Pneumocystis pneumonia

Source: Wikipedia, the free encyclopedia.
Not to be confused with Pneumococcal pneumonia.
Pneumocystis pneumonia
Other namesPneumocystis pneumonia; Pneumocystis jirovecii pneumonia; Pneumocystis jiroveci pneumonia; Pneumocystis carinii pneumonia [outdated term]; pneumocystosis;
pafuramidine maleate and clindamycin
.

Pneumocystis pneumonia (PCP), also known as Pneumocystis jirovecii pneumonia (PJP), is a form of pneumonia that is caused by the yeast-like fungus Pneumocystis jirovecii.[3][4]

Pneumocystis specimens are commonly found in the lungs of healthy people although it is usually not a cause for disease.[5] However, they are a source of opportunistic infection and can cause lung infections in people with a weak immune system or other predisposing health conditions. PCP is seen in people with HIV/AIDS (who account for 30-40% of PCP cases), those using medications that suppress the immune system, and people with cancer, autoimmune or inflammatory conditions, and chronic lung disease.[2]

Signs and symptoms

Signs and symptoms may develop over several days or weeks

shortness of breath and/or difficulty breathing (of gradual onset), fever, dry/non-productive cough, weight loss, night sweats,[6] chills, and fatigue.[2] Uncommonly, the infection may progress to involve other visceral organs (such as the liver, spleen, and kidney).[6]

Complications

X-ray and CT of ground glass opacities and pneumothorax in pneumocystis pneumonia.[7]

Pneumothorax is a well-known complication of PCP.[8] Also, a condition similar to acute respiratory distress syndrome (ARDS) may occur in patients with severe Pneumocystis pneumonia, and such individuals may require intubation.[9]

Pathophysiology

The risk of PCP increases when

dyspnea (breathlessness).[citation needed
]

In addition, in symptomatic cases of P. jirovecii pneumonia, the overgrowth of the fungus is associated to a co-infection with trichomonads, unicellular flagellated parabasalid protist (

Parabasalia) of the family Trichomonadidae. These parasites (including the commensal Trichomonas tenax, Trichomonas vaginalis and Tritrichomonas foetus) exhibit an amoeboid form, without flagellum, which makes it difficult to identify them under the microscope.[11] Amoeboid transformation is an argument in favor of a deleterious action, which nevertheless remains conjectural.[12]

Diagnosis

The diagnosis can be confirmed by the characteristic appearance of the

pulmonary cysts (not to be confused with the cyst-forms of the pathogen).[citation needed
]

  • Chest X-ray of increased opacification (whiteness) in the lower lungs.
    Chest X-ray
    of increased opacification (whiteness) in the lower lungs.
  • These chest radiographs are of two patients. Both show ground glass opacities. The left X-ray shows a much more subtle ground-glass appearance while the right X-ray shows a much more gross ground-glass appearance mimicking pulmonary edema.[7]
    These chest radiographs are of two patients. Both show
    ground glass opacities. The left X-ray shows a much more subtle ground-glass appearance while the right X-ray shows a much more gross ground-glass appearance mimicking pulmonary edema.[7]
  • X-ray of a cyst in pneumocystis pneumonia[7]
    X-ray of a cyst in pneumocystis pneumonia[7]
  • High-resolution computed tomography (HRCT) showing ground-glass attenuation with a geographic or mosaic distribution.[7]
    High-resolution computed tomography (HRCT) showing ground-glass attenuation with a geographic or mosaic distribution.[7]
  • HRCT of cysts of pneumocystis pneumonia. These are usually multiple and bilateral, but range in size, shape and distribution.[7]
    HRCT of cysts of pneumocystis pneumonia. These are usually multiple and bilateral, but range in size, shape and distribution.[7]

