Conditions: Sinus Infections

also known as sinusitis

What are the sinuses?

What is sinusitis?

Sinusitis, also known as paranasal sinusitis, or rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms.  Sinusitis affects about 1 in 8 adults annually and generally occurs when viruses or bacteria infect the sinuses (often during a cold) and begin to multiply. Part of the body’s reaction to the infection causes the sinus lining to swell, blocking the channels that drain the sinuses. This causes mucus and pus to fill up the nose and sinus cavities. Common symptoms include thick nasal mucus, resistance to nasal airflow, and facial pain or pressure.  Other signs and symptoms may include fever, headaches, a poor sense of smell, sore throat, and a cough.  The cough is often worse at night. Serious complications are rare.

 It is defined as acute sinusitis if it lasts less than 4 weeks, and as chronic sinusitis if it lasts for more than 12 weeks. The difference is important because the treatment is different for each. When sinusitis has been present for a period between 4 and 12 weeks, it is called “subacute” sinusitis. When acute sinusitis occurs four or more times per year with no signs or symptoms in-between sinus infections, this is called recurrent acute sinutitis.

Overall, most sinus infections are acute, and most acute sinusitis is caused by a virus, in which infection and symptoms usually come and go within a week. Since viral infections resolve spontaneously, and antibiotics (in the usual sense of the word) are ineffective against viruses, antibiotic are not indicated when the duration of symptoms is less than 10 days. As the duration of symptoms increases, the statistical likelihood that the infection is bacterial increases, so treatment strategies shift toward treating bacteria after 10 days since onset of symptoms. Occasionally, symptoms of a viral sinusitis begin to improve, and then bacteria seize the opportunity to thrive in the inflamed sinuses, leading to a bacterial superinfection, with a corresponding worsening of symptoms. This too shifts treatment toward antibiotics.

How is acute sinusitis diagnosed?

Generally, acute sinusitis is diagnosed when a person has the following symptoms:

1. Colored (not clear) mucus drainage running or being blown out the front of the nose

   and

2. One or both of:

   (a) a stuffy, congested, or blocked nose;

   (b) pain/pressure/fullness in the face, head, or around the eyes.

While imaging such as CT or MRI may demonstrate acute sinusitis, the diagnosis is usually made clinically with moderate accuracy by signs and symptoms.

A sensation of “post-nasal drip” or “sinus drainage” into the throat, not meeting the above criteria, is often due to laryngopharyngeal reflux.

A sensation of facial pain is not definitively diagnostic for sinusitis, as other conditions may cause facial pain. (See nerves of the face.)

How can I tell if my acue sinusitis is caused by viruses or bacteria?

Acute viral sinusitis is likely if you have been sick less than 10 days and are not getting worse.

Acute bacterial sinusitis is likely when

1. One do not improve at all within 10 days of getting sick (as viruses are usually resolved before 10 days)

   or

2. When symptoms get worse within 10 days after beginning to get better. This is characteristic of a situation in which a viral infection creates an environment in which bacteria have an advantage, and bacteria create a “piggyback” infection (also known as a superinfection). Viral sinusitis changing to a bacterial sinusitis occurs in about 1% of the time among adults and about 8% of the time in children.

   Note that the number of days one has been sick can include symptoms other than sinusitis, such as cough, when symptoms of sinusitis could develop on day 4 or 5, for example. Overall, viral sinusitis

Why is it important to tell if sinusitis is caused by bacteria?

Because sinusitis is treated differently according to cause, acute viral sinusitis does not benefit from antibiotics, but some patients with bacterial sinusitis may get better with an antibiotic.

How is chronic sinusitis diagnosed?

Twelve weeks or longer of 2 or more of the following signs and symptoms:

• drainage of discolored mucus (out the nostrils, to the throat, or both)

• nasal obstruction (congestion, or airway resistance)

• facial pain/pressure/fullness, or

• decreased sense of smell.

  AND inflammation is documented by one or more of the following findings by a physician:

• purulent (not clear) mucus or edema in the middle meatus or anterior ethmoid region,

• polyps in nasal cavity or the middle meatus, and/or

• radiographic imaging showing inflammation of the paranasal sinuses, usually by CT or MRI scans.

Other causes of similar symptoms:

A sensation of “post-nasal drip” or “sinus drainage” into the throat, not meeting the above criteria, is often due to laryngopharyngeal reflux.

A sensation of facial pain is not definitively diagnostic for sinusitis, as other conditions may cause facial pain. (See nerves of the face.)

Nasal obstruction, congesti0n, or airway resistance may also be the result of a deviated nasal septum, large turbinates, or a nasal mass, amongst other conditions.

A decreased sense of smell may also be the result of head trauma, a virus affecting the olfactory nerve, or for a nonidentifiable cause.

How is chronic sinusitis different from acute sinusitis?

Chronic sinusitis is a different process from acute sinusitis. In other words, chronic sinusitis is not just a long version of acute sinusitis. The types of organisms and the treatment options are different in acute versus chronic sinusitis.

Chronic sinusitis may be associated with nasal polyps; if so, treatment is more involved.

Immunocompromised states (of which there are several types) promote chronic sinusitis and pose a challenge in treatment.

what conditions might mimic sinusitis?

These conditions may mimic acute sinusitis:

1. Allergies (allergic rhinitis)

2. Enlarged or infected adenoids

3. Structural abnormalities, i.e., deviated septum, sinonasal neoplasm

4. Disorders affecting ciliary function (such as primary ciliary dyskinesia, cystic fibrosis)

5. Referred pain (such as from a dental infection or abscess)

6. Upper respiratory infection

7. Migraine and other headache syndromes

What factors may change the behavior of chronic sinusitis?

Nasal polyps, a weak immune system (immunocompromise), high prevalence of eosinophils (a certain type of white blood cells) in the sinus tissue, and environmental allergies may play a role in development and perstance of chronic sinusitis. Evaluation for these conditions is initially undertaken by taking a history, performing physical exam (including possible nasal endoscopy), and often sinus CT imaging. Evaluation for eosinophils in sinus tissue is performed after biopsy, typically in the setting of sinus surgery.