Complications of Acute Rhinosinusitis
Summary
Acute rhinosinusitis (ARS) is defined as symptomatic inflammation of the nasal cavity and paranasal sinuses lasting less than 12 weeks, whereas chronic rhinosinusitis (CRS) persists longer than 12 weeks.1 Although ARS is an extremely common illness, affecting as many as 30 million patients per year in the United States, because of the use of antibiotics, serious complications seldom occur. However, the complications of sinusitis may be life-threatening. These complications can be orbital, intracranial, and osseous, but combinations often occur. For example, a bony erosion of the lamina papyracea caused by acute ethmoiditis can lead to the formation of an orbital abscess, which, if untreated, can spread to the cavernous sinus. Orbital complications, including pre- and postseptal cellulitis and subperiosteal and orbital abscess, are the most frequent, and children with acute ethmoiditis are especially prone to them. Endocranial complications include epidural or subdural abscesses, brain abscess, meningitis, cerebritis, and superior sagittal and cavernous sinus thrombosis. Osseous complications include osteomyelitis and Pott′s puffy tumor of the frontal sinus. These complications are detailed in this chapter, along with the physical exam, diagnostic work-up, and current treatment recommendations for each complication. Although most episodes of ARS are self-limiting, persisting, severe headache or high temperature for more than 4 to 7 days should raise the index of suspicion for complications. An extremely useful test, although not specific, is the white blood cell count (WBC), which, if elevated in ARS that is unresponsive to treatment, is highly suggestive of a complication.
Introduction
Nowadays complications of ARS are rare. However, the complications of sinusitis may be severe, even life-threatening, and should always be taken seriously. Epidemiological data concerning the complications of rhinosinusitis vary widely, and there is no consensus on the exact prevalence of the different types of complications. In patients hospitalized with sinusitis, the reported rate of complications varies from 3.71 to 20%,2 although, by selecting for severe sinus disease, these series clearly overestimate the incidence of complications. Complications are typically classified as orbital (60–75%), intracranial (15–20%), and osseous (5–10%).3 Overall, sinus disease is the presumed underlying cause of ~10% of intracranial suppuration4,5 and is related to 10% (preseptal cellulitis) to 90% (orbital cellulitis/subperiosteal abscess/intraorbital abscess) periorbital infections.6
Orbital Complications
Orbital cellulitis is typically a complication of acute infection of the paranasal sinuses and is associated in order of decreasing frequency with the ethmoid, maxillary, frontal, and, rarely, sphenoid sinus. In the presence of ethmoiditis, the infection may spread through the thin bone of the medial orbital wall, or lamina papyracea; in maxillary sinusitis, the infection may traverse the orbital floor. Frontal sinusitis may spread to the orbit via the roof of the orbit. The infection may also dissect under the periosteum and lead to subperiosteal abscess. A progressive cellulitis may lead to intraorbital abscess. Oral and intravenous (IV) antibiotics have decreased the incidence of orbital complications secondary to ARS, but orbital infection without appropriate treatment may lead to serious complications, including blindness and death.
Caution
Acute infection may lead to difficulty in identification of landmarks and increased bleeding during endoscopic drainage of subperiosteal or orbital abscesses. Meticulous dissection and careful identification of landmarks, using image guidance if available, should be employed to prevent injury to the optic nerve, carotid artery, and skull base.
Chandler Classification
The spectrum of orbital complications as a result of ARS was detailed in the classic article by Chandler et al.3 This spectrum has become known as the Chandler classification of orbital infection ( Fig. 28.1 and Table 28.1). Clinical presentation corresponds to pathologic and surgical findings in which periorbital signs progress to orbital pathology. Group I comprises inflammatory edema of the preseptal eyelid (anterior to the septum of the eyelid), otherwise known as preseptal cellulitis ( Fig. 28.1 ). This is commonly seen as a disease of early childhood, usually associated with upper respiratory infection. Group II is orbital, or postseptal, cellulitis, in which the infection reaches tissues deep to the orbital septum with diffuse edema of the orbital contents and inflammation and bacterial infection of the periorbital fat but no discrete abscess. Proptosis and chemosis may be followed by ophthalmoplegia. In group III, subperiosteal abscess, there is a collection of purulent abscess fluid between the periosteum and the bony orbital wall. There may be gaze restriction, displacement of the globe, and significant eyelid edema. Group IV comprises intraorbital abscess, in which there is a collection of purulent fluid within the orbit itself. Further extension of the infectious process to the cavernous sinus with venous thrombosis represents cavernous sinus thrombosis, also known as group V (Table 28.1).
