Legionnaires disease
Legionella pneumonia; Pontiac fever; Legionellosis; Legionella pneumophila; Legionnaires' diseaseLegionnaires disease is an infection of the lungs and airways. It is caused by Legionella bacteria.
Causes
The bacteria that cause Legionnaires disease have been found in water delivery systems. They can survive in the warm, moist air conditioning systems of large buildings, including hospitals.
Most cases are caused by the bacteria Legionella pneumophila. The rest of the cases are caused by other Legionella species.
Spread of the bacteria from person to person has not been proven.
Most infections occur in middle-aged or older people. In rare cases, children can get the infection. When they do, the disease is less severe.
Risk factors include:
- Alcohol use
- Cigarette smoking
- Chronic illnesses, such as kidney failure or diabetes
Kidney failure
Acute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...
Read Article Now Book Mark ArticleDiabetes
Diabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.
Read Article Now Book Mark Article - Long-term (chronic) lung disease, such as COPD
COPD
Chronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe. There are two main forms of COPD:Chroni...
Read Article Now Book Mark Article - Long-term use of a breathing machine (ventilator)
- Medicines that suppress the immune system, including chemotherapy and steroid drugs
- Older age
Symptoms
Symptoms tend to get worse during the first 4 to 6 days. They most often improve in another 4 to 5 days.
Symptoms may include:
- General discomfort, loss of energy, or ill feeling (malaise)
- Headache
- Fever, shaking chills
- Joint pain, muscle aches and stiffness
- Chest pain
- Cough that does not produce much sputum or mucus (dry cough)
- Coughing up blood (rare)
- Diarrhea, nausea, vomiting, and abdominal pain
- Shortness of breath
Exams and Tests
The health care provider will perform a physical exam. Abnormal sounds, called crackles, may be heard when listening to the chest with a stethoscope.
Tests that may be done include:
- Arterial blood gases
Arterial blood gases
Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine the acidity (pH) of your blood.
Read Article Now Book Mark Article - Blood cultures or other tests to identify the bacteria
- Bronchoscopy to view the airways and diagnose lung disease
Bronchoscopy
Bronchoscopy is a test to view the airways and diagnose lung disease. It may also be used during the treatment of some lung conditions.
Read Article Now Book Mark Article - Chest x-ray or CT scan
Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
Read Article Now Book Mark ArticleCT scan
A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen....
Read Article Now Book Mark Article - Complete blood count (CBC), including white blood cell count
CBC
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
Read Article Now Book Mark ArticleWhite blood cell count
A WBC count is a blood test to measure the number of white blood cells (WBCs) in the blood. It is a part of a complete blood count (CBC). WBCs are a...
Read Article Now Book Mark Article - Liver blood tests
Liver blood tests
Liver function tests are common tests that are used to see how well the liver is working. Tests include:AlbuminAlpha-1 antitrypsinAlkaline phosphata...
Read Article Now Book Mark Article - Tests and cultures on sputum to identify Legionella bacteria
- Urine tests to check for Legionella pneumophila bacteria
- Molecular tests with polymerase chain reaction (PCR)
Treatment
Antibiotics are used to fight the infection. Treatment is started as soon as Legionnaire disease is suspected, without waiting for results of any lab test.
Other treatments may include receiving:
- Fluids through a vein (IV)
- Oxygen, which is given through a mask or breathing machine
- Medicines that are breathed in to ease breathing
Outlook (Prognosis)
Legionnaires disease can be life threatening. The risk of dying is higher in people who:
- Have long-term (chronic) diseases or compromised immune systems
- Become infected while in the hospital
- Are older adults
When to Contact a Medical Professional
Contact your provider right away if you have any type of breathing problem and think you have symptoms of Legionnaires disease.
References
Edelstein PH, Roy CR. Legionnaires' disease and Pontiac fever. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 232.
Marrie TJ. Legionella infections. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 298.
Legionnaire disease - organism legionella - illustration
Legionnaire disease was first described in 1976 after an outbreak of fatal pneumonia at a Legionnaires convention. The newly described organism which caused the disease was named Legionella pneumophila, shown in this picture. (Image courtesy of the Centers for Disease Control and Prevention.)
Legionnaire disease - organism legionella
illustration
Legionnaire disease - organism legionella - illustration
Legionnaire disease was first described in 1976 after an outbreak of fatal pneumonia at a Legionnaires convention. The newly described organism which caused the disease was named Legionella pneumophila, shown in this picture. (Image courtesy of the Centers for Disease Control and Prevention.)
Legionnaire disease - organism legionella
illustration
Review Date: 1/22/2023
Reviewed By: Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 01/19/2024.