Background

About 35 million people are afflicted with sinusitis—acute, chronic, or recurrent (Kaliner et al. Allergy Clin Immunol 1998;99:S829). Chronic sinusitis is estimated to affect 15% of the US population and so qualifies as one of our most common diseases. The prevalence of sinusitis is highest in adults 18 to 75 years, followed by people living in the Midwest and South, and then children under 15 years of age.

Sinusitis treatment is expensive and is not limited to the outpatient setting. Approximately $2.4 billion per year are spent in direct medical costs. Estimating from current procedural terminology (CPT) discharge coding, there are 16,000 discharges for acute sinusitis and 29,000 for chronic sinusitis. In tabulating outpatient visits, chronic sinusitis accounted for 11.6 million visits. Sinus surgery ranged from 170,000 to 200,000 cases in 1994.

Definitions

Anatomy

Continued ostial obstruction may lead to ciliary dysfunction, mucosal damage, and eventually, chronic inflammation and mucosal thickening. Nosocomial pathogens can also be found in sinus puncture samples. Cultures usually are polymicrobic with Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter sp, or Proteus mirabilis.  

Diagnosis

Sinusitis can be diagnosed by clinical criteria, but I recommend radiographic confirmation because of the expense and length of sinusitis treatment. The major clinical criteria are purulent nasal discharge, purulent pharyngeal drainage, and cough. Minor clinical criteria include periorbital edema, headache and/or earache, facial and/or tooth pain, sore throat, halitosis, increased wheezing, and fever. Sinusitis usually is associated with a preceding viral upper respiratory tract infection or concurrent allergic upper airway disorders. Complications from sinusitis include serious central nervous system problems such as meningitis, brain abscess, subdural empyema, cavernous sinus thrombosis, and cortical vein thrombosis. Other complications are orbital cellulitis, subperiosteal abscess, orbital abscess, and bony osteomyelitis.

Available diagnostic imaging includes transillumination, ultrasonography, plain radiographs, CT, or MRI. Transillumination and ultrasonography have low sensitivity and specificity. Sinus CT is now considered the diagnostic method of choice. CT features that are diagnostic of sinusitis consist of sinus opacification, mucosal thickening, air-fluid levels, polyps, mucocyst or mucocele, and bony erosion.  

Risk Groups

Immunodeficient patients are at special risk of developing sinusitis. Individuals with functional antibody deficiency (lacking adequate response to polysaccharide bacterial antigens) or with low IgG subclass antibodies (IgG2 or IgG3) represent the most common types of immunodeficient patients presenting with sinusitis. Other associated disorders include agammaglobulinemia, selective IgA deficiency, severe combined immunodeficiency, common variable immuno-deficiency, chronic granulomatous disease, leukocyte dysfunction, and the acquired immunodeficiency syndrome. Anatomic risk factors include obstruction of the ostia by such processes as adenoidal hypertrophy, concha bullosa, severe deviated septum, or septal spurs.  

Sinusitis and Asthma

The role of sinusitis in aggravating or causing lower airway dysfunction is controversial. Numerous descriptive clinical studies of adults and children have reported improvement in existing asthma symptoms and reduction in asthma medication requirements during aggressive therapy for sinusitis. How treatment of sinusitis actually affects lower airway responsiveness is not known.

Lavage samples from patients with chronic sinusitis have significant concentrations of inflammatory mediators: histamine, leukotriene C4, and prostaglandin D2 (Georgitis et al. Int Arch Allergy Appl Immunol 1995;106:416). In addition, biopsy specimens have shown activated eosinophils and their products in the thickened mucosa. In chronic sinusitis and nasal polyposis, there are marked increases in inflammatory cytokines such as GM-CSF, IL-3, and tumor necrosis factor which promote eosinophil accumulation and activation, and the cytokines IL-4 and IL-5 which promote eosinophil survival and mast cell accumulation (Hamilos et al. J Allergy Clin Immunol 1993;91:39; Durham et al. J Immunol 1992;148:2390).

