Epidemiology
Risk Factors
- Agammaglobulinemia
- Anti-CD20 Therapy (see Anti-CD20 Therapy): possible risk factor
- Anti-Tumor Necrosis Factor-α (Anti-TNF) Therapy (see Anti-Tumor Necrosis Factor-α Therapy): infliximab, etanercept, adalimumab
- Little is known about the role of TNFα in the host defense against PCP, but infliximab decreases peripheral and gut mucosal CD4 counts in patients with Crohn’s Disease [MEDLINE] [MEDLINE]
- Relative Risk: infliximab > etanercept/adalimumab
- Dosing: patients had received an average of 2 drug infusions
- Mean Latency Between Drug Infusion and Onset of Symptoms: 21 days
- Mortality Rate: 27% [MEDLINE]
- Bendamustine (see Bendamustine): case report
- Chlorambucil (see Chlorambucil)
- Chronic Lymphocytic Leukemia (CLL) (see Chronic Lymphocytic Leukemia): few reported cases of PCP with CLL alone, however, risk appears to be the greatest in CLL patients that have received steroids and/or fludarabine
- Common Variable Immunodeficiency (CVID) (see Common Variable Immunodeficiency)
- Corticosteroids (see Corticosteroids): equivalent to >16 mg prednisone/day for at least 8 wks [MEDLINE]
- Cyclophosphamide (Cytoxan) (see Cyclophosphamide)
- Cyclosporine A (see Cyclosporine A)
- Good’s Syndrome: a B-cell immunodeficiency syndrome
- Human Immunodeficiency Virus (HIV) (see Human Immunodeficiency Virus)
- CD4<250 (most cases occur with CD4 <100 though)
- Only 5% of cases occur in HIV patients with CD4 >400
- Methotrexate (see Methotrexate)
- Tofacitinib (Xeljanz) (see Tofacitinib)
Microbiology
- Pneumocystis Jirovecii: although formerly thought to be a protozoan, rRNA subunit analysis links it phylogenetically to fungi
- Transmission: could be either reactivation of latent infection or airborne acquisition of new infection
Clinical Presentations
General Comments
- Non-AIDS Cases: typically have a more severe clinical presentation and are often associated with the tapering of an immunosuppressive agent (such as prednisone or cyclophosphamide)
- Immune Reconstitution Inflammatory Syndrome (IRIS) (see Immune Reconstitution Inflammatory Syndrome)
Normal Chest X-Ray Presentation
- Epidemiology: occurs in 10% of cases
- However, in such cases, chest CT is abnormal
Alveolar Pneumonia (see Pneumonia)
- Diagnosis
- LDH: elevation is highly sensitive, but not very specific (as can also be elevated in other pulmonary processes, such as bacterial pneumonia or tuberculosis)
- Chest X-Ray (see Chest X-Ray)
- Chest CT (see Chest Computed Tomography)
- Mosaic Pattern or Ground-Glass Infiltrates: most common pattern is that with central densities
- Lymphadenopathy: uncommon
- Pneumatoceles/Pneumocysts: may occur (see Cystic-Cavitary Lung Lesions)
- Bronchoscopy with Bronchoalveolar Lavage (BAL) (see Bronchoscopy): typically higher BAL neutrophil counts and lower organism counts are seen in non-AIDS cases
- Clinical: pneumonia-like presentation
- Epidemiology: xxx
- Clinical: may have pneumonia-like presentation
- Diagnosis
- LDH: elevation is highly sensitive, but not very specific (as can also be elevated in other pulmonary processes, such as bacterial pneumonia or tuberculosis)
- Chest X-Ray (see Chest X-Ray): interstitial infiltrates
- Chest CT (see Chest Computed Tomography): mosaic pattern or ground-glass infiltrates
- Lymphadenopathy: uncommon
- Bronchoscopy with Bronchoalveolar Lavage (BAL) (see Bronchoscopy): typically higher BAL neutrophil counts and lower organism counts are seen in non-AIDS cases
- Clinical
- Example: 40 y/o white female on prednisone 40 mg PO qday, tapered to 30 mg qday 1 wk prior to admission (not on PCP prophylaxis), who presented with faint interstitial infiltrates on CXR 5 days prior to admission, then, worsening interstitial infiltrates on day of admission -> PCP was diagnosed by bronchoalveolar lavage
- Epidemiology: rarely causes pleural effusion
