Development of the Paranasal Sinuses
The pediatric nasal cavity and paranasal sinuses, when compared to those in adults, differ not only in size but also in proportions. Knowledge of the unique anatomy and pneumatization pattern of children’s sinuses is an important prerequisite to understanding the pathogenesis of sinusitis and its complications. It is also important in the evaluation of radiographs and in planning surgical interventions.
17.2.1 Ethmoid Sinus
At birth, the ethmoid sinuses are the only sinuses that are large enough to be clinically significant as a cause of rhinosinusitis. Ethmoidal cells are present at birth and the ethmoid sinus rapidly expands until the age of 5 years due to pneumatization, whereas there is only little expansion in bone width. The final size of the ethmoid is reached by the age of 13 years.
17.2.2 Maxillary Sinus
The maxillary sinuses are present at birth but the volume is extremely small, less than 0.5 mL. The anteroposterior growth of the maxillary sinus increases rapidly during the early years of life, and the volume in patients at 2 years of age is approximately 2 mL ( ▶ Fig. 17.1). At the age of 4 years, the floor of the maxillary sinus is at the level of the hard palate. The lateral walls have advanced two-thirds of the way across the orbital floor past the infraorbital nerve. The maxillary sinus grows rapidly reaching approximately 10 mL in volume around 9 years of age with a variable final adult volume of 13 to 40 mL. Much of the growth that occurs after the 12th year is in the inferior direction with pneumatization of the alveolar process after eruption of the secondary dentition. By adulthood, the floor of the maxillary sinus is usually 4 to 5 mm inferior to the floor of the nasal cavity.
Fig. 17.1 Development of the frontal and maxillary sinuses with age. (Reproduced from Fatu C, Puisoru M, Rotaru M, Truta AM. Morphometric evaluation of the frontal sinus in relation to age. Ann Anat 2006;188:275–280, with permission.)
17.2.3 The Frontal and Sphenoid Sinuses
The frontal sinus is absent at birth and is the last sinus to develop ( ▶ Fig. 17.1). Very often, frontal sinuses cannot be found before the age of 10 years. Their size continues to increase into the late teens, and more than 85% of children will show pneumatized frontal sinuses on computed tomography (CT) scanning at the age of 12 years. 1 The final volume is very variable between 2 and 17 mL. The sphenoid sinus starts to develop in the first year of life but the volume is negligible under the age of 6 years.
17.3 Definition and Classification of Disease
The diagnosis of rhinosinusitis is made by a wide variety of practitioners, including allergologists, otolaryngologists, pulmonologists, primary care physicians, pediatricians, and many others. 2 Therefore, an accurate, efficient, and accessible definition and classification of rhinosinusitis is required. The European position paper on rhinosinusitis and nasal polyps (EPOS) is now widely accepted. 3
In the EPOS guidelines, pediatric rhinosinusitis is defined as follows 3:
An inflammation of the nose and the paranasal sinuses characterized by two or more symptoms one of which should be either nasal blockage/obstruction/congestion or nasal discharge (anterior/posterior nasal drip):
± facial pain/pressure
endoscopic signs of:
nasal polyps, and/or
mucopurulent discharge primarily from middle meatus
edema/mucosal obstruction primarily in middle meatus and/or
mucosal changes within the ostiomeatal complex and/or sinuses
The disease can be divided into acute rhinosinusitis (ARS), which has an acute onset, lasts less than 12 weeks, and shows a complete resolution of symptoms, and chronic rhinosinusitis (CRS), which lasts more than 12 weeks without complete resolution of symptoms. CRS may also be subject to exacerbations. Many etiological factors contribute to ARS and CRS including viral and bacterial infections, genetic defects (such as in cystic fibrosis [CF]), and fungal infections, typically allergic fungal sinusitis [AFS] in the older child). Similar symptoms can occur in patients with allergic inflammation.
