How is the condition diagnosed?

Diagnosis begins with the history and physical exam. This may be all that is needed in some cases. In other cases, further tests are needed.

Different tests may be ordered, depending on the suspected cause. A chest x-ray is commonly done to look for infections, tumors, and lung or heart diseases. Special x-rays such as a chest CT scan will look for tumors, or a cranial MRI can look for nervous system damage. A test of the sweat called a chloride sweat test may be done if cystic fibrosis is suspected.

In some cases, a procedure called endoscopy or bronchoscopy may be used. A small tube is inserted through the mouth and into the throat and windpipe. The tube has a light and camera on the end of it. This allows the doctor to see the inside of the throat and airway. This test is useful to detect conditions such as vocal cord paralysis, or a tumor or cancer in the throat or lungs.