The diagnosis can be definitively confirmed by histological identification of the causative organism in sputum or

periodic acid-Schiff stain, or an immunofluorescence assay shows the characteristic cysts.[13] The cysts resemble crushed ping-pong balls and are present in aggregates of two to eight (and not to be confused with Histoplasma or Cryptococcus, which typically do not form aggregates of spores or cells). A lung biopsy would show thickened alveolar septa with fluffy eosinophilic exudate in the alveoli. Both the thickened septa and the fluffy exudate contribute to dysfunctional diffusion capacity that is characteristic of this pneumonia.[citation needed
]

Pneumocystis infection can also be diagnosed by

histochemical staining of the specimen, and more recently by molecular analysis of polymerase chain reaction products comparing DNA samples. Notably, simple molecular detection of P. jirovecii in lung fluids does not mean that a person has PCP or infection by HIV. The fungus appears to be present in healthy individuals in the general population.[14] A blood test to detect β-D-glucan (a part of the cell wall of many different types of fungi) can also help in the diagnosis of PCP.[citation needed
]

Prevention

In

prophylaxis with co-trimoxazole (trimethoprim/sulfamethoxazole),[15] atovaquone, or regular pentamidine
inhalations may help prevent PCP.

Treatment

Antipneumocystic medication is used with concomitant

pafuramidine maleate (under investigation), and clindamycin
. Treatment is usually for a period of about 21 days. Pentamidine is less often used, as its major limitation is the high frequency of side effects. These include acute pancreatic inflammation, kidney failure, liver toxicity, decreased white blood cell count, rash, fever, and low blood sugar.[citation needed]

Epidemiology

Current epidemiology

Pneumocystis jirovecii

The disease PCP is relatively rare in people with normal immune systems, but common among people with weakened

bone marrow transplantation and after surgery.[17] Infections with Pneumocystis pneumonia are also common in infants with hyper IgM syndrome, an X-linked or autosomal recessive trait.[18]

The causative organism of PCP is distributed worldwide

seropositive by the age of four, which suggests a high background exposure to the organism. A post mortem study conducted in Chile of 96 persons who died of unrelated causes (suicide, traffic accidents, and so forth) found that 65 (68%) of them had pneumocystis in their lungs, which suggests that asymptomatic pneumocystis infection is extremely common.[20] Up to 20% of adults may be asymptomatic carriers at any given time, and asymptomatic infection may persist for months before being cleared by an immune response.[2]

P. jirovecii is commonly believed to be a commensal organism (dependent upon its human host for survival). The possibility of person-to-person transmission has recently gained credence, with supporting evidence coming from many different genotyping studies of P. jirovecii isolates from human lung tissue.[21][22] For example, in one outbreak of 12 cases among transplant patients in Leiden, it was suggested as likely, but not proven, that human-to-human spread may have occurred.[23]

PCP and AIDS

Since the start of the

organ transplant). An unusual rise in the number of PCP cases in North America, noticed when physicians began requesting large quantities of the rarely used antibiotic pentamidine, was the first clue to the existence of AIDS in the early 1980s.[24][25]

Prior to the development of more effective treatments, PCP was a common and rapid cause of death in persons living with AIDS. Much of the incidence of PCP has been reduced by instituting a standard practice of using oral

co-trimoxazole (Bactrim / Septra) to prevent the disease in people with CD4 counts less than 200/μL. In populations who do not have access to preventive treatment, PCP continues to be a major cause of death in AIDS.[citation needed
]

History

The first cases of Pneumocystis pneumonia were described in premature infants in Europe following the

Second World War.[26] It was then known as plasma cellular interstitial pneumonitis of the newborn.[26]

In the era before the existence of HIV/AIDS in humans, clinical transplant immunology, and widespread immunomodulatory therapy for autoimmune diseases, the neonatal and infantile population was the principal immunity-limited population.[citation needed] For example, a 1955 review article stated,[27] "Interstitial plasma cell pneumonia is a type of infantile pneumonia, occurring chiefly in Europe." It also stated, "The etiology is unknown, but the disease acts like an infection in its epidemiology. No present-day therapeutic measures seem to be of any definite value."[27]

