6 Special Considerations for Pediatric Maxillary Sinusitis

Pediatric sinusitis is a relatively common problem in the offices of both pediatricians and otolaryngologists. The average child has six to eight upper respiratory tract infections per year and it is estimated that 5 to 10% of these are complicated by rhinosinusitis.1,2 Despite being relatively common, the sinus disease represents somewhat of an enigma for both parents and primary care physicians, leading to confusion as to the exact scope of the disease. Pediatric sinus disease, including disease specific to the maxillary sinus, can be classified into three categories: acute, subacute, and chronic. Acute rhinosinusitis (ARS) is defined as an upper respiratory infection (URI) that persists without significant improvement for longer than 10 days. This creates some confusion as a viral URI can last longer than 7 to 10 days. A key feature of ARS is that symptoms tend to worsen at 7 to 10 days versus the typical improvement seen with viral illness during this time. Chronic rhinosinusitis (CRS) is a chronic, low-grade infection that persists beyond 3 months. Recurrent acute rhinosinusitis describes recurrent bouts of ARS with interposed symptom-free periods,² in contrast with acute exacerbations of chronic rhinosinusitis.

Clinical Presentation

The key diagnostic dilemma is differentiating a viral URI from true rhinosinusitis, the duration and timing being key factors. ARS presents in children with signs and symptoms of nasal discharge and obstruction, persistent cough, and bad breath (halitosis). These symptoms persist beyond 10 days. A small subset present with a more fulminant condition featuring high fevers and purulent rhinorrhea, and a few children will have complications as presenting symptoms for acute maxillary sinusitis. Unlike adult patients, facial pain and headache are less common, especially in younger children (although adolescents may have these complaints as well).^1,2 Although rhinosinusitis pathophysiology is tied closely to allergy, most parents deny signs and symptoms of allergy. Despite this, a family history of allergy and asthma are common in these patients.³

One classic symptom of pediatric sinusitis is a chronic cough that worsens at night, although this symptom is also common with chronic adenoiditis. This should be differentiated from chronic cough worse in the daytime, which is more suggestive of asthma (although the two entities are closely related).³ Fiberoptic exam may be within normal limits, although frank purulence is sometimes seen (Fig. 6.1).

The role of imaging studies in the diagnosis of sinusitis is different in children versus adults. Plain radiographs are rarely used due to low sensitivity to detect sinusitis. Although computed tomography (CT) is the gold standard for sinus imaging, it is less useful for diagnostic purposes in the pediatric population. Manning et al showed that 47% of children without chronic sinusitis had abnormalities on CT scans. These patients often had resolving URI or allergic symptoms (i.e., very low specificity).⁴ Another study showed that 46% of random CT scans in asymptomatic patients showed mucoperiosteal thickening.⁵ Despite this, several specific imaging findings probably do correlate with severity of disease: air fluid levels/bubbles, expansion of the maxillary sinus outflow tract through the infundibulum, and thickened bony septations.³ Based on the above, CT and plain film imaging serve little purpose in the diagnosis of rhinosinusitis. One exception is the use of lateral neck plain imaging to evaluate the size of the adenoid pad. Many advocate reserving CT imaging until the patient has failed maximal medical therapy. In this context, imaging is used in preoperative planning and serves as a road map for the surgical procedure.

Predisposing Factors

The pathophysiology of pediatric maxillary sinusitis is multifactorial and represents the end point of many possible predisposing conditions. In essence, sinusitis is a presumed bacterial infection of a previously damaged underlying mucosa. This damage can be caused by and altered by many factors. In children, rhinosinusitis is generally a problem of mucosal defense more so than one of anatomic obstruction, although these two factors both come into play. A full discussion of the pathophysiology of sinus disease is beyond the scope of this chapter. Some of the factors that lead to maxillary sinus disease are described below.

