 14

What is an alternative primary prophylaxis regimen for Toxopasma gondii encephalitis?

Answer 14

SMX/TMP DS tab PO daily, SMX/TMP 3x/week or 1 SS PO daily or Dapsone + pyrimethamine + leucovorin or Atovaquone or Atovaquone + pyrimethamine + leucovorin

Question 15

What is the criteria for discontinuing primary prophylaxis regimen for Toxopasma gondii encephalitis?

Answer 15

• CD4 count > 200 cells/mm3 for > 3 months on ART

- Can consider when CD4 count is 100-200 cells/mm3 and viral load has been undetectable for > 3-6 months

Question 16

What is the criteria for starting prophylaxis regimen for Mycobacterium avium complex?

Answer 16

• Not recommended if ART is started immediately
• Initiate if not taking ART and CD4 count < 50 cells/mm3
• Must rule out active disseminated MAC disease

Question 17

What is the preferred primary prophylaxis regimen for Mycobacterium avium complex?

Answer 17

Azithromycin 1,200 mg PO weekly

Question 18

What is the alternative primary prophylaxis regimen for Mycobacterium avium complex?

Answer 18

Azithromycin 600 mg PO twice weekly or Clarithromycin 500 mg PO BID

Question 19

What is the criteria for discontinuing prophylaxis regimen for Mycobacterium avium complex?

Answer 19

Taking fully suppressive ART

Question 20

When is secondary prophylaxis for opportunistic infections given?

Answer 20

After completing initial treatment, secondary prophylaxis is given to prevent recurrence of the infection in patients who continue to be at risk

Question 21

What is the recommendation for treating thrush in patients with HIV?

Answer 21

Even with mild disease, systemic treatment is preferred (rather than localized treatment with agents such as clotrimazole, miconazole or nystatin)

Question 22

What is the preferred regimen for the treatment of Candidiasis (thrush)?

Answer 22

Fluconazole

Question 23

What is an alternative regimen for the treatment of Candidiasis?

Answer 23

• Itraconazole, posaconazole

- Esophageal: voriconazole, isavuconazonium or an echinocandin (e.g. caspofungin)

Question 24

What is the secondary prophylaxis regimen for Candidiasis?

Answer 24

Not usually recommended

Question 25

What is the preferred regimen for the treatment of Cryptococcal meningitis?

Answer 25

Amphotericin B (deoxycholate or liposomal) + flucytosine

Question 26

What is the alternative regimen for the treatment of Cryptococcal meningitis?

Answer 26

Fluconazole +/- flucytosine

Question 27

What is the secondary prophylaxis for the treatment of Cryptococcal meningitis?

Answer 27

Fluconazole (low dose)

Question 28

What is the preferred regimen for the treatment of Cytomegalovirus?

Answer 28

Valganciclovir or Ganciclovir

Question 29

What is the alternative regimen for the treatment of Cryptococcal meningitis?

Answer 29

If toxicities to ganciclovir or resistant strains: foscarnet, cidofovir

Question 30

What is the secondary prophylaxis regimen for the treatment of Cryptococcal meningitis?

Answer 30

None; maintain CD4 count > 100 cells/mm3

Question 31

What is the preferred regimen for the treatment of Mycobacterium avium complex?

Answer 31

(Clarithromycin or azithromycin) + ethambutamol

Question 32

What is the alternative regimen for the treatment of Mycobacterium avium complex?

Answer 32

Add a 3rd or 4th agent using rifabutin, amikacin or streptomycin, moxifloxacin or levofloxacin

Question 33

What is the secondary prophylaxis regimen for the treatment of Mycobacterium avium complex?

Answer 33

Same as treatment regimen

Question 34

What is the preferred regimen for the treatment of Pneumocystis jiroveccii pneumonia?

Answer 34

SMX/TMP (high-dose) +/- prednisone or methylprednisolone

*Duration: 21 days

Question 35

What is the alternative regimen for the treatment of Pneumocystis jiroveccii pneumonia?

Answer 35

Atovaquone or Pentamidine IV or Clindamycin + primaquine or Dapsone + trimethoprim

Question 36

What is the secondary prophylaxis regimen for the treatment of Pneumocystis jiroveccii pneumonia?

Answer 36

Same as primary prophylaxis

Question 37

What is the preferred regimen for the treatment of Toxoplasmosis gondii encephalitis?

Answer 37

Pyrrimethamine + leucovorin + sulfadiazine

Question 38

What is the alternative regimen for the treatment of Toxoplasmosis gondii encephalitis?

Answer 38

SMX/TMP or Clindamycin + pyrimethamine + leucovorin or Atovaquone or Atovaquone + sulfadiazine or Atovaquone + pyrimethamine + leucovorin

Question 39

What is the secondary prophylaxis regimen for the treatment of Toxoplasmosis gondii encephalitis?

Answer 39

Same as treatment (but with reduced doses)