Sinusitis refers to inflammation of the sinuses. This is generally caused by a viral, bacterial, or fungal infection.The sinuses are air-filled spaces around the forehead, cheeks, and eyes that are lined with mucous membranes. Healthy sinuses are sterile (meaning that they contain no bacteria or other organisms) and open, allowing mucus to drain and air to circulate.

When inflamed, the sinuses become blocked with mucus and can become infected. Each year, over 30 million adults and children get sinusitis.

Pain is felt over the cheeks, forehead or the bridge of the nose. There may be partial nasal blockage and green catarrh.

Hospitalization, especially if the reason you are in the hospital is related to a head injury or you needed a tube inserted into the nose (for example, a nasogastric tube from your nose to your stomach).

Cystic fibrosis is one of a number of diseases that prevent the cilia from working properly. Other such diseases that put you at increased risk for sinusitis include Kartagener's syndrome and immotile cilia syndrome.