Conditions: Sinus Infections

also known as sinusitis

What are the sinuses?

What is sinusitis?

 Sinusitis, also called rhinosinusitis, is inflammation of the membranes that line the sinuses and nose, which produces symptoms. It affects roughly 1 in 8 adults each year. It most often begins with a common cold (a viral upper respiratory infection). The lining of the nose and sinuses swells, narrowing the drainage channels, and mucus builds up in the nose and sinus cavities.

Common symptoms include:

• Thick or discolored nasal mucus

• A stuffy, congested, or blocked nose

• Facial pain, pressure, or fullness

Other symptoms may include fever, headache, a reduced sense of smell, sore throat, and cough (sometimes worse at night). Serious complications are uncommon.

How long it lasts defines the type:

• Acute sinusitis: less than 4 weeks

• Subacute sinusitis: 4 to 12 weeks

• Chronic sinusitis: 12 weeks or longer

• Recurrent acute sinusitis: four or more separate acute episodes per year, with complete symptom-free periods in between

This distinction matters because acute and chronic sinusitis involve different processes and different treatments. Chronic sinusitis is not simply a long-lasting version of acute sinusitis.

VIRAL VERSUS BACTERIAL ACUTE SINUSITIS

Most acute sinusitis is caused by a virus, and only a small fraction (roughly 1 in 100 to 2 in 100 colds) becomes a true bacterial infection. Viral sinusitis gets better on its own, and antibiotics do not help viral infections and do not relieve their symptoms. Because of this, antibiotics are not recommended for symptoms lasting less than about 10 days that are not worsening.

A bacterial infection is more likely when:

• Symptoms last 10 days or longer without any improvement, OR

• Symptoms worsen after first starting to improve ("double-worsening")

Occasionally a viral infection sets the stage for bacteria to take hold, causing a second ("piggyback") bacterial infection with worsening symptoms.

Important point about mucus color: Yellow or green mucus does not by itself mean a bacterial infection is present. The color comes from immune cells (neutrophils) responding to inflammation, not from bacteria. Discolored mucus is common in ordinary viral colds.

How is acute sinusitis diagnosed?

Acute sinusitis is usually diagnosed clinically—that is, based on symptoms rather than tests. It is generally diagnosed when there is:

Purulent (discolored, not clear) drainage from the nose

AND one or both of:

• A stuffy, congested, or blocked nose

• Pain, pressure, or fullness in the face, head, or around the eyes

Facial pain without discolored nasal drainage is usually not sinusitis and is often due to migraine or another headache condition.

Imaging such as CT or MRI is not recommended for routine diagnosis. Scans cannot reliably tell viral from bacterial infection, and are reserved for suspected complications or an alternative diagnosis.

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.)

VIRAL VERSUS BACTERIAL ACUTE SINUSITIS

Most acute sinusitis is caused by a virus, and only a small fraction (roughly 1 in 100 to 2 in 100 colds) becomes a true bacterial infection. Viral sinusitis gets better on its own, and antibiotics do not help viral infections and do not relieve their symptoms. Because of this, antibiotics are not recommended for symptoms lasting less than about 10 days that are not worsening.

A bacterial infection is more likely when:

• Symptoms last 10 days or longer without any improvement, OR

• Symptoms worsen after first starting to improve ("double-worsening")

Occasionally a viral infection sets the stage for bacteria to take hold, causing a second ("piggyback") bacterial infection with worsening symptoms.

Important point about mucus color: Yellow or green mucus does not by itself mean a bacterial infection is present. The color comes from immune cells (neutrophils) responding to inflammation, not from bacteria. Discolored mucus is common in ordinary viral colds.

How is chronic sinusitis diagnosed?

Chronic sinusitis requires 12 weeks or longer of two or more of the following:

• Discolored mucus drainage (from the nostrils, into the throat, or both)

• Nasal obstruction (congestion or blocked airflow)

• Facial pain, pressure, or fullness

• decreased sense of smell.

AND objective evidence of inflammation confirmed by a clinician (symptoms alone are not enough):

• Purulent mucus or swelling in the middle meatus or ethmoid region seen on examination

• Nasal polyps in the nasal cavity or middle meatus

• Inflammation of the sinuses shown on CT or MRI imaging

For chronic sinusitis, nasal endoscopy (looking in the nose with a small scope) is often the preferred first step to confirm inflammation and check for polyps, with CT imaging reserved for prolonged, complicated, or surgical cases.

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, congestion, 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 else 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. Migraine and other headache disorders

3. Laryngopharyngeal reflux (a sensation of "post-nasal drip" or drainage in the throat)

4. Deviated septum, enlarged turbinates, or a nasal mass

5. Enlarged or infected adenoids

6. Referred pain from a dental infection or abscess

7. An ordinary cold (upper respiratory infection)

A decreased sense of smell can also result from head trauma, a viral infection of the smell nerve, or an unidentifiable cause.

What factors may change the behavior of chronic sinusitis?

Nasal polyps, a weakened immune system, a high number of eosinophils (a type of white blood cell) in the sinus tissue, and environmental allergies can all contribute to chronic sinusitis and can make it harder to treat. Evaluation begins with history, physical exam (sometimes including nasal endoscopy), and often CT imaging. Testing sinus tissue for eosinophils requires a biopsy, usually taken during sinus surgery.