Pneumocystis jirovecii: Difference between revisions

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Pneumocystis jirovecii
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* Worldwide distribution
* Worldwide distribution
* Most children have been exposed by age 2 or 3
* Most children have been exposed by age 2 or 3
* Only circulates within humans, with children and immunocompromised patients being the reservoir
* Risk factors for infection:
* Risk factors for infection:
** HIV
** HIV

Revision as of 22:08, 25 September 2019

  • Opportunistic fungal infection of the lower respiratory infection

Microbiology

  • Yeast-like fungus in the Ascomycota phylum
  • Has not been able to be grown in culture, and species within the genus have tropism for their specific host
  • P. jirovecii was previously thought to be P. carinii, but it was later realized that they were two species within the same genus
    • P. carinii and P. wakefieldiae infect rats, P. murina infects mice and P. jiroveci infects humans
  • Also previously thought to be a protozoan, but reclassified as fungus based on phylogenetic analysis, most closely related to Schizosaccharomyces pombe

Epidemiology

  • Worldwide distribution
  • Most children have been exposed by age 2 or 3
  • Only circulates within humans, with children and immunocompromised patients being the reservoir
  • Risk factors for infection:
    • HIV
    • Immune-suppression, e.g. from steroids

Presentation

  • Shortness of breath on exertion

Investigations

  • CXR
  • Typical: bilateral diffuse patchy disease
  • Atypical:
    • Normal (15%)
    • Localized
    • Pneumothorax
    • Upper lobe, if on pentamidine
  • LDH increased
  • CBC often normal

Diagnosis

  • Induced sputum or brochoalveolar lavage (normal sputum not sensitive enough)
  • 6min walk test: will desaturate, even if well-oxygenated at rest

Treatment

  • Septra 5-6mg/kg po BID for 3 weeks
  • If pO2 <70mmHg or A-a gradient ≥35: prednisone
  • Alternative: clindamycin-primaquine or IV pentamidine
  • Duration is 21 days (3 weeks)

Prophylaxis

  • Usually instituted if the risk of PJP is greater than 3.5% per year

References

  1. ^  Julien Senécal, Elizabeth Smyth, Olivier Del Corpo, Jimmy M. Hsu, Alexandre Amar-Zifkin, Amy Bergeron, Matthew P. Cheng, Guillaume Butler-Laporte, Emily G. McDonald, Todd C. Lee. Non-invasive diagnosis of Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis. Clinical Microbiology and Infection. 2022;28(1):23-30. doi:10.1016/j.cmi.2021.08.017.
  2. ^  Po-Yi Chen, Chong-Jen Yu, Jung-Yien Chien, Po-Ren Hsueh. Anidulafungin as an alternative treatment for Pneumocystis jirovecii pneumonia in patients who could not tolerate Trimethoprim/sulfamethoxazole. International Journal of Antimicrobial Agents. 2019. doi:10.1016/j.ijantimicag.2019.10.001.
  3. ^  L. Cooley, C. Dendle, J. Wolf, B. W. Teh, S. C. Chen, C. Boutlis, K. A. Thursky. Consensus guidelines for diagnosis, prophylaxis and management ofPneumocystis jiroveciipneumonia in patients with haematological and solid malignancies, 2014. Internal Medicine Journal. 2014;44(12b):1350-1363. doi:10.1111/imj.12599.
  4. ^  N. Goto, S. Oka. Pneumocystis jirovecii pneumonia in kidney transplantation. Transplant Infectious Disease. 2011;13(6):551-558. doi:10.1111/j.1399-3062.2011.00691.x.