Coordinated Health


Pneumonia is a lung infection that can be caused by many different germs, including bacteria, viruses, and fungi.

This article discusses pneumonia that occurs in a person whose ability to fight infection is greatly reduced because their immune system is weakened and not working properly. Such disease is referred to as “pneumonia in an immunocompromised host.”

See also:

  • Hospital-acquired pneumonia
  • Pneumocystis jirovecii (previously called Pneumocystis carinii) pneumonia
  • Pneumonia – cytomegalovirus
  • Pneumonia
  • Viral pneumonia
  • Walking pneumonia

Alternative Names

Pneumonia in immunodeficient patient; Pneumonia – immunocompromised host

Causes, incidence, and risk factors

People whose immune system is not working well are less able to fight off germs. Because of this state, they are more likely to become infected by germs that typically do not cause disease in healthy people. They are also more vulnerable to the usual causes of pneumonia, which can affect anyone.

Your immune system may be weakened or not work well because of:

  • Bone marrow transplant
  • Chemotherapy
  • HIV infection
  • Leukemia, lymphoma, and other conditions that harm your bone marrow
  • Medications (including steroids, and those used to treat cancer and control autoimmune diseases)
  • Organ transplant (including kidney, heart, and lung)


  • Cough (may be dry or produce mucus-like, greenish, or pus-like sputum)
  • Chills with shaking
  • Easy fatigue
  • Fever
  • General discomfort, uneasiness, or ill feeling (malaise)
  • Headache
  • 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:

  • Excessive sweating or night sweats
  • Joint stiffness (rare)
  • Muscle stiffness (rare)
  • Swollen glands

Signs and tests

The doctor may hear crackles or other abnormal breath sounds when listening to the chest with a stethoscope. Reduced or absent breath sounds can be an important sign, because it may mean there is a buildup of fluid between the chest wall and lung, called a 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
  • 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. Patients usually must stay in the hospital, at least during the early stages of the illness.

Oxygen and respiratory treatments to remove fluid and mucus are often needed.

Expectations (prognosis)

The outcome may be poor if the pneumonia is caused by a virus or fungus, or if the patient’s immune system is severely weakened.


  • Respiratory failure (the person needs machines to assist in breathing)
  • Sepsis
  • Spread of the infection
  • Death

Calling your health care provider

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 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

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).