WBR0559

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Infectious Disease
Prompt	[[Prompt::A 44 year old man with history of multiple unprotected sexual encounters was found to have a positive HIV ELISA during a local screening campaign. He was referred to an HIV clinic where he was advised to monitor his CD4 counts once every month. A trend of his CD4 counts for past 10 months are shown below. At which of the following CD4 values would you advise the patient to receive azithromycin prophylaxis? ]]
Answer A	AnswerA::A
Answer A Explanation	[[AnswerAExp::Usually a CD4>500 cells/mL is considered normal does not present with AIDS associated illness.]]
Answer B	AnswerB::B
Answer B Explanation	[[AnswerBExp::A CD4<300 cells/mL is associated with oral thrush and Kaposi's sarcoma but not disseminated MAC.]]
Answer C	AnswerC::C
Answer C Explanation	[[AnswerCExp::A CD4<200 cells/mL is associated most importantly with Pneumocystis jirovecii pneumonia and requires Bactrim (TMP/SMX) prophylaxis not azithromycin.]]
Answer D	AnswerD::D
Answer D Explanation	[[AnswerDExp::A CD4<100 cells/mL is associated most importantly with cerebral toxoplasmosis as well as Pneumocystis jirovecii pneumonia both covered by Bactrim (TMP/SMX) prophylaxis.]]
Answer E	AnswerE::E
Answer E Explanation	[[AnswerEExp::Disseminated MAC is usually seen in patient with a CD4<50. Prophylaxis is recommended once counts drop below that threshold. Azithromycin once weekly (1200mg) is the preferred agent.]]
Right Answer	RightAnswer::E
Explanation	[[Explanation::Azithromycin is used in patients with HIV who progressed to AIDS with a CD4 count lower than 50 cells/mL for the prophylaxis for disseminated mycobacterium avium complex (MAC) infections. Organisms of the Mycobacterium avium complex (MAC) are Mycobacterium avium and intracellulare. They are ubiquitous in the environment and have many modes of transmission thus justifying the need for prophylaxis. However, it is important to note that MAC are not communicable. The table below summarizes the AIDS associated illnesses and the corresponding CD4 counts at which they are observed. Educational Objective: Disseminated MAC is usually seen in AIDS patients with a CD4<50 cell/mL. Azithromycin prophylaxis once weekly is recommended. References: Jung AC, Paauw DS. Diagnosing HIV-related disease: using the CD4 count as a guide. J Gen Intern Med. 1998;13(2):131-6.]]
Approved	Approved::No
Keyword	WBRKeyword::CD4 count, WBRKeyword::AIDS, WBRKeyword::Disseminated MAC
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::