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A 6-year-old is brought in by his mother for persistent rhinorrhea. He had what appeared to be a cold about 2 weeks prior but continues to have a stuffy nose and a constant cough, which is worse at night. He has no fever but his mother says that he appears more tired than usual and has a decreased appetite. On examination, the child has a purulent nasal discharge, nasal mucosal erythema, and allergic shiners (Figure 26-1); he otherwise appears healthy. You diagnose acute bacterial sinusitis (ABS) and prescribe oral amoxicillin-clavulanate. You discuss the lack of benefit of antihistamines and decongestants but offer a prescription for nasal corticosteroids, which the parent declines.
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Sinusitis is symptomatic inflammation of the sinuses, nasal cavity, and their epithelial lining. Mucosal edema blocks mucous drainage creating a culture medium for viruses and bacteria. Sinusitis is classified by duration as acute (<4 weeks), subacute (4-12 weeks), or chronic (>12 weeks).
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Approximately 1 percent of children per year develop sinusitis, accounting for 20 million antibiotic prescriptions; 6 percent to 7 percent of children seeking care for respiratory symptoms have acute bacterial sinusitis.1
Children average six to eight colds per year. Of those, 0.5 percent to 8 percent will develop a sinus infection.2,3
Risk factors include viral upper respiratory tract infection (URI) (about 80% of cases are preceded by a viral URI),2 allergy,4 and day care attendance.5
Only 1/3 to 1/2 of primary care patients with symptoms of sinusitis actually have bacterial infection.6
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Etiology/Pathophysiology
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Sinus cavities are lined with mucus-secreting respiratory epithelium. The mucus is transported by ciliary action through the sinus ostia (openings) to the nasal cavity. Under normal conditions, the paranasal sinuses are sterile cavities and there is no mucus retention.
The maxillary and ethmoid sinuses are present at birth and the frontal sinuses develop from the ethmoid sinuses by age 5 to 6 years.
ABS occurs when ostia become obstructed or ciliary action is impaired, causing mucus accumulation and secondary bacterial overgrowth.
The causes of sinusitis include:
Infection—Most commonly viral (e.g., rhinovirus, parainfluenza, and influenza) followed by bacteria infection (e.g., Streptococcus (S) pneumoniae, Haemophilus influenzae, Moraxella catarrhalis). In the past 10 years, S. pneumoniae has become less common and Haemophilus influenzae more common as the etiologic agent of acute bacterial sinusitis in children.2 In immunocompromised patients, fulminant fungal sinusitis can occur.
Noninfectious obstruction—Allergic, polyposis, barotrauma (e.g., airplane travel), chemical irritants, tumors, and conditions that alter mucus composition (e.g., cystic fibrosis).