Rhinosinusitis is one of the world's most commonly diagnosed diseases, and affects an estimated 15-20% of the pediatric population every year [1]. It has significant adverse effect on health-related quality of life in children. The last 10 years have seen considerable developments in terms of new diagnostic and management concepts. Opinions regarding therapy vary from no treatment to extensive sphenoethmoidectomy. The correct approach lies somewhere between these extremes.

DEFINITIONS
Rhinosinusitis, which is the preferred term, acknowledges that most sinus infections start in the nasal passages as part of a continuum of disease. Bacterial infection of the mucosa of the paranasal sinuses that involves the nasal epithelium, and so what was once simply sinusitis is now more accurately known as rhinosinusitis. Viral rhinitis cannot be differentiated from rhinosinusitis on clinical grounds alone. Isolated rhinitis probably exists, but isolated sinusitis is rare [2].
Rhinosinusitis, defined as the inflammation of one or more of the paranasal sinuses, is considered acute when it lasts for <4 weeks, subacute when it lasts for 1-3 months, and chronic when it lasts for longer. Recurrent rhinosinusitis consists of three or more episodes of acute rhinosinusitis per 6 months, or four or more per year [3].
The American Academy of Pediatrics has proposed the following definition of rhinosinusitis: acute rhinosinusitis is defined as an infection of the paranasal sinuses lasting less than 30 days and often presents as an upper respiratory infection with worsening of symptoms (most notably nasal discharge, cough, halitosis) 7-10 days after onset [4].

MICROBIOLOGY
Bacterial invasion of sinuses is frequently preceded by viral URIs. The bacteria most commonly implicated are Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis. Other organisms implicated are Staphylococcus aureus, Pseudomonas aeruginosa, and certain anaerobes. Resistance to penicillin is seen in 15-50% isolates of Streptococcus pneumoniae, 25-50% isolates of H. influenzae and 90-100% isolates of M. catarrhalis. Resistance to macrolides is seen in 10-40% isolates of S. pneumoniae. Fungi are increasingly being identified as a factor in chronic sinsusitis; the most commonly involved are Bipolaris, Curvularia, Aspergillus, and Dreschlera species [5].
Timir Baran Sahu, Senior Resident, Department of Pediatrics, Dr. B.R. Ambedkar Hospital, Rohini, Delhi-110 085. E-mail : tbsahu@yahoo.co.in
An understanding of predisposing factors is important when considering treatment options. For example, sinusitis caused by allergy is best prevented by knowledge and avoidance of offending allergens, as opposed to chronic antibiotics. More importantly, if these factors are neglected, treatment ultimately may not be successful.
1. URI: - The most common predisposing factor is viral URIs, which are often associated with the evidence of rhinosinusitis. Children average between 6-8 colds in a year, of which 5-10% are complicated by rhinosinusitis. Viral infection causes inflammation of the sinus ostia causing stasis of secretions and poor ventilation of the affected sinuses. This provides a favorable environment for bacterial growth.
2. Allergy: - The relationship between allergy and rhinosinusitis in children is well known. More than 80% of children with rhinosinusitis have a family history of allergy, as opposed to a general population allergy frequency of 15-20% [6]. Allergy can contribute to sinusitis by either nasal congestion and subsequent ostia obstruction, or direct effect on sinus lining cells.
3. Adenoid vegetations: - The adenoids also contribute to rhinosinusitis in children by serving as a bacterial reservoir. Studies have shown that removal of the adenoids will improve rhinosinusitis for 70-80% of children [7].
4. Immunologic defects: -The relative immunodeficient state of young children is another important predisposing factor. This may be due to a slow rise in immunoglobin production, which may be a more important causative factor than is allergy in younger children. This is reflected by a decrease in incidence of rhinosinusitis in older children inspite of increase in prevalence of allergy [8]. Children affected with pathologic immunodeficient states tend to have severe and refractory rhinosinusitis.
5. GERD: - Double-lumen pH probe testing has shown that esophageal reflux can extend to the area of the nasopharynx; therefore the suggestion that GERD may cause rhinosinusitis. A number of studies in children indicate that the medical treatment of GERD significantly improves rhinosinusitis symptoms [3].
6. Cystic fibrosis: - Mucoid secretions in patients with cystic fibrosis tend to be thicker and more tenacious, leading to impaired mucociliary clearance and retention of secretions in sinuses and nasopharynx. This predisposes to bacterial colonization.

