Acute infections (less than 30 days' duration) of the paranasal sinuses are seen in children and adults usually as a complication of viral upper respiratory tract infections or allergic inflammation. Although there are few data on which to base an estimate of the frequency of this disorder, acute sinusitis is commonly encountered in clinical practice.
The anatomic relationships of the sinus cavities are shown in Figure 1. Three shelf- like structures - the superior, middle, and inferior turbinates - protrude from the lateral nasal wall. Beneath each turbinate is a corresponding meatus. The ostia of the maxillary, frontal, and anterior ethmoid sinuses drain into the middle meatus. The ostia of the sphenoid sinuses and the posterior ethmoid air cells drain into the superior meatus. Only the lacrimal duct empties into the inferior meatus.
Of special note is the position of the maxillary ostium in relation to the body of the sinus. The location of this outflow tract, high on the medial wall of the maxillary sinus, impedes gravitational drainage of secretions; ciliary activity is required to move secretions from the body of the maxillary sinus through the ostia to the nose. From there, secretions are carried into the nasopharynx to be either expectorated or swallowed.
The ethmoid sinuses, as seen on the coronal and sagittal sections in Figure 1, are not single large cavities but are divided into three to 15 air cells. These air cells, separated from each other by thin, bony septa, drain by individual ostia into the middle meatus. The lateral wall of the ethmoid sinus, the lamina papyracea, is a paper-thin plate of bone that may permit direct extension of infection from the ethmoid sinus to the orbit through natural dehiscences in the bone.
The frontal sinus, seen on sagittal section in Figure 1, develops either from an anterior ethmoid cell or from a separate evagination of the anterosuperior portion of the middle meatus. In either case, its drainage is similar to that oí the anterior ethmoid sinuses. The sphenoid sinuses, which are immediately anterior to the pituitary fossa, are adjacent to the posterior ethmoid air cells and drain into the superior meatus.
Figure 1. Anatomy of the paranasal sinuses.
In most cases of sinus infection, the maxillary sinus is the principal site of disease. The anatomy of the draining ostia probably accounts for the frequent involvement of the maxillary sinus. In a majority of these patients, the ethmoid air cells are also involved. The drainage of the ethmoid, frontal, and sphenoid sinuses is aided by gravity; however, the narrow ostia of the ethmoid sinuses are easily obstructed by mucosal swelling, thus predisposing them to infection. After the age of 10 years, the frontal sinus assumes greater clinical importance because it becomes a more common site of sinus infection and may serve as a focus for rare, but serious, intracranial complications. Isolated infection of the sphenoid sinuses is uncommon; however, these sinuses may be involved in cases of pansinusitis.
Commonly recognized symptoms of sinusitis in adults and adolescents are facial pain, headache, and fever. However, children and adults with acute sinusitis frequently have less specific complaints. During the course of apparent viral upper respiratory infections, two common clinical developments should alert the clinician to the possibility of bacterial infection of the paranasal sinuses. The first, less common presentation is a cold that seems more severe than usual: the fever is high (greater than 39.00C), nasal discharge is purulent and copious, and there may be associated periorbital swelling and facial pain. The periorbital swelling may involve the upper or lower lid, or both; swelling is gradual in onset and most obvious in the early morning shortly after awakening. The swelling may decrease and actually disappear during the day only to reappear the following day. Another complaint is headache (a feeling of fullness or a dull ache either behind or above the eyes), most often reported in older children and adults. Occasionally, there may be dental pain, either from infection originating in the teeth or referred from the sinus infection.
The second, more common clinical situation in which sinusitis should be suspected is when the signs and symptoms of a cold are protracted. Nasal discharge and daytime cough that continue beyond ten but less than 30 days without improvement are the principal complaints. Most uncomplicated viral upper respiratory infections last five to seven days; although patients may not be asymptomatic, by the tenth day they are usually improved. The persistence of respiratory symptoms beyond the ten-day mark, without appreciable improvement, suggests a complication of the upper respiratory infection. The nasal discharge may be of any quality (thin or thick; clear, mucoid, or purulent) and the cough (which may be dry or wet) must be present in the daytime, although it is often worse at night. Cough occurring only at night is a common residual symptom of an upper respiratory infection. When it is the only residual symptom, the cough is nonspecific and not suggestive of a sinus infection. However, persistent daytime cough is frequently the symptom that prompts medical attention. The patient may not appear very ill, and if fever is present it is usually low grade. Fetid breath is often reported by parents of preschoolers. Facial pain is not usually a prominent complaint; however, intermittent painless morning periorbital swelling may have been noted. In this case, it is not the severity of the clinical symptoms but their persistence that calls for attention.
Figure 2. Transillumination of the right maxillary sinus.
