Which diagnostic test is used to confirm the diagnosis of maxillary and frontal sinusitis?

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Antimicrobial

Antibacterial agents are the primary therapy for acute bacterial sinusitis. In the past 40 years there have been numerous randomized, placebo-controlled trials of antimicrobials in patients with sinusitis. When evaluating the quality of such studies, it is imperative to consider the diagnostic criteria used to enter patients into the trial. If the diagnosis is made on clinical grounds but criteria for subject entry are too liberal, a large number of patients will be included who have viral URI rather than bacterial disease. This will bias the trial toward showing a lack of effectiveness of antibacterial agents.

There has been a recent trend in the literature to publish studies that mimic the “real-world” office setting in which the practitioner is making the diagnosis of sinusitis based on clinical criteria that are not stringent and without any kind of microbiologic confirmation.Table 62.6 summarizes randomized, placebo-controlled trials of antimicrobials in the treatment of sinusitis.105–122 These trials have shown variable benefit to antibiotics over placebo. In one study, in which clinical criteria such as purulent nasal discharge for at least 2 days and pus visualized on rhinoscopy were required for entry, 40% of patients included in the study had normal radiographs, strongly suggesting that these patients did not have sinusitis.112

Further complicating the interpretation of antimicrobial efficacy studies is the fact that patients with sinusitis will have a high rate of spontaneous improvement within 2 weeks of presentation. Studies that included patients who had more severe or prolonged symptoms (i.e., >10 days) or those that used adjunctive diagnostic tests to confirm the diagnosis of sinusitis were more likely to show a benefit to antimicrobials versus placebo.105,108,118,119,121 When patients enrolled in efficacy studies are followed closely over time, those who received antimicrobials show a more rapid improvement in symptoms compared with patients receiving placebo (Fig. 62.3). A recent trial of amoxicillin-clavulanate versus placebo in children, in which sinusitis was diagnosed based on careful clinical criteria in an office setting, demonstrated a cure or improvement in 64% of patients receiving antibiotic compared with 32% of those receiving placebo.121

Several meta-analyses of clinical trials of antimicrobials in sinusitis have been published. These analyses have consistently found a benefit for antimicrobials over placebo despite much heterogeneity in the diagnostic methods, exclusion criteria, and outcome measures found within the studies that were included (Table 62.7). Overall, antimicrobial agents reduce the rate of clinical failure by 25% to 30% within 7 to 14 days of initiating therapy.123 In most studies evaluating the role of antimicrobials, the adverse event rate is higher in the antibiotic arm of the study. Diarrhea is the most common adverse event noted and is usually self-limited.

Clinical Features.

Acute sinusitis is the most common of the sinus conditions that cause pain and is often a complication of the common cold. After a few days, nasal congestion accompanied by a clear discharge can increase, and the patient may complain of pain and tenderness to pressure or swelling over the involved sinus. The pain may also be referred to the premolar and molar teeth on the affected side and these teeth may develop sensitivity to percussion. In the case of a bacterial sinusitis, a green or greenish yellow discharge may accompany the other aforementioned signs and symptoms. In such circumstances, it is important that the teeth be ruled out as a possible source of the pain or infection.

Chronic maxillary sinusitis is a sequela of an acute infection that fails to resolve by 3 months. Generally, no external signs occur except during periods of acute exacerbations when increased pain and discomfort are apparent. Chronic sinusitis may develop with anatomic derangements, including deviation of the nasal septum and the presence of concha bullosa (pneumatization of the middle concha) that inhibit the outflow of mucus, or with allergic rhinitis, asthma, cystic fibrosis, and dental infections.

Differential Diagnosis, Sinusitis

Sinusitis must be differentiated from rhinitis. Sinusitis may be caused by viral infection, bacterial infection, fungal infection, and allergy (Table 398-4).

A rapid onset of sinus-related symptoms suggests a viral upper respiratory infection, especially if the patient also has typical systemic symptoms, such as arthralgia, myalgia, fever, chills, gastrointestinal symptoms, and cough in addition to nasal congestion, postnasal drip, and headache. By comparison, acute bacterial rhinosinusitis causes facial pressure and purulent postnasal discharge. Viral disease can progress to a secondary bacterial infection, which can become chronic. An acute onset of inhalant allergy is often seasonal or can be traced to a particular precipitant.

