Sinusitis

Objectives After completing this article, readers should be able to: The term “sinusitis” describes an inflammation of the paranasal sinuses that can have a viral, allergic, or bacterial origin. The duration of respiratory symptoms can be used to categorize patients who have sinusitis. Acute bacterial sinusitis (ABS) is defined by nasal and sinus symptoms that have been present at least 10 (in most cases) days and fewer than 30 days. Subacute sinusitis is defined by nasal and sinus symptoms lasting longer than 4 weeks and fewer than 12 weeks. There is very little information comparing acute and subacute sinusitis, and this may ultimately prove to be an arbitrary distinction that does not affect etiology, diagnosis, or treatment. Chronic sinusitis is defined by symptoms of at least 12 weeks’ duration. Because the etiology of chronic sinusitis is often unknown, treatment of this condition is controversial.Symptoms affecting the upper respiratory tract (nasal congestion, rhinorrhea, and cough) are the most common complaint in the pediatric office. One of the greatest challenges facing pediatricians is to distinguish between viral upper respiratory tract infections, allergic rhinitis, and sinusitis. A complicating factor is that both allergic rhinitis and viral upper respiratory tract infections predispose patients to acute or chronic sinusitis. Young children experience six to eight viral upper respiratory tract infections per year, of which 5% to 10% are estimated to be complicated by ABS. Allergic rhinitis also is extremely common, with a prevalence approaching 20% by adolescence. It is essential that pediatricians recognize that both allergic rhinitis and viral upper respiratory tract infections are many times more common than ABS.The maxillary and ethmoid sinuses form during the third to fourth gestational month and, although very small, are present at birth. The maxillary sinuses are unique because the outflow tract sits high on the medial wall of the sinus cavity, thereby negating gravitational effects on drainage. The ethmoid sinus is comprised of multiple air cells, with each cell draining through a small, independent ostium into the middle meatus. The narrow caliber of these draining ostia predisposes to obstruction. The frontal sinus develops from an anterior ethmoid cell and moves to a position above the orbital ridge by the fifth or sixth birthday. The sphenoid sinuses are immediately anterior to the pituitary fossa and just behind the posterior ethmoids. Isolated involvement of the sphenoid sinuses is rare; they usually are infected as part of a pansinusitis. The ostiomeatal complex (OMC) is the area between the middle and inferior turbinates that represents the confluence of the drainage areas of the frontal, ethmoid, and maxillary sinuses (FigureF1). Within the OMC are several sites in which two mucosal layers make contact. Because the cilia move in opposite directions, secretions may be retained at these sites, creating the potential for infection even without physical obstruction of the ostia.Three key elements are important to the normal physiology of the paranasal sinuses: the patency of the ostia, the function of the ciliary apparatus, and the quality of secretions. Retention of secretions in the paranasal sinuses is usually due to one or more of the following: obstruction of the ostia, reduction in the number or function of the cilia, and overproduction or change in the viscosity of secretions.The factors predisposing to ostial obstruction can be divided into those that cause mucosal swelling and those that are due to mechanical obstruction (Table 1). Although many conditions may lead to ostial closure, viral rhinosinusitis and allergic inflammation are the most frequent and most important. When the sinus ostium is obstructed completely, there is a transient increase in intrasinus pressure followed by the development of a negative intrasinal pressure. When the ostium opens again, the negative pressure within the sinus cavity relative to atmospheric pressure may allow the introduction of bacteria from the nasopharynx (which is heavily colonized with respiratory flora) into the usually sterile sinus cavity. Alternatively, sneezing, sniffing, and nose blowing associated with altered intranasal pressure may facilitate the entry of bacteria from the posterior nasal chamber into the sinuses.The normal motility of the cilia and the adhesive properties of the mucous layer usually protect respiratory epithelium from bacterial invasion. The mucociliary apparatus may function abnormally because of either a direct cytotoxic effect on the cilia by respiratory viruses or a genetic defect in the microtubule structure of the cilia. The alteration of cilia number, morphology, and function may facilitate secondary bacterial invasion of the nose and the sinuses. Cilia can beat only in a fluid medium. Alterations in the mucus, as in cystic fibrosis or