How Is Pcp Transmitted
The fungus that causes PCP can also be found in people who are not HIV positive. These individuals do not have symptoms because their immune system is able to control the amount of fungus.
Researchers currently believe that PCP infections in individuals with HIV are caused by exposure in the air. The fungus is exhaled into the air from another person who is infected with the fungus. Because of this, PCP can be transmitted easily in a hospital or healthcare setting.2
How Pneumocystis Pneumonia Spreads
PCP spreads from person to person through the air.15-17 Some healthy adults can carry the Pneumocystis fungus in their lungs without having symptoms, and it can spread to other people, including those with weakened immune systems.8
Many people are exposed to Pneumocystis as children, but they likely do not get sick because their immune systems prevent the fungus from causing an infection.18 In the past, scientists believed that people who had been exposed to Pneumocystis as children could later develop PCP from that childhood infection if their immune systems became weakened.8,19 However, it is more likely that people get PCP after being exposed to someone else who has PCP or who is carrying the fungus in their lungs without having symptoms.
Chemoprophylaxis In Patients With Hiv Infection
Two types of outpatient chemoprophylactic therapies exist. Primary prophylaxis is used in immunocompromised patients without a history of PJP. Secondary prophylaxis is used in patients with a prior bout of PJP.
An expert panel overseen by the US Public Health Service and Infectious Disease Society of America has published guidelines on prophylaxis against P jiroveci pneumonia in adult and pediatric patients with HIV infection. Chemoprophylaxis is recommended for the following groups:
One study suggests that discontinuation of prophylaxis may be safe in patients with HIV and CD4 counts of 101-200 cells/L and suppressed viral load.
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How Is Pcp Related To Hiv
PCP is considered an opportunistic infection. This means that it is most likely to affect individuals with weakened immune systems. PCP usually develops in people who are HIV positive when their CD4+ cell count is low, 200 cells/mm3 or less. CD4+ cells are white blood cells that defend the body from infection.2 HIV kills CD4+ cells. Without CD4+ cells, the body has less defense against infection.
What Are The Signs And Symptoms Of Pneumocystis Pneumonia

The signs and symptoms associated with Pneumocystis Pneumonia include:
- Fever: Pneumocystis Pneumonia infection causes low-grade fever in a HIV-infected individual, whereas in a HIV-uninfected individual, the fever is usually high
- Non-productive cough
- Tachypnea over a period of weeks to months
- Crackles
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How Is Pcp Diagnosed
Your healthcare provider can diagnose PCP based on your health history and a physical exam. Your provider may also do these tests:
- Chest X-ray. This test uses a small amount of radiation to make images of internal tissues, bones, and organs, including the lungs.
- Blood tests. Your provider may do blood tests to see if you have an infection and if it has spread to the blood. He or she may also do an arterial blood gas test to check the amount of oxygen in your blood.
- Sputum culture. This test is done on the material that is coughed up from the lungs and into the mouth. A sputum culture is often used to test for the PCP fungus in your lungs.
- Bronchoscopy. This is direct exam of the main airways of the lungs using a flexible tube .
How Is Pneumocystis Pneumonia Diagnosed
The diagnosis of Pneumocystis Pneumonia may include:
- Complete evaluation of medical history along with a thorough physical exam
- The sputum is examined under a microscope to detect the presence of pathogens
- Chest x-ray, to assess the extent of lung involvement
- CD4 cell count: In immune-compromised patients, if the CD4 count is less than 20, then there is a high likelihood of acquiring the infection
- Bronchoalveolar lavage: The lung and airways are examined with the help of a scope. Simultaneously, a tissue sample is taken from the lungs and sent to the laboratory for examination under a microscope by the pathologist
- Lung function test to help examine the structure and the efficiency of the lungs
Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
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Microbiology Of Pneumocystis Jiroveci Pneumonia
Pneumocystis is a genus of unicellular fungi found in the respiratory tracts of many mammals and humans. Distinct genomic variability exists between host-specific members of the genus. The organism was first described in 1909 by Chagas and then a few years later by Delanöes, who ultimately named the organism in honor of Dr. Carini after isolating it from infected rats. Years later, Dr. Otto Jirovec and his group isolated the organism from humans, and the organism responsible for PJP was renamed after him.
