INTRODUCTION — Orbital cellulitis is an infection involving the contents of the orbit (fat and ocular muscles). It must be distinguished from preseptal cellulitis (sometimes called periorbital cellulitis), which is an infection of the anterior portion of the eyelid. Neither infection involves the globe itself.
Although preseptal and orbital cellulitis may be confused with one another because both can cause ocular pain and eyelid swelling and erythema, they have very different clinical implications. Preseptal cellulitis is generally a mild condition that rarely leads to serious complications, whereas orbital cellulitis may cause loss of vision and even loss of life. Orbital cellulitis can usually be distinguished from preseptal cellulitis by its clinical features (ophthalmoplegia, pain with eye movements, and proptosis) and by imaging studies; in cases in which the distinction is not clear, clinicians should treat patients as though they have orbital cellulitis. Both conditions are more common in children than in adults, and preseptal cellulitis is much more common than orbital cellulitis.
The pathogenesis, microbiology, clinical manifestations, complications, diagnosis, and treatment of orbital cellulitis will be reviewed here. Preseptal cellulitis is discussed separately. Orbital infections caused by fungi, mainly the Mucorales (which cause mucormycosis) and Aspergillus spp, and, much more rarely, Mycobacterium tuberculosis are also presented separately. (See "Preseptal cellulitis" and "Mucormycosis (zygomycosis)" and "Epidemiology and clinical manifestations of invasive aspergillosis" and "Tuberculosis and the eye".)
TERMINOLOGY — Preseptal cellulitis and orbital cellulitis involve different anatomic sites, with preseptal cellulitis referring to infections of the soft tissues anterior to the orbital septum, and orbital cellulitis referring to infections posterior to it (figure 1). Orbital cellulitis involves the muscle and fat located within the orbit. Orbital cellulitis does not involve the globe. (See 'Anatomy' below and "Preseptal cellulitis", section on 'Anatomy'.)
There is some debate regarding the appropriate terminology for these infections. Some clinicians use the term “periorbital cellulitis” rather than “preseptal cellulitis” or use the terms interchangeably. We prefer the term “preseptal cellulitis” to make a clear distinction between this infection and the more serious infection, “orbital cellulitis.” Orbital cellulitis is sometimes referred to as “postseptal cellulitis”; we favor the term “orbital cellulitis,” and will use it throughout this topic.
ANATOMY — Basic familiarity with the anatomy of the eye is fundamental to understanding the pathogenesis, clinical manifestations, and complications of orbital cellulitis. The orbit is a cone-shaped structure, lying horizontally, with its apex in the skull. It is surrounded by paranasal sinuses, namely, the frontal (lying superior), ethmoid (medial) and maxillary (inferior) sinuses (figure 2). The orbit is lined by periosteum. The ethmoid sinuses are separated from the orbit by a paper-thin layer called the lamina papyracea, which contains many perforations for nerves and blood vessels as well as some natural fenestrations termed Zuckerkandl’s dehiscences. The most common route of infection of the orbit is by extension from the ethmoid sinuses, presumably through these perforations.
The orbital septum is a membranous sheet that extends from the periosteum of the orbit to the tarsal plate and forms the anterior boundary of the orbital compartment (figure 1). The superior and inferior orbital veins drain blood directly into the cavernous sinus (figure 3). Because of this communication and because the inferior orbital veins are valveless, infection can pass readily from the orbit to intracranial structures [1].
EPIDEMIOLOGY AND PATHOGENESIS — Orbital cellulitis is much more common in young children than in older children or adults. Orbital cellulitis is an uncommon complication of bacterial rhinosinusitis, but rhinosinusitis is the source of most cases of orbital cellulitis; coexisting rhinosinusitis is present in 86 to 98 percent of cases of orbital cellulitis [2-5]. Ethmoid sinusitis and pansinusitis are the forms of rhinosinusitis most likely to lead to orbital cellulitis. (See "Acute sinusitis and rhinosinusitis in adults: Clinical manifestations and diagnosis" and "Acute bacterial sinusitis in children: Clinical features and diagnosis", section on 'Complications of ABS'.)