- Diagnosis: usually exudative
- Epidemiology: predisposed by presence of pneumocysts
- Epidemiology: may be seen in patients who have been receiving inhaled pentamidine prophylaxis
- Diagnosis
- Bronchoscopy with Bronchoalveolar Lavage (BAL) (see Bronchoscopy): typically higher BAL neutrophil counts and lower organism counts are seen in non-AIDS cases
- Clinical: mimics tuberculosis
Treatment
Antimicrobials
- Sulfamethoxazole-Trimethoprim (Bactrim) (see Sulfamethoxazole-Trimethoprim)
- First-Line Therapy
- Regimen: 3 week course
- Resistance: cases of sulfamethoxazole-trimethoprim resistant PCP have been reported
- Alternative Agents
- Antimicrobial Response Rates: believed to be better in AIDS-related cases than in non-AIDS cases
- Indications: room air pO2 <70
- Regimens
Prophylaxis
Indications
Transplant
- Bone Marrow Transplant (BMT)/Stem Cell Transplant (SCT) (see Bone Marrow Transplant)
- Allogeneic: prophylaxis is typically administered for 6 mo after engraftment (as long as immunosuppressives are administered)
- Prophylaxis may be required for longer in patients receiving immunosuppression for graft vs host disease
- Autologous: prophylaxis should be administered in patients with an underlying hematologic malignancy (lymphoma, multiple myeloma, leukemia), especially when intensive treatment regimens have included a purine analog (cladribine, fludarabine) or high-dose corticosteroids
- Solid Organ Transplant: prophylaxis is indicated for 6 mo-1 yr after transplant and during periods of high-dose immunosuppression (such as during the treatment of acute rejection)
Immunosuppressive Administration
- Alemtuzumab (Campath, MabCampath, Campath-1H, Lemtrada) Administration (see Alemtuzumab): prophylaxis is indicated for a minimum of 2 mo after completing therapy or until the CD4 count is >200 cells/ul
- Anti-Tumor Necrosis Factor-α (Anti-TNF) Therapy (see Anti-Tumor Necrosis Factor-α Therapy): prophylaxis should be considered, although this has not been adopted as a standard of care
- Concomitant Purine Analog (Cladribine, Fludarabine) + Cyclophosphamide Administration (see Fludarabine and Cyclophosphamide)
- Concomitant Temozolomide (Temodar, Temodal) + Radiation Therapy (see Temozolomide): prophylaxis is indicated until recovery of lymphopenia
- Concomitant Temsirolimus + Corticosteroids or Other Immunosuppressives (see Temsirolimus, [[Temsirolimus]]): prophylaxis should be considered in these patients
- Corticosteroid Administration (see Corticosteroids, [[Corticosteroids]]): prophylaxis is indicated for those receiving the equivalent of prednisone >20 mg qday for at least 1 mo
Primary Immunodeficiency States
Other
Agents
References
- Pneumocystis carinii pneumonia in patients with connective tissue disease. Chest 1992; 101:375-378
- Pneumocystis carinii pneumonia in patients without AIDS. Clin Infect Dis 1993; 17:S416-S422
- Pneumocystis carinii pneumonia during immunosuppressive therapy for antineutrophil cytoplasmic autoantibody-positive vasculitis. Arch Intern Med. 1995 Apr 24;155(8):872-4 [MEDLINE]
- Treatment and prophylaxis of Pneumocystis carinii pneumonia. Semin Respir Infect 1998; 13:296-303
- Tumor necrosis factor alpha antibody (infliximab) therapy profoundly downregulates the inflammation in Crohn’s ileocolitis. Gastroenterology 1999; 116:22-28 [MEDLINE]
- Pneumocystis carinii pneumonia with oral candidiasis after infliximab therapy for Crohn’s disease. Dig Dis Sci 2004; 1458- 1460 [MEDLINE]
- Pneumocystis jiroveci (carinii) pneumonia after infliximab therapy: a review of 84 cases. Dig Dis Sci 2007; 52:1481-1484 [MEDLINE]
- Pneumocystis carinii pneumonia in a patient on etanercept for psoriatic arthritis. Ir J Med Sci 2007; 176:309-311
- Pneumocystis carinii pneumonia in a rheumatoid arthritis patient treated with adalimumab. Scand J Infect Dis 2007; 39:475-478