DIAGNOSIS
About half of the untreated cases of acute rhinosinusitis resolve spontaneously, usually within 4 weeks of the onset of symptoms; however, an increase in the number of serious complications of untreated rhinosinusitis have been observed in recent years. The best current practice is therefore to establish an accurate diagnosis and prescribe antimicrobial therapy with an agent associated with a probable successful outcome.
Paranasal sinuses are normally considered to be sterile. However, they are contiguous with the nasopharynx and nasal mucosa. Hence, transient contamination with bacteria is commonly seen. These contaminations lead to bacterial colonization, which are mostly low-density in nature. These low-density bacterial colonies are mostly removed by mucociliary clearance. The standard for diagnosis of acute rhinosinusitis is the recovery of high-density bacteria (>104 colony forming unit/ml) from the paranasal cavity. Sinus aspiration is the gold standard procedure for the diagnosis of acute rhinosinusitis. However, it is painful, invasive and time-consuming. It should be performed by ENT specialists only and that too in selected patients. It is not recommended for the routine diagnosis of acute rhinosinusitis in children.
The recommended method for the diagnosis of acute rhinosinusitis is by clinical evaluation in children presenting with severe or persistent upper respiratory symptoms. Persistent symptoms are those that last 10-14 days or more but less than 30 days. These include a nasal or post-nasal discharge (of any nature), daytime cough (which may be worse at night), or both. Severe symptoms include temperature >390C, purulent nasal discharge of at least 3-4 days (especially in an ill-looking child) and facial pain or headache, and at time periorbital edema.
It is very important to differentiate uncomplicated viral URIs from bacterial rhinosinusitis. Viral URIs may last 7-10 days or even longer, but by the 10th day, symptoms have mostly begun to resolve and there is significant clinical improvement. However, if there is persistence of respiratory symptoms without any signs of resolution, it should suggest the presence of bacterial infection.
In uncomplicated viral URIs, fever is present early in the illness, and is usually accompanied bacteria other constitutional symptoms such as headache and myalgia. Constitutional symptoms resolve during the first 48 hours, after which respiratory symptoms become prominent. Purulent nasal discharge usually does not appear until several days after the onset of fever. But in acute bacterial rhinosinusitis, there is concurrent presentation of high grade fever and purulent nasal discharge for at least 3-4 consecutive days.
Physical examination is not of much help in differentiating viral URIs from acute bacterial rhinosinusitis. Erythema of nasal mucosa, swelling of turbinates and mucopurulent discharge are seen in both cases. The examination of tympanic membrane, pharynx and cervical lymph nodes also does not provide any extra information.
Transillumination test is also of limited use in making the diagnosis of rhinosinusitis. The aim of this test is to assess if there is fluid present in the maxillary and frontal paranasal sinuses. It is a difficult test to perform correctly; also, it is unreliable in children <10 years of age.