17.4 Acute Rhinosinusitis
ARS in children is common and usually occurs in the course of an upper respiratory viral illness. The diagnosis is mostly based on the type and duration of the aforementioned symptoms. The diagnosis is most frequently made in the primary care setting without recourse to endoscopy or imaging, so the clinical findings are of paramount importance. In most cases, this is a self-limited process but treatment with antibiotics seems to slightly accelerate resolution. Whether this benefit outweighs the risks associated with frequent antibiotic prescriptions remains to be clarified. Intranasal steroids might be useful adjuncts to antibiotics in the treatment of ARS, and very limited evidence in older children suggests that they may be useful as a single agent. Ancillary therapy in the form of nasal irrigations, antihistamines, decongestants, or mucolytics has not been shown to be helpful. ARS can lead to serious orbital, intracranial, and osseous complications. Management of ARS complications is always multidisciplinary, and the advice of an ophthalmologist in cases of orbital involvement and of neurologist/neurosurgeon in intracranial involvement is mandatory (see ▶ 4).
17.4.1 Incidence of Acute Rhinosinusitis in Children
The incidence of acute sinusitis or ARS is high. It has been estimated that children may suffer 7 to 10 colds per year. Approximately 0.5 to 2% of viral URTIs are complicated by bacterial infection.
17.4.2 Definition and Diagnosis of Acute Rhinosinusitis in Children
The clinical diagnosis of ARS in children is challenging due to the overlap of symptoms with other common childhood nasal diseases such as viral URTIs and allergic rhinitis (AR) as well as the due to the challenges related to physical examination. The symptoms are often subtle and the history is limited to the observations and subjective evaluation by the child’s parent. Because some younger children might not tolerate nasal endoscopy, clinicians are sometimes hindered in their physical examination and have to rely on history and or imaging studies for appropriate diagnosis.
Symptom profiles of ARS in children include the following:
In children, ARS most often presents as either a severe upper respiratory tract illness with fever > 39°C, purulent rhinorrhea, and facial pain or, more commonly, as a prolonged URTI with chronic cough and nasal discharge.
In a study of the relationship between symptoms of acute respiratory infection and objective changes within the sinuses using magnetic resonance imaging (MRI) scans, 60 children (mean age = 5.7 years) were investigated who had symptoms for an average of 6 days before scanning. 4 Approximately 60% of the children had abnormalities in their maxillary and ethmoid sinuses, 35% in the sphenoid sinuses, and 18% in the frontal sinuses. In 26 children with major abnormalities, a follow-up MRI scan taken 2 weeks later showed a significant reduction in the extent of abnormalities irrespective of resolution of clinical symptoms. This study reinforces the notion that, like in adults, every URTI is essentially an episode of rhinosinusitis with common involvement of the paranasal sinuses by the viral process.
ARS in children is characterized by the sudden onset of two or more of the defining symptoms (discolored nasal discharge, nasal blockage/obstruction/ congestion, cough at daytime and nighttime) for less than 12 weeks, with validation by telephone or interview. 3
Symptom-free intervals may exist if the problem is recurrent. Questions on allergic symptoms (i.e., sneezing, watery rhinorrhea, nasal itching, and itchy watery eyes) should be included. As in adults, the “common cold”/acute viral rhinosinusitis is defined by a duration of symptoms of less than 10 days. Acute postviral rhinosinusitis is characterized by an increase of symptoms after 5 days or persistent symptoms after 10 days. The more severe acute bacterial rhinosinusitis (ABRS; ▶ Fig. 17.2) should be considered in the presence of at least three of the following clinical features:
Discolored discharge (with unilateral predominance) and purulent nasal secretions.
Severe local pain (with unilateral predominance).
Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
“Double sickening” (i.e., deterioration after an initial milder phase of illness).
Fig. 17.2 Schematic representation of the timing of the symptoms during episodes of acute rhinosinusitis (left panel) and the relative proportions of upper respiratory tract infections, postviral rhinosinusitis, and acute bacterial rhinosinusitis (right panel). (Reproduced from Fokkens WJ, Lund VJ, Mullol J, et al. European position paper on rhinosinusitis and nasal polyps 2012. Rhinology 2012;50(Suppl 23), with permission.)