Chronic sinusitis is a term that encompasses multiple pathophysiologic mechanisms and implies a prolonged course of sinus symptoms that have been refractory to symptomatic treatment over a period of at least 3 months. Chronic sinusitis presents with nasal congestion, nasal drainage, facial pressure,and sometimes anosmia (seeTable 398-2). In contrast to acute (infectious) sinusitis, headaches are an unusual manifestation of either perennial rhinitis (allergic or nonallergic) or chronic sinusitis, and virtually all patients who complain of “sinus headaches” suffer from atypical migraines (Chapter 370), headaches that occur in a bilateral distribution involving the maxillary or ophthalmic branches of the trigeminal nerve. This distribution, especially when it is combined with vasomotor symptoms such as nasal congestion, rhinorrhea, and conjunctival injection, often leads to misdiagnosis as chronic sinusitis or rhinitis. Because of this overlap in symptoms among chronic sinusitis, perennial rhinitis, and atypical migraines and their synergistic influences on each other, objective evaluation with either CT or rhinoscopy is usually required to establish the diagnosis of chronic sinusitis (Table 398-5).

Endoscopically guided culture techniques combined with CT are the best way to diagnose or excludeinfectious sinusitis. CT can reveal mucoceles, which are blocked individual sinuses that continue to secrete mucus and can slowly erode bone, expand to involve the eye and brain, or become acutely infected. A mycetoma, which is an isolated “fungus ball” in a sinus, has a characteristic hyperdensity within a sinus opacification. Mycetomas (Chapter 322) are noninvasive but may erode bone through pressure necrosis over a long period.

Mucus retention cysts, often present in the maxillary sinus, are manifested as a spherical opacification; an estimated 10% of the population has a mucus retention cyst, which is usually asymptomatic.

Treatment

SUMMARY

Acute sinusitis complicates 1% to 5% of all upper respiratory tract infections in children. The usual pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The clinical presentation is similar to that of a viral URI, and making the diagnosis requires a high index of suspicion. Management should always include 10 to 14 days of antimicrobial therapy directed toward the most common pathogens and should incorporate vasoconstrictor sprays to enhance sinus drainage. The potential for serious complications of acute sinusitis in children is real and underscores the need to be vigilant in management of these patients.

MAJOR POINTS

Acute sinusitis may be defined as a bacterial or viral infection of the sinuses of less than 4 weeks' duration. It may complicate 5% to 10% of all upper respiratory tract infections in children.

Differentiation from viral URI on clinical presentation is often difficult. Prolonged URI symptoms (longer than 7 to 10 days), purulent nasal discharge, and/or significant facial or dental pain strongly suggests the diagnosis of acute sinusitis.

Diagnostic imaging is usually not indicated to establish the diagnosis of acute sinusitis and should be reserved for evaluation of the intensive care patient, when complications are suspected, or in the preoperative evaluation of surgical candidates.

Cultures are not routinely obtained in the evaluation of acute sinusitis but should be assayed in the intensive care or immunocompromised patient, children not responding to appropriate medical management, or patients with complications of sinusitis.

The goals of management are to reestablish sinus drainage to treat the usual pathogens—Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Intensive care patients with acute sinusitis require adequate intravenous antibiotic coverage for gram-negative organisms.

Management should initially include systemic antibiotic therapy and topical decongestion of the sinuses. Surgical drainage of the affected sinus is indicated when medical management fails, in selected immunocompromised patients, and in patients in whom complications are present.

Orbital complications are the most common complication in children and must be treated aggressively to prevent possible intracranial spread and loss of vision.

Intracranial complications of sinusitis are rare and require urgent management by the otolaryngologist and neurosurgeon when diagnosed.