On physical examination mucopurulent discharge may be present in the nose or posterior pharynx. The nasal mucosa is erythematous; the throat may show moderate injection. The cervical lymph nodes are usually not significantly enlarged or tender. None of these characteristics differentiates rhinitis from rhinitis plus sinusitis. Occasionally, facial tenderness will be noted, as the examiner palpates over or percusses the paranasal sinuses, or appreciable periorbital edema - soft, nontender swelling over the upper and lower eyelid with minimal discoloration of the overlying skin - or both. Malodorous breath (in the absence of pharyngitis, poor dental hygiene, or a nasal foreign body) may suggest bacterial sinusitis. In short, in the majority of instances physical examination is not very helpful in making a specific diagnosis of acute sinusitis. However, if the mucopurulent material can be removed from the nose and the nasal mucosa is treated with topical vasoconstrictors, pus may be seen coming from the middle meatus. This observation plus periorbital swelling or facial tenderness (when present) are probably the most valuable physical findings in acute sinusitis.
When clinical signs and symptoms suggest a diagnosis of acute sinusitis, the following procedures may help confirm the diagnosis.
Transillumination may be helpful in diagnosing inflammation of the maxillary or frontal sinuses. The patient and examiner must be in a darkened room. The light source, shielded from the observer, is placed over the midpoint of the inferior orbital rim. The transmission of light through the hard palate is then assessed with the patient's mouth open (Figure 2). In judging light transmission, light passing through the alveolar ridges should be excluded. Transillumination of the frontal sinus is accomplished by placing a high intensity light source inferior to the medial border of the supraorbital ridge and evaluating the symmetry of the blush bilaterally. Transillumination is useful in adolescents and adults if light transmission is either normal or absent. "Reduced" transmission or "dull" transillumination are assessments that correlate poorly with results of sinus aspiration.1 The increased thickness of both the soft tissue and bony vault in children less than 10 years of age limits the clinical usefulness of transillumination in the younger age group.
Figure 3. Ultrasound recordings. A. Anterior wall echo (normal). B. Anterior wall echo, an echo-free space, and a posterior wall echo (fluid-filled sinus).
Radiography has traditionally been used to determine the presence or absence of sinus disease. Standard radiographic projections include anteroposterior, lateral, and occipitomental view. The anteroposterior view is optimal for evaluating the ethmoid sinuses and the lateral view is best for the frontal and sphenoid sinuses. The occipitomental view, taken after tilting the chin upward 45° to the horizontal, allows evaluation of the maxillary sinuses.
The radiographic findings most diagnostic of bacterial sinusitis are the presence of an air-fluid level in or complete opacification of the sinus cavities. In the absence of air-fluid level or complete opacification of the sinuses, measuring the degree of mucosal swelling may be useful. If the width of the sinus mucous membrane is 5 mm or greater in adults or 4 mm or greater in children, the sinus will probably contain pus or yield a positive bacterial culture.2'3 When clinical signs and symptoms suggesting acute sinusitis are accompanied by abnormal maxillary sinus radiographs, bacteria will be present in the sinus aspirate 75% of the time.3 The reliability of radiographic evaluation as a diagnostic tool has been repeatedly demonstrated in adults with acute maxillary sinusitis.1,4
Several recent reports have evaluated ultrasonography as a diagnostic aid in maxillary sinusitis. The alleged advantages of ultrasonography as compared with radiography are the use of nonionizing radiation and supposedly better ability to discriminate between mucosal thickening and retained secretions. Conformity between findings at ultrasound and sinus aspiration have been observed in approximately 90% of patients. 5 In carrying out the procedure, an ultrasound probe is held against the cheek in the area of the sinus. When the ultrasound beam is reflected from the anterior wall of the maxillary sinus, a series of positive deflections is produced, which is referred to as the anterior wall echo (Figure 3A). If the sinus cavity is airfilled, no further deflections will be seen because air is a total reflector of ultrasound; any structure behind an air-filled space will not be "seen" by the ultrasound beam. If the sinus is fluid-filled, the ultrasound beam, after producing an anterior wall echo, is transmitted until it hits the posterior or back wall of the sinus cavity, giving rise to a posterior wall echo (Figure 3B). At present, insufficient experience exists to assess accurately the value of ultrasonography in the diagnosis of sinusitis. The procedure will most likely prove to be helpful in older children (more than 4 years of age) and adults, particularly in charting progress during treatment.
The diagnosis of acute bacterial sinusitis is probably best proved by a biopsy of the sinus mucosa, which demonstrates acute inflammation and invasion by bacteria. In practice, confirmation of the diagnosis is more readily accomplished by culturing an aspirate of sinus secretions. However, when simultaneous mucosal biopsies and sinus aspirates are submitted for bacterial cultures, the former yield positive cultures more often.
