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Tests and diagnosis
By Mayo Clinic staff
Your medical history and physical examination help determine which tests your doctor will order. The goal of testing is to identify the underlying cause of your chronic cough.
Imaging tests
- X-rays. Although a routine chest X-ray won't reveal the most common reasons for a cough — postnasal drip, acid reflux or asthma — it may be used to check for lung cancer and other lung diseases. An X-ray of your sinuses may reveal evidence of a sinus infection.
- Computerized tomography (CT scan). A CT scan takes X-rays from many different angles and then combines them to form cross-sectional images. This technique can provide more-detailed views of your lungs, but it's not a routine exam in the initial evaluation of a chronic cough. CT scans may also be used to check your sinus cavities for pockets of infection.
Lung function tests
These simple, noninvasive tests measure how much air your lungs can hold and how fast you can exhale. Sometimes you may also have an asthma challenge test, which checks how well you can breathe before and after inhaling a drug called methacholine (Provocholine).
Lab tests
If the mucus that you cough up is discolored, your doctor may want you to test a sample of it for bacteria.
Scope tests
These tests use a thin, flexible tube equipped with a light and camera to visualize structures within your body. To evaluate possible causes of chronic cough, this equipment may be inserted into your:
- Windpipe (trachea). This type of test, called a bronchoscopy, checks your bronchial tubes for signs of infection or obstruction.
- Nostrils. The video camera can help your doctor assess the status of the nasal mucosa and the openings to your sinuses.
- Esophagus. If your doctor suspects acid reflux is causing your chronic cough, he or she may want to examine the inside of your esophagus — the tube that connects your mouth to your stomach.
- Cough. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/cough/cough_all.html. Accessed March 11, 2011.
- Chung KF, et al. Cough. In: Mason RJ, et al. Murray and Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa.: Saunders Elsevier; 2010. http://www.mdconsult.com/das/book/body/192068760-2/0/1288/0.html. Accessed March 11, 2011.
- Kraft M. Approach to the patient with cough. In: Goldman L, et al. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/191371208-2/0/1492/0.html#. Accessed March 11, 2011.
- Silvestri RC, et al. Evaluation of subacute and chronic cough in adults. http://www.uptodate.com/home/index.html. Accessed March 11, 2011.
- Weinberger SE, et al. Treatment of subacute and chronic cough in adults. http://www.uptodate.com/home/index.html. Accessed March 14, 2011.
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