Allergy

There is a well-established relationship between pediatric sinusitis and allergy and allergic rhinitis. Although the rate of allergy in the general population is only 15 to 20%, more than 80% of children with rhinosinusitis have a positive family history of allergy.² The role of allergy in the development of sinusitis is twofold. First, allergic congestion can lead to obstruction of the ostiomeatal complex and block outflow of the maxillary sinus. Second, allergic mediators may have direct effects on the sinus mucosa itself.^2,3

Environmental Toxins

The development of sinusitis can be exacerbated by the presence of certain airway pollutants. The most common of these is exposure to second-hand tobacco smoke, but other environmental irritants can also have similar effects. These substances have direct irritant effects on the nasal and sinus mucosa leading to impaired ciliary function.²

Chronic Adenoiditis

The adenoid pad serves as a bacterial reservoir that may play a part in the pathogenesis of both chronic otitis media and chronic sinusitis. An association has been shown between adenoid bacterial load and sinusitis symptom scores. There did not appear to be a relationship between the size of the adenoid pad and the bacterial load.⁶ In addition, there is an 89% correlation between cultures taken from the adenoid pad and the middle meatus, further supporting this as a reservoir for infection.⁷

Gastroesophageal Reflux

Gastroesophageal reflux disease (GERD) has also been implicated as a contributing factor in CRS. Phipps et al studied 30 patients with CRS with dual pH probe monitoring and found that 63% had GERD. Furthermore, 32% of the patients had reflux that reached the nasopharynx; 79% of the patients’ sinusitis improved with treatment of their GERD.⁸ Another study by Bothwell et al showed when 30 patients that were candidates for sinus surgery were treated with antireflux measures, 89% improved such that surgery was avoided. This was a retrospective review, however.⁹ When evaluating patients with CRS, the presence of GERD should be appreciated and included in the medical treatment.

Bacteriology

The microbiology of pediatric maxillary sinusitis does differ greatly from the adult population and consists mainly of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, as well as Staphylococcus aureus and occasionally anaerobes. Drug-resistant organisms are becoming an increasingly common problem. Risk factors for the development of resistance include age younger than 2 years, day-care exposure, and frequent antibiotic treatment. Knowledge of resistance patterns in the community is a powerful tool.¹ See Chapter 3 for a full discussion of the microbiology of maxillary sinusitis. See below for the bacteriology of sinuses in cystic fibrosis.

Special Populations

Primary Immunodeficiency

All very young children essentially have a physiologic immunodeficiency, which will improve as the child’s immune system matures.³ In addition, a subset of patients have true primary immunodeficiency. The four most common immunodeficiencies in pediatric patients are transient hypogamma-globulinemia of infancy, immunoglobulin G (IgG) subclass deficiency, impaired polysaccharide responsiveness (partial antibody deficiency), and selective IgA deficiency. These patients have defects in the humoral immune system, with maintained function of the cellular, phagocytic, and complement systems. All are heterogeneous and include as a component recurrent bacterial upper respiratory infections, including sinusitis (as well as otitis media).¹⁰ In addition, they normally present with recurrent lower respiratory infections including bronchitis and pneumonia.² The genetic factors underlying these conditions are poorly understood and the etiologies are felt to be multifactorial.¹⁰ If one of these conditions is suspected, the physician should order total immunoglobulin, IgG subclasses, and vaccine response testing and should consider referral to a pediatric immunologist.¹

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia is a disorder of respiratory ciliary function. The patients present with recurrent respiratory tract infections, including pneumonia, bronchitis, otitis media, and sinusitis. The incidence is 1:16,000 live births.3 The disorder originates from disorganization of the 9+2 microtubule organization of cilia or a defect in the dynein arms.¹¹ This creates an anatomic distortion in the structure of the cilia and also results in a functional defect noted with decreased ciliary beat frequency.¹² The disease can occur in isolation or as part of Kartagener syndrome (with situs inversus) in ~50% of cases.² The diagnosis is made with electron microscopy of nasal turbinate brushing or formal respiratory tract mucosa biopsy.

Cystic Fibrosis

Cystic fibrosis merits special mention in the discussion of pediatric maxillary sinusitis. This disease is the most common lethal hereditary disorder in the white population with a frequency of 1 in 2000 live births. Affected patients demonstrate a generalized exocrinopathy associated with progressive pulmonary disease and gastrointestinal tract malabsorption.¹³ Patients with cystic fibrosis have almost universal paranasal sinus disease, which is a significant source of morbidity.