Epidemiology and Etiology (Including Pathophysiology)
A recent review noted that of 465 pediatric patients treated for orbital cellulitis, subperiosteal abscess was noted in 68 patients, with orbital abscess noted in 2.7 Sultés et al8 found that of 150 patients with orbital complications of sinusitis, 126 (84%) had preseptal cellulitis, 9 (6%) post-septal/orbital cellulitis, 4 (3%) subperiosteal abscess, and 11 (7%) orbital abscess, with no cavernous sinus thrombosis observed in their series. This illustrates that in the antibiotic era, preseptal cellulitis is by far the most common orbital complication of rhinosinusitis, and to a much lesser extent postseptal/orbital cellulitis and subperiosteal abscess, whereas orbital abscess and cavernous sinus thrombosis are fairly uncommon. The most commonly isolated organisms in children are Streptococcus pneumoniae, nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. Herrmann and Forsen9 reviewed 74 patients with orbital complications related to ARS. They noted a different frequency of intracranial complications in pediatric patients admitted for orbital complications of ARS of 0% for those younger than 7 years and 9.3% for patients 7 years and older. If surgical intervention was required for orbital disease, these risks were 0 and 24%, respectively. The authors noted that subperiosteal abscesses located superiorly or superolaterally within the orbit were more frequently associated with orbital complications, as was significant frontal sinus disease.
In the literature on adult cases, Goldstein and Shelsta10 reviewed 11 patients, with an average age of 29 years, with methicillin-resistant S. aureus (MRSA) periorbital cellulitis. They noted that most cases of periorbital cellulitis seen at their institution in a 2-year period were MRSA positive. Their younger, teenage cohort of patients had focal abscesses with surrounding cellulitis that were easily drained and treated with oral antibiotics on an outpatient basis. Six adult patients had more aggressive infections that spread along tissue planes with multiple microabscesses and cellulitis requiring hospitalization, IV antibiotics, and, in some cases, multiple surgeries. All of their patients with MRSA preseptal or orbital cellulitis demonstrated a worsening clinical course early in the infection. The combination of a high index of suspicion with appropriate antibiotics, early and aggressive surgical drainage with debridement, and the occasional use of steroids allowed all 11 patients with MRSA to recover with minimal to no long-term sequelae.
Pomar Blanco et al11 retrospectively examined eight patients with postseptal orbital infection (Chandler groups II–V) caused by sinusitis during 1999 to 2003. They found that polymicrobial infections including anaerobes were cultured most frequently. Four of the eight patients required surgical drainage, with the remainder treated with IV antibiotics.
These series demonstrate that the adult population differs from the pediatric population in that polymicrobial, anaerobic, and odontogenic organisms predominate, in contrast to the S. pneumoniae, nontypeable H. influenzae, and M. catarrhalis that predominate in the pediatric population. Single aerobic pathogens are more common in infection within the first decade of life as compared with polymicrobial infection and more severe presentation of postseptal infection in the older group.
Clinical Features
Preseptal Cellulitis and Orbital Cellulitis
Clinical signs of orbital complications of rhinosinusitis vary with the anatomical and clinical extent of each Chandler group. Both preseptal cellulitis and orbital cellulitis may present with swelling and erythema of the tissues surrounding the orbit, with or without accompanying fever ( Fig. 28.2 ). Preseptal cellulitis commonly arises from an infection of the soft tissues of the face and eyelids resulting from acute dacryocystitis (32.6%), sinusitis/upper respiratory infection (28.8%), and trauma/recent surgery (27.8%). It is unusual for untreated preseptal cellulitis to progress to orbital cellulitis by local extension through the orbital septum; however, orbital cellulitis may be indistinguishable from preseptal cellulitis early in its course, creating the appearance that stepwise extension has occurred.12–14
On local examination, which may prove painful and difficult due to a swollen eyelid, there is no globe displacement in preseptal cellulitis, as opposed to subperiosteal or intraorbital abscess or orbital cellulitis. Although orbital cellulitis is supposed to generate an axial proptosis, as opposed to subperiosteal abscess, orbital imaging (or surgery) is required to make the definitive diagnosis.
