Granulomatous Lung Diseases

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Lung granulomas are clumps of chronically inflamed tissue usually caused by a fungal or bacterial infection. They can also form due to noninfectious diseases, or from irritation of lung tissue by a foreign body. Granulomas consist of clusters of certain immune system cells and may eventually progress to localized areas of scar tissue in the lungs.


Tuberculosis, or TB, is a bacterial infection caused by Mycobacterium tuberculosis. The disease can spread from person to person through air that is contaminated with the tuberculosis organisms. Once inhaled, the bacteria infect the lungs. In an effort to contain the bacterial invasion, the immune system works to wall off the infected areas, producing granulomas. If the immune system is not successful in killing the organisms, active TB results, producing symptoms of weight loss, night sweats, fever and cough.

Most people infected with TB bacteria heal completely and never experience signs, or symptoms of the illness. One infected person in 10, however, may develop active tuberculosis at some point, according to the National Institute of Allergy and Infectious Diseases.


Histoplasmosis is another infectious disease that produces lung granulomas. It is caused by inhaling spores of the fungal organism Histoplasma capsulatum. Most infections with histoplasma produce no symptoms, or only mild illness. More severe forms of histoplasmosis occur as either self-limiting, acute disease, chronic lung disease or a very serious progressive form that affects many organ systems.

Severe disease is more common in infants and those with weakened immunity. When the infection is bad enough to produce symptoms, a person will have fever and a cough and feel generally unwell. This acute form usually resolves within two to six weeks, according to Merck Manuals Online Medical Library. The chronic form causes weight loss, fever and breathing problems. Most people slowly recover, but this form can lead to destruction of lung tissue and eventual death. The progressive form causes fever and weakness and may also cause enlargement of the lymph nodes, spleen and liver. Without treatment, this form is usually fatal.


Sarcoidosis is an inflammatory disease potentially involving many different organs, but most often affects the lungs. Many granulomas can form in various parts of the body, and symptoms will vary depending on the areas involved.

When granulomas form in the lungs, a person may experience coughing, wheezing or chest pain. Fatigue, night sweats, and weight loss are also common to the disease.

Sarcoidosis has a variable course. Many people with the illness will have few symptoms or the illness might resolve. Others have severe disease affecting the heart and brain. Although rare, sarcoidosis sometimes results in death.