17.4.3 Differential Diagnosis
When a child presents with the aforementioned symptoms of ARS, the differential diagnosis includes intranasal foreign body ( ▶ Fig. 17.3) and unilateral choanal stenosis or atresia. In these entities, the symptoms are usually unilateral and can be relatively easily differentiated clinically from ARS by history and physical examination, including nasal endoscopy.
Adenoiditis can have a very similar clinical presentation including anterior and posterior purulent drainage and cough and is very relevant in the differential diagnosis in the pediatric age group, although more in CRS than in ARS. AR will usually not manifest with purulent drainage as part of the clinical presentation. Migraine and tension type headaches also occur in children and should be differentiated from (recurrent) ARS.
Fig. 17.3 (a) A child with unilateral right-sided nasal discharge. Endoscopy showed mucus in the right nasal cavity (b) and a foreign object (c), which was removed successfully. The nose shows mild irritation (d) at the site of the removed foreign object (e), which turned out to be foam from the mattress. Unilateral foul smelling nasal drainage is the typical presentation of a child with a nasal foreign body.
17.4.4 Pathogenesis of Acute Rhinosinusitis
Knowledge of the pathogenesis of ARS in children is very limited. However, we might consider it to be quite the same as in adults.
Factors that predispose children toward ARS are as follows:
Exposure to individuals with viral URTIs.
The most significant predisposing factor is likely to be URTIs or the common cold. Children have on average six to eight colds per year, with 0.5 to 2% developing acute sinus infections.
There seems to be an association between ARS and atopy and AR , and an association between ARS and smoking. As in adults the relationship between anatomical abnormalities and ARS is very unclear and most likely unimportant.
Microbiology of Viral (Common Cold), Postviral, and Acute Bacterial Rhinosinusitis
Viral, postviral, and bacterial ARS show a considerable overlap both in their inflammatory mechanisms and their clinical presentation. Viral infection of the nose and sinuses induces multiple changes including postviral inflammation, which increases the risk of bacterial superinfection. These changes include epithelial damage and alteration of mechanical, humoral, and cellular defenses. The most common viruses isolated in pediatric viral rhinitis and rhinosinusitis are adenovirus and rhinovirus. Other viruses found are enterovirus, coronavirus, (para)influenza virus, and respiratory syncitial virus (RSV). The microbiology of ABRS, as documented in early maxillary antral puncture studies, is mainly as follows:
Viral infection of the nose and sinuses induces multiple changes that increase the risk of bacterial superinfection. Viral infection induces epithelial disruption, increases the number of goblet cells, and decreases the number of ciliated cells. Eventually, these changes contribute to the obstruction of the sinus ostia in the nasal cavity. A transient increase in pressure develops in the sinus cavity due to mucus accumulation. This is quickly followed by the development of negative pressure in the sinus cavity due to impaired sinus aeration with rapid absorption of the oxygen that is left. This worsens local congestion, promotes further mucus retention, impairs normal gas exchange within the integrated airspace, decreases both the oxygen and pH content, impedes clearance of infectious material and inflammatory debris, and increases the risk of secondary bacterial infection. All these local changes in the nasal and paranasal space form an ideal environment for pathological bacterial colonization and growth.
17.4.5 The Diagnostic Work-Up
The most important aspect of the diagnosis is the history.
Most frequently, children present with symptoms of URTI that have persisted for more than 10 days or there is a worsening of symptoms after an initial improvement.
The rhinorrhea is usually mucoid or purulent.
The cough, which may be wet or dry, occurs in the daytime but is often worse at night.
The child is mild to moderately ill and usually does not have high fever.
The mother is worried about the persistence or increase of the symptoms.
A totally different presentation is the severely ill child with high fever that already persists for 3 to 4 days, much longer than expected with a common cold. The fever is accompanied by thick purulent rhinorrhea that is usually unilateral.
