II. Epidemiology

  1. United States Incidence: 20,000 to 60,000 cases/year
  2. HIV without prophylaxis develops PCP sometime: 75-90%

III. Risk Factors

  1. HIV with CD4 Count related risk of Pneumocystis
    1. CD4 Count >200: Risk <1% over 6 months
    2. CD4 Count <200 (Accounts for 85-95% of cases)
      1. Risk 6% over 6 months
      2. Risk 18% at 1 year
  2. Immunosuppression in non-HIV conditions
    1. Solid organ pr Hematopoietic Stem Cell Transplant recipients
    2. High dose Corticosteroids (Prednisone 20 mg or higher)
      1. Cancer Chemotherapy patients
      2. Rheumatologic Disease
    3. References
      1. Fillatre (2014) Am J Med 127(12): e11-7 +PMID: 25058862 [PubMed]

IV. Pathophysiology

  1. Pneumocystis defies classification
    1. Both Protozoan and Fungal Characteristics
  2. Recently renamed as Pneumocystis jiroveci
  3. Ubiquitous organism
    1. Most humans and mammals exposed early in life
  4. Clinical infection may represent reactivation

V. Symptoms

  1. Symptoms usually develop over 1-2 weeks
    1. Typical Bacterial Pneumonia develops over 3-5 days
  2. Initial Symptoms (occur in 66%, often subtle)
    1. Fever
    2. Cough
    3. Dyspnea
  3. Pronounced Symptoms
    1. Sputum production
    2. Chest Pain
    3. Chills

VI. Labs

  1. White Blood Cell Count Normal
    1. Elevated WBC Count in typical Bacterial Pneumonia
  2. Sputum induction
    1. Methods
      1. Sputum PCR (preferred)
      2. Sputum DFA
    2. Efficacy
      1. Sensitivity 80-90% for Pneumocystis
      2. Negative Predictive Value only 50-60%
    3. Examination stains
      1. Methenamine silver
      2. Giemsa stains
  3. Other methods
    1. Serum Beta D-Glucan
      1. High False Positive Rate
      2. Negative Predictive Value >95%
      3. Karageorgopoulos (2013) Clin Microbiol 19(1): 39-49 +PMID: 22329494 [PubMed]

VII. Imaging: Chest XRay

  1. Diffuse bilateral Interstitial Infiltrates (80-95%)
    1. Seen in Tuberculosis
    2. Seen in Bacterial Pneumonia
  2. Focal infiltrates rarely seen with Pneumocystis
  3. Images
    1. RadPneumocystisPneumoniaMedPix1121.jpgFrom MedPix with permission.
    2. RadPneumocystisPneumoniaMedPix6563.jpgFrom MedPix with permission.

VIII. Prognosis

  1. Treated appropriately: 60-90% survive
  2. Untreated: Uniformly fatal

IX. Management: General

  1. Treatment Duration for 21 days (followed by PCP Prophylaxis)
  2. Treatment protocols are based on level of illness (esp if PaO2 <70 mmHg)
  3. Initiate Antiretroviral therapy within 2 weeks of PCP diagnosis (HIV patients)

X. Management: First-line agents

  1. Duration: 21 days of treatment and then prophylaxis
  2. Not critically ill (PaO2 >70 mmHg) and able to take oral medications
    1. No Corticosteroids indicated
    2. Trimethoprim-Sulfamethoxazole (Bactrim, Septra) DS 2 tabs orally every 8 hours (15 mg/kg of trimethoprim/day)
      1. Adverse reactions occur in 40-60% within 3 weeks
    3. Alternative (Fewer dose limiting adverse reactions)
      1. Dapsone 100 mg orally every 24 hours AND Trimethoprim 5 mg/kg orally every 8 hours
  3. Critically ill (PaO2 <70 mmH) or unable to take oral medications
    1. Start Corticosteroids 15-30 min before antibiotics (see dosing below)
    2. Trimethoprim-Sulfamethoxazole (Bactrim, Septra) 15-20 mg/kg of trimethoprim/day IV divided every 6-8 hours

XI. Management: Alternative Regimen

  1. Duration: 21 days of treatment and then prophylaxis
  2. Not critically ill (PaO2 >70 mmHg) and able to take oral medications
    1. No Corticosteroids indicated
    2. Clindamycin 600 mg IV or 300-400 mg PO every 6 hours AND
    3. Primquine 15-30 mg of based every 24 hours or Atovaquone 750 mg po bid
  3. Critically ill (PaO2 <70 mmH) or unable to take oral medications
    1. Start Corticosteroids 15-30 min before antibiotics (see dosing below)
    2. Clindamycin 600 mg IV every 8 hours AND Primquine 15-30 mg of based every 24 hours OR
    3. Pentamidine 4 mg/kg/day IV (or IM)

