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• Introduction
• Causes
• Risk Factors
• Symptoms
• Complications
• Diagnosis
• Prevention
• Treatment for Acute Sinusitis
• Treatment for Chronic Sinusitis
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Sinusitis

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of sinusitis.

Alternative Names

Nasal congestion; Rhinosinusitis

Introduction

The skull contains a number of air-filled spaces called sinuses . They perform the following functions:

• Reduce the weight of the skull
• Provide insulation for the skull
• Provide resonance for the voice

Four pairs of sinuses, known as the paranasal air sinuses , connect to the nasal passages (the two airways running through the nose) and are those that are involved in sinusitis. These sinuses are the following:

• Frontal sinuses (behind the forehead)
• Maxillary sinuses (behind the cheekbones)
• Ethmoid sinuses (between the eyes)
• Sphenoid sinuses (behind the eyes)

Defense System in the Sinuses

Healthy sinuses are sterile and contain no bacteria. (The nasal passage, on the other hand, normally contains many bacteria that enter through the nostrils.) Maintaining sinus health depends on a cycle that involves a number of important factors and processes:

• The sinuses are lined with a membrane that secretes mucus. Mucus drains down into the nasal passage from a small channel in each sinus. The mucous membranes must be intact and free of injury.
• The mucus must be fluid in order to flow freely while being sticky enough to absorb pollutants and entrap bacteria.
• The mucus must also contain sufficient amounts of bacteria-fighting substances, including immune factors called antibodies.
• Small, hair-like projections called cilia must beat in unison to propel mucus outward, expelling bacteria and other particles.
• The sinus passages must be open to allow mucus drainage and the circulation of air through the nasal passage.

Sinusitis

The Disease Process. Sinusitis is an infection that occurs if one or more of the defense processes or factors are amiss, causing obstruction, and bacterial growth occurs in the paranasal sinuses. Among the many causes of such obstruction or congestion are the common cold, allergies, certain medical conditions, abnormalities in the nasal passage, and change in atmosphere. In any of these cases, sinusitis can develop as follows:

• Mucus drainage and airflow are blocked.
• Secretions build up, encouraging the growth of certain bacteria.
• The resulting infection, swelling, and inflammation create further blockage, which may cause the sinuses to close up completely.

Forms of Sinusitis. Sinusitis is classified as acute, subacute, or chronic, or recurrent. The classification is based on how long symptoms last:

• Acute: Less than 4 weeks
• Subacute: 4 - 8 weeks
• Chronic: 8 weeks or longer
• Recurrent: 3 or more acute episodes in 1 year

• Review Date: 3/23/2007
• Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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