Definitions of Acute and Chronic Rhinosinusitis

In order to understand the pathogenesis and pathophysiology of rhinosinusitis, it is important to realize that different types of rhinosinusitis have been defined, and the inciting mechanism may vary dramatically among the different subtypes. Althoughsinusitis is the term commonly used for any inflammation or infection of sinuses, this term has largely been replaced byrhinosinusitis, because the nose is almost always involved with the infection or inflammation at the same time as the sinuses.1 Because many potential factors can contribute to rhinosinusitis, some debate has ensued concerning the exact definition. In general terms,rhinosinusitis is defined as “a group of disorders characterized by inflammation of the mucosa of the paranasal sinuses.”2 In 1997, the Rhinosinusitis Task Force of the American Academy of Otolaryngology–Head and Neck Surgery3 developed a now well-accepted classification of rhinosinusitis, and this was reported by Lanza and Kennedy.1 This classification relies on the identification of symptoms to make a diagnosis. The symptoms are broken into major symptoms—purulent nasal drainage, nasal congestion, facial pressure or pain, decreased smell, and posterior purulent drainage—and various minor symptoms.1 When a patient describes two major criteria or one major and two minor criteria, rhinosinusitis can be diagnosed (Table 40.1). The classification of rhinosinusitis types was based primarily on time frames from the onset of symptoms. More recently, a stricter division for chronic rhinosinusitis (CRS) has been described based on endoscopic findings. These include CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP). The 2012 European position paper on rhinosinusitis and nasal polyps (EPOS 2012)4 further defines the disease process for both the adult and pediatric populations (Box 40.1).

An inflammatory response is an expected sequela of an infectious process. Sinonasal inflammation can result from a variety of elements that result in sinus ostia obstruction and predisposes patients to infection. Many factors have been described that play a role in the development of acute bacterial rhinosinusitis (ABRS).1,4–6 These include factors related to the host: genetic factors such as immotile cilia syndrome or cystic fibrosis; certain systemic diseases or medical treatments that predispose individuals to infections; neoplasms; and allergic or immune disorders. Although anatomic abnormalities such as large septal spurs and large paradoxic turbinates have been suggested to be associated with rhinosinusitis, it is not currently clear whether a relation exists. Rhinosinusitis may also develop in relationship to environmental factors that include bacterial, viral, or fungal infections or inflammation that occurs secondary to fungal or bacterial colonization2,7; trauma; primary or secondary tobacco smoke exposure;8 chronic or acute irritants or noxious chemicals; or iatrogenic factors such as surgery, medications, nasal packing, or nasogastric tube placement.9 Evidence shows that individuals with allergic rhinitis have a higher incidence of developing both acute and CRS, and an association of ABRS with asthma has also been suggested, although this may also relate to the presence of allergic rhinitis.6–8

Sinus and Orbital Infections

Uncomplicated acute sinusitis is typically clinically diagnosed and managed. On imaging, findings of acute sinusitis are not very specific. An air–fluid level within a sinus can suggest acute sinusitis; however, lack of this finding does not mean a patient does not have acute sinusitis. Occasionally, hyperdense opacification in the paranasal sinuses can be seen; the hyperdensity can reflect hemorrhage related to trauma, trapped proteinaceous debris, or fungal infection. Fungal infection is an important diagnostic consideration, since steroids probably should be incorporated into the treatment regimen if the cause is related to allergic disease (Fig. 1-65).

When more advanced sinus disease is of concern, imaging plays a more definitive role. Complicated sinus disease should be clinically suspected if the patient presents with visual changes, altered mental status, or seizures. Initial imaging for workup of complicated sinusitis can begin with CT. At our institution, axial images through the facial bones are routinely acquired at 1.25-mm intervals with coronal and sagittal reformats using bone and soft tissue algorithms. If there is concern for intracranial or orbital extension of infection, contrast-enhanced CT using similar imaging parameters can provide additional critical information. If there is clinical concern for intracranial extension, the entire brain should be imaged. Since complicated sinus infection usually warrants close follow-up imaging, MR is the preferred imaging modality to minimize radiation exposure, especially in the pediatric setting. Typical brain MR protocol includes sagittal T1, axial FLAIR, fat-suppressed T2, gradient echo, and diffusion-weighted images, followed by multiplanar postcontrast T1 images of the brain. If orbital extension is of clinical concern, high spatial resolution T2 images with and without fat suppression through the orbits, and axial and coronal pre- and postcontrast T1-weighted images, can provide excellent diagnostic detail.