The taxonomic classification of the Pneumocystis genus was debated for some time. It was initially mistaken for a trypanosome and then later for a protozoan. In the 1980s, biochemical analysis of the nucleic acid composition of Pneumocystis rRNA and mitochondrial DNA identified the organism as a unicellular fungus rather than a protozoan. Subsequent genomic sequence analysis of multiple genes including elongation factor 3, a component of fungi protein synthesis not found in protozoa, further supported this notion.
The organism is found in 3 distinct morphologic stages, as follows:
- The trophozoite , in which it often exists in clusters
- The sporozoite
Pearls And Other Issues
Pneumocystis was once considered an AIDS-defining illness, but due to prophylaxis and antiretroviral therapy, the incidence of disease in HIV-infected individuals has been drastically reduced.
Symptoms include fever, exertional dyspnea, and dry cough, and the diagnosis should be suspected in anyone with compromised immunity such as cancer, transplant patients, or those on immunosuppressive therapies.
Treatment is with trimethoprim-sulfamethoxazole although other lines of therapy exist for those with allergies or severe illness.
Prophylaxis is also with trimethoprim-sulfamethoxazole and recommended in certain populations such as HIV- infected individuals with CD4+ counts less than 200 cells/microL or CD4+ less than 14%, presence of oropharyngeal candidiasis, and a CD4+ of 200-250 cells/microL when ART cannot be started or if monitoring of CD4+ count every 3 months is not possible.
The illness can be categorized as mild, moderate, or severe and new recommendations suggest the use of glucocorticoids in HIV-infected patients with a room air arterial blood gas partial pressure of oxygen that is less than or equal to 70 mm Hg, an alveolar-arterial gradient greater than or equal to 35 mm Hg, or hypoxia on pulse oximetry should receive steroids.
Any patients needing corticosteroids should be admitted to the hospital for monitoring and into the ICU for respiratory failure and continued monitoring.
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Diagnosis And Treatment Of Pneumocystis Pneumonia
The diagnosis of pneumocystis pneumonia is confirmed with the help of several tests. X-ray chest shows infiltration marking in the lungs with ground glass opacity of lungs. CT scan of chest, blood PCR test, sputum PCR test, bronchoscopic biopsy all assist in determining and confirming pneumocystis jiroveci causing pneumonia.
In majority of the treatment choice remains use of antibacterial medicines. The doctor after selecting appropriate dose of antibacterial medicine either recommends the patient to take it orally or may need intravenous administration of the drug.
Oral formulations are found to be effective in mild or moderate cases, while in serious life threatening pneumocystis pneumonia the drug is administered intravenous route. Steroids are often combined with the therapy.
What Is The Prognosis Of Pneumocystis Pneumonia
- Pneumocystis Pneumonia is a life-threatening infection that needs early and effective treatment
- It has an increased probability for recurrence. The severity of the condition increases with each episode of the infection each time the disease causes more severe damage to the lungs and other body organs
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How Common Is Pneumocystis Pneumonia
It is particularly common in people living with HIV/AIDS.1 PCP was rare before the 1980s, but the number of cases increased as the HIV/AIDS epidemic progressed. Now, PCP cases have dropped since doctors have been able to prescribe long-term preventative treatment for people living with HIV/AIDS.
Currently, PCP is most often seen in people who do not know they have acquired HIV. Often, being diagnosed with PCP results in testing and confirmation of an HIV diagnosis. Though PCP is less common today, it is still the most common opportunistic infection among those living with HIV.2
What Are The Causes Of Pneumocystis Pneumonia

Pneumocystis Pneumonia is caused by a fungus named Pneumocystis jiroveci. Individuals may be infected by inhaling the fungal spores from the environment.