Although by no means a routine procedure, aspiration of the maxillary sinus (the most accessible of the sinuses) can be accomplished easily in an outpatient I setting with minimal discomfort to the patient. Pune- I ture is best performed by the transnasal route with the needle directed beneath the inferior turbinate through } the lateral nasal wall. This route for aspiration is preferred in children to avoid injury to the natural ostium and permanent dentition. In adults, an anterior approach to the maxillary sinus is a Caldwell-Luc antrotomy. If the patient is unusually apprehensive or too young to cooperate, a short acting narcotic agent can be used for sedation.
Indications for sinus aspiration in patients with suspected sinusitis include: clinical unresponsiveness to conventional therapy; sinus disease in an immunosuppressed patient; severe symptoms such as headache or facial pain; and life-threatening complications such as intraorbital or intracranial suppuration at the time of clinical presentation.
The most convincing data, reported in adults in several elegant studies with careful attention to bacteriologie technique, show nontypeable Hemophilus influenzae and Streptococcus pneumoniae to be the most commonly found pathogens, accounting for approximately 74% of all significant bacterial strains recovered from adult patients.1'2 Anaerobic bacteria accounted for 9% of isolates. Other bacteria implicated include Branhamella catarrhalis (formerly Neisseria catarrhalis), Streptococcus pyogenes (group A streptococcus) and alpha-hemolytic streptococcus. Mixed infection with heavy growth of two bacterial species was occasionally found, although most cultures grew only a single organism. Viruses were recovered from 12 of the 103 positive specimens: 7 isolates of rhinovirus, 3 of influenza A, and 2 of parainfluenza virus. Five of these 11 specimens also had significant growth of bacteria.
A recent study performed in 50 children with acute maxillary sinusitis has shown the bacteriology of sinus secretions to be similar to that found in adults.6 The predominant organisms include S pneumoniae, B catarrhalis, and H influenzae. Both H influenzae and B catarrhalis may be beta-lactamase-producing and consequently ampicillin-resistant. Of interest, only a single anaerobic isolate, a peptostreptococcus, was recovered from; a sinus secretions during this study. Staphylococcus aureus was not isolated in this series. Several viruses including adenovirus and parainfluenza were also recovered.6
It would be desirable to culture the nose, throat, or nasopharynx of patients with acute sinusitis if the predominant flora isolated from these surface cultures were predictive of the bacterial species recovered from the sinus secretions. Unfortunately, the results of surface cultures have no predictive value; therefore, these cultures cannot be recommended as a guide to the bacteriology and therapy of acute or chronic sinusitis.1,3
Medical therapy with an antimicrobial agent is recommended in patients diagnosed as having acute maxillary sinusitis. The relative frequency of the various bacterial agents suggests that ampicillin (100 mg/kg/ day, orally, in four divided doses) or amoxicillin (40 mg/kg/day, orally, in three divided doses) are appropriate agents. Amoxicillin is usually prescribed to a maximum dose of 500 to 750 mg three times a day. The prevalence of beta-lactamase-positive, ampicillinresistant H influenzae and B catarrhalis may vary geographically. In areas where ampicillin-resistant organisms are prevalent or when the patient is allergic to penicillin or when there has been an apparent antibiotic failure, several alternative regimens are available. The combination agent, sulfamethoxazole-trimethoprim (40 and 8 mg/kg/day, respectively, orally, divided into two doses) has been shown to be efficacious in acute maxillary sinusitis in adults. The maximum adult dose is one double-strength tablet twice daily. It is important to remember, however, that this agent may be ineffective in patients with group A streptococcal infections. Cefaclor (40 mg/kg/day, orally, in three divided doses to a maximum dose of 500 mg or 750 mg three times daily) or the combination of erythromycin-sulfisoxazole (50 and 150 mg/kg/ day, respectively, orally, in four divided doses) are also suitable. Augmentin*, a combination of amoxicillin and potassium clavulanate, is another potential therapeutic agent for use in patients with beta-lactamaseproducing bacterial species in their maxillary sinus secretions. Potassium clavulanate irreversibly binds the beta-lactamase, if present, and thereby restores amoxicillin to its original spectrum of activity. Augmentin® is prescribed in the same dose as is amoxicillin.7
Clinical improvement is prompt in nearly all patients treated with an appropriate antimicrobial agent. Patients febrile at the initial encounter will become afebrile, and there is a remarkable reduction of nasal discharge and cough within 48 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 for precise bacteriologie information. Alternately, an antimicrobial agent that is effective for beta-lactamase-producing bacterial species should be prescribed.
