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Pneumonia - weakened immune system
Pneumonia is a lung infection. It can be caused by many different germs, including bacteria, viruses, and fungi.
This article discusses pneumonia that occurs in a person who has a hard time fighting off infection because of problems with the immune system. This type of disease is called "pneumonia in an immunocompromised host."
Related conditions include:
Pneumonia in immunodeficient patient; Pneumonia - immunocompromised host
People whose immune system is not working well are less able to fight off germs. This makes them prone to infections from germs that do not often cause disease in healthy people. They are also more vulnerable to regular causes of pneumonia, which can affect anyone.
Your immune system may be weakened or not work well because of:
- Cough (may be dry or produce mucus-like, greenish, or pus-like sputum)
- Chills with shaking
- Easy fatigue
- General discomfort, uneasiness, or ill feeling (malaise)
- Loss of appetite
- Nausea and vomiting
- Sharp or stabbing chest pain that gets worse with deep breathing or coughing
- Shortness of breath
Other symptoms that may occur:
- Heavy sweating or night sweats
- Stiff joints (rare)
- Stiff muscles (rare)
Exams and Tests
The doctor may hear crackles or other abnormal breath sounds when listening to your chest with a stethoscope. Lack of breath sounds key sign. This may mean there is a buildup of fluid between the chest wall and lung (pleural effusion).
Tests may include:
- Arterial blood gases
- Blood chemistries
- Blood culture
- Bronchoscopy (in certain cases)
- Chest CT scan (in certain cases)
- Chest x-ray
- Complete blood count
- Lung biopsy (in certain cases)
- Serum Cryptococcus antigen test
- Serum ß-glucan test
- Serum galactomannan test
- Sputum Gram stain
- Sputum immunofluorescence tests (or other immune tests)
- Urine tests (to diagnose Legionnaire's disease)
Antibiotics or antifungal medicines are used, depending on the type of germ that is causing the infection. You may need to stay in the hospital during the early stages of the illness.
Oxygen and treatments to remove fluid and mucus from the respiratory system are often needed.
Factors that may lead to a worse outcome include:
- The pneumonia that is caused by a virus or fungus.
- The patient has a very weak immune system.
- Respiratory failure (the person needs machines to assist breathing)
- Spread of the infection
When to Contact a Medical Professional
Call your health care provider if you have a weakened immune system and you have symptoms of pneumonia.
If you have a weakened immune system and are in the hospital, you may receive daily antibiotics to prevent some types of pneumonia.
Ask your health care provider if you should receive the influenza ("flu") and pneumococcal ("pneumonia") vaccines.
Practice good hygiene. Thoroughly wash your hands with soap and water:
- After being outdoors
- After changing a diaper
- After doing housework
- After going to the bathroom
- After touching body fluids, such as mucus or blood
- After using the telephone
- Before handling food or eating
Other things you can do to reduce your exposure to germs include:
- Keep your house clean.
- Stay away from crowds.
- Ask visitors who have a cold to wear a mask or not to visit.
- Do not do yard work or handle plants or flowers (they can carry germs).
Donnelly JP, Blijlevens NMA, DePauw BE. Infections in the immunocompromised host. In: Mandell GL, Bennett JE, Dolin R eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. 7th ed. Philadelphia, PA: Saunders Elsevier; 2009:chap 308.
Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007 Mar 1;44 Suppl 2:S27-72.
Marr KA. Approach to fever and suspected infection in the compromised host. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 289.
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.