Pathophysiology of Sinus Disease in Cystic Fibrosis

The respiratory tree from the nasal cavity and sinuses down to the level of the distal bronchioles is lined with a ciliated pseudostratified epithelium that acts as an effective barrier against foreign particles, irritants, and microorganisms. The key to the effective function of this “mucociliary elevator” is the coordinated beating of the cilia. For this to occur, the overlying mucus layer must also be optimal. The classical hypothesis holds that the mucus layer is in fact two layers, a deep low-viscosity fluid that bathes the cilia (the sol layer) and a superficial more viscous gel layer. The former is made up of water and ions regulated by active transport by the epithelium, thus generating a transepithelial electrical potential difference. The thicker gel layers serve to catch inhaled foreign particles that are transported along the layer by the ciliary beat.^13,14

Patients with cystic fibrosis have mutations in the cystic fibrosis transmembrane regulator (CFTR) gene on chromosome 7 that encodes for a chloride ion transporter. Secondary to this, chloride ion gradients are altered and the hydration and viscoelastic properties of mucus are altered. How this directly affects ciliary function is not well understood. Nevertheless, patients with cystic fibrosis have decreased mucociliary clearance that ranges from moderate to severe. Long-standing chronic inflammation is thought to produce changes in the mucosa including goblet cell hyperplasia, squamous cell metaplasia, and loss of ciliated cells. This further compromises mucosal function. In addition, bacterial byproducts may directly alter ciliary function.¹⁴ In addition to the impaired mucosal function, patients with cystic fibrosis have mechanical obstruction of sinus ostia due to the altered mucus viscosity. This leads to infection and inflammation that further compromises sinus drainage.¹⁴

Nasal Polyposis in Cystic Fibrosis

Nasal polyposis is common in patients with cystic fibrosis with a reported incidence from 6 to 48%. Polyps tend to occur in this population between the ages of 5 to 20 years. Interestingly, the histopathology of cystic fibrosis polyps is different from those found in other patients. Specifically, CF polyps have a thin basement membrane, acidic mucin, and an absence of submucosal hyalinization and eosinophilia. In contrast, atopic polyps have a thick basement membrane, neutral mucin, and abundant eosiniphils.¹⁴

Anatomy of the Cystic Fibrosis Sinus

The maxillary sinus of patients with cystic fibrosis differs anatomically in that they are smaller in volume. This is thought to be secondary to decreased postnatal growth and pneumatization of the sinuses due to chronic inflammation. This is corroborated by the fact that these patients often have absent sphenoid and frontal sinuses (which in contrast to the maxillary sinus, initiate development postnatally).¹⁴ Cystic fibrosis patients also have demineralization of the uncinate process and medial displacement of the lateral nasal wall. In addition, when these patients also have nasal polyposis, erosion or destruction of the lateral nasal wall is common. This has been hypothesized to be secondary to physical pressure of inspissated mucus and polyps on the thin bone or osteitis of the bone itself. These changes are commonly associated with the formation of a maxillary sinus mucocele, which is extremely rare in children and should raise the suspicion of cystic fibrosis in patients without the diagnosis.^14,15

Bacteriology of Sinuses in Cystic Fibrosis

The bacteriology of sinus cultures in cystic fibrosis patients varies with age. In younger patients, Staphylococcus aureus and Haemophilus influenzae are most common. In older children and adults, Pseudomonas aeruginosa predominates. Cultures are polymicrobial 25 to 44% of the time and include the more typical respiratory pathogens mentioned above.¹⁶

Treatment

Medical Management

Acute Rhinosinusitis

The primary treatment of both acute rhinosinusitis and chronic rhinosinusitis is medical therapy. The initial treatment should address the appropriate controlling of the risk factors described above. Any treatment that fails to take these into account risks failure.3 In addition, treatment must be planned in light of the fact that approximately two-thirds of pediatric ARS will resolve spontaneously. An evidence-based consensus practice guideline from the American Academy of Pediatrics in 2001 recommends amoxicillin in normal dose (45 mg/kg) or high dose (90 mg/kg) as first-line treatment in children that have mild to moderate disease. For more severe disease or those with high risk of resistant Staphylococcus pneumoniae should be given high-dose amoxicillin/clavulanate (90 mg/kg). Patients with mild penicillin allergy should receive cefdinir, cefuroxime, or cefpodoxime. Severe penicillin allergy warrants use of a macrolide.^2,16 Duration of therapy has not been well studied, but 7 to 10 days is generally regarded as acceptable. These recommendations have not changed substantially since 2001.