The antimicrobial regimens recommended to treat acute sinusitis are similar (in type and duration) to those used to treat acute otitis media. The usual duration of antimicrobial therapy is ten to 14 days. This recommendation is based on an experience in adults, which demonstrated that 20% of sinus aspirates obtained after seven days of antimicrobial treatment were still culture positive.2 When the patient is improved but not completely recovered by ten or 14 days, it seems reasonable to extend the duration of the antimicrobial agent for another week.
Decongestants or Antihistamines
The effectiveness of antihistamines or decongestants or combination antihistamine-decongestants applied topically (by inhalation) or administered by mouth in patients with acute or chronic sinus infection has not been adequately studied. Limited investigation of specific agents in clinical rhinitis have shown that some produce a decrease in nasal resistance.89 However, in one study performed on patients with sinorhinitis, oral phenylpropanolamine did not significantly increase the size of the maxillary ostium.10
Topical decongestants such as phenylephrine or oxymetazoline shrink the nasal mucous membrane, improve ostial drainage, and provide symptomatic improvement; however, they cause ciliostasis. Ciliary motion is an important local defense mechanism; the entire mucus covering of the maxillary antrum is normally cleared every 10 minutes. By inhibiting ciliary motion topical decongestants may delay clearance of infected material. In addition, by decreasing blood flow to the mucosa, topical decongestants may further lower oxygen tension and impair diffusion of antimicrobial agents into the sinuses. The net effect of the various topical preparations on clinical recovery from sinusitis or the incidence of complications is unknown.
Irrigation and Drainage
Irrigation and drainage of the infected sinus may result in dramatic relief from pain for patients with acute sinusitis. In addition, by relieving pressure in the sinus, oxygenation and blood flow improve, thus restoring compromised defense mechanisms.11 Local immunoglobulin and complement levels increase and proteolytic enzymes decrease in sinus secretions after irrigation procedures. Drainage procedures are usually reserved for those who fail medical therapy with antimicrobials or who have a suppurative intraorbital or intracranial complication. If an episode of acute or chronic sinusitis cannot be effectively treated by medical therapy alone or medical therapy and simple sinus puncture, more radical surgery may be necessary.
The floor of the maxillary sinus is formed by the alveolar process of the maxillary bone. Afterbirth, as the alveolar process and the sinus develop, the roots of the teeth and the sinus come into close proximity, at times separated only by paper-thin bone or sinus mucosa. Because of this proximity, periapical abscesses or periodontitis of the upper teeth may extend into the sinus cavity and cause maxillary sinusitis.12 Perforation may occur from minor trauma to the area, dental instrumentation, extraction, or displacement of a chronically inflamed tooth. Congenital bony defects or dental cysts may provide a direct channel to the sinus without the need to traverse bone. If perforation of the sinus mucosa is not recognized, the tract may become epithelialized and an oroantral fistula may form.
The incidence of odontogenic sinusitis in children is unknown but is probably significant, particularly in adolescents. In adults, 10% to 15% of all cases of maxillary sinusitis are thought to be of dental origin.
Symptoms are similar to those of primary sinusitis. A fetid odor may be prominent because the infection is often caused by anaerobic organisms. If a fistula is present, the patient may complain that pus is dripping into the mouth; fluids and air may pass from the oral cavity into the sinus and nose. Treatment consists of drainage of the dental abscess and operative closure of the oroantral fistula, if present, coupled with antimicrobial therapy.
ALLERGY AND SINUSITIS
Individuals with atopic disease, both allergic rhinitis and asthma, have an increased frequency of sinusitis. The nasal and sinus mucosa of these patients are hypersecretory. Histologically, there is mucosal hyperplasia and infiltration with plasma cells and eosinophils. Secondary to this immune-mediated hyperplastic sinusitis, ostial obstruction followed by bacterial infection is common. This may result in acute exacerbations of respiratory symptoms (particularly cough and rhinorrhea) or in difficulty controlling symptoms with usual therapy (nasal congestion and wheezing).
Maxillary sinus aspirates obtained from asthmatic children with exacerbations of asthma despite bronchodilator therapy show bacterial isolates similar to those obtained from nonasthmatic children with acute sinusitis.13 Clinical symptoms and pulmonary function improve after antibiotic therapy.14 Selection of antimicrobial agents in the treatment of an infectious episode in the atopic individual is no different from treatment in the nonallergic patient except that duration of therapy may need to be protracted beyond 14 days.
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13. Friedman R. Ackerman M. WaId E. et al: Asthma and bacterial sinusitis in children. ] Allergy CUn Immunol 1984; 74:185-189.
14. Rachelefsky GS, Siegel SC. Kati RM: Chronic sinusitis in allergic children: The role of antimicrobials. I Allergy Clin Immunol 1982; 169:382.