Nomenclature

Both Pneumocystis pneumonia and pneumocystis pneumonia[1] are orthographically correct; one uses the genus name per se and the other uses the common noun based on it. (This is the same reason, for example, why "group A Streptococcus" and "group A streptococcus" are both valid.) Synonyms for PCP include pneumocystosis[1] (pneumocystis + -osis), pneumocystiasis[1] (pneumocystis + -iasis), and interstitial plasma cell pneumonia.[1]

The older species name Pneumocystis carinii (which now applies only to the Pneumocystis species that is found in rats[28]) is still in common usage. As a result, Pneumocystis pneumonia (PCP) is also known as Pneumocystis jiroveci[i] pneumonia and (incorrectly) as Pneumocystis carinii pneumonia.[29][30][31]

Regarding nomenclature, when the name of Pneumocystis pneumonia (PCP) changed from P. carinii pneumonia to P. jirovecii pneumonia, it was at first asked whether "PJP" should replace "PCP". However, because the short name "PCP" was already well established among physicians that managed patients with Pneumocystis infection, it was widely accepted that this name could continue to be used, as it could now stand for pneumocystis pneumonia.[32]

References

  1. ^ a b c d e f g Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.
  2. ^ a b c d e f g "Pneumocystis pneumonia | Fungal Diseases | CDC". www.cdc.gov. 2020-07-27. Retrieved 2020-08-10.
  3. ^
    PMID 18565802
    .
  4. ^ Bennett NJ, Gilroy SA (2017-08-08). "Pneumocystis jiroveci Pneumonia (PJP) Overview of Pneumocystis jiroveci Pneumonia". Medscape.
  5. S2CID 13097433
    .
  6. ^ a b c "Pneumocystis Pneumonia". NORD (National Organization for Rare Disorders). Retrieved 2020-08-10.
  7. ^
    PMID 20981180
    . Creative Commons Attribution License
  8. S2CID 7041746
    .
  9. ^ Bennett NJ (2017-08-08). "What are possible complications of Pneumocystis jiroveci pneumonia (PJP)?". Medscape.
  10. OCLC 1101189928.{{cite book}}: CS1 maint: location missing publisher (link
    )
  11. S2CID 33897311
    .
  12. PMID 33271170
    .
  13. ^ "Supplementary Information: Microscopic appearance of Pneumocystis jiroveci from bronchial washings". Archived from the original on 18 July 2009. Retrieved 5 June 2009.
  14. PMID 15752442
    .
  15. PMID 25269391
    .
  16. ISBN 978-0-8385-8529-0
    .
  17. PMID 19517677
    .
  18. PMID 35379217
    .
  19. ^
    PMID 15504255
    .
  20. S2CID 13097433
    .
  21. PMID 18216217
    .
  22. PMID 11825780
    .
  23. PMID 17407029
    .
  24. ^ Fannin S, Gottlieb MS, Weisman JD, et al. (1982). "A Cluster of Kaposi's Sarcoma and Pneumocystis carinii pneumonia among homosexual male residents of Los Angeles and Range Counties, California". MMWR Weekly. 31 (32): 305–7.
  25. PMID 6975437
    .
  26. ^
    PMID 20736243
    .
  27. ^
    PMID 14368443
    .
  28. PMID 12194762
    .
  29. ^ Cushion MT (1998). "Ch. 34: Pneumocystis carinii". In Collier L, Balows A, Sussman M (eds.). Topley and Wilson's Microbiology and Microbial Infections (9th ed.). New York: Arnold and Oxford Press. pp. 645–683.
  30. PMID 9872627
    .
  31. PMID 15120144
    .
  32. PMID 12194762
    .

External links

Wikimedia Commons has media related to Pneumocystis pneumonia.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Pneumocystis_pneumonia&oldid=1197832959"