Microbiology

Acute bacterial frontal sinusitis, on the other hand, typically occurs in the context of a more diffuse process with involvement of other paranasal sinuses and is suggested by failure to respond to conservative management in a timely fashion. Isolated acute bacterial frontal sinusitis is an uncommon entity when viewed in the larger context of sinonasal disease and most commonly occurs in the adolescent or young adult population. This is thought to be due to the rapid pneumatization of the frontal sinuses that occurs between 6 and 20 years of age and is elaborated on later. Studies evaluating the bacteriology of acute bacterial frontal sinus infections have typically shown Haemophilus influenzae , Streptococcus pneumoniae , and Moraxella catarrhalis as the causative organisms. In this regard, antimicrobial management of acute frontal sinusitis does not dramatically differ from that of acute maxillary sinusitis. The increasing incidence of penicillin resistant and β-lactamase–producing bacterial colonies has subsequent ramifications on antimicrobial therapy.

Antibiotic Therapy

For those patients who meet indications for antimicrobial therapy, treatment of acute bacterial frontal sinusitis must be targeted towards these commonly cultured microbes. Several evidence-based antibiotic treatment guidelines have been published and recommended amoxicillin with or without clavulanate for 5 to 10 days as a viable first-line option. The decision to opt for amoxicillin-clavulanate versus amoxicillin alone is based on several factors, such as patient age, preceding antibiotic use, severity of infection, and underlying health. To optimize therapy, local resistance patterns must also be taken into account and may influence the decision to expand coverage. Other options for antibiotic therapy include either second-generation or third-generation cephalosporins as well as fluoroquinolones. Additionally, for penicillin-allergic patients, options include doxycycline and fluoroquinolones. Ideally, antimicrobial therapy should be culture directed and consideration should always be given to obtaining endoscopically guided sinonasal cultures.

Adjuvant Therapy

In addition to antibiotics, medical management for acute bacterial frontal sinusitis should be aimed at improving sinus ventilation and drainage. Adjuvant pharmacotherapy includes decongestants, mucolytics, nasal saline, and corticosteroids. Decongestants, whether systemic or intranasal, result in mucosal vasoconstriction and thus improve drainage via the frontal sinus drainage tract and the ostiomeatal complex. Intranasal decongestants, however, avoid the systemic side effects of α-agonists while offering superior nasal mucosal decongestion. Care should be taken to avoid prolonged courses of topical decongestant given the risk of rhinitis medicamentosa. Nasal saline solutions have also been demonstrated to improve mucocilliary clearance, with hypertonic saline solutions specifically shown to increase nasal airway patency. Expectorants, such as guaifenesin, are another adjuvant for improved mucus clearance and symptomatic treatment but, admittedly, with limited clinical evidence supporting their use.

Corticosteroids

In contrast, the role of corticosteroids in acute rhinosinusitis has been studied thoroughly. Ultimately, the utility of corticosteroids in the context of acute frontal sinusitis depends on the mechanism of delivery. Several meta-analyses have been performed to evaluate the impact of both intranasal and systemic delivery of corticosteroid both as monotherapy and in combination with antibiotic therapy. Whereas intranasal corticosteroid therapy has demonstrated success in reducing symptomatology in acute sinusitis, with a relatively benign side-effect profile, systemic corticosteroid therapy has not. Systemic corticosteroids were not shown effective as monotherapy and demonstrated only modest symptom relief when used in conjunction with antibiotic therapy. Additionally, the use of systemic corticosteroids inherently bears an increased risk of side effects not shared by intranasal delivery. In the context of acute frontal sinusitis, intranasal corticosteroids can be used as a useful adjuvant pharmacotherapy with systemic corticosteroids playing a limited role.

Pediatric Population

As discussed previously, frontal sinusitis has an increased incidence in the pediatric population, coinciding with the development of the frontal sinuses. In light of this, medical management of acute bacterial frontal sinusitis in pediatric patients warrants special attention. Given the location of the frontal sinuses, as well as the their relationship with the valveless diploic veins, untreated frontal sinusitis can lead to significant morbidity and even mortality. Acute bacterial frontal sinusitis in pediatric or young adult patients requires aggressive treatment to avoid such complications. Although complicated cases often fall within the realm of surgical management, uncomplicated cases – those without intracranial extension or abscess formation – can often be treated medically in the form of antibiotics, topical corticosteroids, and decongestants. Depending on the severity of disease, intravenous antibiotics and short courses of systemic steroids also may be warranted. Vigilance against the progression of frontal sinusitis is of the utmost importance to avoid delaying any potentially needed surgical intervention.

Antibiotic Therapy

Studies evaluating the bacteriology in chronic frontal sinusitis have demonstrated the existence of a wide variety of microbes, including gram-negative rods, such as Pseudomonas aeruginosa , anaerobes, coagulase-positive staphylococci and coagulase-negative staphylococci, and streptococci. On this basis, initial antibiotic therapy for chronic frontal sinusitis does not significantly differ from that for acute bacterial frontal sinusitis, with amoxicillin with clavulanate providing adequate coverage on an empiric basis, albeit for longer initial durations. Although the microbiology of acute bacterial frontal sinusitis lends itself to narrow-spectrum antimicrobial therapy, antibiotic therapy for either initial medical management or acute exacerbations of chronic frontal sinusitis may require broader-spectrum therapy and also may be more likely to result in treatment failures. In addition, current research has suggested an increasing prevalence of methicillin-resistant strains of Staphylococcus , thus further stressing the importance of culture-directed antibiotics, especially in an era of growing concern over antibiotic resistance.

