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ID Rounds: Antibiotics Controversial for Chronic Sinusitis

Isaacs, Lawrence MD

doi: 10.1097/01.EEM.0000394581.03743.b8
ID Rounds
CT scan of the sinus.

CT scan of the sinus.

Sinusitis is the true “bread and butter” of emergency medicine. For such a common complaint, usually seen in the ED's fast track, it is often mismanaged, according to the literature. Acute sinusitis is defined as an infection of the paranasal sinuses, with accompanying symptoms, present for more than 10 days and less than four weeks. Chronic sinusitis lasts longer than eight weeks. (Arch Otolaryngol Head Neck Surg 2000;126[2]:174.) In the past, it was thought that chronic sinusitis was an extension of acute sinusitis; now it is regarded as a different disease, inflammatory, not infectious. Approximately 20 percent of outpatient antibiotic prescriptions are filled for this complaint. (Otolaryngol Head Neck Surg 2006;135[3]:341.)

Acute sinusitis is usually preceded by a viral URI, which leads to sinus inflammation and obstruction of the ostiomedial complex (OMC), a narrow pathway draining the anterior ethmoid, frontal, and maxillary sinuses. This obstruction leads to changes in the sinus cavity, making bacterial infection more likely. Approximately 0.5 percent to two percent of viral URIs will progress to acute bacterial sinusitis. (Clin Infect Dis 1996;23[6]:1209.) This is an important statistic: The vast majority of viral URIs stay viral. One general guideline is that a typical viral sinusitis resolves within 10 days, but bacterial will persist longer. The complications of sinusitis include orbital abscess, brain abscess, and meningitis. These are very rare in adults. A review of placebo-controlled studies failed to find an increased risk of complications in patients who did not receive antibiotics. (Evid Rep Technol Assess (Summ) 1999;[9]:1.)

Chronic sinusitis is poorly understood. The etiology and pathogenesis are still unclear, although theories suggest anatomic, infectious, allergic, and inflammatory etiologies. Unlike acute sinusitis, obstruction of the OMC is unlikely the precipitating factor. One theory suggests immune hyper-responsiveness to colonized bacteria; another suggests the same response to colonized fungi.

Diagnosing sinusitis is challenging because of the large overlap between a viral URI (technically a viral sinusitis and obviously not requiring antibiotics) and bacterial sinusitis (which does require antibiotics). In one study, CT scans of the sinus were performed on subjects with colds; 87 percent of the subjects had sinus inflammation of their maxillary or ethmoid sinuses. (N Engl J Med 1994;330[1]:25.) This is an important point to remember when considering imaging. The gold standard for diagnosing acute bacterial sinusitis is maxillary sinus puncture with culture, a procedure obviously not performed by an emergency Physician. Physical examination is often not helpful, but findings like maxillary or frontal sinus tenderness, abnormal sinus transillumination, and maxillary tooth tenderness are often taught and quoted in texts, but none is sensitive or specific. Texts also suggest visualizing the secretions coming from the middle meatus, but this is nearly impossible in the ED with the instruments we have. Examining the inside of the nose is also suggested, looking for purulent secretions draining from the sinuses, but this too is not sensitive or specific enough to rule in or rule out acute bacterial sinusitis. One often-quoted study identified five symptoms and signs that lead to a 92% probability of bacterial sinusitis: maxillary toothache, abnormal transillumination, poor response to decongestants, purulent secretions, and colored nasal discharge. (Ann Intern Med 1992;117[9]:705.)

Radiology can be helpful to confirm an equivocal case or when conventional treatment fails. Plain films, either the Waters view (occipito-mental) or Caldwell (AP) can visualize the frontal, maxillary, and sphenoid sinuses. Note the ethmoids are not seen in either of these views. These can be helpful if positive, indicating air-fluid levels, opacification, or mucosal thickening. Noncontrast CT scan is the modality of choice, but this has its limits. CT can't distinguish between bacterial and viral, many asymptomatic patients will have abnormal mucosal changes, and the severity of the changes on CT does not correlate with symptom severity. (J Allergy Clin Immunol 2004;114[4]:981.) It is indicated when looking for an abscess or spread of infection to the orbital, intracranial, or facial regions.

So, what is the best, most cost-effective approach to diagnosing acute bacterial sinusitis with reasonable certainty? I personally use the length of symptoms (longer than seven to 10 days) with some of the five signs and symptoms noted above, without any imaging.

The most common pathogens in acute bacterial sinusitis are Streptococcus pneumoniae, Haemophilus influenza, and Moraxella catarrhalis. In chronic sinusitis, it is usually a mix of aerobic and anaerobic bacteria, including Staphylococcus aureus. The role of fungi in sinusitis is a well documented disease called allergic fungal sinusitis. An eosinophilic response to fungi is seen with polyps and allergies to fungi; treatment is surgical. Interestingly, one overlooked cause of chronic sinusitis is gastroesophageal reflux disease. In one small study, 68 percent of chronic sinusitis patients had GERD symptoms, and after a subset were treated with a proton pump inhibitor, 67 percent reported an improvement in their sinus symptoms. (Ann Inter Med 1998;129[12]:1078.)

Treatment of acute bacterial sinusitis first consists of antibiotics. Appropriate first-line agents include amoxicillin and trimethoprim-sulfamethoxazole for adults and children and doxycycline for adults only. The duration of therapy is 10 to 14 days. Second-line choices if patients do not improve after 48 hours include second- and third-generation cephalosporins, amoxicillin-clavulanate, or azithromycin. Two caveats: First-generation cephalosporins do not provide adequate coverage against H. influenza, and should not be used. Although it is tempting to use a quinolone, I would not, given the increasing resistance and multiple other options (also keep in mind the age restriction).

Antihistamines are not recommended unless there is an allergic component to the sinusitis. No good data evaluate the efficacy of topical or oral decongestants. They may work in theory, and I do recommend them to my patients. Lastly, inhaled nasal steroids have been shown to help symptomatically, and I prescribe them to all patients I treat for sinusitis. (J Allergy Clin Immunol 2000;106[4]:630.)

Treating chronic sinusitis differs from acute bacterial sinusitis. Antibiotics are not always indicated and controversial. Although a chronic sinusitis patient sometimes will get a bacterial infection, it is more often a noninfectious cause (i.e., allergic). Treating the underlying cause is more appropriate. Oral corticosteroids are indicated, and have been shown to improve symptom scores (J Allergy Clin Immunol 2006;118[1]:128), as are inhaled steroids.

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Dr. Isaacs

Dr. Isaacs

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