Pneumocystosis
Medical condition
From Wikipedia, the free encyclopedia
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]
- Lungs: respiratory failure[4]
- Skin: Perforated ear drum[6]
| Pneumocystosis | |
|---|---|
| Other names | Pneumocystis jiroveci pneumonia,[1] Pneumocystis pneumonia,[2] PCP, Pneumocystis carinii pneumonia[3] |
| |
| Pneumocystis jirovecii cysts | |
| Specialty | Infectious diseases[1] |
| Symptoms | |
| Complications |
|
| Types |
|
| Causes | Pneumocystis jirovecii[1] |
| Risk factors | Poor immunity, HIV/AIDS[4] |
| Diagnostic method | Medical imaging, bronchoalveolar lavage, immunofluorescence assay, biopsy[2] |
| Prevention | Trimethoprim/sulfamethoxazole (co-trimoxazole) in high risk groups[7] |
| Medication | Trimethoprim/sulfamethoxazole (co-trimoxazole)[4] |
| Frequency | Uncommon,[4] 97% in lungs[7] |
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] The GMS stain has high sensitivity and specificity for Pneumocystis from lung tissue specimens.[14]
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) prophylaxis 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
Epidemiology
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]