As has been noted above, the ethmoid sinuses are separated from the orbit by the lamina papyracea, a thin structure with many fenestrations. Computed tomography (CT) scanning often shows the predominant site of inflammation to be the medial aspect of the orbit, adjacent to the ethmoid sinuses, and subperiosteal abscesses most often occur in the same location (figure 2). (See 'Anatomy' above and "Preseptal cellulitis", section on 'Anatomy'.)
Although bacterial rhinosinusitis is the most common cause of orbital cellulitis, other potential causes are:
Fungal rhinosinusitis can also lead to orbital cellulitis. (See 'Fungi and mycobacteria' below and "Fungal rhinosinusitis".)
MICROBIOLOGY — The causative organisms of orbital cellulitis are often difficult to identify. Cultures from the orbit are only obtained if surgical intervention is needed, usually to drain an abscess. Sinus cultures obtained during surgery can be used to guide antimicrobial therapy [18], but may not accurately reflect the pathogen(s) in the orbit. Blood cultures are sometimes positive in children, the percentages ranging from 0 to 33 percent in various retrospective series [19-23]. They are rarely positive in adults. In one series of patients with orbital cellulitis, blood cultures were positive in 33 percent of children younger than four years of age but in only 5 percent of adults [20].
Bacteria — Orbital cellulitis is often a polymicrobial infection. The most commonly identified pathogens in orbital cellulitis are Staphylococcus aureus and streptococci (table 1) [2-4,24]. In one series of 94 children admitted to a tertiary care children’s hospital with orbital cellulitis between 2004 and 2009, members of the Streptococcus anginosus (milleri) group were the most commonly identified pathogens (15 percent) followed by S. aureus (9 percent), group A beta-hemolytic streptococci (Streptococcus pyogenes, 6 percent), and Streptococcus pneumoniae (4 percent) [3]. Only one patient had methicillin-resistant S. aureus (MRSA) infection but one would expect an increasing proportion of MRSA infections given the rising prevalence of community-acquired MRSA (CA-MRSA) among strains of S. aureus. Cases of neonatal and infantile orbital cellulitis caused by CA-MRSA have been reported [25].
Uncommon causes of orbital cellulitis include Haemophilus influenzae and nonspore-forming anaerobes [24,26], Aeromonas hydrophila [27], Pseudomonas aeruginosa [28] and Eikenella corrodens [29]. H. influenzae type b, formerly an important cause of orbital cellulitis in children, has become rare with the widespread use of the vaccine [24,30,31].
Fungi and mycobacteria — Although most cases of orbital cellulitis are caused by bacteria, fungi, especially Mucorales (which causes mucormycosis) and Aspergillus spp can cause life-threatening, invasive orbital infections. Mucormycosis and invasive aspergillosis should be considered in patients with defects in host defenses. Mucormycosis primarily affects patients with diabetic ketoacidosis and sometimes in patients with renal acidosis. Aspergillus infection of the orbit occurs in patients with severe neutropenia or other immune deficiencies, including HIV infection. These infections are discussed briefly below and more fully elsewhere. (See 'Diagnosis' below and "Mucormycosis (zygomycosis)" and "Fungal rhinosinusitis" and "Epidemiology and clinical manifestations of invasive aspergillosis".)
Fungal causes of orbital cellulitis have been reported rarely in apparently immunocompetent infants [32].
Rarely, fungal pathogens other than the Mucorales or Aspergillus spp [33] or mycobacteria (especially Mycobacterium tuberculosis) cause orbital infections. (See "Tuberculosis and the eye", section on 'Orbital tuberculosis'.)