Could these inflammatory products be directly aspirated into the lower airways or indirectly carried systemically to the lower airways leading to altered ß₂-receptor responsiveness and a change in the neural response of the lower airways? Clearly, there is an association between sinusitis and asthma, but the mechanisms involved have yet to be elucidated.

Allergic fungal sinusitis is a unique, probably underdiagnosed condition similar to the lower airway disorder, allergic bronchopulmonary aspergillosis. Characteristic features of fungal sinusitis are signs of symptoms of chronic sinusitis unresponsive to antibiotic therapy. The sinus contents in patients with fungal sinusitis contain allergic mucin, a thick cheese-like secretion, Charcot-Leyden crystals, and fungal elements. The fungi associated with this condition include Aspergillus, Curvularia, Drechslera, Bipolaris, Exserohilium, Alternaria, Helminthosporium, and Fusarium.

The diagnosis of fungal sinusitis involves the following set of criteria: (1) radiographic evidence of sinusitis; (2) identification of allergic mucin by rhinoscopy or surgery; (3) demonstration of fungal elements; (4) absence of diabetes, previous immunodeficiency, or immunosuppressive medications; and (5) absence of invasive fungal disease at diagnosis (De Shazo and Swaim. J Allergy Clin Immunol 1995;96:24). Treatment of fungal sinusitis consists of antifungal therapy and removal of sinus secretions at surgery. Some studies suggest the use of allergen immunotherapy to treat underlying atopic disease.  

Treatment

Oral antibiotics remain the cornerstone of therapy for acute, chronic, and recurrent sinusitis. Broad-spectrum antibiotics are recommended as first-line therapy. Treatment should consist of at least 10 to 20 days of continuous use (Table 2). In cases of persistent sinusitis or allergy to first-line choices, second-line antibiotics include third-generation or higher cephalosporins and/or macrolides. In some cases, intravenous antibiotic therapy may be needed to clear the sinusitis.

Common mistakes in treating sinusitis include inadequate length of antibiotic therapy and inadequate treatment of underlying upper airway problems. A rule of thumb is, if 20 continuous days of first-line therapy are ineffective, a second-line choice should be tried for 20 days or longer (except clarithromycin which should be used for 10 days) together with adjunctive therapy.

Adjunctive therapy is probably as important as antibiotics in treating sinusitis. Intranasal cortico-steroids treat the nasal mucosal edema and chronic activation of nasal mast cells, other inflammatory cells, and their products. Oral antihistamines in combination with sympathomimetics help treat underlying chronic rhinitis. Nasal sympathomimetics are helpful in acute treatment but should be used for only 3 to 5 days to help promote nasal drainage. Other therapies are designed for symptomatic control of fever, headache, cough, and mucus production.

For persistent, unresponsive disease, the patient should be examined for possible immunodeficiency states or underlying disorders such as severe allergic rhinitis, nasal polyposis, cystic fibrosis, or an anatomic obstruction. In addition, sinus puncture for microbial documentation and antibiotic sensitivity identification may be indicated for chronic sinusitis.

For severe chronic sinusitis, functional endoscopic sinus surgery (FESS) is an intervention designed to improve ostial-meatal function. FESS provides adequate sinus drainage, and allows ready access to the sinuses for biopsies, irrigation, and culture. A major note of caution about FESS is warranted, however. The procedure can be associated with serious and life-threatening complications. These include injury to orbital muscles or optic nerve, orbital hematoma, cerebrospinal fluid leak, subarachnoid hemorrhage, or infection. Therefore, FESS should be the last step in the management of sinusitis. Unfortunately, even after FESS, patients often still need repeated courses of aggressive antibiotic therapy.

John W. Georgitis, MD, FCCP
Professor of Pediatrics
Wake Forest University Baptist Medical Center
Winston-Salem, North Carolina  

Perhaps the single most important message in this Perspective is the importance of long-term treatment of sinusitis. The usual 7- to 10-day courses of antibiotics useful for bronchitis are usually inadequate in the treatment of acute sinusitis, and chronic sinusitis requires even longer therapy than acute disease. From the pulmonologist's perspective, it is also extremely important to suspect sinusitis as an exacerbating factor in asthma, COPD, or chronic cough.

— Editor