What is the drug of choice for his pneumonia?
Patient was noted to have a postitive HSV 2 swab from buttock lesion. Patient also noted to have lymphopenia which should prompt HIV screening. In this patient, the HIV Ab returned positive with an HIV-1 VL of 790k and CD4 of 10 (5%)
Learning point #1: Clues Pointing towards PJP
Pneumocystis Pneumonia (PJP) is the most common respiratory OI in HIV with CD4<200 when not on prophylaxis.
In this case, findings suggestive of PJP include
- CT w/ widespread heterogeneous pulmonary ground glass opacities & several pulmonary cysts
- Elevated LDH (>200, high sensitivity, low specificity)
- B-D Glucan >500
Check out this article which discusses the pros and cons of B-D glucan use:
Learning Point #2: Role of PJP DFA testing
Induced sputum PJP DFA yield is 50-90% in HIV patients. So while it can be helpful if positive, you can’t always rely on this to rule out disease.
However, if you check PJP DFA from a BAL sample, the yield increases to >90% in PWH
Both yields are lower in patients without HIV. Here is an article that helps explain this in more detail.
Learning point #3: Imaging for PJP
Typically: bilateral interstitial infiltrates. Can also see cysts, nodules, pneumothorax
However, LAD or pleural effusion are not typically seen with PJP
CT chest is much more sensitive, so a negative CT chest likely rules this diagnosis out
Learning point #4: PJP Treatment (Preferred and Alternatives)
For PWH: combination treatment with Antibiotic (see below)+ ART (if possible) +/- steroids (based on severity)
Drug of choice is still TMP/SXZ (15-20mg/kg/d of TMP in 3-4 doses) PO or IV x 21d.
Alternatives: (Clindamycin + primaquine) or (Dapsone + TMP) [for mild-mod] or atovaquone [mild] or IV pentamidine-severe
Learning point #5: When do we use steroids?
Indications for steroids:
-PaO2 <70 on RA or
-A-a O2 gradient >= 35
Learning point #6: Don’t forget secondary PPx!!
Don’t forget to start PPx after treatment as this is a common cause for relapse!
Primary PPx indicated for CD4 <200 or CD4% <14%
Secondary PPx post PJP infection recommended till CD4 >200 for 3m or more
(Agent of choice TMP-SMX; alt: dapsone, atovaquone, inhaled pentamidine)
Learning point #7: When can we stop PPx?
Guidelines mention that individuals who are consistently virally suppressed > 6 months can consider stopping PJP ppx if CD4 > 100 but fails to rise above 200. This is based on this study:
Other Learning Points (Distractors)
Azithromycin would be an appropriate choice for atypical pneumonia pathogens including Legionella species
Ceftriaxone + (azithromycin or doxycycline) is the regimen recommended for CAP
HSV PNA presents with multifocal ground-glass predominantly peri-bronchial on CT chest.
HSV PNA is rare. IV acyclovir is the most widely used and effective therapy.
Case reviewed by @BradCutrellMD