Subperiosteal Abscess
As with pre- and postseptal cellulitis, subperiosteal abscess is often seen without concomitant postseptal/orbital cellulitis. Subperiosteal abscess can present with minimal symptomatology but can also be the initial result of extension of sinusitis into the orbit, especially in ethmoid sinusitis.15,16 In some cases, subperiosteal abscess may lead to orbital cellulitis or cavernous sinus thrombosis ( Figs. 28.3 , 28.4, 28.5, and 28.6 ).
Subperiosteal abscesses secondary to sinusitis in children up to 9 years of age are likely to contain a single aerobic species and frequently respond to antibiotic therapy. A recent series of children with subperiosteal abscesses found that medial abscesses were highly amenable to antibiotic treatment.17,18 More superiorly located subperiosteal abscesses tend to occur in older children; these more superior abscesses carry a greater risk of associated intracranial abscess, especially in patients with frontal sinusitis. Because of the lack of frontal sinus aeration in younger patients, intracranial extension is more likely to occur, as the diploic veins bridge the orbit with the dural compartment.
Orbital Abscess
Orbital abscess may be clinically indistinguishable from orbital cellulitis. It may present with more severe proptosis, globe displacement, and ophthalmoplegia related to inflammation of the oculomotor muscles, and patients are more likely to appear toxic. Infection may extend to the orbital apex, causing decreased visual acuity, or intracranially, causing intracranial abscess, meningitis, or septic cavernous sinus thrombosis. Intracranial involvement may present with oculomotor nerve palsies, mental status changes, contralateral cranial nerve palsy, or bilateral orbital cellulitis ( Fig. 28.7 ).
Cavernous Sinus Thrombosis
Cavernous sinus thrombosis (Chandler group V) is a potentially life-threatening complication of rhinosinusitis. Strictly speaking, it is an intracranial complication. However, because of its close proximity to the orbit, it is discussed here. The cavernous sinus is the most centrally located dural sinus and the most frequent site of infection and thrombosis. It is positioned just lateral to the base of the sella turcica and the sphenoid sinus and collects the venous blood from the sphenoid sinus mucosa and orbit. This explains how orbital cellulitis may diffuse to the cavernous sinus, or, alternatively, how sphenoiditis may give rise to cavernous sinus thrombosis. Sphenoid sinus infection is particularly difficult to diagnose, and treatment is often delayed, providing time for the infection to spread to the cavernous sinus.19–21 The cavernous sinus is bridged by two intercavernous sinuses passing anteriorly and posteriorly to the sella turcica and the pituitary gland, which accounts for the bilaterality observed in some rare cases.
Numerous cranial nerves (CNs) travel along the lateral wall of each cavernous sinus: the oculomotor (CN III), trochlear (CN IV), ophthalmic (CN V1), and maxillary (V2) nerves. The abducens nerve (CN VI) is located more medially, near the internal carotid artery that also tracks through the cavernous sinus. Because of this intimate relationship, cavernous sinus thrombosis may result in ophthalmoplegia. The early symptoms of cavernous sinus thrombosis are not specific to the diagnosis. However, in a patient with orbital signs and/or headache, the presence of cranial neuropathies should raise clinical suspicion of cavernous sinus thrombosis. Headache is the most common early symptom and generally precedes fever and periorbital signs by several days. Headache associated with cavernous sinus thrombosis usually presents as a sharp pain with progressive increase in severity not relieved by analgesics. The pain is typically localized to the distribution of the ophthalmic and maxillary branches of the trigeminal nerve (CN V1 and V2), is usually unilateral, and involves the retro-orbital and frontal areas with occasional radiating occipital pain. The headache may be confused with migraine, especially given the atypical variants of migraine without classical migraine symptoms such as aura, or even cluster headache. The presence of additional signs and symptoms such as periorbital swelling, diplopia resulting from CN III, IV, and VI palsies, mental status changes, ptosis, epiphora, and photophobia should alert the clinician to the possibility of cavernous sinus thrombosis. Mental status changes are more frequently seen in fatal cases. Physical examination may reveal fever as well as varying combinations of ptosis, proptosis, chemosis, and gaze restriction. Careful ophthalmologic and neurologic examination with particular attention to the cranial nerves should be performed. Periorbital edema may be the earliest physical finding, whereas exophthalmos and chemosis may result from occlusion of the ophthalmic veins and may present concomitantly with ophthalmoplegia. Sixty to 70% of patients with cavernous sinus thrombosis will have an abnormal fundoscopic exam with papilledema or dilated retinal veins noted.
