Causes and Diagnoses

Causes and Diagnoses of Sarcoidosis

The exact cause of sarcoidosis is unknown. Sarcoidosis researchers believe that inhaling bacteria, viruses or chemicals can cause an overreaction of the immune system, causing the body to attack itself. The immune system cells cluster and form into small growths, or granulomas.

There is evidence that some people are genetically predisposed to developing sarcoidosis. Some risk factors include:

  • Age: Sarcoidosis often strikes between 20 and 40 years of age.
  • Gender: Women are more likely to develop sarcoidosis.
  • Race: Rates are higher among African-Americans and the effects may be more severe.
  • Family history: You have a higher chance of developing sarcoidosis if someone in your family has had it.

Diagnosing sarcoidosis

Diagnosis of sarcoidosis begins with a physical exam and discussion of your symptoms. Other tests may include:

  • X-ray: A chest X-ray can identify the presence of granuloma, lung damage or enlarged lymph nodes.
  • Pulmonary function testing (PFT): Tests to determine the severity of your respiratory impairment, often using a spirometer, measure the volume of air inhaled and exhaled by your lungs.
  • Computed tomography (CT) scan: This test combines X-ray and computer technology to produce detailed cross-sectional images of your chest cavity.
  • Bronchoscopy: An endoscope (a thin, flexible tube with a light and camera on the end) is inserted into your airway to check for scarring and take a biopsy of the lung tissue.
  • Bronchoalveolar lavage: Using a bronchoscope, a sterile saline solution is introduced into the lungs and then suctioned out. The lung cells that come out with the solution can be examined for infection or other causes of sarcoidosis.
  • Positron emission tomography (PET) scan: The PET scan will light up the nodule if it is rapidly growing or active. The brighter the nodule appears on the PET scan, the more likely that it is cancer. The PET scan also looks at the rest of the body and can identify if the cancer has spread.
  • Blood test: Blood samples can be tested to determine overall health as well as liver and kidney function.
  • Eye exam: An eye exam with dilation can reveal damage caused by sarcoidosis.

Diagnostic Tests