Chronic rhinosinusitis (CRS) affects nearly 37 million people in the United States each year and accounts for approximately $6 billion in direct and indirect health care costs. Despite its prevalence and significant impact, little is known about its exact cause and pathophysiology, and significant controversy remains regarding appropriate treatment options. Basic science research, however, has shown recent promise toward improving understanding of the innate and environmental factors underlying the pathophysiology of CRS. The hope is that this will also lead to advances in treatment for children adversely affected by this common yet complicated disease.
Key points
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Chronic rhinosinusitis (CRS) represents a heterogeneous spectrum of diseases.
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The definition of CRS has largely been accepted as the persistence of characteristic signs and symptoms beyond 12 weeks.
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Few randomized, placebo-controlled trials or systematic reviews of the literature exist with recommendations for treatment of CRS in children.
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The medical management of CRS has traditionally included combinations of antihistamines, decongestants, nasal saline irrigation, topical nasal steroids, and oral antibiotics.
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When prolonged efforts at medical therapy have failed, children with persistent CRS should be referred to an otolaryngologist for further evaluation and possible surgical intervention.
Classification of CRS
Rhinosinusitis can be considered a spectrum of disease characterized by concurrent inflammatory and infectious processes that affect the nasal passages and the contiguous paranasal sinuses. Diagnosis and management are aided by the classification of this diverse condition into categories based primarily on the duration of symptoms. In addition, pediatric rhinosinusitis, whether acute or chronic, should be considered a unique conditions because of the differences in predisposing factors and the anatomy of the sinuses seen between children and adults.
Because common viral upper respiratory infections (URI) and acute sinusitis can be difficult to distinguish clinically, acute episodes of sinusitis have traditionally been defined as the persistence of signs and symptoms beyond 10 days, or the concomitant occurrence of related complications, such as orbital abscess or meningitis. Other classifications described in the literature include recurrent acute sinusitis, subacute sinusitis, eosinophilic sinusitis, sinusitis with and without nasal polyps, and relatively distinct disease processes, including invasive and allergic fungal sinusitis.
The definition of CRS has largely been accepted as the persistence of characteristic signs and symptoms beyond 12 weeks. This extended period of chronic symptoms may also be punctuated by episodes of acute exacerbations.
Classification of CRS
Rhinosinusitis can be considered a spectrum of disease characterized by concurrent inflammatory and infectious processes that affect the nasal passages and the contiguous paranasal sinuses. Diagnosis and management are aided by the classification of this diverse condition into categories based primarily on the duration of symptoms. In addition, pediatric rhinosinusitis, whether acute or chronic, should be considered a unique conditions because of the differences in predisposing factors and the anatomy of the sinuses seen between children and adults.
Because common viral upper respiratory infections (URI) and acute sinusitis can be difficult to distinguish clinically, acute episodes of sinusitis have traditionally been defined as the persistence of signs and symptoms beyond 10 days, or the concomitant occurrence of related complications, such as orbital abscess or meningitis. Other classifications described in the literature include recurrent acute sinusitis, subacute sinusitis, eosinophilic sinusitis, sinusitis with and without nasal polyps, and relatively distinct disease processes, including invasive and allergic fungal sinusitis.
The definition of CRS has largely been accepted as the persistence of characteristic signs and symptoms beyond 12 weeks. This extended period of chronic symptoms may also be punctuated by episodes of acute exacerbations.
Pathophysiology
Along with the nasal passages, the paranasal sinuses filter, warm, and humidify inspired air. They are also key in reducing the overall weight of the human skull. Sinuses grow in size and shape throughout childhood, although this progression may be affected by various disease processes, such as cystic fibrosis (CF). The result is an underdeveloped or hypoplastic sinus. The frontal sinuses are the last to fully develop, and generally reach adult size by puberty.
The mucosa of the paranasal sinuses is composed of a ciliated, pseudostratified, columnar epithelium with goblet cells for mucous production, and is similar to that found in the remainder of the tracheobronchial passages. Normal function of the sinuses depends on patent ostia, including the important common pathway of drainage and aeration known as the osteomeatal complex (OMC) ( Fig. 1 ), and on normal mucous secretion and normal ciliary function. The primary common factor in the pathophysiology of sinus disease is thought to be obstruction of the sinus ostium, either through mechanical means or mucosal inflammation and edema, rather than initial bacterial infection. Obstruction leads to retained secretions and blocks the normal exchange of air, resulting in hypoxia of the sinus mucosa. This process leads to a cycle of mucosal dysfunction characterized by impaired cilia, further retention of secretions, and secondary infection.
Traditionally, normal sinuses, unlike other areas of the upper aerodigestive tract, have been thought to be sterile and without a normal and possibly protective microbial population, although some recent studies suggest otherwise. Abreu and colleagues describe a reduced diversity of sinus microbes in patients with CRS compared with healthy controls. They also used a murine model of CRS to demonstrate the possible protective effects of one organism in particular: Lactobacillus sakei . Although many questions remain, these findings may support a new paradigm in which the disturbance of normal sinus microbial populations proves to be an important factor in the pathogenesis of CRS in children. Given their overuse in routine URIs, antibiotics are certainly one factor that might be expected to disrupt normal sinus flora and therefore could potentially be more causative than curative in CRS.
