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."
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:
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.
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).
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.
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.
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.