Understanding Sinuses & Sinus Infections

At Rancho ENT we aim to treat the underlying causes of sinus disease as well as relieve the symptoms through medical and surgical care.

The sinuses are 4 paired air spaces that connect to the nasal passages. The maxillary sinuses are at the level of the cheeks. The frontal sinuses are at the level of the for-head. The ethmoid sinuses are multiple spaces within the nasal cavity itself. The sphenoid sinuses sit deep within the head underneath the brain and pituitary. The purposes of the sinuses are unknown, but they are thought to decrease the weight of the head on the neck to allow better neck mobility.

Illustration of healthy vs. inflamed sinuses from Rancho ENT in Poway

The sinuses are self-cleaning by design. They produce a mucus layer on the perimeter of the air spaces. Small hair-like arms on the lining of the sinuses known as cilia move the mucous around the sinus to keep the sinuses clear of debris and infection. The mucous is removed out of the sinuses through small openings/doors (known as antra) that deposit the mucous into the nose where it is eventually swallowed as it drips back down the throat. Ideally the sinuses are kept sterile this way, and the usual progression of mucous down the throat is imperceptible.

Sinuses can get infected for a variety of reasons. Typically there is some sort of swelling or inflammation in the nose that causes the lining inside the nose to swell and block the drainage pathway for the sinuses. Causes for swelling include a cold virus, inflammation from allergies, or physical obstruction from bad anatomy or cold virus, inflammation from allergies, or physical obstruction from bad anatomy or growths such as polyps within the nose. Mucous then collects inside the sinus when it is blocked. Bacteria from the nose then have a culture media to grow in. As bacteria find their way back into the sinus from the nose they grow and replicate there, resulting in an infection.

Distinguishing between a common viral infection (a common cold) of the nose and a true sinus infection is important. Antibiotics will not be beneficial for a viral infection, whereas a viral infection that results in a secondary bacterial infection of the sinuses will be often treated with antibiotics.

Patients with recurrent infections can have debris or thick mucus trapped in the sinus, chronic inflammatory conditions that keep the passage ways swollen, or poorly shaped sinuses that do not allow the sinuses to drain properly. Less likely, the sinuses may have improper function of the cilia or the immune system that make infections more likely.