Health Encyclopedia

Pneumocystis jiroveci pneumonia

Definition

Pneumocystis jiroveci pneumonia is a fungal infection of the lungs. The disease used to be called Pneumocystis carini or PCP pneumonia.

Alternative Names

Pneumocystis pneumonia; Pneumocystosis; PCP; Pneumocystis carinii; PJP pneumonia

Causes

This type of pneumonia is caused by the fungus Pneumocystis jiroveci. This fungus is common in the environment and rarely causes illness in healthy people.

However, it can cause a lung infection in people with a weakened immune system due to:

Cancer
Long-term use of corticosteroids or other medicines that weaken the immune system
HIV/AIDS
Organ or bone marrow transplant

Pneumocystis jiroveci was a rare infection before the AIDS epidemic. Before the use of preventive antibiotics for the condition, most people in the United States with advanced AIDS often developed this infection.

Symptoms

Pneumocystis pneumonia in people with AIDS usually develops slowly over days to weeks or even months, and is less severe. People with pneumocystis pneumonia who do not have AIDS usually get sick faster and are more severely ill.

Symptoms include:

Cough, often mild and dry
Fever
Rapid breathing
Shortness of breath, especially with activity (exertion)

Exams and Tests

Your health care provider will examine you and ask about your symptoms.

Tests that may be ordered include:

Blood gases (both arterial and venous)
Bronchoscopy (with lavage)
Lung biopsy
X-ray of the chest
Sputum exam to check for fungus that causes the infection
CBC
Beta-1,3 glucan level in the blood and/or lavage fluid from bronchoscopy

Treatment

Anti-infection medicines can be given by mouth (orally) or through a vein (intravenously), depending on how severe the illness is.

People with low oxygen levels and moderate to severe disease are often prescribed corticosteroids as well.

Outlook (Prognosis)

Pneumocystis pneumonia can be life threatening. It can cause respiratory failure that can lead to death. People with this condition need early and effective treatment. For moderate to severe pneumocystis pneumonia in people with HIV/AIDS, the short term use of corticosteroids has decreased the incidence of death.

Possible Complications

Complications that may result include:

Pleural effusion (extremely rare)
Pneumothorax (collapsed lung)
Respiratory failure (may require breathing support)

When to Contact a Medical Professional

If you have a weakened immune system due to AIDS, cancer, transplantation, or corticosteroid use, contact your provider if you develop a cough, fever, or shortness of breath.

Prevention

Preventive therapy is recommended for:

People with HIV/AIDS who have CD4 counts below 200 cells/microliter or 200 cells/cubic millimeter
Bone marrow transplant recipients
Organ transplant recipients
People who take long-term, high-dose corticosteroids
People who have had previous episodes of this infection
People who take long-term immunomodulatory drugs

References

Kovacs JA. Pneumocystis pneumonia. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 321.

Miller RF Walzer PD, Smulian AG. Pneumocystis species. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 269.

Review Date:11/23/2021
Reviewed By:Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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