**9. Medical management**

tal foreign bodies. Although sinus X-ray may demonstrate an air-fluid level when present in an abscess cavity, gas-free abscesses may not be readily visible. [15] Ultrasound may de‐ tect an abscess of the anterior orbit or the medial wall with 90% accuracy, [25] although an acute abscess may be poorly delineated. Currently, the investigative procedure of choice to diagnose an orbital infection is the CT-scan, although MRI can be utilized when there is a contra-indications for CT-scan. [8], [27], [35] By CT-scan, orbital walls, extraocular muscles, optic nerve, intraconal area and adipose tissue can be seen clearly. An orbital abscess can be seen as a homogenous, a ring-like, or a heterogenous mass. In these studies, the site of origin, orbital or subperiosteal, and extent of abscess are readily visible. [8], [22] When ad‐ ministered, contrast-media can enhance the surrounding wall of an abscess. Computed to‐ mography scan will not differentiate between preseptal cellulitis and eyelid edema but will differentiate between preseptal and orbital cellulitis. [15] Beside foreign bodies, sinus dis‐ ease and intracranial complications may also be visible on the CT-scan. [8] Our experience has shown that CT-scan may be the most comprehensive source of information about orbi‐ tal infections and the most sensitive means of monitoring resolving orbital or intracranial lesions. [8], [27] Computed tomography scan is indicated in all patients with periorbital in‐ flammation in whom proptosis, ophthalmoplegia, or a decrease in visual acuity develop, in whom a foreign body or an abscess is suspected, severe eyelid edema prevents an ade‐ quate examination, or surgery is contemplated. [8], [15], [20], [22], [35] In our study of the 218 patients with orbital cellulitis, diagnosis was made clinically and confirmed by CTscans or U/S in 90.4% and 36.2% orbits, respectively. [8] Orbital abscesses were identified in 53.2% of orbits. In all cases of orbital cellulitis, there was evidence of inflammatory or infective changes of the orbital structures. Abscess location was found to be medial in 35%, superior in 33%, intraconal in 13%, superomedial in 6%, inferomedial in 6% and lateral in

In the reported series, the bacteriology of orbital abscesses has received little attention. In series in which the contents of the abscess cavity have been cultured, a wide range of organisms have been reported. [8], [36] Most commonly reported bacterial species from the abscesses of the orbit and periorbital area include Staphylococcus aureus, Staphylococcus epidermidis, Streptococci, Diphtheroids, Haemophilus influenzae, Escherichia Coli, multiple species of aerobes and anaerobes. There was no growth in up to 25% of abscesses. [15], [17] Microbio‐ logical results from Ferguson and McNab, [1] series varied, with differences in the rate of testing between the pediatric age group and the older age group. In their series, some forms of cultures were performed in 93% of their patients. Fifty percent of their patiens had blood cultures none of which yielded positive results. According to their study, cultures taken from abscesses were more likely to yield positive results. The authors noted that there was no correlation between cultures taken from conjunctival swab and the etiological organisms recovered from the abscesses of those patients with positive cultures. In their study, Staphy‐ lococcus aureus was the most common micro-organism recovered. In their pediatric age group

2% of orbits. [8]

132 Common Eye Infections

**8. Bacteriology of orbital infection**

Medical management depends on the patient's appearance, ability to take oral medications, compliance and clinical progression of the disease. Patients presenting with signs and symptoms of eyelid edema, diplopia, reduced visual acuity, abnormal light reflexes, ophthal‐ moplegia and proptosis need admission (Figure 10). Further, if a patient appears toxic and eye exam is difficult to be completely performed, along with signs of CNS involvement as evident by lethargy, vomiting, seizures, headache or cranial nerve deficit, admission is needed for further evaluation and proper treatment. Intravenous antibiotics are usually started once the diagnosis of orbital cellulitis is suspected, broad-spectrum antibiotics that cover most gram positive and gram negative bacteria are considered initially. The recommendations for antibiotics are usually based on the microorganisms most frequently suspected from abscesses; Staphylococcus aureus, Staphylococcus epidermidis, Streptococci, and Hemophilus species. [15] Empiric antibiotics should cover methicillin-resistant Staph.aureus if suspected. [38], [39] One should suspect mixed infections including aerobic and anaerobic species in the abscesses. [20] Warm compresses over the involved area may help to improve the softening of the tissues to bring in more blood circulation in the area where blood supply is already abundant. If no improvement occurs in 24-48 hours of systemic antibiotics, one may consider Infectious Disease, Ear, Nose and Throat and/or Neurosurgery consultations. [27]

