Pneumocystosis

Pneumocystosis
Pneumocystosis
Other names	Pneumocystis jiroveci pneumonia, Pneumocystis pneumonia, PCP, Pneumocystis carinii pneumonia
	Pneumocystis jirovecii cysts
Specialty	Infectious diseases
Symptoms	Lungs: Cough, difficulty breathing, fever.; Disseminated: Depends on affected organ; Skin: Lump or fluid in ear;
Complications	Lungs: respiratory failure; Skin: Perforated ear drum;
Types	Pneumocystis pneumonia (lung),; Disseminated: lymph nodes, spleen, liver, bone marrow; Skin;
Causes	Pneumocystis jirovecii
Risk factors	Poor immunity, HIV/AIDS
Diagnostic method	Medical imaging, bronchoalveolar lavage, immunofluorescence assay, biopsy
Prevention	Trimethoprim/sulfamethoxazole (co-trimoxazole) in high risk groups
Medication	Trimethoprim/sulfamethoxazole (co-trimoxazole)
Frequency	Uncommon, 97% in lungs

Pneumocystosis is a fungal infection that most often presents as Pneumocystis pneumonia in people with HIV/AIDS or poor immunity.^[1]^[7] It usually causes cough, difficulty breathing and fever, and can lead to respiratory failure.^[4] Involvement outside the lungs is rare but, can occur as a disseminated type affecting lymph nodes, spleen, liver, bone marrow, eyes, kidneys, thyroid, gastrointestinal tract or other organs.^[5]^[7] If occurring in the skin, it usually presents as nodular growths in the ear canals or underarms.^[3]

It is caused by Pneumocystis jirovecii, a fungus which is usually breathed in and found in the lungs of healthy people without causing disease, until the person's immune system becomes weakened.^[7]

Diagnosis is by identifying the organism from a sample of fluid from affected lungs or a biopsy.^[3]^[4] Prevention in high risk people, and treatment in those affected is usually with trimethoprim/sulfamethoxazole (co-trimoxazole).^[4]^[8]

The prevalence is unknown.^[7] Less than 3% of cases do not involve the lungs.^[7] The first cases of pneumocystosis affecting lungs were described in premature infants in Europe following the Second World War.^[9]

Signs and symptoms

Pneumocystosis is generally an infection in the lungs.^[4] Involvement outside the lungs is rare but, can occur as a disseminated type affecting lymph nodes, bone marrow,^[5]^[7] liver^[5]^[10] or spleen.^[5]^[11] It may also affect skin,^[3] eyes,^[12] kidneys, thyroid, heart, adrenals and gastrointestinal tract.^[5]^[13]

Lungs

When the lungs are affected there is usually a dry cough, difficulty breathing and fever, usually present for longer than four weeks.^[2]^[7] There may be chest pain, shivering or tiredness.^[8] The oxygen saturation is low.^[2] The lungs may fail to function.^[4]

Eyes

Pneumocystosis in eyes may appear as a single or multiple (up to 50) yellow-white plaques in the eye's choroid layer or just beneath the retina.^[12] Vision is usually not affected and it is typically found by chance.^[12]

Skin

If occurring in the skin, pneumocystosis most often presents as nodular growths in the ear canals of a person with HIV/AIDS.^[3]^[6] There may be fluid in the ear.^[6] Skin involvement may appear outside the ear, usually palms, soles or underarms; as a rash, or small bumps with a dip.^[6] It can occur on the face as brownish bumps and plaques.^[6] The bumps may be tender and the ulcerate.^[3] Infection in the ear may result in a perforated ear drum or destruction of the mastoid bone.^[6] The nerves in the head may be affected.^[6]

Cause

Pneumocystosis is caused by Pneumocystis jirovecii, a fungus which is generally found in the lungs of healthy people, without causing disease until the person's immune system becomes weakened.^[7]

Risk factors

Pneumocystosis occurs predominantly in people with HIV/AIDS.^[8] Other risk factors include chronic lung disease, cancer, autoimmune diseases, organ transplant, or taking corticosteroids.^[8]

Diagnosis

Diagnosis of Pneumocystis pneumonia is by identifying the organism from a sample of sputum, fluid from affected lungs or a biopsy.^[4]^[3] A chest X-ray of affected lungs show widespread shadowing in both lungs, with a "bat-wing" pattern and ground glass appearance.^[2]^[7] Giemsa or silver stains can be used to identify the organism, as well as direct immunofluorescence of infected cells.^[3]