- Generally, individuals with a healthy immune system carry the fungus in their lungs, but do not develop any signs and symptoms. When the immune system weakens , the fungus starts growing in the body, especially in the lungs, resulting in the signs and symptoms
- Pneumocystis Pneumonia is a serious infection in those with poor immune systems and is present in higher numbers among AIDS patients. It does not affect the normally healthy people
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Pneumocystis Pneumonia Diagnosis And Tests
A technician will use a microscope to look for traces of the fungus in fluid or tissue from your lungs. Your doctor will help you cough up fluid. Or they might use a special tool called a bronchoscope, which goes through your mouth and into your airways, to take a sample. They could also do a biopsy, using a needle or a knife to remove a tiny amount of cells from your lung.
A test called PCR makes copies of specific pieces of DNA so it can find smaller amounts of the fungus in samples.
You might also get a chest X-ray or blood tests to check for low oxygen levels or high levels of something called beta-D-glucan.
Can Pcp Be Prevented Or Avoided
If youre at risk of PCP because you have HIV, you may be able to lower your risk. A good medicine for preventing PCP is trimethoprim-sulfamethoxazole, or TMP-SMX. TMP-SMX is a combination of 2 medicines. Ask your doctor if you should be taking this medicine to prevent illness.
Talk to your doctor about medicines you might be able to take if you have other medical conditions that weaken your immune system.
The pneumonia vaccine does not protect you against PCP. It protects you against a different kind of pneumonia. There is no vaccine for PCP.
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What Are The Risk Factors For Pneumocystis Pneumonia
Following are the risk factors associated with Pneumocystis Pneumonia:
- Premature birth
- Post organ transplantation individuals on immunosuppressants
- Pneumocystis Pneumonia is most commonly associated with AIDS-affected individuals
- Cancer patients on chemotherapy drugs
It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.
Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.
Prevention Of Pneumocystis Pneumonia
With the rise of HIV/AIDS in the late 1980s, the number of PCP cases jumped drastically. It was estimated that 75 percent of people living with AIDS developed PCP during that time.1 Today, individuals living with HIV are often treated with antiretroviral therapy and are prescribed TMP/SMX as a long-term preventative treatment.1 Because of this, PCP cases are much less frequent.
PCP is still a major health concern for people living with HIV because it can be fatal.1 Because it is most likely to infect people with weakened immune systems, it is important to follow good hygiene practices.
If you think you may have PCP, contact your healthcare provider to be tested.
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Treatment Of Pneumocystis Jirovecii Pneumonia
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Trimethoprim/sulfamethoxazole
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Corticosteroids if PaO2 < 70 mm Hg
Treatment is with trimethoprim/sulfamethoxazole 4 to 5 mg/kg IV or orally 3 times a day for 14 to 21 days. Treatment can be started before diagnosis is confirmed because P. jirovecii cysts persist in the lungs for weeks. Adverse effects of treatment are more common among patients with acquired immunodeficiency syndrome and include rash, neutropenia, hepatitis, and fever.
Alternative regimens, which are also given for 21 days, are
-
Pentamidine 4 mg/kg IV once a day
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Atovaquone 750 mg orally 2 times a day
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Trimethoprim 5 mg/kg orally 4 times a day with dapsone 100 mg orally once a day
-
Clindamycin 300 to 900 mg IV every 6 to 8 hours with primaquine base 15 to 30 mg orally once a day
The major limitation of pentamidine is the high frequency of toxic adverse effects, including acute kidney injury, hypotension, and hypoglycemia.
Adjunctive therapy with corticosteroids is recommended for patients with a PaO2 < 70 mm Hg. The suggested regimen is prednisone 40 mg orally twice a day for the first 5 days, 40 mg orally once a day for the next 5 days , and then 20 mg orally once a day for the duration of treatment.
Overview Of Pneumocystis Jiroveci Pneumonia
Pneumocystis jiroveci pneumonia , formerly known as Pneumocystis carinii pneumonia , is the most common opportunistic infection in persons with HIV infection.