CLINICAL MANIFESTATIONS — It is important to distinguish preseptal from orbital cellulitis because the two conditions have very different clinical implications (table 2 and table 3) [2-5,34]. Both orbital cellulitis and preseptal cellulitis cause ocular pain and eyelid swelling with erythema (picture 1); in some cases of orbital cellulitis, eyelid erythema is absent. Only orbital cellulitis causes swelling and inflammation of the extraocular muscles and fatty tissues within the orbit, leading to pain with eye movements, proptosis, and ophthalmoplegia with diplopia. Chemosis (conjunctival swelling) may occasionally occur in severe cases of preseptal cellulitis, but is more common with orbital cellulitis. In both conditions, but especially in orbital cellulitis, there may be fever and peripheral leukocytosis with a predominance of neutrophils [2,35]. In a retrospective study that included 262 children, fever occurred more commonly in those with orbital cellulitis than in those with preseptal cellulitis (94 versus 47 percent) [2]. Rarely in orbital cellulitis, there may be visual impairment, and even blindness, arising from inflammation or ischemia of the optic nerve [36].
The frequencies with which the signs and symptoms of orbital and preseptal cellulitis have been reported in different studies are summarized in the table (table 2).
COMPLICATIONS — Although it is much less common than preseptal cellulitis, orbital cellulitis is a far more consequential infection because it can be sight- or even life-threatening [34,37]. It can be complicated by subperiosteal abscess, orbital abscess, vision loss, cavernous sinus thrombophlebitis, and/or brain abscess [18,34]. The most common complications of orbital cellulitis are subperiosteal abscess and orbital abscess. These complications may develop rapidly; therefore, close monitoring is indicated, with daily checks of visual acuity and assessment of the pupillary light reflex. A sluggish or absent pupillary light reflex or a relative afferent pupillary defect indicates optic nerve involvement. Any worsening of the patient’s symptoms or signs should lead to a contrast-enhanced computed tomography (CT) scan of the orbits and sinuses (or repeat CT if one was done earlier) to detect an abscess. (See 'Imaging studies' below.)
Orbital cellulitis results in loss of vision in 3 to 11 percent of patients and in death in 1 to 2 percent of patients [37].
Rare complications include cavernous sinus thrombosis and central retinal artery occlusion [38,39]. These complications are discussed separately. (See "Septic dural sinus thrombosis", section on 'Septic cavernous sinus thrombosis' and "Central and branch retinal artery occlusion".)
Subperiosteal abscess — Subperiosteal abscess is a fairly common complication of orbital cellulitis, occurring in 15 to 59 percent of cases in various retrospective series (table 2) [2-4,40]. It is difficult to distinguish subperiosteal abscess from simple orbital cellulitis on clinical grounds, although marked displacement of the globe is suggestive of abscess. Orbital imaging or surgery is necessary to make the diagnosis (picture 2).
In some patients, a subperiosteal abscess, arising by extension from a sinus infection, precedes orbital cellulitis [41] or occurs without orbital cellulitis. The abscess can present with minimal symptoms [42] until it ruptures into the orbit.
Subperiosteal abscesses in younger children tend to lie medially in the orbit [43], to be amenable to antibiotic treatment without surgery (when small or in the form of poorly organized phlegmons) [18,43,44], and to contain a single aerobic species [44]. Nonmedial abscesses in older children, and abscesses located superiorly (near the frontal sinus) appear to be at highest risk for intracranial abscess. Abscesses in older patients usually contain mixtures of aerobic and anaerobic microbes [45,46] and are more likely to require drainage than those in children.
Orbital abscess — Like subperiosteal abscess, orbital abscess is difficult to distinguish from uncomplicated orbital cellulitis. It has been reported in up to 24 percent of cases of orbital cellulitis (table 2) [2-5,35]. Patients with orbital abscess typically have more severe signs (proptosis, ophthalmoplegia) and symptoms (pain with eye movements) than those with uncomplicated orbital cellulitis [35].