Diagnosis in the eye involves fundoscopy.^[12] A biopsy of the retina and choroid layer may be performed.^[12] In affected liver, biopsy shows focal areas of necrosis and sinusoidal widening.^[10] H&E staining show extracellular frothy pink material.^[10] Typical cysts with a solid dark dot can be seen using a Grocott silver stain.^[10]

Differential diagnosis

Pneumocystosis may appear similar to pulmonary embolism or adult respiratory distress syndrome.^[2] Other infections can present similarly such as tuberculosis, Legionella, and severe flu.^[2]

Prevention

There is no vaccine that prevents pneumocystosis.^[8] Trimethoprim/sulfamethoxazole (co-trimoxazole) might be prescribed for people at high risk.^[8]

Treatment

Treatment is usually with co-trimoxazole.^[4]^[8] Other options include pentamidine, dapsone and atovaquone.^[2]

Outcomes

It is fatal in 10-20% of people with HIV/AIDS.^[3] Pneumocystosis in people without HIV/AIDS is frequently diagnosed late and the death rate is therefore higher; 30-50%.^[3]

Epidemiology

The exact number of people in the world affected is not known.^[7] Pneumocystosis affects lungs in around 97% of cases and is often fatal without treatment.^[7]

History

The first cases of pneumocystosis affecting lungs were described in premature infants in Europe following the Second World War.^[9] It was then known as plasma cellular interstitial pneumonitis of the newborn.^[9]

Pneumocystis jirovecii (previously called Pneumocystis carinii) is named for Otto Jírovec, who first described it in 1952.^[2]

References

^ ^a ^b ^c ^d "ICD-11 - ICD-11 for Mortality and Morbidity Statistics". icd.who.int. Retrieved 30 June 2021.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Russell-Goldman, Eleanor; Milner, Dan A.; Solomon, Isaac (2020). "Pneumocystosis". In Milner, Danny A. (ed.). Diagnostic Pathology: Infectious Diseases. Elsevier. pp. 310–313. ISBN 978-0-323-61138-1.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Pneumocystosis | DermNet NZ". dermnetnz.org. Archived from the original on 24 July 2021. Retrieved 24 July 2021.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l "Orphanet: Pneumocystosis". www.orpha.net. Archived from the original on 24 July 2021. Retrieved 24 July 2021.
^ ^a ^b ^c ^d ^e ^f ^g Ioachim, Harry L.; Medeiros, L. Jeffrey (2009). "28. Pneumocystosis lymphadenitis". Ioachim's Lymph Node Pathology (4th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 156–157. ISBN 978-0-7817-7596-0.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Calonje, J. Eduardo; Grayson, Wayne (2020). "18. Infectious diseases of the skin". In Calonje, J. Eduardo; Brenn, Thomas; Lazar, Alexander J.; Billings, Steven D. (eds.). McKee's Pathology of the Skin, 2 Volume Set (5th ed.). Elsevier. p. 964. ISBN 978-0-7020-6983-3.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o "CDC - DPDx - Pneumocystis". www.cdc.gov. 22 January 2019. Archived from the original on 25 July 2021. Retrieved 25 July 2021.
^ ^a ^b ^c ^d ^e ^f ^g "Pneumocystis pneumonia | Fungal Diseases | CDC". www.cdc.gov. 1 December 2020. Archived from the original on 26 July 2021. Retrieved 26 July 2021.
^ ^a ^b ^c Carmona, Eva M.; Limper, Andrew H. (February 2011). "Update on the diagnosis and treatment of Pneumocystis pneumonia". Therapeutic Advances in Respiratory Disease. 5 (1): 41–59. doi:10.1177/1753465810380102. ISSN 1753-4666. PMC 6886706. PMID 20736243.
^ ^a ^b ^c ^d Zaki, Sherif R.; Alves, Venancio A. F.; Hale, Gillian L. (2018). "7. Non-hepatotropic viral, bacterial, and parasitic infections of the liver". In Burt, Alastair D.; Ferrell, Linda D.; Hubscher, Stefan G. (eds.). MacSween's Pathology of the Liver (7th ed.). Philadelphia: Elsevier. p. 477. ISBN 978-0-323-50869-8.
^ O'Malley, Dennis P. (2013). "7.4. Infections: Fungi". Atlas of Spleen Pathology. Springer. pp. 151–155. ISBN 978-1-4614-4671-2.
^ ^a ^b ^c ^d ^e Papaliodis, George N. (2017). "9. Pneumocystis jirovecii". In George N. Papaliodis (ed.). Uveitis: A Practical Guide to the Diagnosis and Treatment of Intraocular Inflammation. Springer. p. 71. ISBN 978-3-319-09125-9.
^ Gigliotti, Frances; Wright, Terry W. (2008). "13. Pneumocystosis". In Hospenthal, Duane R.; Rinaldi, Michael G. (eds.). Diagnosis and Treatment of Human Mycoses. Totowa, New Jersey: Humana Press. ISBN 978-1-59745-325-7.

