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How to Diagnose Sinusitis
Your doctor will ask about your symptoms. A physical examination may reveal tenderness when your doctor taps or presses over the area of your sinuses or on the teeth in your upper jaw. In many cases of acute sinusitis, your doctor can diagnose sinusitis based on your symptoms and the physical exam. However, in recurrent and chronic sinusitis, other tests may be performed.
These tests may include:
This simple procedure involves shining a bright light (as from a flashlight) over your cheek in a dark room. If no light illuminates certain areas of your face, then it's likely that you have a sinus infection. This test, though, is not very reliable and is not commonly performed.
Your doctor might send a sample of your nasal discharge to a laboratory, where it can be tested for the presence of bacteria. Accurate evaluation of a nasal culture usually requires that the culture be obtained during nasal endoscopy. Some patients with chronic sinusitis may benefit from nasal culture. However, if you are healthy and have acute sinusitis, a nasal culture is usually not done.
Your doctor might send a sample of your nasal discharge to a laboratory to help determine other causes of your sinusitis.
X-rays of the sinuses are of limited use for diagnosing the presence of sinusitis within certain sinuses. Infection in other pairs of sinuses (such as the ethmoid sinuses) may require other types of imaging tests.
This type of imaging study can be very useful for diagnosing sinusitis, including in those areas not well visualized by sinus x-rays. CT scans are particularly effective for diagnosing chronic sinusitis.
Magnetic Resonance Imaging (MRI)
Your doctor may order this test if a tumor or fungal infection is suspected. Overall, MRI is not very helpful for diagnosing this condition.
Sweat Chloride Test
Blood Tests for Immune Function
These tests may be requested by your doctor if you have recurrent or chronic sinusitis.
This is a specialized test performed if all other tests fail to identify the cause of recurrent, chronic sinusitis.
If there's some confusion about your diagnosis, your doctor may choose to send you to a specialist to have a sinus puncture performed. This involves using a needle to remove a bit of fluid from within your sinuses. This fluid will then be sent to a lab to identify the infecting bacteria and to determine the most effective type of antibiotic for treatment. In most cases, nasal endoscopy with culture provides the same amount of information with less discomfort.
This procedure uses a slim, flexible tube with a fiberoptic light at the end (endoscope). It is inserted into your nose. Your doctor can inspect the the mucosa of the nose and the openings of the sinuses. If indicated, he can also take samples or biopsies through the endoscope for lab examination to look for fungus, tumor, or other uncommon cause of your sinusitis.