Pneumocystis jirovecii pneumonia: Difference between revisions

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*CXR - bat wing appearance (bilat interstitial infiltrates)
*CXR - bat wing appearance (bilat interstitial infiltrates)
*A-a gradient
*A-a gradient
**P(A-a)O2 = 145 – PaCO2 – PaO2 (normal is <10 in young, healthy pts)
**P(A-a)O2 = 150 (PaCO2/0.8) – PaO2 at sea level (normal is <10 in young, healthy pts)


===Evaluation===
===Evaluation===

Revision as of 17:49, 16 February 2016

Background

  • Pneumocystis (carinii) jiroveci
  • Most common opportunistic infection in AIDS pts
  • 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

Acute dyspnea

Emergent

Non-Emergent

HIV associated conditions

Diagnosis

Work-Up

  • CBC
  • Chemistry
  • LDH
  • 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 (normal is <10 in young, healthy pts)

Evaluation

  • Imaging
    • CXR
      • Normal in 25% of cases
      • Diffuse, interstitial infiltrates
    • CT Chest
      • Sn 100%, Sp 89%
      • May see ground glass infiltrative pattern
  • Labs
    • LDH
      • Low Sn, Sp
    • ABG
      • Hypoxemia, increased A-a gradient

Treatment

Antibiotics

  • Require HCAP or CAP (ceftriaxone and azithromycin) coverage as well[2]

Mild Disease

  • TMP/SMX 2 DS tablets PO q8hrs daily OR
    • High incidence of allergy in HIV
  • Dapsone 100mg PO once daily + TMP 5mg/kg PO q8hrs OR
    • caution: dapsone can cause methemoglobinemia
  • Atavaquone 750mg PO q12hrs OR
  • Primaquine 30mg PO q24hrs + Clindamycin 450mg PO q8hrs

Severe Disease

  • TMP/SMX 5mg/kg IV q8hrs daily x 21 days OR
  • Pentamidine 4mg/kg IV daily infused over 60 minutes OR
    • Watch for side effects of hypoglycemia and hypotension
  • Primaquine 30mg PO once daily + Clindamycin 900mg IV q8hrs daily

Prophylaxis

  • TMP/SMX 1 double strength tablet daily, but one single strength tablet daily or one double-strength three times weekly is acceptable.[3]

Corticosteroids

  • Only in pts with HIV with severe respiratory parameters:
    • Room air PaO2 < 70 mmHg
    • OR A-a gradient > 35 mmHg
  • Treatment schedule for moderate to severe PCP[4]
    • Day 1-5: 40 mg prednisone BID
    • Day 6-10: 40 mg prednisone once daily
    • Day 11-21: 20 mg prednisone once daily
    • Pts 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

  1. Gutteridge, David L MD, MPH, Egan, Daniel J. MD. The HIV-Infected Adult Patient in The Emergency Department: The Changing Landscape of the Disease. Emergency Medicine Practice: An Evidence-Based Approach to Emergency Medicine. Vol 18, Num 2. Feb 2016.
  2. 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.
  3. CDC Guidelines for Prophylaxis Against Pneumocystis carinii Pneumonia for Children Infected with Human Immunodeficiency Virus http://www.cdc.gov/mmwr/preview/mmwrhtml/00001957.htm
  4. 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.