The nasal examination in children should begin with anterior rhinoscopy examining the middle meatus, inferior turbinates, mucosal character, and presence of purulent drainage. This is often accomplished easily using the largest speculum of an otoscope or, alternatively, a headlight and nasal speculum. Topical decongestion may be used to improve visualization.
Nasal endoscopy that will allow a good view of the middle meatus, adenoid bed, and nasopharynx is strongly recommended in children who are able to tolerate the examination. An oral cavity examination may reveal purulent postnasal drainage, cobblestoning of the posterior pharyngeal wall, or tonsillar hypertrophy. Obtaining a culture is usually not necessary in the context of uncomplicated ARS. The diagnosis of ARS in children is generally made on clinical grounds, and radiology (CT or MRI) should be reserved for patients with suspected complications.
17.4.6 Treatment of Acute Rhinosinusitis in Children
Medical Treatment of Acute Rhinosinusitis
Fig. 17.4 Management scheme for acute pediatric rhinosinusitis. (Modified after Fokkens WJ, Lund VJ, Mullol J, et al. European position paper on rhinosinusitis and nasal polyps 2012. Rhinology 2012;50(Suppl 23), with permission.)
Grade of recommendation
Yes in ABRS
Yes mainly in postviral ARS studies only done in children 12 y and older
Addition of topical steroid to antibiotic
Yes in ABRS
Abbreviations: ABRS, acute bacterial rhinosinusitis; ARS, acute rhinosinusitis.
Source: Reproduced from Fokkens WJ, Lund VJ, Mullol J, et al. European position paper on rhinosinusitis and nasal polyps 2012. Rhinology 2012;50(Suppl 23):1–12, with permission.
aStudy with negative outcome. bGrade A recommendation not to use.
Antibiotics are the most frequently used therapeutic agents in ARS. Published trials in children and adults were reviewed in a recent meta-analysis of randomized controlled trials (RCTs) evaluating antibiotic treatment for ARS in which 3 of the 17 evaluated studies were performed in the pediatric age group. 5 In total, 3,291 outpatients (2,915 adults and 376 children) were treated in the trials included in the meta-analysis. The diagnosis of ARS in the trials was based on clinical criteria in most studies and radiological and other laboratory criteria in the rest. In most studies, inclusion of patients with viral URTIs was avoided by enrolling patients whose symptoms were more than 7 to 10 days in duration. The results suggest that compared with placebo, antibiotics were associated with a higher rate of cure or improvement within 7 to 15 days, with the rate of resolution of symptoms being faster with antibiotics in most RCTs. The overall positive effect in favor of antibiotics was significant but very modest. The results suggest that most cases of uncomplicated acute sinusitis will improve irrespective of treatment used but will do so a little faster if given antibiotics.
Based on this evidence, it would seem reasonable to recommend only symptomatic treatment for uncomplicated episodes of ARS in children. Antibiotic therapy would be reserved to children with complications (strength of recommendation: A).
When considering antibiotic choices, uncomplicated ARS in a child who has not received multiple previous courses of antibiotics can still be treated with amoxicillin (40 or 80 mg/kg/day). Other reasonable and safe choices are amoxicillin–clavulanate and cephalosporins that provide good coverage of typical organisms, especially those producing β-lactamase. If hypersensitivity to any of the aforementioned antimicrobials is suspected, alternative choices include trimethoprim/sulfamethoxazole, azithromycin, or clarithromycin.
In a pediatric trial, 89 children with ARS received amoxicillin–clavulanate and were randomized to additionally receive either budesonide or placebo nasal sprays for 3 weeks. 6 There were significant improvements in the scores of cough and nasal discharge at the end of the second week in the steroid group compared to placebo, suggesting a benefit of adding intranasal steroids to antibiotics in the treatment of ARS. Several trials in mixed adult and pediatric populations (usually 12–14 years and older) have demonstrated similar benefits of using an intranasal steroid along with an antibiotic for the treatment of ARS. 3
There is reasonable evidence to support the addition of an intranasal steroid to antibiotics if antibiotics are needed in the treatment of ARS (strength of recommendation: A).