CT is particularly useful in establishing the integrity of paranasal sinus walls and can effectively demonstrate areas of bony dehiscence. Intracranial or orbital spread of infection can occur directly through areas of bony dehiscence or indirectly by perivascular extension, most commonly secondary to frontal or ethmoid sinus disease. Perivascular spread more commonly occurs in the pediatric setting. Intracranial extension is usually seen in the setting of frontal sinus infection, with involvement of the anterior cranial fossa and frontal lobes (Fig. 1-66). Imaging can demonstrate associated dural enhancement, epidural or subdural collections, and meningoencephalitis with abscess formation. There may be concomitant swelling of the soft tissues of the forehead, known as Pott’s puffy tumor (Fig.1-67). This does not imply neoplastic involvement, but rather describes osteomyelitis with extracranial soft tissue abscess formation. The presence of pachymeningeal enhancement does not necessarily imply that brain parenchyma is involved, and may only reflect dural reaction. Epidural and subdural collections can be demonstrated on either CT or MR as extra-axial fluid, possibly compressing the subjacent brain parenchyma. Subdural collections can cross sutures and generally maintain a crescentic shape, whereas epidural collections are restricted by sutures and may have a lentiform (biconvex) shape. While a reactive subdural effusion may be associated with smooth pachymeningeal enhancement, an infected subdural or epidural collection can demonstrate restricted diffusion and thickened, more irregular dural enhancement on MR. Leptomeningeal involvement is demonstrated as curvilinear enhancement extending into sulci. This may be accompanied by FLAIR hyperintensity in a corresponding distribution, which is a sensitive but nonspecific finding. Parenchymal involvement can be demonstrated by FLAIR hyperintensity and enhancement. Frank abscess formation can be demonstrated by CT or MR as a peripherally enhancing fluid collection. Restricted diffusion in the collection can support this impression.

While posterior ethmoid disease can also lead to intracranial involvement, more commonly, untreated ethmoid sinusitis can extend into the medial aspect of the orbit (Fig. 1-68). Infection can spread in a subperiosteal fashion along the medial wall of the orbit, appearing as an elliptical shaped phlegmon or fluid collection. This may cause displacement of extraocular muscles. Without treatment, the phlegmon or abscess can then break through the periosteum and extend directly into the orbit and into the extraocular muscles. Depending on the size of the inflammatory process, there can be displacement of extraocular muscles and the globe, along with distortion, stretching, and compression of the optic nerve. Such findings constitute an ophthalmologic emergency, as prolonged mass effect on the optic nerve can result in permanent blindness.

Other possible critical complications of orbital infection include extension of infection and involvement of contents of the orbital apex (cranial nerve II), superior orbital fissure (cranial nerves III, IV, V1, VI, and superior orbital vein), and inferior orbital fissure (V2, infraorbital nerve). Idiopathic inflammation involving the cavernous sinus, known as Tolosa-Hunt syndrome, can manifest clinically as palsies of the cranial nerves that traverse the cavernous sinus, namely, III, IV, V1, V2, and VI.

Venous sinus thrombosis can result from ethmoid or sphenoid sinus or orbital infection, and careful attention to the cavernous sinuses on postcontrast images is necessary. Facial soft tissue, dental, and ear infections are other possible causes. Direct signs of septic cavernous sinus thrombosis, also termed cavernous sinus thrombophlebitis (CST), include an enlarged sinus with a convex border, and a single large or multiple irregular filling defect(s). Normal neural structures and intracavernous fat deposits should not be mistaken as true filling defects. Indirect signs include dilation of the superior ophthalmic vein, exophthalmos, soft tissue edema, thrombi in the superior ophthalmic vein, superior and inferior petrosal, or sigmoid sinuses, and decrease in caliber of the internal carotid artery. Thin-section, contrast-enhanced CT with coronal reformats may be equivalent to MR for the detection of these findings. However, once venous sinus thrombosis is suspected, MR imaging of the brain may confirm the diagnosis and evaluate for possible complications of meningitis, subdural empyema, cerebritis, and even pituitary necrosis. Postcontrast T1 coronal and axial images are generally sufficient to make the diagnosis. Contrast-enhanced MR venography may also offer support in diagnosis. (Phase contrast MR venography is generally limited for this evaluation. Contrast-enhanced CT [CT venography] and MR with thin slices are generally more helpful to diagnose CST.) Prior to the antibiotic era, CST was almost always fatal. In the modern era, mortality in the range of to 30% may still be expected. In addition to antibiotics, early institution of anticoagulant therapy may reduce mortality. Morbidity may result from cranial nerve dysfunction including blindness, pituitary insufficiency, and hemiparesis.