asthma, may impair ciliary activity. The presence of purulent material in the acutely infected sinus also may impair ciliary movement, further compounding the effects of ostial closure.ABS has two common clinical presentations that distinguish it from an uncomplicated episode of viral rhinosinusitis. The most common presentation involves persistent respiratory symptoms, including either nasal discharge of any quality (thin or thick; clear, mucoid, or purulent) or a cough that is present in the daytime, although it often worsens at night. Malodorous breath frequently is reported by parents of preschoolers. Complaints of facial pain and headache are rare, although the parent may note occasional painless morning eye swelling. The child may not appear very ill, and if fever is present, it usually is low grade. The persistence rather than the severity of symptoms in this presentation is of note. In the context of ABS, persistent symptoms are those that last from 10 to 30 days without improvement. The 10-day mark separates simple viral rhinosinusitis from ABS. Most uncomplicated episodes of viral rhinosinusitis last 5 to 7 days. Although patients may not be asymptomatic by the tenth day, they are virtually always improved. Upper respiratory tract symptoms in children are common, but symptoms persisting for longer than 10 days are seen in a minority (<10%) of patients.The second, less common presentation of ABS is a “cold” that seems more severe than usual. The severity is defined by a combination of high fever (at least 39.0°C lsqb;102.2°F]) and purulent nasal discharge. The quality of nasal discharge changes frequently during the course of an uncomplicated viral upper respiratory tract infection. It begins as a watery discharge and becomes thicker, colored, and opaque after a few days. Most often it remains purulent for several days, then clears again to a mucoid or watery consistency before resolving. If fever is present during the course of an episode of viral rhinosinusitis, it is at the outset and in association with other constitutional symptoms such as headache and myalgias. Usually the fever disappears and the respiratory symptoms begin. Accordingly, the combination of high fever and purulent nasal discharge for at least 3 to 4 consecutive days may signal a secondary bacterial infection of the paranasal sinuses. Affected patients may suffer from headaches behind or above the eye and occasionally experience periorbital swelling.Patients who have subacute or chronic sinusitis present with a history of protracted (more than 30 days and not improving) respiratory symptoms. Nasal congestion (obstruction) and cough (day and night) are most common. Sore throat results from mouth breathing due to nasal obstruction. Nasal discharge (of any quality) and headache are less common; fever is rare. It is important to distinguish between protracted symptoms and recurrent symptoms because of implications for both etiology and treatment.In general, physical examination of children who have either acute or chronic upper respiratory tract symptoms is most helpful in identifying conditions that may predispose to sinusitis. Unfortunately, the examination cannot distinguish between viral upper respiratory tract infections and ABS. Patients who have nasal polyps, poor growth, clubbing of the fingers, barrel chest, and respiratory findings may have cystic fibrosis. The immotile cilia syndrome almost always is associated with middle ear disease, and 50% of patients have situs inversus. The presence of atopic dermatitis, intermittent wheezing, Morgan-Dennie lines (skin folds under the lower eyelid), or a nasal crease suggests an allergic diathesis. Adenoidal hypertrophy either can predispose to ABS or, when the adenoids are infected, masquerade as sinusitis. The adenoids cannot be assessed by routine examination, requiring instead either radiographic imaging or flexible endoscopy of the nasopharynx. Patients who have immunodeficiency may lack tonsillar tissue and other lymph nodes and exhibit poor growth, clubbing of the fingers, and other signs of infection. However, normal findings on the physical examination do not rule out the possibility of immunodeficiency, and if the clinical history is compelling, additional laboratory evaluation is appropriate.The need, if any, for radiographic imaging (plain film versus computed tomography [CT]) for children who have symptoms of sinusitis is controversial. Recent national guidelines on the treatment of sinusitis have emphasized the role of the clinical diagnosis, moving away from the use of radiographic imaging in patients who have uncomplicated ABS. Plain films are appropriate in older children who have recurrent acute sinusitis, vague symptoms, a poor response to antibiotic therapy, or a history of antibiotic hypersensitivity that makes therapy risky. Radiographic findings in patients who have ABS include diffuse opacification, mucosal thickening