Finally, in a randomized, placebo controlled trial in patients older than 12 years with ARS, mometasone, 200 μg twice daily (twice the AR dose), was more effective in controlling symptoms than placebo and amoxicillin. 7 Thus, there is also some evidence that a high dose of intranasal steroids in older children might be effective as monotherapy for ARS. Although studies in AR have shown that intranasal corticosteroids are safe in younger children, we do not have good data to support their efficacy for ARS in this age group; thus, individual clinical decision-making should be exercised relating to the administration of these medications for ARS in younger children.
A systematic review of the literature was undertaken to evaluate the efficacy of decongestants (oral or intranasal), antihistamines, and nasal irrigation in children with clinically diagnosed acute sinusitis. 8 RCTs or quasi-RCTs that evaluated children between 0 and 18 years of age with ARS defined as 10 to 30 days of rhinorrhea, congestion, or daytime cough were included. The authors conclude that there is no evidence to determine whether the use of the aforementioned agents is efficacious in children with ARS. In another publication, erdosteine, a mucolytic agent, was investigated in a randomized, placebo controlled trial. 9 In total, 81 patients completed the study, and their average age was 8.5 years and all had symptoms consistent with ARS. They were randomized to receive either erdosteine or placebo for 14 days and their symptoms recorded. Both treatment groups had an improvement in symptoms on day 14, but there were no statistically significant differences between the active and placebo groups.
There is no good evidence to support the use of ancillary therapies in the treatment of ARS in children (strength of recommendation: A–, negative recommendation). 10
17.4.7 Complications of Acute Rhinosinusitis
In the preantibiotic era, complications of rhinosinusitis represented common and dangerous clinical events. Today, thanks to more reliable diagnostic methods (CT and MRI), improved surgical techniques, and the wide range of available antibiotics, their incidence and related mortality have dramatically decreased. However, despite antibiotics, serious complications of rhinosinusitis do occur.
Complications of rhinosinusitis are classically defined as follows:
Combinations often occur.
The incidence of complication of ARS in children is 3 to 10 cases per million of population per year (or approximately 1 per 12,000 ARS episodes). 3 There is a clear seasonal pattern of complications, mirroring the incidence of URTIs and appearing more often during winter months. In almost all studies, males are significantly more frequently affected than females. While orbital complications tend to occur primarily in small children, intracranial complications can occur at any age. Orbital complications, including pre- and postseptal cellulitis and subperiosteal and orbital abscess, are the most frequent, and children with acute ethmoiditis are especially prone to them ( ▶ Fig. 17.5, ▶ Fig. 17.6, ▶ Fig. 17.7, ▶ Fig. 17.8, ▶ Fig. 17.9, ▶ Fig. 17.10). Endocranial complications include epidural or subdural abscesses, brain abscess ( ▶ Fig. 17.11), meningitis, cerebritis, and superior sagittal and cavernous sinus thrombosis. Osseous complications include steomyelitis and “Pott’s puffy tumor” of the frontal sinus. Obstruction of the ethmoid sinus can result in an ethmoidal mucocele ( ▶ Fig. 17.12).
Fig. 17.5 Periorbital cellulitis, a typical clinical sign of an impending complication associated with acute bacterial sinusitis. This clinical picture should raise the suspicion of a subperiosteal orbital abscess.
Fig. 17.6 Chandler classification of orbital complications of acute sinusitis. Schematics A to E depict increasing severity of such infections as they progress through the orbit to reach the cavernous sinus. A, Inflammatory edema (preseptal cellulitis); B, orbital cellulitis; C, subperiosteal abscess; D, orbital abscess; E, cavernous sinus thrombosis. (Reproduced from Chandler JR, Langenbrunner DJ, Stevens ER. The pathogenesis of orbital complications in acute sinusitis. Laryngoscope 1970;80(9):1414–1128, with permission.)