Multiple investigations into novel antibiotic regimens for use in chronic sinusitis have also been performed. Although long-term antibiotic therapy is not recommended for chronic frontal sinusitis, there is some debate regarding the utility of long-term macrolide antibiotic administration given their unique anti-inflammatory and immunomodulatory effects. Low-dose daily macrolide therapy has been shown to inhibit the predominantly neutrophilic inflammation seen in chronic sinusitis without polyposis in vitro. Ultimately, although this may lead to modest improvement in select patients, further study is necessary and current literature is limited. Similarly, topical antibiotic administration has also been debated. Thus far, studies into topical delivery of antibiotics, via either solution or nebulization, have not demonstrated statistically significant clinical improvement in patient symptomatology or objective measures compared with placebo. These studies are greatly limited by the use of empiric, not culture-directed, antibiotics. Currently, both these approaches remain investigatory and are not yet recommended based on current clinical evidence.

Corticosteroids

In broad strokes, chronic rhinosinusitis is currently categorized based on the presence or absence of polyposis. Nasal polyposis and its predominantly eosinophilic inflammation have profound implications on the medical management of chronic rhinosinusitis – especially because it pertains to corticosteroids. As in acute rhinosinusitis, intranasal corticosteroids have proved useful for the treatment of chronic rhinosinusitis with or without polyposis, leading to decreased mucosal edema and significant symptomatic relief. Furthermore, they have proved relatively safe for long-term treatment of chronic sinusitis as well as any underlying allergic rhinitis. In contrast to the treatment of acute frontal sinusitis, oral corticosteroid therapy has been shown to play a crucial role for the treatment of chronic frontal sinusitis, particularly in cases of chronic sinusitis with polyposis. Systemic corticosteroids have been shown to produce significant decrease in polyp burden as well as improved scores on sinonasal quality-of-life measures and thus have been used as a sort of medical polypectomy. As discussed previously, however, prescribers must always take into account and inform patients of the potential side effects of systemic corticosteroids, particularly for prolonged courses that may be required for treatment of chronic rhinosinusitis with polyps.

The success of corticosteroids in chronic sinusitis have sparked interest in more-aggressive topical corticosteroid regimens in hopes of achieving the same beneficial clinical impact of systemic administration while maintaining the safety profile of topical administration. One particularly promising approach is the use of high-dose intranasal budesonide irrigations. In the context of chronic rhinosinusitis with polyposis, budesonide aqueous nasal solutions have been demonstrated to lead to reduced polyp burden and improved symptom scores, suggesting that they may be helpful in the context of chronic frontal sinusitis secondary to nasal polyposis. Additionally, although budesonide may have more systemic absorption compared with topical nasal steroid sprays, it has not been shown to cause any significant derangement of the hypothalamic-pituitary axis. According to the most current clinical practice guidelines, however, their use is not yet recommended, because more rigorous investigation is still needed.

Antifungals

The role of antifungals in the medical management of chronic rhinosinusitis is one that has been hotly debated. Early research into the pathophysiology of chronic rhinosinusitis identified eosinophilic predominance, which, in conjunction with the presence of fungi on cultures of surgical specimens, led to the theory that chronic rhinosinusitis is the result of a deranged immunologic response to common environmental fungi. Systemic and topical antifungals were suggested as a possible pharmacotherapy that could hold promise for the treatment of chronic rhinosinusitis. Despite initial promise, however, subsequent well-designed studies did not demonstrate the anticipated clinical benefit of antifungals in chronic sinusitis. As such, antifungals are not recommended for the medical management of chronic frontal sinusitis.

Allergy Testing and Immunotherapy

Current understanding of chronic rhinosinusitis suggests that it is the result of local factors leading to mucosal edema, impaired sinus drainage, and bacterial overgrowth, all of which may contribute to sinonasal inflammation. Therefore, any discussion of medical management of chronic frontal sinusitis is incomplete without identification of these local factors and implementation of adjuvant therapies aimed at addressing them. For those patients with a clinical picture suggestive of allergic rhinitis, allergy testing may prove a useful diagnostic effort. Initiation of allergy immunotherapy is a powerful adjuvant that can alleviate mucosal inflammation and thus improve sinus ventilation and drainage. Allergy testing and immunotherapy have not demonstrated sufficient clinical benefit to warrant use in acute bacterial rhinosinusitis.

Adjuvants

Finally, as with acute frontal sinusitis, the use of over-the-counter adjuvant therapies has also been shown useful. Nasal saline is an effective tool in the removal of tenacious mucus and secretions; however, consideration should be given to the mechanism of delivery. Although both saline irrigations and sprays are effective tools, irrigations have been shown more effective in the context of chronic sinusitis. Furthermore, as in acute frontal sinusitis, topical nasal decongestants have been shown to decrease mucosal edema and thus improve sinus drainage and ventilation.