Historically, cultures from the conjunctiva, nose and throat are usually not representative of the pathogens cultured from the abscesses and blood cultures may frequently be negative and are not usually helpful. [15] Most patients in the reported series, had received a combination of a third-generation cephalosporin and flucloxacillin. [1], [8] According to those reports, most patients had received oral antibiotics on discharge for varying periods of time. [40] For example, all patients in the Ferguson and McNab's [1], series had received intravenous antibiotic treatment during their admission and most of these patients had received multidrug therapy with up to 5 different antibiotics at some point. In these cases treatment regimens were empirically based and instituted prior to the identification of responsible organisms. [1] In our experience, most of our patients also had multiple antibiotic regimens administered during their stay in the hospital and most of them were discharged on at least one antibiotic therapy. [8] In our study of 218 patients having orbital cellulitis and abscess, all patients received systemic antibiotic treatment, and in all patients, treatment regimens were empirically based and were instituted before the identification of any responsible organisms. [8] In our study, the most common antibiotic regimen included cephalosporins in 90%, and aminoglycosides in 66% with a combination of other antibiotics. These antibiotics included flucloxacillin in 15%, vancomycin in 13%, ampicillin in 6%, metronidazole in 4%, and penicillin in 3% of patients. In our study, most patients received oral antibiotics on their discharge for varying periods, ranging from 3 days to 3 weeks. [8]

**Figure 10.** Patient from Figure 1 after medical treatment of her left-sided orbital cellulitis.

From the reported series, patient age has been identified as a factor in the bacteriology and the response of these patients to treatment for their orbital abscesses. [16], [17], [20] In general, children aged <9 years have been found to have simpler, more responsive infections, primarily caused by single aerobic pathogen. Older children and adults have been found to harbor more complex infections caused by multiple aerobic and anaerobic organisms, resistant to both medical and surgical treatment. [20] In addition to starting systemic antibiotics, emergent drainage of the orbital abscesses may be necessary in patients with compromised vision regardless of patient age. Urgent drainage (within 24 hour of presentation) has been recom‐ mended for large abscesses, for extensive superior or inferior orbital abscesses, for patients with central nervous system complications and for infections following dental work in which anaerobes might be expected. [20] These patients require surgical option if improvement does not occur as expected. In these patients, careful monitoring of the clinical course is mandatory and comparison of serial CT-scan may be necessary as an adjunct to clinical judgment. In Harris's series 27 of 29 patients which were younger than 9 years old recovered with antibiotic treatment alone with a good clinical outcome. [20] He described "sliding scale" of risk associated with increasing age and argued that patients in the older age group who present with orbital process should undergo prompt sinus surgery even before orbital or intracranial abscesses develop. Once sinus infection in older children or adults has extended into the orbit as an abscess, urgent drainage may include the orbit along with the infected sinuses. [20] Computed tomography scan may not be accurate in assessing clinical course in some of these patients. In a review of 37 cases of orbital abscesses, Harris, found that subperiosteal material could not be predicted from the size or relative radiodensity of the collections from the CTscans. [22] Initial scans were not as predictive of the clinical course. In fact the serial scans showed enlargement of abscesses during the first few days of systemic antibiotic therapy regardless of the final outcome of the response to treatment. He concluded that expansion of orbital abscess on the serial CT-scans during the initial treatment may not be equated to failure of the infection to respond to the medical management in the form of antibiotics alone. [22]