XII. Management: Corticosteroids

  1. Efficacy
    1. Prevents alveolar inflammation and exudation
    2. Results from the killing of Pneumocystis organisms
    3. Reduces the risk of intubation and death by 50%
  2. Indications (based on Arterial Blood Gas)
    1. Arterial pO2 < 70 mmHg
    2. A-a Gradient > 35 mmHg on room air
  3. Dosing: Prednisone
    1. Start: 40 mg twice daily for 5 days
    2. Next: 40 mg every 24 hours for 5 days
    3. Taper: 20 mg every 24 hours for 11 days

XIII. Prevention: Pneumocystis prophylaxis

  1. Indications
    1. CD4 Count <200 cells
    2. HIV patients with respiratory symptoms
  2. Duration
    1. Continue prophylaxis until CD4 Count >200 for at least 3 months
  3. First-Line Protocol
    1. Trimethoprim-Sulfamethoxazole (Bactrim, Septra)
      1. One DS or SS tab orally daily OR
      2. One DS 3 times weekly OR
  4. Alternative Protocols
    1. Pentamidine 300 mg in 6 ml sterile water aerosolized every 4 weeks OR
    2. Atovaquone 1500 mg orally every 24 hours with food OR
    3. Dapsone 200 mg and Pyrimethamine 75 mg AND Folinic Acid 25 mg once each week

XIV. References

  1. Gilbert (2017) Sanford Guide (accessed IOS version 8/3/2017)
  2. Weller (2001) BMJ 322:1350-4 [PubMed]

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Ontology: Pneumocystis carinii (C0032276)

Definition (SNOMEDCT_US) The rat specific species of Pneumocystis.
Definition (SCTSPA) Especie de Pneumocystis específica de la rata.
Definition (MSH) The prototype species of PNEUMOCYSTIS infecting the laboratory rat, Rattus norvegicus (RATS). It was formerly called Pneumocystis carinii f. sp. carinii. Other species of Pneumocystis can also infect rats.
Definition (CSP) opportunistic pathogen which can cause a fatal pneumonitis in an immunocompromised host; occurs in 75% of AIDS patients.
Concepts Fungus (T004)
MSH D045363
SnomedCT 639000, 699877004, 79909001
English Pneumocystis carinii, Finding of Pneumocystis carinii present, Pneumocystis carinii f. sp. ratti, carinii, Pneumocystis, Pneumocystis carinius, carinius, Pneumocystis, Pneumocystis carinus, carinus, Pneumocystis, carini, Pneumocystis, pneumocystis carini, pneumocystis carinii, carinii pneumocystis, Pneumocystis carinii (organism), Pneumocystis carinii f. sp. carinii, Pneumocystis carini
Swedish Pneumocystis carinii
Czech Pneumocystis carinii
Finnish Pneumocystis carinii
Japanese カリニ肺炎菌, ニューモシスチス・カリニ, ニューモシスチスカリニ
Croatian PNEUMOCYSTIS CARINII
Polish Pneumocystis carini
Norwegian Pneumocystis carini, Pneumocystis carinii
Spanish Pneumocystis carinii (organismo), Pneumocystis carinii
French Pneumocystis carini, Pneumocystis carinii
German Pneumocystis carinii
Italian Pneumocystis carinii
Russian PNEUMOCYSTIS CARINII
Dutch Pneumocystis carinii
Portuguese Pneumocystis carinii

Ontology: Pneumocystis jiroveci (C0320385)

