Risk Factors for PJP (Pneumocystis Jiroveci) Pneumonia

-Advanced immunosuppression (esp. HIV with CD4 count <200), hematologic malignancy, s/p BMT
-Previous episodes of PCP
-Oral thrush
-Recurrent bacterial PNA

Timing

–SUBACUTE indolent symptoms (on average, ~3 weeks)-not as acute as bacterial PNA!

S&S

-Progressive exertional dyspnea (95 % of patients)
-Fever (90 % of patients)
-Non-productive cough (90 % of patients)
Pearl: make sure you walk your patients with suspected PCP as it will reveal their hypoxemia!

Labs to obtain to suggest diagnosis

-HIV (look for CD4 count <200, off Bactrim prophylaxis)
-ABG to evaluate for A-A gradient and hypoxemia
-LDH (elevated LDH has high specificity/low sensitivity)
-1,3 Beta D Glucan (>80 can support diagnosis, but not specific)

How do you make the diagnosis?

-Must visualize the cystic/trophic form directly, cannot be cultured
-Use a SILVER stain to make the diagnosis

Step 1: Sputum induction (sensitivity 55-90 %, specificity 100 %). If negative, go to step 2!
Step 2: Bronchoalveolar Lavage, 90-100 % sensitivity.

If still negative, lung biopsy has a sensitivity/specificity of 90-100 % but very invasive!

Treatment 

Bactrim 15-20 mg/kg x 21d

When do you add adjunctive steroids?

Only for moderate to severe hypoxemia! 
If PaO2<70, or A/A gradient >35, treat with Prednisone 40 PO BID x 5d, 40 mg PO daily x 5d, 20 mg PO daily x 11d.

See article here by NEJM and Cochrane study on the use of steroids in PCP.