A 30-year-old male with a history of IVDU and HIV presents to the ED complaining of cough, dyspnea, and chills for the past week. He is unsure when he last took ART. CXR reveals focal infiltrates consistent with pneumonia. What is the #1 cause of pneumonia in patients with HIV similar to this man?

A. Pneumocystis Jiroveci

B. Strep Pneumoniae

C. Staph Aureus

D. Mycoplasma Pneumoniae

B. Strep Pneumoniae. Despite this patient’s HIV status, he remains most likely to have pneumonia secondary to strep pneumoniae similar to the general population, so don’t be fooled on the boards by this one! A CD4 count <200 increases the risk of PCP (pneumocystis jirovecii pneumonia) for which TMP-SMX is first line treatment. Steroids are added for PaO2 <70 or an A-a gradient >35mmHg. See below for a common presentation of PCP on CXR - however keep in mind that CXR can be normal for up to 25% of PCP infections.

https://www.grepmed.com/images/1261/infectiousdisease-opportunistic-prop...

See this prior EM Daily post about PCP: https://emdaily.cooperhealth.org/content/board-review-pneumocystis-pneum...