Definition (SNOMEDCT_US) The human specific species of Pneumocystis.
Definition (SCTSPA) Especie de Pneumocystis específica del ser humano.
Definition (MSH) A species of PNEUMOCYSTIS infecting humans and causing PNEUMOCYSTIS PNEUMONIA. It also occasionally causes extrapulmonary disease in immunocompromised patients. Its former name was Pneumocystis carinii f. sp. hominis.
Concepts Fungus (T004)
MSH D045382
SnomedCT 79909001
LNC LP17137-8, MTHU025383
Swedish Pneumocystis jiroveci
English Pneumocystis jirovecii, jiroveci, Pneumocystis, jirovecus, Pneumocystis, jirovecii, Pneumocystis, Pneumocystis jirovecus, jirovecius, Pneumocystis, Pneumocystis jirovecius, Pneumocystis jiroveci (organism), Pneumocystis jirovecii (organism), Pneumocystis carinii f. sp. hominis, Pneumocystis jiroveci
Portuguese Pneumocystis jirovecii
Finnish Pneumocystis jirovecii
French Pneumocystis jiroveci, Pneumocystis jirovecii
German Pneumocystis jirovecii, Pneumocystis jiroveci
Italian Pneumocystis jirovecii, Pneumocystis jiroveci
Russian PNEUMOCYSTIS JIROVECII, PNEUMOCYSTIS JIROVECI
Czech Pneumocystis jiroveci, Pneumocystis jirovecii
Polish Pneumocystis jiroveci, Pneumocystis jirovecii
Japanese ニューモシスチス・イロベジイ
Norwegian Pneumocystis jiroveci, Pneumocystis jirovecii
Spanish Pneumocystis jirovecii (organismo), Pneumocystis jirovecii, Pneumocystis jiroveci (organismo), Pneumocystis jiroveci
Dutch Pneumocystis jiroveci

Ontology: Pneumocystis Infections (C0851886)

Definition (MEDLINEPLUS)

Pneumocystis jirovec is a tiny fungus that lives in the lungs of many people. Most people's immune systems keep the fungus under control. But if your immune system is weak, the fungus can make you very sick.

The most common problem of infection is pneumocystis pneumonia (PCP). PCP once was the major cause of death for people with HIV/AIDS. But now, it is possible to prevent or treat most cases. The key to surviving PCP is early treatment. The first signs of PCP are difficulty breathing, fever and a dry cough. If you have these symptoms, see your doctor right away.

Definition (MSH) Infections with species in the genus PNEUMOCYSTIS, a fungus causing interstitial plasma cell pneumonia (PNEUMONIA, PNEUMOCYSTIS) and other infections in humans and other MAMMALS. Immunocompromised patients, especially those with AIDS, are particularly susceptible to these infections. Extrapulmonary sites are rare but seen occasionally.
Concepts Disease or Syndrome (T047)
MSH D016720
SnomedCT 111918002
English PNEUMOCYSTIS CARINII INFECTION, Pneumocystis carinii Infection, PNEUMOCYSTIS CARINII INFECT, PNEUMOCYSTIS INFECT, Pneumocystis infections, Pneumocystis Infections, Pneumocystis Infections [Disease/Finding], Infection by Pneumocystis carinii, Infection by Pneumocystis carinii (disorder), Pneumocystis carinii infection, Pneumocystis carinii Infections, Infection, Pneumocystis, Infections, Pneumocystis, Pneumocystis Infection, Pneumocystis carinii; infection, infection; Pneumocystis carinii
Italian Infezioni da Pneumocystis, Infezione da Pneumocystis carinii, Infezioni da Pneumocystis carinii
Japanese ニューモシスティス感染, ニューモシスティスカンセン, ニューモシスチス感染症, ニューモシスティスカリニカンセン, ニューモシスティスカリニ感染
Swedish Pneumocystis infektioner
Finnish Pneumocystis-infektiot
Russian PNEUMOCYSTIS INFEKTSII, PNEUMOCYSTIS CARINII INFEKTSII, PNEUMOCYSTIS CARINII ИНФЕКЦИИ, PNEUMOCYSTIS ИНФЕКЦИИ
Portuguese INFECCAO A PNEUMOCISTIS CARINI, Infecção a Pneumocystis carinii, Infecções a Pneumocystis, Infecções por Pneumocystis
Spanish INFECCION PNEUMOCISTYS CARINII, infección por Pneumocystis carinii, infección por Pneumocystis carinii (trastorno), Infección por Pneumocystis carinii, Infecciones por pneumocystis, Infecciones por Pneumocystis
French INFECTION A PNEUMOCYSTIS CARINII, Infection à Pneumocystis carinii, Infections à Pneumocystis carinii, Infections à Pneumocystis
German PNEUMOCYSTIS CARINII INFEKTION, Pneumocystis carinii Infektion, Pneumocystis-Infektionen, Pneumocystis-carinii-Infektionen
Czech Pneumocystové infekce, Infekce vyvolaná Pneumocystis carinii, infekce Pneumocystis carinii, Pneumocystis - infekce
Croatian PNEUMOCYSTIS CARINII, INFEKCIJE, PNEUMOCISTOZA
Hungarian Pneumocystis fertőzések, Pneumocystis carinii fertőzés
Polish Infekcje Pneumocystis, Infekcja Pneumocystis, Zakażenia Pneumocystis
Dutch Pneumocystis carinii-infectie, Pneumocystis carinii; infectie, infectie; Pneumocystis carinii, Infecties, pneumocystis-carinii-, Pneumocystis-carinii-infectie, Pneumocystis-carinii-infecties, Pneumocystis-infecties
Norwegian Pneumocystis carinii-infeksjoner, Pneumocystisinfeksjoner