Chronic Rhinosinusitis

Chronic rhinosinusitis treatment begins with appropriate antimicrobial treatment. Initial treatment is with high-dose amoxicillin/clavulanate (90 mg/kg) or the above alternatives in the case of penicillin allergy. Unlike ARS, short courses of antibiotics commonly lead to treatment failure. Although there are no well-designed clinical trials supporting it, most experts advocate a duration of therapy ranging from 3 to 6 weeks.^2,3

Adjuvant medical therapies complement antimicrobial treatment. Nasal saline rinses are used to remove inspissated mucus and secretions and improve patient comfort. Topical nasal steroids are routinely used, although the literature supporting their efficacy in children is sparse. Mometasone furoate is approved for children 2 years and older and has shown no effect on growth or pituitary function in children.^17,18 Fluticasone propionate is approved for children 4 years and older. Other sprays including budesonide and triamcinolone are approved for children 6 years and older. For a complete discussion of the medical treatment of sinusitis, see Chapter 4.

Surgical Management of Pediatric Sinusitis

In a subset of patients, symptoms or sinusitis persist despite maximal medical therapy. Several options exist for the surgical management of these patients. As mentioned above, computed tomography abnormalities are not a sufficient indication for surgical intervention. The criteria for surgery are the failure of prolonged maximal medical treatment after predisposing risk factors have been appropriately addressed.

Adenoidectomy

The first-line surgical treatment for pediatric is adenoidectomy. Several studies have provided support for efficacy in the treatment of rhinosinusitis. A prospective study of 37 children with chronic rhinosinusitis treated with adenoidectomy demonstrated a significant decrease in episodes of sinusitis and improvement in nasal obstruction.¹⁹ A recent meta-analysis examined the effect of adenoidectomy on sinusitis. The review found improvement in pediatric sinusitis after adenoidectomy in 69.3% of patients.²⁰ This was based on caregiver-reported symptom scores.

Ramadan et al looked at risk factors for failure of adenoidectomy in the treatment of CRS. In 143 patients treated with adenoidectomy for CRS, 61 children “failed” with persistent symptoms postoperatively and subsequently underwent functional endoscopic sinus surgery. In their analysis, the presence of asthma and age <7 years were statistically significant for adenoidectomy failure. The presence of allergic rhinitis, CT score, and sex were not predictive.²¹ In another recent study by the same author, children had improvement in cure rates when adenoidectomy was accompanied at the time of surgery by maxillary sinus washout.²² Based on the current literature, adenoidectomy is a safe initial treatment for pediatric chronic rhinosinusitis that has failed medical therapy. The procedure is simple, can be done on an outpatient basis, and has little risk.

Functional Endoscopic Sinus Surgery

When medical management and adenoidectomy have failed to control CRS or when the patient has an anatomic or pathologic indication (i.e., mucocele), functional endoscopic sinus surgery (FESS) is a safe and effective therapy. Other indications include suppurative complications, nasal polyposis, neoplasms, and alteration of systemic disease by the presence of sinusitis (see below on cystic fibrosis). One difficulty is that there are currently no studies in the literature using validated outcomes measures to assess outcomes. A meta-analysis of pediatric FESS patients showed positive outcomes in 88.4% of the cases examined. The average combined follow-up time was 3.7 years and the complication rate was 0.6%. Other studies have shown that on longer follow-up, patients have high recurrence rates and lower cure rates.³ FESS in children has prompted questions about the effect of surgery on subsequent facial growth. Several animal studies suggested this effect^23,24; human studies have not substantiated this concern.^25,26

Most authors agree that the concept of “less is more” applies specifically to children undergoing FESS. The two goals of surgery are to (1) restore patent physiologic communication between diseased sinuses and the nasal cavity, and (2) preserve normal anatomy.