Fig. 17.7 Coronal computed tomography scan with contrast (soft-tissue windows) of a patient with a right-sided subperiosteal orbital abscess. Note pan-opacification of the visualized portions of the anterior ethmoid and maxillary sinuses. Also note lateral and inferior displacement of the right eye and rim enhancing abscess cavities on the medial aspect of the orbit alongside the lamina papyracea.
Fig. 17.8 Axial computed tomography scan with contrast (soft-tissue windows) of the same patient. Note proptosis of the right eye (left of the picture) and rim enhancing abscess cavity along the superior aspect of the lamina papyracea. The medial rectus muscle and the optic nerve are displaced laterally by the abscess.
Fig. 17.9 Magnetic resonance imaging (MRI) appearance of a subperiosteal orbital abscess. Coronal T2-weighted MRI. Please note the fluid filled abscess in the right eye (left side of the picture) with lateral displacement of orbital contents. Ipsilateral maxillary sinus is seen filled with fluid on this view.
Fig. 17.10 Axial T1-weighted magnetic resonance image of the same abscess. Note proptosis of the right eye (left of the picture) and rim enhancing abscess cavity along the superior aspect of the lamina papyracea. The medial rectus muscle and the optic nerve are displaced laterally by the abscess.
Fig. 17.11 Axial computed tomography image with contrast of a brain abscess secondary to an episode of acute rhinosinusitis. Note the rim enhanced abscess cavity in the right frontal area (left of the picture) with significant shift of the intracranial structures.
Fig. 17.12 Radiological and intraoperative pictures of a 15-month-old male with cystic fibrosis who presented with left eye proptosis. (a) Coronal computed tomography scan shows a large ethmoid mucocele, which is pushing the left orbital contents laterally. (b) T2-weighted magnetic resonance imaging shows the same mucocele with inflammation of the membrane and low signal intensity in the middle of the mucocele, which corresponds to inspissated mucus. (c) Intraoperative endoscopy of the left nasal cavity shows bulging of the lateral nasal wall medially (*) and complete obliteration of the middle meatal area. After unroofing the mucocele, it was filled with (d) inspissated thick mucus, which after evacuation resulted in return of the eye to normal position.
17.5 Chronic Rhinosinusitis in Children
17.5.1 Classification and Diagnosis
CRS is defined as the presence of the symptoms of discolored nasal discharge and/or nasal blockage/obstruction/congestion, combined with cough at daytime and nighttime, or facial pain for at least 12 weeks.
CRS is primarily due to infection, allergy, or, in some cases, a combination of the two. Although some of the aforementioned symptoms could also apply to AR, facial pain, cough, and discolored nasal drainage are not prominent in allergic disease, and sneezing and itching are not common in CRS. Because of the close association of the two entities, questions on allergic symptoms (i.e., sneezing, watery rhinorrhea, nasal itching, and itchy watery eyes) should therefore be included when taking a history. The adenoids are a prominent contributor to CRS in the pediatric age group.
CRS in children is not as well studied as the same entity in adults. Multiple factors contribute to the disease, including bacteriological and inflammatory factors. The mainstay of therapy is medical with surgery reserved for the minority of patients who do not respond to medical treatment.
17.5.2 Prevalence of Chronic Rhinosinusitis in Children
The exact prevalence of CRS in children is difficult to determine as only a small percentage of cases present to the physician’s office. Many studies that address prevalence have been performed in select populations, typically in children, who have upper respiratory complaints. In one such study, CT scans were obtained in 196 children between 3 and 14 years of age presenting with chronic rhinorrhea, nasal congestion, and cough. 11 Maxillary involvement was noted in 63%, ethmoid involvement in 58%, and sphenoidal sinus involvement in 29% of the children of the youngest age groups. This contrasts with 10% of the ethmoids, 0% of sphenoids, and 65% of the maxillaries being involved in the older 13 to 14-year-old age group. There are few studies that follow the prevalence over time and suggest a decrease in the prevalence of rhinosinusitis after 6 to 8 years of age.