Ontology: Pneumocystis jiroveci pneumonia (C1535939)

Definition (NCI) Pneumonia resulting from infection with Pneumocystis carinii, frequently seen in the immunologically compromised, such as persons with AIDS, or steroid-treated individuals, the elderly, or premature or debilitated babies during their first three months. Patients may be only slightly febrile (or even afebrile), but are likely to be extremely weak, dyspneic, and cyanotic. This is a major cause of morbidity among patients with AIDS.
Definition (CSP) pulmonary disease in humans occurring in immunodeficient or malnourished patients or infants, characterized by dyspnea, tachypnea, and hypoxemia; Pneumocystis pneumonia is a frequent opportunistic infection in AIDS; also found in other mammals where it is caused by related species of Pneumocystis.
Definition (MSH) A pulmonary disease in humans occurring in immunodeficient or malnourished patients or infants, characterized by DYSPNEA, tachypnea, and HYPOXEMIA. Pneumocystis pneumonia is a frequently seen opportunistic infection in AIDS. It is caused by the fungus PNEUMOCYSTIS JIROVECII. The disease is also found in other MAMMALS where it is caused by related species of Pneumocystis.
Concepts Disease or Syndrome (T047)
MSH D011020
ICD9 136.3
ICD10 B59
SnomedCT 88860002, 57541005, 155557008, 415125002
English Pneumocystoses, Pneumonia, Interstitial Plasma Cell, Pneumonias, Pneumocystis carinii, interstitial plasma cell pneumonia, PCP - Pneumocyst carinii pneum, PCP - Pneumocystis carinii pneumonia, PNEUMOCYSTIS PNEUMONIA, Pneumocytosis, Pneumocystis carinii pneumonia (diagnosis), plasma cell interstitial pneumonia (diagnosis), Pneumocystis jiroveci pneumonia (diagnosis), plasma cell interstitial pneumonia, lymphoplasmacytic interstitial pneumonia, Pneumocystis Jiroveci Pneumonia, Pneumocystis, PCP, PJP, Pneumocystis Carinii Pneumonia, Pneumocystis jiroveci pneumonia, Pneumonia due to Pneumocystis carinii, Pneumonia, Pneumocystis [Disease/Finding], pneumocystis pneumonia, pneumocystis carinii pneumonia (PCP), pneumocystis carinii pneumonia, Pneumocystis carinii pneumonia (disorder), Pulmonary pneumocystosis (disorder), Pneumocystis carinii pneumonia, Interstitial plasma cell pneumonia, Pneumocystis jirovecii pneumonia, Pneumocystis pneumonia, Pneumocystosis jiroveci pneumonia, Pneumocystosis jirovecii pneumonia, Pneumocystosis jiroveci pneumonia (disorder), Pneumocystosis jirovecii pneumonia (disorder), Pneumocystis carinii Pneumonia, Pneumocystosis, Pneumonia, Pneumocystis carinii, Pneumonia, Pneumocystis, Pneumocystis Pneumonias, Pneumocystis Pneumonia, Pneumonias, Pneumocystis, Pneumocystosis (disorder), pneumocystosis, Pulmonary pneumocystosis, PCP - Pneumocystis pneumonia, Pneumocystosis pneumonia
Czech pneumocystóza, pneumocystová pneumonie, pneumonie pneumocystová, Zánět plic vlivem pneumocystis jiroveci, Pneumocystová pneumonie, Pneumonie způsobená Pneumocystis jirovecii, Pneumonie vyvolaná Pneumocystis carinii, PCP, Pneumocystóza, Intersticiální pneumonie s plasmocytickou infiltrací
Finnish Pneumocystis-keuhkokuume
