Diagnosis

Patients who have sinusitis symptoms that do not clear up within a few days, are severe, or are accompanied by high fever or acute illness should see a doctor. It should be noted, however, that only one-half to two-thirds of patients with such symptoms actually have sinusitis. Some experts complain that too many patients are diagnosed with true sinusitis and given unnecessary antibiotics when their symptoms would actually resolve easily in days with over-the-counter medications or no drugs at all. Others believe that true sinusitis is often mistakenly diagnosed as an allergy and not treated, which could lead to serious illness.

The first goal in diagnosing sinusitis is to rule out other possible causes of symptoms, and then determine:

• The site where the infection has occurred
• Whether the condition is acute or chronic
• The organism causing the infection (if possible)

Ruling Out Other Causes of Sinusitis Symptoms

Ruling Out Sinus Symptoms Due to Cold or Flu Viruses. It is often difficult to tell when a viral infection converts to a bacterial infection. Studies have found that between 40 - 85% of patients with the common cold show signs of inflamed sinuses on x-rays or CT scans. A cold, however, unlike sinusitis, typically clears up without treatment within a week. (Only about 0.5 - 2% of adults with viral colds or flus actually develop bacterial infections.) In general, the doctor should suspect a bacterial infection under the following circumstances:

• If sinus symptoms persist for 10 days or longer after a cold or flu, or
• If symptoms become worse after 5 to 7 days

Ruling Out Allergies. Symptoms of both sinusitis and allergic rhinitis include nasal obstruction and congestion. The conditions often occur together. People with allergies and no sinus infection may have:

• Thin, clear, and runny nasal discharge
• Itchy nose, eyes, or throat (do not occur with bacterial sinusitis)
• Recurrent sneezing
• Symptoms of allergies appear only during exposure to allergens

Ruling Out Migraine and Other Headaches. Many primary headaches, particularly migraine or cluster, may closely resemble sinus headache. In fact, results presented at a 2004 meeting of the American Headache Society suggest that 90% of people who thought they had a sinus headache actually had migraines. Migraine and sinus headaches may even coexist in many cases. Sinus headaches are usually more generalized than migraines, but it is often difficult to tell them apart, particularly if headache is the only symptom of sinusitis. The following symptoms suggest a migraine rather than a sinus headache:

• The headache is recurrent
• It has a significant impact on daily activities
• The headache does not get worse over time

Ruling Out Neuralgia. In some cases, headache that persists after successful treatment of chronic sinusitis may be due to neuralgia (nerve-related pain) in the face. This condition requires specific drugs, such as tricyclic antidepressants or carbamazepine. Trials using such drugs may identify patients with neuralgia and help avoid unnecessary invasive treatments for chronic sinusitis.

Ruling Out Other Conditions. A number of other conditions can mimic sinusitis. They include:

• Dental problems
• A foreign object in the nasal passage
• Temporal arteritis (headache caused by inflamed arteries in the head and neck)
• Persistent upper respiratory tract infections
• Chronic fatigue syndrome (CFS) or fibromyalgia. However, researchers reported in the Archives of Internal Medicine that there may be a link between CFS and sinusitis. In the study, patients with unexplained chronic fatigue were 9 times more likely to suffer sinus problems than those without fatigue.
• Temporomandibular disorders (problems in the joints and muscles of the jaw hinges)
• Vasomotor rhinitis, a condition in which the nasal passages become congested in response to irritants or stress. It often occurs in pregnant women.

Diagnostic Approach to Acute Sinusitis

Medical History. The patient should describe all symptoms such as nasal discharge and specific pain in the face and head, including eye and tooth pain.