17.5.3 Pediatric Chronic Rhinosinusitis and Quality of Life
CRS has a marked impact on quality of life. Children with CRS have significantly lower quality-of-life scores when compared to healthy children and children with other common chronic childhood diseases such as asthma, attention deficit hyperactivity disorder, juvenile rheumatoid arthritis, and epilepsy. 12 The differences were most marked in the physical domains of the quality-of-life questionnaires, such as bodily pain and limitation in physical activity. There is also limited evidence showing improvement of quality of life using a validated sinus and nasal quality of life measure (the SN-5 tool) in patients with CRS after surgical intervention, for example, adenoidectomy or endoscopic sinus surgery. 13
17.5.4 Pathogenesis of Chronic Rhinosinusitis in Children
Predisposing Factors for Chronic Rhinosinusitis in Children
Although day care, that is, where several children congregate and spread of infection might be facilitated, is often thought to have a negative influence on URTIs and thus potentially on CRS, the available data suggest the opposite. 14, 15
There is evidence to suggest that children with a family history of atopy or asthma who attend day-care centers (crèches) in the first year of life have 2.2 times higher odds of having doctor-diagnosed sinusitis than children who do not attend day care.
Cigarette smoking and exposure to second-hand smoke is common and significantly independently associated with CRS. Other lifestyle-related factors are involved in the chronic inflammatory processes of CRS. For instance, low income was associated with a higher prevalence of CRS. The role of environmental factors in the development of CRS is unclear.
Similar to adults, the osteomeatal complex is believed to be the critical anatomical structure in rhinosinusitis and is entirely present, though not at full size, in newborns. Studies in children and adults suggest that despite the common occurrence of anatomical variations such as pneumatized middle turbinate, Haller’s cell, and the agger nasi cell, these do not seem to correlate with the degree and existence of CRS and most likely do not play a role in the pathophysiology of CRS.
A number of pathological conditions may predispose to CRS in children ( ▶ Table 17.2).
AR is a common coexisting disease in pediatric patients with CRS. The data about the association between the two diseases in children are variable. The causal relationship between allergies and CRS in children is still controversial and probably nonexistent.
Asthma is another disease that is commonly associated with CRS in the pediatric age group.
There are some studies supporting the concept that clinical control of CRS may be important in optimizing the control of difficult-to-treat asthma. However, the limitations of most available studies include the lack of good controls and randomization to different treatment modalities; therefore, the relationship between CRS and asthma in children remains largely descriptive.
GERD has been associated with rhinosinusitis in several studies. In a large case–control study, at Texas Children’s hospital, 1,980 children with GERD and 7,920 controls (ages 2–18 y) were identified based on ICD-9 codes. 16 The number of cases with a concomitant diagnosis of sinusitis was significantly higher in the children with GERD (4.19%) compared to the control group (1.35%). The differential diagnosis between GERD and postnasal drip can be difficult. Although some evidence supports an association between GERD and CRS, more controlled studies are required to confirm this association and validate it. Routine antireflux treatment of children with CRS is not warranted based on current evidence.
Abnormalities in immunity are frequently described in children with recurrent/chronic rhinosinusitis with IgG subclass deficiency and poor response to pneumococcal antigen being the most often reported. Therefore, it seems prudent to evaluate immune function in the child with recurrent/chronic rhinosinusitis with a total and subclass immunoglobulin quantitation, and titers to tetanus, diphtheria, and pneumococci. We usually measure titers for 23 common streptococcal serotypes. If responses are abnormal, a repeat set of titers 6 wk postpneumococcal vaccination is appropriate. We do not routinely evaluate immune function in every child with CRS and reserve this work-up for children with frequent infections in other organs such as otitis media and pneumonia, as well as children who have disease severe enough to consider surgical intervention. If abnormalities in humoral immunity are detected, the patient is managed jointly with colleagues from allergy/clinical immunology. Intravenous immunoglobulin therapy, usually administered monthly, has been used with success in some patients with documented immunodeficiencies. Another option is to consider prophylactic antibiotics.
