Pneumonia - weakened immune system
Pneumonia in immunodeficient patient; Pneumonia - immunocompromised host; Cancer - pneumonia; Chemotherapy - pneumonia; HIV - pneumonia
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:
- Hospital-acquired pneumonia
- Pneumocystis jiroveci (previously called Pneumocystis carinii) pneumonia
- Pneumonia cytomegalovirus
- Fungal pneumonia
- Viral pneumonia
- Walking pneumonia
Everyone coughs from time to time. You might pick up a cold, have an allergy, or just get a tickle from something irritating your throat. But if you're really hacking and coughing up yellow or green mucus, and you've also got a fever, chills, and shortness of breath, you may have picked up a more serious infection, called pneumonia. And sometimes pneumonia's symptoms aren't as obvious. Pneumonia is caused by an infection in your lung. Bacteria or viruses like these can sometimes get into your lungs through your nose or mouth and make you sick. You're more likely to get pneumonia if you've got a problem with your immune system that makes it harder to fight off infections. You're also at greater risk if you've got a lung disease like COPD or cystic fibrosis, you've recently had the flu, or you're exposed to cigarette smoke. People who live in nursing homes are also more likely to get pneumonia. With pneumonia, you may cough up greenish or yellow phlegm. You also may run a fever and have the chills. Pneumonia can make it hard to breathe. You may feel like you've run up a flight of stairs when you were just sitting still. Your doctor can tell that you have pneumonia and not just a cold by listening with a stethoscope for crackle sounds in your chest. You may need a chest x-ray or blood tests to know for sure that you have pneumonia. If bacteria caused your pneumonia, your doctor can give you antibiotics, drugs that kill bacteria. Keep taking the antibiotic until you finish the whole prescription so you don't re-infect yourself. To help loosen all of that mucus clogging your lungs, breathe in the warm mist from a humidifier and drink plenty of water. Take it easy too. Don't try to run back to work and infect everyone else. Rest until you feel better. Whatever you do, don't smoke, it will only make your pneumonia worse. If your pneumonia is really severe or you have another serious health problem, your doctor may recommend that you get treated in the hospital. While there, you'll get antibiotics and fluids through a vein. You may also be given oxygen to help you breathe easier. The best way to deal with pneumonia is to avoid getting it in the first place. Older adults, children, and people with serious conditions like diabetes, asthma, cancer, and emphysema should talk to their doctor about getting vaccinated against pneumonia and the illnesses that cause it. Once you get treated, your pneumonia should clear up within a couple of weeks. Your doctor may want to check your lungs to make sure they're clear. Sometimes pneumonia can lead to serious lung complications, so call your doctor right away if your breathing problems get worse, you have chest pain, or you cough up blood.
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:
Symptoms may include:
- Cough (may be dry or produce mucus-like, greenish, or pus-like sputum)
- Chills with shaking
- 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
Your health care provider may hear crackles or other abnormal breath sounds when listening to your chest with a stethoscope. Decreased volume of breath sounds is a key sign. This finding 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
- COVID test
- Lung biopsy (in certain cases)
- Serum cryptococcus antigen test
- Serum galactomannan test
- Galactomannan test from bronchial alveolar fluid
- Sputum culture
- Sputum Gram stain
- Sputum immunofluorescence tests (or other immune tests)
- Urine tests (to diagnose Legionnaire's disease or Histoplasmosis)
Antibiotics or antifungal medicines may be used, depending on the type of germ that is causing the infection. Antibiotics are not helpful for viral infections, but newer medicines may treat some viral infections for example COVID-19. 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 fungus.
- The person has a very weak immune system.
Complications may include:
- Respiratory failure (a condition in which a patient can't take in oxygen and get rid of carbon dioxide without the use of a machine to deliver breaths.)
- Spread of the infection
When to Contact a Medical Professional
Contact your provider if you have a weakened immune system and you have symptoms of pneumonia.
If you have a weakened immune system, you may receive daily antibiotics to prevent some types of pneumonia.
Ask your provider if you should receive the influenza (flu), pneumococcal (pneumonia), and COVID-19 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:
- Consider wearing a face mask when outside of your house.
- 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).
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Perkins J, Waasdorp CP. The immunocompromised patient. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 182.
Sifri CD, Marr KA. Approach to fever and suspected infection in the immunocompromised host. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 265.
Wunderink RG, Restrepo MI. Pneumonia: considerations for the critically ill. In: Parrillo JE, Dellinger RP, eds. Critical Care Medicine: Principles of Diagnosis and Management in the Adult. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 40.
Last reviewed on: 5/19/2023
Reviewed by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.