Table of contents

Pneumocystis pneumonia


Key sources

The following summarized guidelines for the evaluation and management of pneumocystis pneumonia are prepared by our editorial team based on guidelines from the British HIV Association (BHIVA 2024), the Infectious Diseases Society of America (IDSA/CDC/NIH/HIVMA 2024), the American College of Radiology (ACR 2019), the Infectious Diseases Society of America (IDSA/ASCO 2018), the European Conference on Infections in Leukaemia (ECIL 2016), ...
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Screening and diagnosis

Diagnosis: as per BHIVA 2024 guidelines, suspect PCP in any patients with HIV developing new-onset, or worsening of pre-existing, respiratory symptoms, with an abnormal chest radiograph.
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Classification and risk stratification

Severity assessment: as per ECIL 2016 guidelines, classify non-HIV infected patients with PCP as having mild versus moderate-to-severe disease severity.
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Miller criteria for PCP severity assessment
Symptoms and signs
Dyspnea on exertion with or without cough and sweats
Dyspnea on minimal exertion, occasional dyspnea at rest, fever, cough
Dyspnea at rest, tachypnea at rest, persistent fever, cough
Arterial oxygen tension (PaO2) at rest, room air
> 11.0 kPa (> 82.5 mmHg)
8.1-11.0 kPa (60.75-82.5 mmHg)
< 8.0 kPa (< 60 mmHg)
SaO2 (SaO₂) at rest, room air
> 96%
< 91%
Normal or minor perihilar shadowing
Diffuse interstitial shadowing
Extensive interstitial shadowing with or without diffuse alveolar shadowing
PCP severity cannot be accurately assessed

Diagnostic investigations

Respiratory tract specimen testing: as per BHIVA 2024 guidelines, obtain immunofluorescence, histochemistry, or PCR of induced sputum or BAL for the diagnosis of PCP.
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  • Blood tests

  • Chest imaging

Respiratory support

Noninvasive ventilation: as per ECIL 2016 guidelines, monitor patients with PCP for acute respiratory failure to ensure timely admission to the ICU, as late ICU transfers are associated with increased mortality rates.
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Medical management

Indications for treatment: as per ECIL 2016 guidelines, use composite criteria to assess the need for diagnostic bronchoscopy and empiric treatment against P. jirovecii, as single clinical diagnostic criteria are insufficient to prove the diagnosis. Factors that increase clinical suspicion include:
patient at risk
clinical signs and symptoms: dyspnea and/or cough, fever (May rarely be absent), hypoxemia (May not yet be present), chest pain (rare; usually from pneumothorax)
radiology findings compatible with PCP (preferably thoracic CT scan)
with or without unexplained serum LDH elevation.

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  • Route and duration of treatment

  • First-line antimicrobial therapy

  • Second-line antimicrobial therapy

  • Adjunctive corticosteroids (HIV-positive)

  • Adjunctive corticosteroids (HIV-negative)

  • ART

Preventative measures

Primary prophylaxis, indications: as per BHIVA 2024 guidelines, initiate primary prophylaxis for PCP in all adult patients with HIV infection with a CD4 count < 200 cells/µL.
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  • Primary prophylaxis (first-line regimens)

  • Primary prophylaxis (alternative regimens)

  • Primary prophylaxis (discontinuation)

  • Secondary prophylaxis (initiation)

  • Secondary prophylaxis (first-line regimens)

  • Isolation

Follow-up and surveillance

Management of drug adverse events: as per BHIVA 2024 guidelines, continue TMP/SMX prophylaxis, if possible, in patients experiencing minor adverse reactions, and offer supportive care before discontinuation.
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  • Assessment of treatment response