The guideline from the American Academy of Otolaryngology—Head and Neck Surgery on managing sinusitis in adults¹ provides physicians with a clear definition of rhinosinusitis. The term rhinosinusitis is preferred because sinusitis almost always involves the nasal cavity.

Uncomplicated rhinosinusitis is defined as rhinosinusitis without clinically evident inf lammation outside the paranasal sinuses and nasal cavity at the time of diagnosis (e.g., no neurologic, ophthalmologic, or soft tissue involvement). Rhinosinusitis may be further classified by duration: acute (less than four weeks), subacute (four to 12 weeks), or chronic (more than 12 weeks, with or without acute exacerbations). Acute rhinosinusitis may be further classified as acute bacterial rhinosinusitis or viral rhinosinusitis. If four or more episodes of acute bacterial rhinosinusitis occur per year without persistent symptoms between episodes, the condition is termed recurrent acute rhinosinusitis.

Acute bacterial rhinosinusitis manifests as purulent (not clear) nasal drainage lasting up to four weeks that is accompanied by nasal obstruction; facial pain, pressure, or fullness; or both. Purulent nasal drainage as a sole criterion lacks sensitivity for distinguishing between viral and bacterial infection.² If a patient meets diagnostic criteria for acute rhinosinusitis, radiologic imaging is not needed, thereby avoiding unnecessary delays in diagnosis and radiation exposures.^3,4

Evaluation of acute bacterial rhinosinusitis should include pain assessment, and treatment may include analgesia and symptom relief. Adjunctive treatments that may help relieve symptoms include alpha-adrenergic decongestants, corticosteroids, saline irrigation, and mucolytics. However, none of these therapies have been approved by the U.S. Food and Drug Administration (FDA) to treat acute rhinosinusitis, and few data from controlled clinical studies support their use.

For selected adults with uncomplicated acute bacterial rhinosinusitis who have mild illness (i.e., mild pain and temperature less than 101° F [38.3° C]) and in whom follow-up can be assured, the guideline notes that antibiotics may be deferred and management may be limited to symptom relief and observation. Antibiotics should be initiated if the patient's condition fails to improve after seven days, or worsens at any time. Observing patients with uncomplicated acute bacterial rhinosinusitis is consistent with other practice guidelines.^4–6

The rationale for recommending observation in patients with uncomplicated acute bacterial rhinosinusitis is based on randomized controlled trials (RCTs) that show a modest absolute increase in positive outcomes within seven to 12 days in patients taking antibiotics (absolute rate difference = 14 to 15 percent; number needed to treat = 7) compared with the high rate of spontaneous improvement in patients receiving placebo. However, after 14 or 15 days, the impact of antibiotic therapy is insignificant.⁷ Also, adverse events occur more often with antibiotics than with placebo (number needed to harm = 9).

If acute bacterial rhinosinusitis worsens or fails to improve during the seven-day interval, the physician should reassess the patient to confirm the diagnosis, exclude other causes of illness, and detect complications. If acute bacterial rhinosinusitis is confirmed, antibiotic therapy should be initiated. The recommendation to assess treatment failure seven days after initial diagnosis is based on clinical outcomes in RCTs demonstrating that seven to 12 days after trial enrollment, 73 percent of patients receiving placebo have clinical improvement; this increases to 85 percent when antibiotics are administered.⁷

Although dozens of RCTs have assessed the comparative effectiveness of antibiotics in adults with acute bacterial rhinosinusitis, no significant differences among antibiotics have been noted.⁸ As a result, if a decision is made to treat a patient with an antibiotic, amoxicillin should be the first-line therapy for most adults because of its safety, effectiveness, low cost, and narrow microbiologic spectrum.^6,8–12 For patients allergic to penicillin, folate inhibitors (e.g., trimethoprim/sulfamethoxazole [Bactrim/Septra]) are cost-effective alternatives.^9,10,13–15 The macrolide class of antibiotics may also be used in patients with penicillin allergy.

The choice of initial antibiotic therapy may also be affected by factors, such as recent antibiotic use; local antibiotic resistance patterns; dosing schedules; and children in the household who attend day care and are at increased risk of penicillin-resistant Streptococcus pneumoniae infection, for which high-dose amoxicillin is an option.

Educational tools such as laminated teaching cards or other visual aids summarizing diagnostic criteria and the typical clinical course of viral and acute bacterial rhinosinusitis may facilitate the differentiation of these conditions in busy clinical settings. The Centers for Disease Control and Prevention's Get Smart campaign has produced educational material that can help physicians clarify misconceptions about viral illness and nasal discharge.¹⁶ Potential barriers to patient observation can be overcome with educational pamphlets and information sheets that outline the favorable natural history of uncomplicated acute bacterial rhinosinusitis, the modest incremental benefit of antibiotics on clinical outcomes, and the potential adverse effects of oral antibiotics (including induced bacterial resistance).

Unanswered questions provide potential opportunities for research. These questions are addressed in the guideline. The full guideline is available for a limited time at http://www.entlink.net/qualityimprovement/Adult-Sinusitis.cfm.