of at least 4 mm, or an air-fluid level. When these radiographic criteria were used in the clinical setting of either “persistent” or “severe” ABS, maxillary sinus aspirates contained a high density of bacteria in 75% of children.CT should be reserved for patients who have either complicated ABS or who are being considered as surgical candidates (for either recurrent or chronic sinusitis). When CT imaging is obtained in these circumstances, a complete CT is indicated. Any patient who has proptosis, impaired vision, limited extraocular movements, severe facial pain, notable swelling of the forehead or face, deep-seated headaches, or toxic appearance should receive a CT scan. The CT scan should not be used in patients who have simple upper respiratory tract symptoms because it does not distinguish between mucosal abnormalities due to viral infection and those due to ABS. CT scans of the paranasal sinuses in adults who had acute “colds” showed substantial mucosal abnormalities that resolved spontaneously, underscoring the fact that mucosal abnormalities within the paranasal sinuses are common in patients who have upper respiratory tract symptoms. In the setting of chronic sinusitis, the CT scan should be used as a guide for surgical intervention for patients who do not improve after completing maximal medical therapy. CT scans appear normal in up to one third of patients who have symptoms of chronic sinusitis.Although maxillary sinus aspiration is not a routine procedure, it can be performed safely by a skilled otolaryngologist in the ambulatory setting using a transnasal approach. Current indications for maxillary sinus aspiration include: 1) failure to respond to multiple courses of antibiotics, 2) severe facial pain, 3) orbital or intracranial complications, and 4) evaluation of an immunocompromised host. Material aspirated from the maxillary sinus should be sent for quantitative aerobic and anaerobic cultures (if possible), fungal cultures, and Gram stain. The recovery of bacteria in a density of at least 104 cfu/mL is considered to represent true infection. The finding of at least one organism per high-power field on Gram stain of sinus secretions correlates with the recovery of bacteria in a density of 105 cfu/mL.Data on the microbiology of patients who have acute (10 to 30 days) and subacute (30 to 120 days) illnesses have highlighted the important bacterial pathogens as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. S pneumoniae is most common in all age groups, accounting for 30% to 40% of isolates. H influenzae and M catarrhalis are similar in prevalence, each accounting for approximately 20% of cases. Both H influenzae and M catarrhalis may be beta-lactamase-producing and, therefore, resistant to amoxicillin. Neither staphylococci nor respiratory anaerobes are common in ABS. Respiratory viral isolates include adenovirus, parainfluenza, influenza, and rhinovirus in approximately 10% of patients. For children who have chronic sinusitis, the role of bacterial agents is less clear. The results of cultures from children who have chronic sinusitis have been extremely variable; a high percentage of patients have had either sterile cultures or known contaminants, and the presence of anaerobes has ranged from almost 0 to more than 90%. The persistence of symptoms despite multiple courses of antimicrobials is counter to the hypothesis that bacterial pathogens play an important role in the etiology of chronic sinusitis.Antimicrobial therapy is the backbone of the medical management of ABS. Recent guidelines published jointly by the Centers for Disease Control and Prevention and the American Academy of Pediatrics promoting the “Judicious Use of Antimicrobial Agents” suggest amoxicillin as a reasonable first choice for most cases of ABS in children. This is especially true if the episode of ABS is uncomplicated and mild to moderate in severity and if the patient has not recently (<1 mo) been treated with antimicrobial agents. The problem that has emerged during the past 5 years in the management of ABS is infection caused by S pneumoniae strains that are resistant to penicillin. The frequency of penicillin-resistant pneumococci varies geographically, and many isolates of pneumococci are resistant to other commonly used antimicrobials, such as cephalosporins, sulfamethoxazole-trimethoprim, and macrolides. Clinical situations in which alternative regimens are appropriate include: 1) failure to improve with conventional doses of amoxicillin, 2) recent treatment with amoxicillin (<1 mo), 3) attendance at child care, 4) occurrence of frontal or sphenoidal sinusitis, and 5) presentation with protracted (>30 d) symptoms. Therapeutic options include high-dose amoxicillin (80 to 90 mg/kg per day), amoxicillin (45 mg/kg per day) plus amoxicillin with clavulanate (45 mg/kg per day), cefuroxime axetil, and cefpodoxime. Antibiotic selection should be guided by susceptibility