Pneumocystis first came to attention as a cause of interstitial pneumonia in severely malnourished and premature infants during World War II in Central and Eastern Europe. Before the 1980s, fewer than 100 cases of PJP were reported annually in the United States, occurring in patients who were immunosuppressed . In 1981, the Centers for Disease Control and Prevention reported PJP in 5 previously healthy homosexual men residing in the Los Angeles area.
P jiroveci is now one of several organisms known to cause life-threatening opportunistic infections in patients with advanced HIV infection worldwide. Well over 100,000 cases of PJP were reported in the first decade of the HIV epidemic in the United States in people with no other cause for immunosuppression.
While officially classified as a fungal pneumonia, PJP does not respond to antifungal treatment. Although a histopathologic demonstration of the organism is required for a definitive diagnosis , treatment should not be delayed. Treatment of PJP may be initiated before the workup is complete in severely ill high-risk patients. Treatment of PJP depends on the degree of illness at diagnosis, determined on the basis of the alveolar-arterial gradient. See the A-a Gradient calculator.
For other discussions on pneumonia, see the following:
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Can Pcp Be Prevented
If you have a disease that weakens your immune system, your healthcare provider will check your blood count regularly to see how strong your immune system is. If you have a weak immune system, your healthcare provider may give you medicine to prevent PCP before it happens.
Smokers are also at a greater risk of getting PCP. If you smoke, quitting will make your lungs healthier. It will also help keep you from getting lung infections like PCP.
The best way to prevent PCP if you have a weak immune system is to get regular blood tests and take preventive medicines when needed.Although flu and pneumococcal vaccines prevent people from getting certain types of pneumonia, they do not prevent PCP. In addition, people with weakened immune systems may not be candidates for their use. Talk to your healthcare provider about immunizations and which one may be appropriate for you.
Enhancing Healthcare Team Outcomes

PCP is best managed by an interprofessional team that includes a pulmonologist, infectious disease expert, pharmacist, intensivist, nurse, respiratory therapist and a dietitian. Once the diagnosis of PCP is made, the patient should be urged to discontinue smoking, as nicotine tends to worsen the symptoms and complicates therapy. Since most patients with PCP are frail, a dietary consult should be sought to increase calorie intake. The pharmacist should educate the patient on the importance of medication compliance. Patients receiving corticosteroids should be followed closely to monitor the side effects, which both nursing and pharmacy can do, reporting any concerns to the prescriber. Finally, these patients need lifelong follow up with monitoring of CD 4 counts, viral load, and progression of the disease.
Outcomes
In the past, PCP carried a high mortality, but over the past two decades, the mortality rates have dropped because of earlier diagnosis and treatment. Currently, at least 10-20% of patients with PCP will die. PCP carries an even worse prognosis in patients without HIV infection, with mortality rates over 50%. In general, the mortality rates are much higher when there is an underlying lung disorder and in patients who require mechanical ventilation.
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Signs And Symptoms Of Pcp
The most important thing that you should know about PCP is that it does show its symptoms during the early stages. However, if you are HIV-positive or have a weakened immune system and you experience the following symptoms, having PCP can be dangerous. The symptoms are:
- rapid breathing
- shortness of breath
PCP can also be graded according to its severity. PCP develops under three major stages:
Classification And Antigenic Types
Antigenic differences have been demonstrated between organisms obtained from humans and from lower mammals such as the rat, rabbit, and ferret. The taxonomy of P carinii has not been established. It is either a protozoan or a fungus, although membership in a heretofore undescribed category cannot be excluded. Recent studies show rRNA sequences, thymidylate synthase, dihydrofolate reductase, beta tubulin, mitochondrial DNA and chitin in the cell wall of P carinii more closely resemble fungi than protozoa. Eriksson’s treatise places P carinii in a new family, Pneumocystidaceae, and in a new order, Pneumocystidales .
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