IMAGING TECHNIQUES
In the 1980s, children between the ages of 2 and 16 years presenting with either persistent or severe symptoms were evaluated with sinus radiographs. Presently, however, rhinosinusitis is seen mostly in children <6 years of age. Also, a positive history frequently predicts the findings of abnormal sinus radiograph; therefore, sinus radiographs can safely be omitted and a diagnosis of acute bacterial rhinosinusitis can be made on clinical criteria alone.
In contrast to the general agreement that radiographs are not necessary in children 6 years of age or younger with persistent symptoms, the need for radiographs as a confirmatory test of acute sinusitis in children older than 6 years with persistent symptoms and all children with severe symptoms is controversial. A normal radiograph is powerful evidence that bacterial sinusitis is not the cause of the clinical syndrome. However, the American college of Radiology has taken the position that the diagnosis of acute uncomplicated sinusitis should be made on clinical grounds only [9]. The arguments given in favor of omitting radiographs for the diagnosis of acute rhinosinusitis are that plain radiographs of the paranasal sinuses are technically difficult to perform, particularly in very young children. Correct positioning may be difficult to achieve and therefore the radiographic images may overestimate and underestimate the presence of abnormalities within the paranasal sinuses. In addition, the Caldwell projection does not localize ethmoid disease, and the Waters projection does not show ethmoid involvement. Lateral sinus radiographs are of little value in patients under 4 years of age and the fourth view, the submentovertex does not contribute to the depiction of soft tissue changes in the paranasal sinuses. The American College would reserve the use of images for situations in which the patient does not recover or worsens during the course of appropriate antimicrobial therapy.
The recommendations of the American College of Radiology are in agreement with the guidelines generated by the Sinus and Allergy Health Partnership which does not recommend either radiographs or CT or MRI scans to diagnose uncomplicated cases of acute bacterial rhinosinusitis in any age group [10]. If there is suspicion for complication of sinusitis, such as preseptal or postseptal cellulites, subperiosteal abscess, orbitial cellulites or abscess, cavernous sinus thrombosis, osteomyelitis of the frontal bone, subdural empyema, epidural or brain abscess, meningitis, brain infarction, or mycotic aneurysm, then cranial CT with contrast including the brain and sinuses in indicated. MRI with gadolinium is especially useful if intracranial involvement is suspected. It is essential to recognize that abnormal images of the sinuses (either radiographs, CT, or MRI) cannot stand alone as diagnostic evidence of acute bacterial sinusitis under any circumstances. Images can serve only as confirmatory measures of sinus disease in patients whose clinical histories are supportive of the diagnosis.

SYSTEMIC TREATMENT [4]
As in otitis media, the treatment of acute rhinosinusitis in children must take into account the natural history and spontaneous resolution of the disease in one out of three to two out of three children. First of all, a viral URI or an allergic inflammation should be ruled out before starting antibiotic therapy. Its is essential that children diagnosed as having acute bacterial rhinosinusitis meet the defining clinical presentation of “persistent” or “severe” disease as described previously.
Amoxicillin is the drug of choice for treatment of acute rhinosinusitis; the starting dose of 45mg/kg twice daily can be increased to 90mg/kg twice daily in presence of specific risk factors or resistances. It is generally effective, relatively inexpensive, and side effects are rare. Approximately 80% of children with acute bacterial sinusitis will respond to treatment with amoxicillin. Risk factors for the presence of bacterial species that are likely to be resistant to amoxicillin include 1) attendance at day care, 2) recent receipt (<90 days) of antimicrobial treatment, and 3) age less than 2 years.
If the patient is allergic to amoxicillin, either cefdinir (14mg/kg/day in 2 divided doses), cefuroxime (30mg/kg/day in 2 divided doses), or cefpodoxime (10 mg/kg/day once daily) can be used (only if the allergic reaction was not a type 1 hypersensitivity reaction). In cases of serious allergic reactions, clarithromycin (15 mg/kg/day in 2 divided doses) or azithromycin (10 mg/kg/day on day1, 5 mg/kg/day for 4 days as a single daily dose) can be used in an effort to select an antimicrobial of an entirely different class. Alternative therapy in the penicillin-allergic patient who is known to be infected with a penicillin-resistant S. pneumoniae is clindamycin at 30-40 mg/kg/day in 3 divided doses.
Most patients with acute bacterial rhinosinusitis who are treated with an appropriate antimicrobial agent respond promptly (within 48-72 hours) with a diminution of respiratory symptoms (reduction of nasal discharge and cough) and an improvement in general well-being. If a patient fails to improve, either the antimicrobial is ineffective or the diagnosis or sinusitis is not correct.
If a patient does not improve while receiving the usual doses of amoxicillin (45 mg/kg/day), or has risk factors that suggest resistance to amoxicillin, therapy should be initiated with high-dose amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component, with 6.4 mg/kg/day of clavulanate in 2 divided doses). This dose of amoxicillin will yield sinus fluid levels that exceed the minimum inhibitory concentration of all S. pneumoniae that are intermediate in resistance to penicillin and most, but not all, highly resistant S. pneumoniae. There is sufficient potassium clavulanate to inhibit -lactamase producing H.influenzae and M.catarrhalis. Alternative therapies as mentioned previously include cefdinir, cefuroxime, or cefpodoxime.
A single dose of ceftriaxone (at 50 mg/kg/day), given either intravenously or intramuscularly, can be used in children with vomiting that precludes administration of oral antibiotics. Twenty-four hours later, when the child is clinically improved, an oral antibiotic is substituted to completer the therapy.
Traditionally, trimethoprim-sulfisoxazole and erythromycin have been considered first-line and second line antimicrobials for acute bacterial rhinosinusitis. However, recent patterns of resistance observed in pneumococci preclude the use of these agents in the management of rhinosinusitis.
For patients who do not improve with a second course of antibiotics or who are acutely ill, there are two options. An ENT specialist should be consulted to obtain a sample of sinus fluid by aspiration, so that culture and sensitivity can be carried out and treatment adjusted accordingly. The other option is to start intravenous cefotaxime or ceftriaxone and refer to an ENT specialist only if patient does not improve on i.v. antibiotics.
The optimal duration of therapy for patients with acute bacterial sinusitis has not received systematic study. Therapy is usually carried out for 10, 14, 21 or 28 days. A more logical approach is that antibiotic therapy should be continued until the patient becomes free of symptoms and then for another 7 days. This results in a minimum course of 10 days and avoids prolonged course of antibiotics in patients who are asymptomatic.