German Pneumonie, Pneumocystis-carinii-, Pneumonie, Pneumocystis-, Pneumocystis-Pneumonie, Pneumocystosis, Pneumozystose, Pneumocystose, Pneumonie durch Pneumocystis jiroveci, Pneumocystis jirovecii-Pneumonie, PCP, interstitielle Plasmazellenpneumonie, Pneumonie durch Pneumocystis carinii, Pneumonie durch Pneumocystis, Pneumocystis-carinii-Pneumonie, Pneumonie, interstitielle plasmazelluläre
Russian PNEVMONIIA, PNEUMOCYSTIS, PNEVMONIIA INTERSTITSIAL'NAIA PLAZMOKLETOCHNAIA, PNEVMOTSISTOZ, PNEVMONIIA, PNEUMOCYSTIS CARINII, PNEVMOTSISTNAIA PNEVMONIIA, ПНЕВМОНИЯ, PNEUMOCYSTIS CARINII, ПНЕВМОНИЯ, PNEUMOCYSTIS, ПНЕВМОНИЯ ИНТЕРСТИЦИАЛЬНАЯ ПЛАЗМОКЛЕТОЧНАЯ, ПНЕВМОЦИСТНАЯ ПНЕВМОНИЯ, ПНЕВМОЦИСТОЗ
Japanese 肺炎-カリニ, ニューモシスチス肺炎, ニューモシスチス・カリニ肺炎, Pneumocystis肺炎, Carinii肺炎, 肺炎-ニューモシスチス, ニューモシスティスカリニ肺炎, ニューモシスティスショウ, ニューモシスティス肺炎, ニューモシスチス・イロベチイ肺炎, カンシツケイシツサイボウセイハイエン, ニューモシスティスハイエン, ニューモシスティスカリニハイエン, ニューモシスティス症, ニューモシスチスイロベチイハイエン, Pneumocystis carinii肺炎, カリニ肺炎, ニューモシスチスカリニ肺炎, 肺炎-間質形質細胞性, 間質形質細胞性肺炎, ニューモシスチス-カリニ肺炎, 肺炎-Pneumocystis carinii, 肺炎-ニューモシスチスカリニ
Swedish Lunginflammation, Pneumocystis
Italian Pneumocistosi, Polmonite interstiziale plasmacellulare, PCP, Polmonite da Pneumocystis jiroveci, Polmonite da Pneumocystis, Polmonite da Pneumocystis jirovecii, Polmonite interstiziale plasmocitaria, Polmonite da Pneumocystis carinii
Korean 폐포자충증
Polish Zapalenie płuc wywołane Pneumocystis carinii, Zapalenie płuc pneumocystozowe, Zapalenie płuc plazmatycznokomórkowe
Spanish neumocistosis pulmonar, neumocistosis pulmonar (trastorno), neumonía por Pneumocystis carinii, Neumonía plasmocitioide intestinal, Neumonía por P carinii, Neumonía por Pneumocystis jiroveci, Neumocistiasis, Neumonía por pneumocystis, Neumonía por Pneumocystis jirovecii, Neumonía por Pneumocystis carinii, neumocistosis (trastorno), neumocistosis, neumonía por Pneumocystis jiroveci (trastorno), neumonía por Pneumocystis jiroveci, Neumocistosis, Neumonía Intersticial de Células Plasmáticas, Neumonía por Pneumocystis
Dutch pneumocystose, Pneumocystis jiroveci-pneumonie, interstitiële plasmacelpneumonie, PCP, Pneumocystis carinii-pneumonie, Pneumocystose, Pneumocystis-pneumonie, Pneumonie, interstitiële plasmacel-, Pneumonie, Pneumocystis-
French PCP, Pneumonie à Pneumocystis jirovecii, Pneumonie à Pneumocystis Carinii, Pneumonie interstitielle à cellules plasmatiques, Pneumonie à pneumocytose, Pneumonie à Pneumocystis jiroveci, Pneumonie interstitielle à Pneumocystis carinii, Pneumocystose, Pneumonie à Pneumocystis carinii, Pneumonie à Pneumocystis, Pneumopathie à Pneumocystis
Hungarian Pneumocystis jirovecii pneumonia, pneumocystosis, Pneumocystis jiroveci pneumonia, Pneumocystis carinii pneumonia, PCP, Interstitialis plazmasejtes pneumonia, Pneumocystis pneumonia
Portuguese Pneumonia intersticial de plasmocitos, Pneumonia a Pneumocystis, Pneumonia por Pneumocystis jirovecii, Pneumonia a Pneumocystis carinii, Pneumonia a Pneumocystis jiroveci, Pneumocistose, Pneumonia Intersticial de Células Plasmáticas, Pneumonia por Pneumocystis
Norwegian Pneumocystis carinii pneumoni, Pneumocystose, Pneumocystis-lungebetennelse