View source for Pneumocystis jirovecii pneumonia

''Note: this page is about the infection. For the drug PCP, see [[phencyclidine toxicity]]''
==Background==
*Formerly known known as "pneumocystis ''carinii'' pneumonia" (i.e. "PCP")
*An atypical fungus <ref>Chapman, M., Muse, V., Mojica, J., &amp; Anahtar, M. (2021). Case 35-2021: A 50 Year Old woman with Pain in the Left Upper Quadrant and Hypoxemia. The New England Journal of Medicine, 385(21), 1995–2001. </ref>
*Most common opportunistic infection in [[AIDS]] patients
**Most common identifiable cause of death

===Risk factors===
*CD4 < 200
*Immunosuppressive medications
*Cancer
*Primary immunodeficiencies
*Severe malnutrition

==Clinical Features==
*[[Fever]] (62%)
*Dry [[cough]]
*[[Shortness of breath]] (progressive from exertion only to at rest)

==Differential Diagnosis==
{{SOB DDX}}

{{HIV associated conditions}}

==Evaluation==
[[File:PMC3392316 jkss-83-50-g002.png|thumb|PA [[CXR]] and CT of pneumocystis jirovecii pneumonia before (A and B) and after (C and D) treatment.]]
[[File:PMC4536784 ccrpm-suppl.1-2015-019f3.png|thumb|CT of Pneumocystis jirovecii pneumonia, showing small nodular lesions surrounded by diffuse GGO.]]
[[File:PMC4536784 ccrpm-suppl.1-2015-019f2.png|thumb|CT of Pneumocystis jirovecii pneumonia, showing diffuse GGO with interlobular septal lines and cyst formation.]]
[[File:PMC4536784 ccrpm-suppl.1-2015-019f1.png|thumb|CT of Pneumocystis jirovecii pneumonia showing diffuse GGO with inhomogeneous distribution unrelated to secondary lobules and with spared peripheral lung parenchyma.]]
===Workup===
*CBC
*Chemistry
*LDH elevation - sensitive but not specific
*[[ABG]]
*CD4 count
*[[CXR]] - bat wing appearance (bilat interstitial infiltrates)
*A-a gradient
**P(A-a)O2 = 150 – (PaCO2/0.8) – PaO2 at sea level on RA (normal is <10 in young, healthy patients)
**Increased in PCP pneumonia secondary to decreased diffusion thru thick aveoli

===Diagnosis===
*Imaging
**[[CXR]]
***Normal in 25% of cases
***Diffuse, interstitial infiltrates
**CT Chest
***Sn 100%, Sp 89%
***May see ground glass infiltrative pattern

==Management==
===[[Antibiotics]]===
*Require [[HCAP]] or [[CAP]] ([[ceftriaxone]] and [[azithromycin]]) coverage as well<ref>Rothmans RE, Marco CA, Yang S. Human immunodeficiency virus infection and acquired immunodeficiency syndrome, in Tintinalli JE, Stapczynski JS, Ma OJ, et al (eds): Tintinalli’s Emergency Medicine, ed 7. New York, The McGraw-Hill Companies Inc., 2011.</ref>
{{PCP pneumonia antibiotics}}

===Corticosteroids===
''When used early, found to reduce the risk of progression of hypoxemia, respiratory failure, and death. <ref>Chapman, M., Muse, V., Mojica, J., &amp; Anahtar, M. (2021). Case 35-2021: A 50 Year Old woman with Pain in the Left Upper Quadrant and Hypoxemia. The New England Journal of Medicine, 385(21), 1995–2001. </ref>''
*Only in patients with [[HIV]] with severe respiratory parameters:
**Room air PaO2 < 70 mmHg
**'''OR''' A-a gradient > 35 mmHg

*Treatment schedule for moderate to severe PCP<ref>Wilken A, Feinberg J. Pneumocystis carinii Pneumonia: A Clinical Review. Am Fam Physician. 1999 Oct 15;60(6):1699-1708. http://www.aafp.org/afp/1999/1015/p1699.html.</ref>
**Day 1-5: 40mg [[prednisone]] BID
**Day 6-10: 40mg [[prednisone]] once daily
**Day 11-21: 20mg [[prednisone]] once daily
**Patients too ill to take PO may take equivalent IV methylprednisolone

==Disposition==
*Symptoms usually worsen 2-3d after start of treatment
*Patients with disease severe enough to warrant IV therapy or steroids should be admitted

==References==
<references/>
[[Category:ID]]