ADJUVANT TREATMENT
Topical treatments are widespread in the treatment of rhinosinusitis. However, their effectiveness remains to be ascertained. Available agents include saline nasal irrigation (hypertonic or normal saline), antihistamines, decongestants (topical or systemic), mucolytic agents, and topical intranasal steroids. The scientific rationale behind using these preparations has not been established. Saline irrigation may be of some use, because it prevents crust formation and liquefies secretions, thereby aiding mucociliary clearance. It also exerts a mild vasoconstrictor effect. In general, adjuvant therapies are not necessary in the treatment of uncomplicated acute rhinosinusitis, though saline spray may make children feel better by clearing out secretions, and the newer non-sedating antihistamines may be beneficial in those children with acute rhinosinusitis where allergy is suspected as the causative factor. Antihistamines should not be used where allergy is not an underlying cause.

SURGERY [11]
Initial management of rhinosinusitis should be medical, based primarily on antibiotics, and when maximal medical management fails, then surgery should be considered. The other indication of surgical management of acute rhinosinusitis is the occurrence of complications. Complications of acute and recurrent acute rhinosinusitis are generally rare, but in children they pose a serious problem because of the thin bones surrounding the sinuses and to the characteristics of the growth of the sinuses that ends around the age of 12 years. While these complications are rare, the morbidity and mortality remain high, so extreme diligence from the physician is warranted for early detection.
Children with underlying immune deficiency, cystic fibrosis, allergy, asthma, and mucociliary dyskinesia are more likely to require surgical intervention.

1. Adnoidectomy :
In children with rhinosinusitis characterized by moderate to severe nasal obstruction caused by adenoid hypertrophy, adenoidectomy has been shown to be beneficial, as the cause of resolution. The degree of symptomatic improvement is greatest when the adenoid pads are large. Adenoidectomy should be considered as the first-line treatment in a child with rhinosinusitis symptoms and an obstructive adenoid pad.

2. Antral lavage :
Antral lavage is not a viable therapeutic modality for the treatment of rhinosinusitis, because it involves only the maxillary sinus and not the ethmoid sinuses. Although lavage is no longer used as therapeutic modality, it remains a valuable diagnostic tool in the immunocompromised patient. An accepted use of lavage is where the disease is primarily maxillary.

3. Nasal antral window :
The inferior antrostomy has not been a successful modality for treating rhinosinusitis. The most important reason is that the cilia continue to beat towards the obstructed natural ostium. In addition, the diseased ethmoid sinuses are not addressed. Inferior antrostomy is much more useful in ciliary dysmotility and cystic fibrosis.