In a retrospective cohort study that included 298 otherwise healthy children admitted to a pediatric emergency department who underwent CT scanning for suspected acute periorbital (preseptal) or orbital cellulitis, six (2 percent) were found to have an orbital abscess [35]. Proptosis, pain with external ocular movement, and ophthalmoplegia were associated with the presence of an orbital abscess, although 51 percent of patients with abscess did not have these findings. On multivariate analysis, other factors associated with orbital abscess were a peripheral absolute neutrophil count (ANC) >10,000 per microL, absence of conjunctivitis, periorbital edema, age >3 years, and previous antibiotic therapy. (See 'Imaging studies' below.)
Extraorbital extension — Infection may rarely extend to the orbital apex, causing visual loss, or intracranially, causing epidural or subdural empyema, brain abscess, meningitis, cavernous sinus thrombosis, or dural sinus thrombosis [18]. The visual loss associated with orbital cellulitis is thought to result from any of the following processes [36]:
Intracranial complications may be heralded by severe headache, protracted vomiting, mental status changes and, in patients with cavernous sinus thrombosis, cranial nerve palsies. Bilateral cranial nerve palsies can be a sign of bilateral cavernous sinus thrombosis.
Intracranial extension may be more common in patients with frontal sinus involvement [18,47]; of note, frontal sinusitis does not occur in young children since the frontal sinuses do not develop until at least six years of age, and do not develop fully until mid-adolescence. (See "Acute bacterial sinusitis in children: Clinical features and diagnosis", section on 'Anatomy'.)
DIFFERENTIAL DIAGNOSIS — The differential diagnosis of orbital cellulitis includes a range of infectious and noninfectious diseases. Although orbital cellulitis is most commonly caused by bacteria, in patients with certain risk factors, fungal pathogens (and occasionally tuberculosis) should be considered. As noted below, it is critical to distinguish preseptal cellulitis from the more serious orbital cellulitis. (See 'Diagnosis' below.)
Diseases that should be considered in the differential diagnosis of orbital cellulitis include:
Certain findings are suggestive of the following serious conditions:
DIAGNOSIS — The diagnosis of orbital cellulitis is suspected clinically and can be confirmed by computed tomography (CT) scanning. During the initial evaluation, it is critical to distinguish preseptal cellulitis from the more serious orbital cellulitis. It is also important to look for complications of orbital cellulitis, such as subperiosteal abscess, orbital abscess, visual loss, and intracranial extension. Although both preseptal cellulitis and orbital cellulitis typically cause eyelid swelling with or without erythema, the presence of ophthalmoplegia, pain with eye movement, and/or proptosis occur only with orbital cellulitis. Another finding that is more common with orbital cellulitis, and rare or absent with preseptal cellulitis, is chemosis. Fever is more common with orbital cellulitis than with preseptal cellulitis [2,4].
It is important for an ophthalmologist to evaluate patients with suspected orbital cellulitis in order to evaluate the extraocular movements and visual acuity, and to assess for proptosis. In patients with extensive rhinosinusitis, an otolaryngologist should generally be consulted as well. (See 'Surgery' below.)
Imaging studies — The goals of imaging studies are to support the diagnosis of orbital cellulitis and to search for an abscess or other complications requiring surgical drainage. (See 'Surgery' below.)
Imaging modalities — CT scanning and magnetic resonance imaging (MRI) are useful for the diagnosis of orbital cellulitis and its complications. There are no controlled trials comparing these modalities and the choice is usually based on the availability of the test and on the clinical experience of the physicians involved. CT scanning of the orbits and sinuses is used most commonly to evaluate for possible orbital cellulitis and its complications. MRI is superior to CT scan in following the progression of soft tissue disease [59], but may not be readily available and may require sedation in young children.
When cavernous sinus thrombosis is suspected, an imaging study that includes venography should be performed, such as magnetic resonance (MR) venography or CT venography. These modalities are discussed in detail separately. MR venography is used most commonly, and would show nonfilling of the cavernous sinus in patients with cavernous sinus thrombosis. (See "Etiology, clinical features, and diagnosis of cerebral venous thrombosis", section on 'Diagnosis'.)