Ophthalmoplegia is an important finding and results from dysfunction of CN III (oculomotor nerve) innervating the medial, superior, and inferior recti and the inferior oblique; CN IV (trochlear nerve) innervating the superior oblique muscle responsible for downward gaze, especially when the eye is adducted (turned inward); and CN VI (abducens nerve) innervating the lateral rectus muscle responsible for lateral gaze. CN III, IV, and VI palsy is caused by inflammation of these cranial nerves as they travel through the cavernous sinus. Lateral gaze palsy (isolated CN VI dysfunction) may precede full-blown ophthalmoplegia, particularly in cases of chronic sphenoid sinusitis. Unlike CN III and IV, which are located in the lateral wall of the cavernous sinus and are protected by a fibrous sheath, the abducens nerve is situated medially in the cavernous sinus and is surrounded by blood, making it more susceptible to inflammatory damage (see also Chapter 38, Figs. 38.2b and 38.10a ).
Ptosis, mydriasis, and eye muscle weakness result from oculomotor (CN III) dysfunction. Total palsy of the nerve may lead to an eye that is facing down and lateral. CN III also innervates the levator palpebrae superioris muscle, which raises the eyelid, and contains parasym-pathetic fibers to the ciliary ganglion that regulates the sphincter muscle of the iris. Additionally, the maxillary and ophthalmic divisions of the trigeminal nerve travel through the cavernous sinus; consequently, with cavernous sinus thrombosis, patients may present with hypoor hyperesthesia in the dermatomes served by these branches. Orbital complications of sinusitis and intracranial infection may coexist in nearly 50% of cases of cavernous sinus thrombosis.
Diagnostic Work-up
Physical Examination
Physical examination is key in the diagnosis of orbital complications of ARS. Visual acuity and fundoscopic exam, as well as ocular motility assessment, are mandatory. Thorough assessment of the cranial nerves should be performed, with particular attention to CN II, III, IV, V1, V2, and VI in assessing cranial neuropathies resulting from orbital or cavernous sinus infection.
Radiology Studies
Computed Tomography
Although there have been no randomized, controlled trials examining the utility of radiologic studies (e.g., computed tomographic [CT] scanning, orbital ultrasonography, or magnetic resonance imaging [MRI]) in the diagnosis of orbital cellulitis or in distinguishing preseptal from orbital cellulitis, CT with contrast is generally the radiological study of choice due to the relatively wide availability of CT scans, anatomical detail versus ultrasound, and ability to concomitantly assess sinusitis and body changes.22 CT scanning with contrast can confirm the extension of inflammation into the orbit when enhancement of fat is observed, detect coexisting sinus disease or intracranial complication, and identify an orbital or subperiosteal abscess. Thrombosis of the cavernous sinus is suspected when there is dilation of the superior ophthalmic vein with a tunnel-like appearance and confirmed when enhancement of the cavernous sinus is altered as opposed to the contralateral sinus. CT scan without contrast, however, is not 100% sensitive for subperiosteal abscess. Patt and Manning14 found that CT without contrast missed subperiosteal abscess in 16% of patients later found to have subperiosteal abscess on surgical exploration. An additional advantage of CT scans is the use of image guidance protocol CTs for both diagnostic purposes and intraoperative navigation if surgical drainage is required. These CT scans can be merged with MRI for even greater anatomical detail during intraoperative navigation.
