What are the Causes of Lung Nodules?

There are several reasons the lungs may develop nodules, small bumps on the surface of the pulmonary tissue, including cancer, tuberculosis, or a fungal infection. These lesions are typically found by imaging tests such as x-rays, MRI, and CAT scan exams. In most cases, lung nodules are non-cancerous and can be handled easily by treating the root cause of the nodule. Regardless of the cause, pulmonary nodules may appear singularly or in clusters or groups, and the patient may experience shortness of breath, difficulty breathing, and other common lung symptoms before diagnosis. People experiencing any type of lung or respiratory problems are advised to seek the advice of their physician as quickly as possible.

Cancer is the cause of lung nodules most feared by many people. The appearance of these lesions on the lung tissue may be an indication of lung cancer, though in many cases, the nodules are benign. Once the patient's medical team has discovered the nodules, the doctor may order a biopsy of the affected tissue to further examine the cause. During a biopsy, the patient is sedated and a needle is inserted into the nodule to remove a small sample of the tissue for lab examination. These test results are used to diagnosis the lung nodule's cause and begin appropriate treatment.

Another common cause of lung nodules is tuberculosis, a pulmonary disease characterized by shortness of breath and coughing. Tuberculosis (TB) is an air-borne bacterial infection that most commonly affects people with a weak or compromised immune system. In addition to lung imaging exams, a person can be tested easily for TB with a skin prick test. Small particles of the bacteria are placed just under the first layers of the skin, normally on the inside of the forearm, and left for 24 hours. If the skin reacts, tuberculosis bacteria are present, and the patient should be treated accordingly.

Lung nodules may also be caused by a host of fungal infections, including histoplasmosis. The spores of this fungus are inhaled and thrive in the nutrient and oxygen rich environment of the lung tissue. This form of fungus is often found in bird droppings, making urban dwellers more likely to contract this type of infection. With the use of oral medications, doctors are able to kill the infection and restore lung health. Most physicians recommend avoiding large flocks of birds, especially in a city setting where the concentration of feces is likely to be high.