Preoperative Evaluation

The most critical aspect of preoperative preparation is setting appropriate expectations for the caregivers. Surgery is generally a mechanism for reducing the severity of symptoms or increasing the time between episodes versus a true cure. Patients with cystic fibrosis and patients on prolonged antibiotics courses may have malabsorption and vitamin K deficiency that can predispose to bleeding.2

Maxillary Antrostomy/Uncinectomy

As with adults, the key to success with sinus surgery is successful removal of the uncinate process and the restoration of appropriate clearance through the ostiomeatal complex (OMC). Young children tend to have more narrow ethmoid cavities and a concave middle meatus. The uncinate itself is often immediately apposed to the lamina papyracea, which may project medially (thus predisposing to inadvertent orbital injury). The uncinate is retracted off of the lamina medially and a window created using a back biting forceps. This allows identification of the infundibulum and the natural ostium. The complete uncinate is removed (see Video 6.1). If necessary, the maxillary antrostomy in communication with the natural ostium is created in the posterior fontanelle. Care is taken not to disturb the anterior fontanelle of the natural ostium to prevent damage to the nasolacrimal system. Some authors advocate a “mini-FESS” procedure that includes an uncinectomy ± maxillary antrostomy and opening of the ethmoid bullae.²⁷ Others believe that the minimal surgery indicated is a formal maxillary antrostomy and anterior ethmoidectomy (Fig. 6.2).²

Postoperative Care

Postoperatively, patients are given nasal saline sprays twice daily and treated with topical nasal steroids. In the past, FESS was a two-stage procedure and the patient was brought back to the operating room 2 to 4 weeks after the initial surgery for debridement under anesthesia. Currently, this second stage is reserved for patients with specific needs for the procedure, including very ill patients and all patients with systemic abnormalities including cystic fibrosis, primary ciliary dyskinesia (PCD), and immunodeficiency.²⁸

Like the disease process itself, the treatment of rhinosinusitis has several unique aspects. Similar to typical patients, medical therapy consists of long-term antibiotics and adjunct treatment with nasal saline irrigation. Only one clinical trial looking at inhaled steroids in the CF population exists in the literature. This study showed significant symptom improvement and a decrease in polyp size in patients treated with 100 μg of betamethasone twice daily for 6 weeks, although the study was in adults with CF and follow-up was limited.29 Nasally inhaled dornase alfa (Pulmozyme; Hoffmann-La Roche, Basel, Switzerland) is a highly purified solution of recombinant human deoxyribonuclease I that has been used as a mucolytic in CF patients. A trial compared 24 CF patients that underwent FESS and were then randomized to one year treatment with dornase alfa or placebo. The treatment group showed improvement in symptoms, CT appearance, and endoscopic exam score.³⁰

The use of topical tobramycin treatment for CRS in CF patients is well described in the literature, specifically in the perioperative period surrounding lung transplant. The sinuses are thought to serve as a reservoir for Pseudomonas aeruginosa in these patients, a microorganism that is the cause of several serious postoperative complications in these patients. In one study, patients underwent FESS with the placement of a maxillary sinus irrigation catheter at the end of the case. Tobramycin was given for 10 days postoperatively. Weekly administration was performed under local anesthesia for up to 3 weeks. The study’s clinical outcome measures were vague, but they did demonstrate negative sinus P. aeruginosa cultures at the completion of treatment.³¹ Another study used the same protocol and found dramatically decreased rates of need for revision surgery and recurrence of disease, but no difference in P. aeruginosa sinus colonization.³²

Studies have demonstrated FESS to be a safe procedure for those with cystic fibrosis with low rates of complications such as bleeding.³² The surgical approach is similar to nonCF patients, although studies have shown better symptom scores and lower rate of recurrence with more extensive surgery. Future research is centered on the use of intranasal gentamicin and low-dose systemic macrolide therapy as novel treatments for CRS in CF patients.³³

Conclusion

Pediatric maxillary sinusitis is a common problem whose primary medical treatment leads to resolution for the majority of patients. Adenoidectomy and FESS provide safe alternatives for those that fail maximum medical therapy. Physicians treating these patients should be attuned to the specific needs of the pediatric population and those of patients with other systemic diseases.