Imaging findings — In preseptal cellulitis, inflammation is confined to the eyelids. In orbital cellulitis, inflammation of extraocular muscles, fat stranding, and anterior displacement of the globe are common findings. It is important to note that some cases of orbital cellulitis will have subtle abnormalities by CT scan. There is almost always evidence of rhinosinusitis, most commonly ethmoid sinusitis, and the most intense inflammatory response in the orbit is often seen adjacent to the ethmoid sinus.
Subperiosteal abscesses and orbital abscesses appear as low-density collections on CT scan. Subperiosteal abscesses lie between the periosteum and the wall of the bony sinus (picture 2). Both types of abscesses, but especially subperiosteal abscesses, are often found adjacent to the ethmoid sinus (figure 2).
Indications for imaging — Whether every patient with suspected orbital cellulitis should have a CT scan is controversial [19,26,60,61]. Clinicians may be reluctant to obtain a CT scan due to concern about exposure of the pediatric patient to radiation. Guidelines for the management of orbital cellulitis from the United Kingdom offer the following indications for CT scanning: inability to assess vision; proptosis, ophthalmoplegia, bilateral edema, or deteriorating visual acuity; lack of improvement after 24 hours of administration of intravenous antibiotics; ”swinging” fevers not resolving within 36 hours; or signs or symptoms of central nervous system (CNS) involvement [60].
In the study of CT scanning in children with suspected acute preseptal or orbital cellulitis described above, the presence of edema beyond the eyelid margin or an absolute neutrophil count (ANC) >10,000 cell/microL were independent risk factors for an orbital abscess; the authors concluded that the presence of either of these findings should necessitate an expedited evaluation, including emergent CT scanning [35]. (See 'Orbital abscess' above.)
In addition, CT scanning should be done in all patients in whom surgical drainage is being considered [5].
Based on the studies and guidelines described above, we recommend that patients with suspected orbital cellulitis with any of the following features undergo a contrast-enhanced CT scan of the orbits and sinuses:
Microbiologic studies — Despite the low yield, we recommend obtaining blood cultures from patients with suspected orbital cellulitis before the administration of antibiotics. If surgery is performed, the material obtained should be examined by Gram stain and, in patients with risk factors for a fungal and/or mycobacterial etiology, by special stains for fungi and mycobacteria. Cultures should be done for ordinary bacterial pathogens and, depending on the circumstances, fungi and mycobacteria.
TREATMENT
Antibiotic regimens — Most patients with uncomplicated orbital cellulitis can be treated with antibiotics alone [4,5,62]. Even in patients who are initially treated with antibiotics alone, an ophthalmologist and an otolaryngologist should be consulted because the physical examination requires ophthalmologic and/or otolaryngologic expertise and surgery is sometimes required. (See 'Surgery' below.)
There are no randomized controlled trials evaluating empiric antibiotic regimens for the treatment of orbital cellulitis. Treatment regimens are usually empiric and designed to address the most common pathogens because, in the absence of surgical intervention, reliable culture results are difficult to obtain.
The usual choices are a parenterally administered broad-spectrum regimen aimed at S. aureus (including methicillin-resistant S. aureus [MRSA]), S. pneumoniae and other streptococci, as well as gram-negative bacilli. When intracranial extension is suspected, the regimen should also include coverage for anaerobes. Prompt treatment is important because delayed intervention can lead to loss of vision and/or other serious complications [12,18,36].
Appropriate antibiotic regimens for empiric treatment in patients with normal renal function include a combination of:
In patients with suspected intracranial extension who are being treated with ceftriaxone or cefotaxime, metronidazole (in children: 30 mg/kg IV or orally per day in divided doses every 6 hours; in adults: 500 mg IV or orally every 8 hours) should be added to include coverage for anaerobes. (See "Treatment and prognosis of brain abscess".)