After assessing symptoms, the doctor should take a thorough medical history of the patient:

• Any history of allergies or headaches
• Recent upper respiratory infection (colds, flus, infection)
• History of sinusitis episodes that is unresponsive to antibiotic treatment. (In such cases, the doctor will usually diagnose chronic or recurrent acute sinusitis and refer the patient to a specialist for more advanced testing.)
• Exposure to cigarette smoke or other environmental pollutants
• Recent travel
• Recent dental procedures, particularly if there is pain toward the back of the mouth
• Medications being taken (particularly decongestants)
• Any known structural abnormalities in the nose and face
• Injury to the head or face
• History of medical conditions, such as chronic fatigue syndrome or fibromyalgia, which can produce tender areas in the face or sinus regions and nonspecific symptoms of ill health.
• Any family history of allergies, immune disorders, cystic fibrosis, or immotile cilia syndrome
• In small children with sinusitis, whether they attend a day care center or nursery school

Physical Examination

The doctor will press the forehead and cheekbones to check for tenderness and check for other signs of sinusitis, including yellow to yellow-green nasal discharge. The doctor will also check the inside of the nasal passages using a device with a bright light to check the mucus and look for any structural abnormalities.

Laboratory Tests

In some cases, tests may be used to detect that presence of immune factors in sinus tissues that would suggest persistent inflammation. Such findings would strongly suggest a chronic or allergic condition. In 2005, a new laboratory test became available for diagnosing chronic sinusitis. The CRS Fungal Profile tests mucus samples for eosinophil major basic protein (a protein involved in allergic and inflammatory reactions) and a type of fungi.

Nasal Endoscopy (Rhinoscopy)

Nasal endoscopy, or rhinoscopy, is now used for diagnosing chronic and recurrent acute sinusitis and for differentiating between allergies and true acute sinusitis. It involves the insertion of a flexible tube into the nasal passage and the use of a fiberoptic light that enables the doctor to see inside the sinuses. Endoscopy allows detection of even very small abnormalities in the sinuses. It can determine whether surgery is necessary and if medications are having any effect. Bacterial cultures can also be taken from samples removed using endoscopy. (Endoscopy is also used for treating sinusitis.)

Imaging Techniques

Computer Tomography. Computed tomography (CT) scanning is the best method for viewing the paranasal sinuses. There is little relationship, however, between symptoms in most patients and findings of abnormalities on a CT scan. CT scans are recommended for acute sinusitis only if there is a severe infection, complications, or a high risk for complications. CT scans are useful for diagnosing chronic or recurrent acute sinusitis and for surgeons as a guide during surgery. They show inflammation and swelling and the extent of the infection, including that in deep hidden air chambers missed by x-rays and nasal endoscopy. Often, they can detect the presence of fungal infections.

X-Rays. Until the availability of endoscopy and CT scans, x-rays were commonly used. They are not as accurate, however as these procedure in identifying abnormalities in the sinuses. For example, more than one x-ray is needed for diagnosing frontal and sphenoid sinusitis. X-rays do not detect ethmoid sinusitis at all, which can be the primary site of an infection that has spread to the maxillary or frontal sinuses.

Magnetic Resonance Imaging. MRI is not as effective as CT in defining the paranasal anatomy and therefore is not typically used to image the sinuses for suspected sinusitis. MRI is also more expensive than CT. However, it can help rule out fungal sinusitis and may help differentiate between inflammatory disease, malignant tumors, and complications within the skull. It may also be useful for showing soft tissue involvement.

Transillumination

Transillumination is a procedure aimed at visualizing maxillary and frontal sinuses. First the doctor shines a bright light against the patient's cheek or forehead in a completely darkened room. If the sinuses are clear, the doctor will observe a glow on the hard palate of the open mouth or in the areas of the cheek where the sinus passages are located. It is fast, safe, and inexpensive, but it is useful only in adults and only to rule out any problems. It has largely been supplanted by more accurate diagnostic techniques.

Sinus Puncture and Bacterial Culture

Sinus puncture with bacterial culture is the gold standard for diagnosing a bacterial sinus infection. It is invasive, however, and is performed only when antibiotics have not worked. Sinus puncture involves using a needle to withdraw a small amount of fluid from the sinuses. It requires a local anesthetic and is performed by a specialist. The fluid is then cultured to determine what type of bacteria is causing sinusitis.