Cystic fibrosis is a genetic disease with autosomal recessive inheritance that affects approximately 1 in 3,500 newborns. It is caused by a mutation in the CFTR gene on chromosome 7, which leads to disruption in cAMP-mediated chloride secretion in epithelial cells and exocrine glands. This leads to increased viscosity of secretions resulting in bronchiectasis, pancreatic insufficiency, CRS, and nasal polyposis. The prevalence of chronic sinusitis is very high and nasal polyps occur in 7–50% of affected patients.
The normal movement of mucus by mucociliary transport toward the natural ostia of the sinuses and eventually to the nasopharynx can be disrupted by any ciliary dysfunction or mucosal inflammation. The most common cause of severe ciliary dysfunction is PCD, an autosomal recessive disorder involving dysfunction of cilia and present in 1 of 15,000 of the population. 17 Half of the children with PCD also have situs inversus, bronchiectasis, CRS, and Kartagener’s syndrome. The diagnosis should be suspected in a child with atypical asthma, bronchiectasis, chronic wet cough and mucus production, rhinosinusitis, and chronic and severe otitis media (especially with chronic drainage in children with ear tubes). Typically, the child already has these symptoms before the age of 6 mo. Screening tests for PCD include measuring nasal nitric oxide (very low levels). Specific diagnosis requires examination of cilia by light and electron microscopy, which is usually available only in specialized centers. The most commonly described structural abnormality involves lack of cilial outer dynein arms or a combined lack of both inner and outer dynein arms.
Data on the prevalence of nasal polyps in patients with PCD are variable from none 18 to 25%.
Abbreviations: AR, allergic rhinitis; cAMP, cyclic adenosine monophosphate; CRS,chronic rhinosinusitis; GERD, gastroesophageal reflux disease; ICD-9, International Classification of Diseases, Ninth Revision; IgG, immunoglobulin G; PCD, primary ciliary dyskinesia; SNOT, Sino-Nasal Outcome Test.
Pathophysiology of Chronic Rhinosinusitis
The pathogens in CRS are difficult to identify due to low bacterial concentration rates and inconsistent data and because most cultures are obtained at the time of surgery after patients have had antibiotic therapy.
The most common bacterial species recovered during surgery are as follows:
Alpha hemolytic streptococci.
Anaerobic organisms are grown from <10% of specimens. The incidence of anaerobic organisms recovered increases with chronic infections.
The role of “biofilms” is now well documented in adults with rhinosinusitis, but more research is needed to clearly characterize their contribution to the pathophysiology of CRS in children.
Biofilms are complex aggregations of bacteria distinguished by a protective and adhesive matrix and have recently been implicated in CRS ( ▶ Fig. 17.13). They form when planktonic bacteria adhere and coalesce to various surfaces through glycoconjugate moieties and form well-organized ecosystems within the human host. Biofilms are also characterized by surface attachment, structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of polymeric substances, which all contribute to their resistance to antibiotic treatment. Intermittently, planktonic bacteria shed from the biofilm, migrate, and colonize other surfaces. It is therefore hypothesized that biofilms may provide a chronic reservoir for bacteria and may be responsible for the resistance to antibiotics seen in pediatric patients with CRS.
Fig. 17.13 Biofilm maturation is a complex developmental process involving five stages: stage 1, initial attachment; stage 2, irreversible attachment; stage 3, maturation I; stage 4, maturation II; stage 5, dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing Pseudomonas aeruginosa biofilm. All photomicrographs are shown to same scale. (Image credit D Davis. Reproduced from Monroe D. Looking for chinks in the armor of bacterial biofilms. PLoS Biol 2007;5(11):e307, with permission.)