ILLUSTRATIVE CASE
A 23-year-old woman presents to your office with a 1-week history of cough, purulent nasal discharge, and unilateral facial pain. You diagnose acute sinusitis.
Should you prescribe an antibiotic?
No. Yet it’s no wonder that most adults treated for acute sinusitis leave the doctor’s office with a prescription for antibiotics. Until the publication of the meta-analysis by Young and colleagues1 featured in this PURL, we have lacked A-level evidence from studies conducted in realistic settings—like your practice and ours.
Review of serial data from the National Ambulatory Medical Care Surveys (NAMCS) from 1999 through 2005 does show a slight downward trend in antibiotic prescribing for acute sinusitis: 1999-2002 data showed that 83% of cases of acute sinusitis were treated with an antibiotic.2 Data from the 2004 and 2005 NAMCS reveal that family physicians prescribed antibiotics for 80% of patients with acute sinusitis in 2004 and 76% of patients in 2005 (S. Medvedev, unpublished data, NAMCS database, March 2008).
Is this continued high rate of antibiotic prescribing justified?
Do antibiotics improve symptoms and shorten the duration of illness or not?
These questions are important, obviously, not only because of the high rate of prescribing but also because sinusitis is one of the most common diagnoses: approximately 20 million cases annually in the United States, or about 21% of all outpatient antibiotic prescriptions for adults.2
Which patients might benefit from antibiotics?
Common clinical signs and symptoms cannot identify patients with rhinosinusitis for whom treatment is clearly justified, given the cost, adverse events, and bacterial resistance associated with antibiotic use
- Severity of symptoms is important only in that signs suggestive of a serious complication are the sole reason for immediate antibiotic treatment
- Purulent discharge noted in the pharynx on exam was associated with a higher likelihood of benefit from antibiotics, but NNT was 8
- Antibiotics are not justified even if a patient reports having symptoms for longer than 7-10 days
Source: Young et al.1
A diagnostic dilemma
Before we discuss the evidence that is summarized in the excellent meta-analysis by Young and colleagues,1 let’s acknowledge that acute sinusitis is undeniably a diagnostic dilemma. Distinguishing bacterial from viral infection is nearly impossible on clinical grounds because the symptoms are so similar. A litany of identical upper respiratory symptoms accompanies both viral and bacterial sinus infections. Purulent nasal secretions, maxillary facial pain (especially with unilateral predominance), maxillary tooth pain (which is uncommon with sinus infection), altered sense of smell, and worsening illness after improvement constitute the short list of signs and symptoms that has some predictive value, but even the presence of all of these is not a terrific predictor of bacterial sinus infection. Plain x-rays have low accuracy in distinguishing viral from bacterial infection. Computed tomography (CT) sinus scans are better but far from perfect, are not readily available in practice, and are expensive.
Sinusitis in the real world
How effective are antibiotics for patients diagnosed not by sinus x-rays or CTs, but by signs and symptoms—as we typically do in daily practice?
A meta-analysis3 of 13 randomized controlled trials (RCTs) found that sinusitis improved without antibiotics, but it included trials in which patients were recruited based on results of imaging studies and cultures, which are not normally used in primary care clinical practice. That study compared antibiotic treatment to placebo for acute uncomplicated sinusitis; 35% of placebo-treated patients were clinically cured by 7 to 12 days and 73% were improved after 7 days. Antibiotic therapy increased cure rates by 15% and improvement rates by 14%, yielding a number needed to treat of 7 to achieve 1 additional positive outcome at 7 days.