results when available. Patients who have orbital or central nervous system complications of sinusitis should be hospitalized and receive a parenteral antibiotic, subspecialty consultation, and surgical drainage when appropriate. If penicillin-resistant pneumococci are suspected, cefotaxime (300 mg/kg per day in four doses) with or without vancomycin (60 mg/kg per day in four doses) should be administered intravenously. The sinus should be aspirated to identify the infecting organism and aid in the selection of appropriate antimicrobial therapy. Clinical improvement is prompt in nearly all children treated with an appropriate antimicrobial agent for uncomplicated ABS. Patients who are febrile at the initial encounter will become afebrile, and there is a remarkable reduction of nasal discharge and cough within 48 to 72 hours. If the patient does not improve or worsens in 48 hours, clinical re-evaluation is appropriate. If the diagnosis is unchanged, sinus aspiration may be considered to obtain precise bacteriologic information. Alternatively, an antimicrobial agent effective against beta-lactamase-producing bacterial species and penicillin-resistant pneumococci should be prescribed.The appropriate duration of antimicrobial therapy for patients who have ABS has not been investigated systematically. Most can be treated with 10 to 14 days of therapy. Longer treatment courses have been used in those who have chronic sinusitis to avoid surgery. However, the use of antibiotic therapy for more than a few weeks is not supported by clinical studies, exposes patients to developing allergic hypersensitivity, and may increase the development of resistant organisms. Although antimicrobial prophylaxis has not been studied in patients who have recurrent ABS, it has proved useful to reduce symptomatic episodes of acute otitis media in patients who experience recurrent ear disease. A trial of antimicrobial prophylaxis may be appropriate for patients in whom there is no treatable underlying disorder and who have a history of responding to antibiotic therapy. Patients selected for a trial of antibiotic prophylaxis should have had at least three episodes of ABS in 6 months or four episodes in 12 months.Adjuvant therapies such as antihistamines, decongestants, and anti-inflammatory agents have received little evaluation. Because antihistamines and decongestants have not been studied in patients who have sinusitis and have as much potential for harm as for benefit, they should not be used for treatment of ABS. The potential role of topical intranasal steroids as an adjunct to antibiotics has been evaluated recently in children and adults. The availability of agents that have a rapid onset of activity prompts their consideration for the management of acute symptoms, but the very modest beneficial effect of treatment does not justify their use. Nasal irrigation using either hypertonic or isotonic solutions has been shown to have a positive effect in some patients. Saline nasal irrigation is inexpensive, readily available, and devoid of side effects other than mild discomfort from hypertonic solutions. Further prospective studies are necessary to evaluate the role of these agents fully in sinusitis.The major complications of ABS are rare and involve contiguous spread of infection to the orbit, bone, or central nervous system (Table 2). Subperiosteal abscess of the orbit and intracranial abscesses are the most common. Orbital infection is signaled by eye swelling, proptosis, and impaired extraocular eye movements; intracranial infection is suggested by signs of increased intracranial pressure, meningeal irritation, and focal neurologic deficits.Patients who have ABS seldom require surgical intervention unless they present with orbital or central nervous system complications. Rarely, sinus aspiration may be required in those who do not respond to aggressive antimicrobial management both to ventilate the sinuses and to obtain material for culture. When patients who have chronic sinusitis fail to improve with maximal medical therapy, sinus surgery might be considered. One academic otolaryngology center has reported that comprehensive evaluations for conditions that predispose children to chronic sinusitis combined with appropriate therapy directed toward these conditions dramatically reduced the number of surgical procedures. At present, the focus of surgical therapy is the ostiomeatal complex. Using an endoscope, most current surgical efforts attempt to enlarge the natural meatus of the maxillary outflow tract (by excising the uncinate process and the ethmoid bullae) and perform an anterior ethmoidectomy. The outcome of endoscopic sinus surgery is difficult to assess; all studies, including one meta-analysis, have been limited by retrospective designs and an absence of control groups. The precise population of children most likely to benefit from this surgery has not been delineated.