Like vancomycin, daptomycin, linezolid and telavancin also are active against MRSA, but there is little experience using them for orbital or intracranial infections. Moreover, linezolid concentrations in the central nervous system (CNS) have been inconsistent in children and, accordingly, linezolid is not recommended for children with CNS infections [63]. Therefore, unless there is a contraindication to its use (eg, allergy), vancomycin is the preferred agent for MRSA coverage of orbital cellulitis.
Adults and children with a serious allergy to penicillins and/or cephalosporins can be treated with a combination of vancomycin and either ciprofloxacin or levofloxacin. In adults, ciprofloxacin is given at a dose of 400 mg IV twice daily (or 500 to 750 mg orally twice daily) and levofloxacin is given at a dose of 500 to 750 mg IV or orally once daily. In children, ciprofloxacin is given at a dose of 20 to 30 mg/kg per day divided every 12 hours with a maximum dose of 1.5 grams orally daily or 800 mg IV daily. Limited information regarding levofloxacin use in pediatric patients is available. Some centers recommend a dose for infants ≥6 months and children <5 years of 10 mg/kg per dose every 12 hours, and for children ≥5 years of 10 mg/kg per dose every 24 hours (maximum daily dose 500 mg).
Desensitization to a penicillin or cephalosporin may be considered in patients with a history of an IgE-mediated (anaphylactic) reaction to these agents. (See "Allergy to penicillins", section on 'Desensitization'.)
If a pathogen is retrieved on cultures of blood or orbital or subperiosteal aspirates, or from sinuses from cultures obtained by endoscopic sinus surgery, treatment should be modified accordingly. For example, if a methicillin-susceptible strain of S. aureus (MSSA) is recovered, treatment should be changed from vancomycin to oxacillin or nafcillin (in children: 100 to 200 mg/kg/day in divided doses every six hours, maximum daily dose 12 g; in adults: 2 g IV every four hours) because these agents are more rapidly bactericidal for MSSA than vancomycin. Because these infections are often polymicrobial, broad-spectrum therapy is usually continued until anaerobic culture data are available, usually for approximately five days after collection.
Response to therapy — Patients should begin to show improvement within 24 to 48 hours of initiating appropriate therapy; if this does not occur, repeat imaging should be performed to search for an abscess or another indication for surgery. (See 'Surgery' below.)
Duration and switch to oral therapy — There have been no controlled trials to define the optimal duration of antimicrobial therapy in orbital cellulitis or when to switch from intravenous to oral treatment. For patients with uncomplicated orbital cellulitis (ie, without abscess or other complications) whose infection responds well, it is reasonable to switch to oral therapy. We generally switch to oral therapy after the patient is afebrile and the eyelid and orbital findings have begun to resolve substantially, which usually takes three to five days.
If there are no definitive culture data, appropriate empiric oral regimens include:
The recommendation to use clindamycin alone is based primarily on published susceptibility data rather than on clinical efficacy data for patients with orbital cellulitis. However, the drug has shown good efficacy for skin and soft tissue infections caused by staphylococci and streptococci [64]. (See "Treatment of skin and soft tissue infections due to methicillin-resistant Staphylococcus aureus in adults", section on 'Clindamycin' and "Evaluation and management of suspected methicillin-resistant Staphylococcus aureus skin and soft tissue infections in children".)
In adults and children who have serious allergies to penicillins and cephalosporins, appropriate alternatives to the agents listed above are ciprofloxacin or levofloxacin. In adults, ciprofloxacin is given at a dose of 500 to 750 mg orally twice daily and levofloxacin is given at a dose of 500 to 750 mg orally once daily. In children, ciprofloxacin is given at a dose of 20 to 30 mg/kg per day divided every 12 hours with a maximum dose of 1.5 grams orally daily. Limited information regarding levofloxacin use in pediatric patients is available. Some centers recommend a levofloxacin dose for infants ≥6 months and children <5 years of 10 mg/kg per dose every 12 hours, and for children ≥5 years of 10 mg/kg per dose every 24 hours (maximum daily dose 500 mg). When a fluoroquinolone is used, it should be combined with clindamycin or trimethoprim-sulfamethoxazole to cover MRSA. Desensitization to a penicillin or cephalosporin or may be considered in patients with a history of an IgE-mediated (anaphylactic) reaction to these agents. (See "Allergy to penicillins", section on 'Desensitization'.)