4. Endoscopic sinus surgery (ESS) :
Endoscopic sinus surgery should be performed only when children have failed previous therapies. In contrast to older traditional techniques of sinus surgery, ESS focuses on enlarging the natural ostia of the maxillary and ethmoid sinuses, while preserving most of the sinus mucosa. Good outcomes occur in large percentage of children who undergo endoscopic procedures. Preoperative CT scan is essential in defining the specific diseased sinuses, and in looking for anatomic abnormalities that need to be addressed, including septal deviation, concha bullosa, and paradoxical middle turbinate. The typical procedure consists of uncinectomy plus limited posterior ethmoidectomy. The surgery should be performed by an ENT specialist experienced in pediatric ESS.

The absolute indications for ESS are :
1. Complete nasal obstruction cused by: Cystic fibrosis, Allergic fungal sinusitis,
Antrochoanal polyps, Other causes of nasal polyps.
2. Intracranial complications
3. Cavernous sinus thrombosis
4. Mucoceles and mucopyoceles
5. Subperiosteal and orbital abscess
6. Traumatic injury to optical canal (decompression)
7. Dacrocystorhinitis rom rhinosinusitis
8. Allergic or invasive fungal rhinosinusitis
9. Meningoencephalocele
10. CSF leaks
11. Tumors of the nasal cavity and sinuses

The relative indications for ESS are :
1. Subacute rhinosinusitis after failure of optimal medical therapy
2. Chronic rhinosinusitis after failure of optimal medical therapy
3. Recurrent enough sinusitis occurring frequently enough that patient takes
antibiotics most of the time.

CONCLUSION
Rhinosinusitis in children is a multifactorial disease with changing predisposing conditions that evolve with age. The successful management of rhinosinusitis in children depends on careful diagnosis, recognition of causative factors, and judicious yet adequate antibiotic usage. Children who do not recover inspite of optimal medical therapy may be candidates for surgical management.

REFERENCES :
1. Zacharisen M, Casper R. Pediatric sinusitis. Immunol Allergy Clin North Am
2005; 25: 313-32.
2. Wald ER. Rhinitis and acute and chronic sinusitis. In: Bluestone CE, editor.
Pediatric otolaryngology, 3rd ed. Philadelphia; WB Saunders: 1996, p. 845- 6.
3. Slavin RG, Spector SL et al. The diagnosis and management of sinusitis: a
practice parameter update. J Allergy Clin Immunol 2005; 116(Suppl 6): S13- 47.
4. American Academy of Pediatrics. Subcommittee on Management of
sinusitis and Committee on Quality Improvement. Clinical Practice
Guideline: management of sinusitis. Pediatrics 2001; 108: 798-808.
5. Principi N, Esposito S. New insights into pediatric rhinosinusitis. Pediatr
Allergy Immunol. 2007; 18(Suppl, 18): 7-9.
6. Shapiro GG, Rachelevsky GS. Introduction and definition of sinusitis. J
Allergy Clin Immunol. 1992; 90: 417-18.
7. Vandenberg SJ, Heatley DG. Efficacy of adenoidectomy in reliving symptoms of chronic sinusitis in children. Arch Otolaryngol Head Neck Surg
1997; 123:675-78.
8. Lund VJ, Neijens HJ, Clement PA. The treatment of chronic sinusitis: a
controversial issue. Int J Pediatr Otorhinolaryngol 1995; 32(Suppl): 51-32.
9. McAlister WH, Starain JD, Cohen HL, et al. Sinusitis in the pediatric
population. In: ACR Appropriateness Criteria. Reston, VA: American
College of Radiology, 2006 Available at: http:// www.acr.org (accessed 15
April, 2008).
10. Sinus and Allergy Health Partnership. Antimicrobial treatment guidelines for
acute bacterial rhinosinusitis. Otolaryngol Head Neck Surg 2000; 123:5-31.
11. Lusk RP, Stankiewicz JA. Pediatric rhinosinusitis. Otolaryngol Head Neck
Surg 1997; 117: S53-S57.