Pneumonia - weakened immune system

Pneumococci organism — This picture shows the organism Pneumococci. These bacteria are usually paired (diplococci) or appear in chains. Pneumococci are typically associated with pneumonia, but may cause infection in other organs such as the brain (pneumococcal meningitis) and blood stream (pneumococcal septicemia). (Image courtesy of the Centers for Disease Control and Prevention.)

Also known as: Pneumonia in immunodeficient patient and Pneumonia - immunocompromised host

Definition

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

This article discusses describes 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."

Causes, incidence, and risk factors

A person whose immune system is not working well is less able to fight off germs. Because of this, 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
Certain medications (including steroids and those used to treat cancer)
Chemotherapy
HIV infection
Leukemia, lymphoma, and other conditions that harm your bone marrow
Organ transplant (such as kidney, heart, or lung)

Symptoms

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 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.

Tests may include:

Arterial blood gases
Blood culture
Bronchoscopy
Chest CT scan (in certain cases)
Chest x-ray
Complete blood count
Lung biopsy (in certain cases)
Sputum gram stain
Urine tests (to diagnose Legionnaire's disease)

Treatment

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.

Complications

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 are immunosuppressed and you have symptoms of pneumonia.

Prevention

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 flu and pneumonia vaccines.

Practice good hygiene. Thoroughly ash 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).

References

American Thoracic Society. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005 Feb 15;171(4):388-416.

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.

Young LS. Approach to fever and suspected infection in the compromised host. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 303.

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Review date:: June 10, 2009
Reviewed by:: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PhD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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