Acute Rhinosinusitis: Pathogenesis, Treatment, and Complications

Definitions of Acute and Chronic Rhinosinusitis

In order to understand the pathogenesis and pathophysiology of rhinosinusitis, it is important to realize that different types of rhinosinusitis have been defined, and the inciting mechanism may vary dramatically among the different subtypes. Although sinusitis is the term commonly used for any inflammation or infection of sinuses, this term has largely been replaced by rhinosinusitis , because the nose is almost always involved with the infection or inflammation at the same time as the sinuses. Because many potential factors can contribute to rhinosinusitis, some debate has ensued concerning the exact definition. In general terms, rhinosinusitis is defined as “a group of disorders characterized by inflammation of the mucosa of the paranasal sinuses.” In 1997, the Rhinosinusitis Task Force of the American Academy of Otolaryngology–Head and Neck Surgery developed a now well-accepted classification of rhinosinusitis, and this was reported by Lanza and Kennedy. This classification relies on the identification of symptoms to make a diagnosis. The symptoms are broken into major symptoms—purulent nasal drainage, nasal congestion, facial pressure or pain, decreased smell, and posterior purulent drainage—and various minor symptoms. When a patient describes two major criteria or one major and two minor criteria, rhinosinusitis can be diagnosed ( Table 40.1 ). The classification of rhinosinusitis types was based primarily on time frames from the onset of symptoms. More recently, a stricter division for chronic rhinosinusitis (CRS) has been described based on endoscopic findings. These include CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP). The 2012 European position paper on rhinosinusitis and nasal polyps (EPOS 2012) further defines the disease process for both the adult and pediatric populations ( Box 40.1 ).

An inflammatory response is an expected sequela of an infectious process. Sinonasal inflammation can result from a variety of elements that result in sinus ostia obstruction and predisposes patients to infection. Many factors have been described that play a role in the development of acute bacterial rhinosinusitis (ABRS). These include factors related to the host: genetic factors such as immotile cilia syndrome or cystic fibrosis; certain systemic diseases or medical treatments that predispose individuals to infections; neoplasms; and allergic or immune disorders. Although anatomic abnormalities such as large septal spurs and large paradoxic turbinates have been suggested to be associated with rhinosinusitis, it is not currently clear whether a relation exists. Rhinosinusitis may also develop in relationship to environmental factors that include bacterial, viral, or fungal infections or inflammation that occurs secondary to fungal or bacterial colonization ; trauma; primary or secondary tobacco smoke exposure; chronic or acute irritants or noxious chemicals; or iatrogenic factors such as surgery, medications, nasal packing, or nasogastric tube placement. Evidence shows that individuals with allergic rhinitis have a higher incidence of developing both acute and CRS, and an association of ABRS with asthma has also been suggested, although this may also relate to the presence of allergic rhinitis.

The distinctions between acute rhinosinusitis (ARS), recurrent acute rhinosinusitis (RARS), subacute rhinosinusitis (SARS), and CRS and acute exacerbation of CRS (AECRS) are based on the temporal differences in the presentation and in some cases on the clinical presentation. Each of these subcategories may be associated with different pathophysiologic processes, and the predisposition to their development may vary from patient to patient. Given these differing etiologies, the pathogenesis will be described based on this classification.