Chapter 151 Bacterial Sinusitis
The most common predisposing factor in acute bacterial sinusitis is viral upper respiratory infection (the common cold). Allergic rhinitis and other factors that interfere with normal protective mechanisms may precede the viral infection and therefore are the more likely predisposing factors. Any factor that induces edema of the mucous membranes may result in obstruction of meatal drainage. The transudate that is produced serves as a suitable medium for bacterial overgrowth, with streptococci, pneumococci, staphylococci, and Haemophilus influenzae being most commonly cultured.
In chronic bacterial sinusitis an allergic background is commonly present, and in 25% of cases of chronic maxillary sinusitis there is an underlying dental infection. Although vasoconstrictors and antihistamines cause transient relief, their chronic use is contraindicated because there is usually a reflex reaction following continual administration.
Although antibiotic therapy is the dominant treatment of acute and chronic bacterial sinusitis, it is of limited value.1 A detailed analysis to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodologic quality of placebo-controlled double-blind randomized trials concluded: “The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.”2 Nonetheless, in severe or unresponsive cases, antibiotics may be appropriate. In a Cochrane review it was shown that, although 80% of participants treated without antibiotics improve within 2 weeks, antibiotics have a small treatment effect in patients with uncomplicated acute sinusitis in a primary care setting with symptoms for more than 7 days. Newer, more potent antibiotics (e.g., lactam antibiotics) appear to be more effective than penicillin, amoxicillin, and other less potent antibiotics.3
In children, there is even less evidence that antimicrobial therapy is of significant benefit.4 Overuse of antibiotics in children with sinusitis or otitis media is a growing concern, as it is leading to antibiotic-resistant strains of bacterial pathogens.
In chronic sinusitis, antibiotics are also of little or no benefit.5 Clearly, the most rational approach seems to be to address the underlying cause of chronic sinusitis (e.g., respiratory or food allergens) along with providing supportive therapy (e.g., saline nasal sprays, immune-enhancing herbs, natural decongestants).
Studies indicate that most patients with chronic sinusitis, perhaps as many as 84%, have allergies.6,7 Patients with chronic sinusitis should be aggressively screened for environmental and food allergies. Environmental control requires the elimination of dust mites (warm-water washing at a temperature of least 58°C), use of air-filtering vacuum cleaners, installation of an air cleaner with a high-efficiency particulate air filter, and whatever methods are necessary to maintain the humidity under 50%. Some particularly sensitive patients may need to have all pets removed, along with carpeting and featherbedding.8
Airway mucociliary clearance depends on the properties and volume of secreted mucus, ciliary function, and mucociliary interactions. In chronic sinusitis, mucus viscoelasticity is higher than the optimal values for mucociliary clearance. Mucolytic agents such as N-acetylcysteine (NAC) and proteolytic enzymes can reduce viscoelasticity and promote mucociliary clearance.9
NAC is the most commonly used mucolytic agent. The free sulfhydryl group of NAC interacts with the disulfide bonds of mucus glycoproteins, thereby breaking the protein network into less viscous strands. Although NAC is often used as a 10% solution by dilution with saline, sodium bicarbonate, and sterile water, it can also be used orally for sinusitis, as it has been shown to be effective for chronic bronchitis.10
Proteolytic enzymes may break down complex proteins at the site of inflammation, exert some antimicrobial effects, or act directly on the naked peptide region of mucus glycoproteins. Trypsin, chymotrypsin, Serratia peptidase, bromelain, and streptokinase are the proteolytic enzymes that can break down mucus glycoproteins and other proteins when they are administered topically. When Serratia peptidase was given at a dose of 30 mg/day for 4 weeks to patients with chronic sinusitis, it significantly reduced the viscosity but not the elasticity of nasal mucus.11
It has been reported that the ratio of the viscosity to the elasticity is an important determinant of mucociliary transport. When Serratia peptidase was administered at the same dose to patients with chronic bronchitis, it significantly increased mucociliary clearance.12 A multicenter double-blind placebo-controlled study of 193 subjects suffering from various acute or chronic ear, nose, or throat disorders, including sinusitis, demonstrated a greater efficacy and rapid action of the peptidase against all the symptoms examined.13 Orally administered bromelain has also shown benefit in the treatment of chronic sinusitis.14
Extracts from the rhizomes and tubers of P. sidoides have been shown to exert a number of effects beneficial in upper respiratory tract infections, particularly acute bronchitis, an indication for which it is an approved drug in Germany (see Chapter 153, “Bronchitis and Pneumonia”). P. sidoides has demonsrated immune-enhancing effects as well as antibacterial and antiviral effects and the ability to prevent adhesion of bacteria to epithelial cells.15 In one double-blind placebo-controlled trial, 103 patients with acute rhinosinusitis of presumably bacterial origin were given an ethanolic extract of P. sidoides (EPs 7630) or matching placebo at a dose of 3 mL three times daily for a maximum 22 days.16 The mean decrease in the Sinusitis Severity Score was 5.5 points in the EPs 7630 group compared with 2.5 points in the placebo group, a difference of 3.0 points. This result was confirmed by all secondary parameters, indicating a more favorable course and a faster recovery in the EPs 7630 group.