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 or 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
    2. Clinically Significant infection occurs in AIDS with CD4 Count <250 cell/ul
  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. Malaise
    3. Non-productive Cough
    4. Exertional Dyspnea
  3. Pronounced Symptoms
    1. Sputum production
    2. Chest Pain
    3. Chills
    4. Exertional Dyspnea
      1. Profound Hypoxia occurs with even just a few steps taken

VI. Labs

  1. White Blood Cell Count Normal
    1. Elevated WBC Count in typical Bacterial Pneumonia
  2. Lactate Dehydrogenase (LDH)
    1. Increased in PCP Pneumonia
  3. 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
  4. 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
    3. Bat winging appearance
  2. Focal infiltrates rarely seen with Pneumocystis
  3. Images
    1. RadPneumocystisPneumoniaMedPix1121.jpgFrom MedPix with permission.
    2. RadPneumocystisPneumoniaMedPix6563.jpgFrom MedPix with permission.

VIII. Diagnosis

  1. Clinical diagnosis
  2. Definitive diagnosis is typically by bronchoalveolar lavage

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, but risk of Methemoglobinemia)
      1. Dapsone 100 mg orally every 24 hours AND Trimethoprim 5 mg/kg orally every 8 hours
  3. Critically ill with Hypoxia (PaO2 <70 mmHg or A-a Gradient >35) 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 mmHg or A-a Gradient >35) 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. Prognosis

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

XV. References

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

Images: Related links to external sites (from Bing)

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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
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French Pneumocystis jiroveci, Pneumocystis jirovecii
German Pneumocystis jirovecii, Pneumocystis jiroveci
Italian 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
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Definition (MEDLINEPLUS)

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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
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
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

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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
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