[ICD-11-1] "ICD-11 - ICD-11 for Mortality and Morbidity Statistics". icd.who.int. Retrieved 30 June 2021.

[Russ2020-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Russell-Goldman, Eleanor; Milner, Dan A.; Solomon, Isaac (2020). "Pneumocystosis". In Milner, Danny A. (ed.). Diagnostic Pathology: Infectious Diseases. Elsevier. pp. 310–313. ISBN 978-0-323-61138-1.

[Dermnetz-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Pneumocystosis | DermNet NZ". dermnetnz.org. Archived from the original on 24 July 2021. Retrieved 24 July 2021.

[Orphanet-4] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l "Orphanet: Pneumocystosis". www.orpha.net. Archived from the original on 24 July 2021. Retrieved 24 July 2021.

[Ioachim2009-5] ^ ^a ^b ^c ^d ^e ^f ^g Ioachim, Harry L.; Medeiros, L. Jeffrey (2009). "28. Pneumocystosis lymphadenitis". Ioachim's Lymph Node Pathology (4th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 156–157. ISBN 978-0-7817-7596-0.

[Calonje2020-6] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Calonje, J. Eduardo; Grayson, Wayne (2020). "18. Infectious diseases of the skin". In Calonje, J. Eduardo; Brenn, Thomas; Lazar, Alexander J.; Billings, Steven D. (eds.). McKee's Pathology of the Skin, 2 Volume Set (5th ed.). Elsevier. p. 964. ISBN 978-0-7020-6983-3.

[CDC/DPDx-7] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o "CDC - DPDx - Pneumocystis". www.cdc.gov. 22 January 2019. Archived from the original on 25 July 2021. Retrieved 25 July 2021.

[CDCFungal-8] ^ ^a ^b ^c ^d ^e ^f ^g "Pneumocystis pneumonia | Fungal Diseases | CDC". www.cdc.gov. 1 December 2020. Archived from the original on 26 July 2021. Retrieved 26 July 2021.

[Carm2011-9] Carmona, Eva M.; Limper, Andrew H. (February 2011). "Update on the diagnosis and treatment of Pneumocystis pneumonia". Therapeutic Advances in Respiratory Disease. 5 (1): 41–59. doi:10.1177/1753465810380102. ISSN 1753-4666. PMC 6886706. PMID 20736243.

[Zaki2018-10] Zaki, Sherif R.; Alves, Venancio A. F.; Hale, Gillian L. (2018). "7. Non-hepatotropic viral, bacterial, and parasitic infections of the liver". In Burt, Alastair D.; Ferrell, Linda D.; Hubscher, Stefan G. (eds.). MacSween's Pathology of the Liver (7th ed.). Philadelphia: Elsevier. p. 477. ISBN 978-0-323-50869-8.

[O'Malley2013-11] O'Malley, Dennis P. (2013). "7.4. Infections: Fungi". Atlas of Spleen Pathology. Springer. pp. 151–155. ISBN 978-1-4614-4671-2.

[Papaliodis2017-12] Papaliodis, George N. (2017). "9. Pneumocystis jirovecii". In George N. Papaliodis (ed.). Uveitis: A Practical Guide to the Diagnosis and Treatment of Intraocular Inflammation. Springer. p. 71. ISBN 978-3-319-09125-9.

[Gigliotti2008-13] Gigliotti, Frances; Wright, Terry W. (2008). "13. Pneumocystosis". In Hospenthal, Duane R.; Rinaldi, Michael G. (eds.). Diagnosis and Treatment of Human Mycoses. Totowa, New Jersey: Humana Press. ISBN 978-1-59745-325-7.

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