Whether every patient with suspected orbital cellulitis needs a CT scan is controversial.23–26 Some experts suggest that a CT scan be performed only in those patients who fail to respond within 24 hours of IV antibiotics, as the majority of patients with orbital cellulitis do well with conservative medical management. In the retrospective review from Miami Children′s Hospital of 101 pediatric patients with orbital infection, only 25 (25%) underwent CT scan.24 Clinician reluctance in obtaining a CT scan is due to the exposure of the pediatric patient to radiation. In another retrospective review of 465 consecutive pediatric orbital cellulitis admissions, CT scan was performed on 240 (52%) patients.26
Guidelines for the management of orbital cellulitis recommend the following indications for CT scanning23:
Inability to accurately assess vision
Gross proptosis, ophthalmoplegia, bilateral edema, or deteriorating visual acuity
No improvement despite 24 hours of IV antibiotics
Signs or symptoms of central nervous system (CNS) involvement
In agreement with these guidelines, we suggest that patients with suspected orbital cellulitis (those with proptosis, globe displacement, limitation of eye movements, double vision, or vision loss) and those patients in whom the physician cannot accurately assess vision (usually patients younger than 1 year) at presentation have a baseline CT scan with contrast. Note that color vision (especially the color red) deteriorates first, and Ishihara color charts can be very helpful in early diagnosis of optic nerve compromise.
Note
Indications for CT scanning:
Inability to accurately assess vision
Gross proptosis, ophthalmoplegia, bilateral edema, or deteriorating visual acuity
No improvement despite 24 hours of IV antibiotics
Signs or symptoms of CNS involvement
Magnetic Resonance Imaging and Diffusion
MRI is superior to CT in the resolution of soft tissue disease; however, it is not usually performed because of the need for sedation in pediatric patients and because MRI is rarely immediately available, is not available at some smaller centers, and is more expensive than CT.
Herrmann and Forsen9 noted that MRI was superior to CT for identification of intracranial extension, and thus recommended MRI in addition to CT scan along with aggressive management in children older than 7 years admitted with orbital complications of ARS who also demonstrate risk factors for intracranial disease. Nakamura and coworkers27 reported a case of frontal sinusitis with orbital subperiosteal abscess and cavernous sinus thrombosis and noted excellent imaging of the abscess on the T1-weighted MRI with contrast.
Sepahdari et al28 examined the use of diffusion-weighted imaging (DWI) MRI in the diagnosis of orbital cellulitis and abscess. Abscesses exhibit restricted diffusion, likely secondary to the viscosity and dense cellular packing of purulent fluid. The researchers noted a significant difference in interpretation of abscess versus cellulitis between the noncontrasted T1- and T2-weighted images and the diffusion-weighted images, but there was a high degree of correlation between the contrast-enhanced and diffusion-weighted interpretations, as well as a high degree of correlation between the diffusion-weighted and contrast-enhanced interpretation and the final diagnosis. In nearly every case of orbital abscess, DWI increased diagnostic confidence, and in three cases, DWI was thought to provide at least as much information as IV contrast-enhanced sequences. The authors concluded that DWI is a valuable tool for imaging orbital cellulitis and can be used in place of contrast-enhanced imaging in some cases. They pointed out, however, that IV contrast enhancement often provided useful additional diagnostic information, further improved interobserver agreement, increased diagnostic confidence in most cases, and should still be used in patients without a contraindication to contrast. They concluded that in patients with a contraindication to gadolinium contrast, such as renal impairment, the use of diffusion-weighted MRI was a viable alternative in the detection of orbital or subperiosteal abscess.
Kapur et al29 retrospectively compared orbital MRI with T1- and T2-weighted and postcontrast images with diffusion-weighted MRI in the diagnosis of orbital cellulitis and the differentiation of orbital inflammatory syndrome (OIS), orbital lymphoid lesions, and orbital cellulitis. A significant difference was noted in DWI intensities and apparent diffusion coefficients between OIS, orbital lymphoid lesions, and orbital cellulitis (P < 0.05). OIS lesions were significantly brighter than cellulitis. The authors concluded that DWI MRI may aid in the diagnosis of orbital cellulitis and may help differentiate OIS from lymphoid lesions and cellulitis.
Tips and Tricks
Image guidance is helpful in endoscopic drainage of subperiosteal or orbital abscess, particularly in pediatric patients. An image guidance protocol should be specified for diagnostic CT scans in patients with suspected orbital complications of paranasal sinusitis.
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