A host of other innate and environmental factors also contribute to the common pathophysiologic pathways in CRS ( Table 1 ). Local or anatomic factors include direct sinus obstruction caused by anatomic abnormalities, such as the presence of concha bullosa, septal deviation, nasal polyposis, trauma, and foreign bodies. Conditions contributing to mucosal inflammation and secondary obstruction include URI, bacterial infection, allergy, and gastroesophageal reflux disease (GERD). GERD in particular is known to be prevalent in children with CRS and, in a retrospective study, Bothwell and colleagues demonstrated a significant decrease in the need for sinus surgery among children on antireflux therapy. In addition to allergens, environmental irritants such as air pollutants or tobacco smoke may occasionally play a role in chronic mucosal inflammation.
| Local | Inflammatory | Systemic |
|---|---|---|
| Sinus obstruction | URI | CF |
| Septal deviation | Bacterial infection | Primary ciliary dyskinesia |
| Nasal polyps | Allergy | Immune deficiencies |
| Trauma | Gastroesophageal reflux disease | |
| Foreign body | Tobacco smoke |
Bacterial infection has long been considered a key component of CRS, and the pathogens found in children are generally similar to those in adults. The common isolates associated with CRS include those found in acute sinusitis ( Streptococcus pneumoniae, Moraxella catarrhalis , and nontypeable Haemophilus influenzae ) and Staphylococcus aureus, Pseudomonas , and anaerobes. The possible role of relatively ubiquitous fungi in the CRS inflammatory response has also been proposed, although this remains controversial.
Recent evidence has also supported the role of bacterial exotoxins and biofilm formation in the pathogenesis of CRS. Exotoxins are released by bacteria and may contribute to a symptomatic immune response. In particular, Wang and colleagues demonstrated the presence of staphylococcal exotoxin and its effect on T cells in patients with CRS with nasal polyps. Biofilms form when bacteria aggregate on surfaces within an external matrix of polysaccharides, nucleic acids, and proteins. In CRS, biofilm formation may decrease the efficacy of antimicrobials by as much as 100 fold, allowing bacteria to thrive for a prolonged period within the nose and sinus cavities. In 2005, Sanclement and colleagues used electron microscopy to demonstrate the presence of biofilms in sinus biopsies from 80% of patients undergoing functional endoscopic sinus surgery (FESS) for CRS, whereas none were seen in healthy controls. Other studies have reported the presence of biofilms in adenoid tissue from patients with chronic infectious disease of the upper airways, including CRS. The literature suggests that both exotoxins and biofilms may be important factors in the role of bacterial infection in CRS.
When evaluating a child with symptoms of CRS, one should always consider the possibility of underlying disease as a contributing factor. Diseases impacting normal sinonasal function include CF, primary ciliary dyskinesia (PCD), and a variety of immune deficiencies, including the still-developing immature immunity of normal young children.
Diagnosis
Careful history and physical examination is clearly important in the evaluation of this heterogeneous and multifactorial disease. The symptoms of CRS in children are different than in adult patients and include persistent cough, and prolonged anterior and posterior nasal drainage, congestion, low-grade fever, irritability, and behavioral difficulties ( Box 1 ). Headache, especially in the frontal area, is a less common complaint among children than adults. Parents may report a history of frequent URI or recurrent acute episodes of sinusitis requiring treatment. Additional history should focus on identification of any potential underlying diseases or contributing environmental factors. The diagnosis of CRS is rarely made in isolation, and commonly associated findings include allergy, asthma, dental disease, CF, PCD, and immunodeficiency syndromes. A nasal foreign body should be considered in children with a history of prolonged unilateral rhinorrhea and a foul odor reported by parents.
Nasal congestion
Purulent rhinorrhea
Chronic cough
Postnasal drainage
Low-grade fevers
Irritability
Behavioral issues
Physical examination includes a complete head and neck evaluation with careful attention to the middle ear, because otitis media with effusion (OME) is another common comorbidity. Anterior rhinoscopy ( Fig. 2 ) should be performed with a nasal speculum or otoscope using a large ear speculum. Characteristic findings are summarized in Table 2 and include mucosal erythema and irritation, thickened nasal mucous, polyps, and frank purulent drainage. Periorbital allergic shiners or a pronounced nasal crease may indicate adenoid enlargement or disease. Otolaryngologists will usually include fiberoptic sinonasal endoscopy as part of their examination when possible, allowing improved visualization of the middle meatus, a common site of polyps or purulent drainage from the maxillary and ethmoid sinuses. Endoscopy is also useful for visualizing the posterior nasal cavity, nasopharynx, and adenoid tissue.
| Nasal Examination | Head & Neck Examination |
|---|---|
| Nasal congestion Purulent drainage Mucosal erythema Increased mucous Nasal polyps | OME Allergic shiners Nasal crease Sinus tenderness Reduced transillumination |
The radiologic evaluation of children with suspected CRS is generally reserved for those with disease refractory to medical management. Plain films, computed tomography (CT), and magnetic resonance imaging have all been used in the evaluation of chronic sinusitis; however, CT scanning is generally considered the preferred study ( Fig. 3 ). CT provides a much higher resolution of bone and soft tissue without the interference of overlying structures compared with plain radiography.
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