HIV PBL Flashcards
What organisms are responsible for pulmonary infections in HIV+ patients who have normal CD4+ counts? [2]
bacterial pneumonia and sinusitis
What organisms are responsible for pulmonary infections in HIV+ patients who have CD4+ counts <200? [1]
Pneumocystitis pneumonia caused by Pneumocystitis jirovecii
How does Pneumocystitis pneumonia caused by Pneumocystitis jiroveciiI present in CXR?
Ground glass opacities representative of interstitial infiltrates
What organisms are responsible for pulmonary infections in HIV+ patients who have CD4+ counts <50? [2]
Mycobacterium avium-intracellulare (MAI) and Mycobacteriumavium complex (MAC) will cause infections resulting in patients presenting with nonspecific systemic symptoms (fever, night sweats, weight loss) or focal lymphadenitis
Rifampin/Rifabutin MOA
Inhibits DNA dependent RNA polymerase
Rifampin/Rifabutin SE [2]
- Minor hepatotoxicity and drug interactions due to increased p450 activity,
- orange body fluids.
Is rifampin or rifabutin preferred in HIV patients, why?
Rifabutin is preferred in HIV patients due to decreased cytochrome p450 stimulation
(RifAMPin rAMPs up cytochrome p450 activity, BUT rifaBUTin does not)
Isoniazid MOA
Inhibits mycolic acid synthesis
requires bacterial catalase-peroxidase to convert INH to active metabolite (encoded by KatG)
Only agent used for solo prophylaxis against TB
Ethambutal MOA
Blocks arabinosyltransferase –> decreased carbohydrate (arabinoglycan) polymerization of mycobacterium cell wall
What does RIPE stand for?
Rifampin, Isoniazid, Pyrazinamide, Ethambutal
Why would you add a low dose of ritonavir to an HIV regimen?
Ritonavir inhibits CYP3A4 and so reduces metabolism of the other protease inhibitors and increases their effect. Can’t use at high doses because it is not tolerated.
Maraviroc MOA
binds specifically and selectively to the host protein CCR5 which is a necessary chemokine receptor for entry of HIV into CD4+ T cells