For patients with uncomplicated orbital cellulitis, we suggest that antibiotics be continued until all signs of orbital cellulitis have resolved, and for a total of at least two to three weeks. A longer period (at least four weeks), is recommended for patients with severe ethmoid sinusitis and bony destruction of the sinus [26,65]. The management of the complications of orbital cellulitis is discussed separately. (See "Septic dural sinus thrombosis" and "Treatment and prognosis of brain abscess" and "Epidural abscess".)
Surgery — The main indications for surgery are a poor response to antibiotic treatment, worsening visual acuity or pupillary changes, or evidence of an abscess, especially a large abscess (>10 mm in diameter) or one that fails to respond promptly to antibiotic treatment [66,67]. In some cases, drainage of affected sinuses is also required to control the infection. The results of cultures and susceptibility testing from samples obtained during surgery can be used to tailor therapy.
Medial subperiosteal abscesses in children often respond to medical therapy without surgery [43,44]. In one series of 68 children with subperiosteal abscess, only 21 (31 percent) underwent surgery [40]. Those undergoing surgery had, on average, larger abscesses (>10 mm in diameter). Another study also found the volume of the abscess to be an important criterion for surgery, with volumes <1250 mm3 not requiring surgery [68]. In another study in children, the degree of proptosis was the only significant predictor of the need for surgical intervention [69].
We suggest that patients with large abscesses (>10 mm in diameter) be strongly considered for surgery. Patients with smaller abscesses can generally be followed clinically and with repeat imaging unless impairment of vision is a concern. If either the clinical findings or CT scan show no improvement within 24 to 48 hours, surgical drainage is generally indicated. Surgery is almost always indicated in patients with intracranial extension of the infection. Surgery may also be indicated to obtain culture material (eg, in patients with suspected fungal or mycobacterial infection of the orbit).
External approaches (through the orbit) and endoscopic transcaruncular surgery have been employed [70-73]. The transcaruncular approach involves a lower eyelid transconjunctival incision extended medially around the lacrimal caruncle [71].
Sinus surgery is indicated for debridement in patients with severe, destructive rhinosinusitis.
OUTCOMES — The outcomes of orbital cellulitis depend on whether complications are present. The majority of patients with orbital cellulitis respond rapidly and completely to appropriate therapy. The most serious complications are cavernous sinus thrombosis, intracranial extension, and vision loss, which can lead to permanent sequelae and, in the case of complications in the former two, death. These complications are rare. (See 'Complications' above.)
SUMMARY AND RECOMMENDATIONS — Orbital cellulitis is an infection involving the contents of the orbit (fat and ocular muscles). Preseptal cellulitis and orbital cellulitis involve different anatomic sites, with preseptal cellulitis referring to infections of the soft tissues anterior to the orbital septum and orbital cellulitis referring to infections posterior to it (figure 1). Although the two entities may initially be confused with one another, it is important to distinguish between them because they have very different clinical implications. Preseptal cellulitis is generally a mild condition that rarely leads to serious complications, whereas orbital cellulitis may cause loss of vision and even loss of life. Orbital cellulitis can usually be distinguished from preseptal cellulitis by its clinical features (ophthalmoplegia, pain with eye movements, and proptosis) and by imaging studies; in cases in which the distinction is not clear, clinicians should treat patients as though they have orbital cellulitis. Both conditions are more common in children than in adults. (See 'Introduction' above and 'Terminology' above.)
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