Sinusitis

Children with acute sinusitis often have headache, nasal drainage, facial pain, and congestion, whereas those with chronic sinusitis have more subtle signs.20 Infection, allergic reactions, anatomic obstruction, and underlying disease are among the causes that must be differentiated.21 Acute sinusitis frequently follows upper respiratory tract infections. Children with chronic sinusitis can complain of nasal obstruction, postnasal drip, and intermittent facial pain, with symptoms persisting for 3 months or more.22 Predisposition to the condition may be caused by rhinitis (allergic or nonallergic) or aberrant anatomy resulting in poor drainage and chronic infection of the sinuses. Quite often sinus disease can cause pain referred to other areas, confusing the diagnosis (Figure 18-2).18 Palpation and percussion over the affected sinus can help localize the source of pain. Generally, plain radiographic views and sinus transillumination are of little value in young children. Computed tomography is much more sensitive, but the relevance of its findings for treatment decisions in children is controversial.23

SURGICAL MANAGEMENT

Patients with acute sinusitis rarely require surgical intervention in the absence of orbital or central nervous system complications. An appreciation for the fact that a large group of pediatric patients with chronic sinusitis have underlying allergic rhinitis or other medical problems such as gastroesophageal reflux has led to more aggressive medical management and less enthusiasm for surgical solutions.29 Occasionally, sinus aspiration is required to ventilate a sinus in a patient with no response to aggressive antimicrobial therapy.

In the rare child who has failed conventional treatment with oral antibiotics and an array of local and systemic adjuvants to therapy, antibiotic therapy delivered via a percutaneous intravenous catheter may be a worthwhile trial.30 This can be combined with adenoidectomy, or adenoidectomy may be undertaken either as a solo intervention or performed in conjunction with functional endoscopic surgery.31,32

When functional endoscopic sinus surgery is performed, the focus is on the ostiomeatal complex, highlighted in Figure 34-3. This is the area between the middle and inferior turbinates that represents the confluence of drainage areas of the frontal, ethmoid, and maxillary sinuses. In the ostiomeatal complex, there are several areas where two mucosal layers come into contact, predisposing to local impairment of mucociliary clearance. Using an endoscope, the natural meatus of the maxillary outflow tract is enlarged by excising the uncinate process and the ethmoid bullae and performing an anterior ethmoidectomy. Ramodan recently reported a group of 66 children undergoing either adenoidectomy or endoscopic surgery for chronic rhinosinusitis.31 The group undergoing endoscopic sinus surgery had the greatest improvement in overall symptom scores. As our understanding of the pathogenetic factors predisposing to sinusitis expands and our therapy of these mucosal diseases becomes more effective, the pediatric candidates for surgical management of their sinus disease will continue to decrease. Judicious use of endoscopic surgery in children younger than 5 years is strongly advised.33

Prognosis and therapy

The treatment of acute sinusitis should involve eradication of the causative bacteria and improvement of sinus drainage and aeration. Sinus puncture and irrigation allow for specimen collection for bacterial culture, and thus the initiation of directed antimicrobial therapy. It also relieves symptoms due to sinus pressure. Endoscopic sinus surgery can address anatomic causes of impaired drainage. Topical sprays and oral vasoconstrictors can be used to reduce edema and further aid sinus drainage. Amoxicillin, clarithromycin, and azithromycin are the recommended first-line antimicrobials to cover S. pneumoniae, H. influenzae, Moraxella catarrhalis, and anaerobic bacteria.

Chronic sinusitis requires at least 3 to 4 weeks of antimicrobial therapy, ideally guided by culture results. Amoxicillin-clavulanate, second-generation cephalosporins, and erythromycin-sulfisoxazole are recommended first-line antibiotics. Other individualized supportive therapies include steroids, decongestants, nasal irrigations, mucolytic agents, antihistamines, and antiallergic immune therapies. Patients should be supported with smoking cessation programs. Patients who are refractory to medical therapy or have evidence of anatomic obstruction may undergo (endoscopic) sinus surgery.

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