### **10. Surgical intervention**

by lethargy, vomiting, seizures, headache or cranial nerve deficit, admission is needed for further evaluation and proper treatment. Intravenous antibiotics are usually started once the diagnosis of orbital cellulitis is suspected, broad-spectrum antibiotics that cover most gram positive and gram negative bacteria are considered initially. The recommendations for antibiotics are usually based on the microorganisms most frequently suspected from abscesses; Staphylococcus aureus, Staphylococcus epidermidis, Streptococci, and Hemophilus species. [15] Empiric antibiotics should cover methicillin-resistant Staph.aureus if suspected. [38], [39] One should suspect mixed infections including aerobic and anaerobic species in the abscesses. [20] Warm compresses over the involved area may help to improve the softening of the tissues to bring in more blood circulation in the area where blood supply is already abundant. If no improvement occurs in 24-48 hours of systemic antibiotics, one may consider Infectious

Historically, cultures from the conjunctiva, nose and throat are usually not representative of the pathogens cultured from the abscesses and blood cultures may frequently be negative and are not usually helpful. [15] Most patients in the reported series, had received a combination of a third-generation cephalosporin and flucloxacillin. [1], [8] According to those reports, most patients had received oral antibiotics on discharge for varying periods of time. [40] For example, all patients in the Ferguson and McNab's [1], series had received intravenous antibiotic treatment during their admission and most of these patients had received multidrug therapy with up to 5 different antibiotics at some point. In these cases treatment regimens were empirically based and instituted prior to the identification of responsible organisms. [1] In our experience, most of our patients also had multiple antibiotic regimens administered during their stay in the hospital and most of them were discharged on at least one antibiotic therapy. [8] In our study of 218 patients having orbital cellulitis and abscess, all patients received systemic antibiotic treatment, and in all patients, treatment regimens were empirically based and were instituted before the identification of any responsible organisms. [8] In our study, the most common antibiotic regimen included cephalosporins in 90%, and aminoglycosides in 66% with a combination of other antibiotics. These antibiotics included flucloxacillin in 15%, vancomycin in 13%, ampicillin in 6%, metronidazole in 4%, and penicillin in 3% of patients. In our study, most patients received oral antibiotics on their discharge for varying periods,

Disease, Ear, Nose and Throat and/or Neurosurgery consultations. [27]

**Figure 10.** Patient from Figure 1 after medical treatment of her left-sided orbital cellulitis.

ranging from 3 days to 3 weeks. [8]

134 Common Eye Infections

From their vast experience with the management of orbital abscesses, Garcia and Harris [23], concluded that surgical therapy for orbital abscesses may be contemplated based on several factors, including the sinuses involved, the presumed pathogens, the anticipated bacterial response to administered antibiotic, visual status, the size and location of the orbital abscess and potential intracranial complications. They recommended emergency drainage of the orbital abscesses and sinuses of patients of any age whose optic nerve or retinal function is compromised. Urgent drainage for large abscesses, in cases of extensive superior or inferior abscesses that might not quickly resolve despite clearance of sinusitis by medical treatment has been recommended, (Figure 11). In cases of intracranial complications at the time of presentation and in frontal sinusitis, in which the risk of intracranial extension is increased, and when complex infections that include anaerobes are suspected, urgent drainage of an abscess is recommended. [23] Again, expectant approach has been recommended for patients younger than 9 years of age in whom simple infections may be suspected. Surgical option may still be exercised if clinical improvement does not occur in a timely manner and if relative afferent pupillary defect develops at any time. Further, surgical option should be considered in cases of fever not abating within 36 hours of systemic antibiotic treatment suggesting that the infection may not be responding to the choice of antibiotics being administered. Surgery should also be considered when there has been deterioration of vision despite 48 hours of appropriate antibiotic therapy and no improvement despite 72 hours of such treatment. Usually, CT-scan improvement should be expected to lag behind the clinical picture. In fact, the CT findings may worsen during the first few days of hospitalization despite successful treatment with antibiotics alone. [23]

**Figure 11.** External photograph of an 8-year-old boy who required drainage of his right orbital abscess after failing 3 days of by systemic antibiotic treatment. CT-scan (axial and saggital cuts) showed an evidence of maxillary sinusitis and an abscess formation in the superior orbit.

In majority of the cases, surgical intervention is indicated for significant underlying sinus disease, orbital or subperiosteal abscess, or both in the children, (Figure 11). [1], [5], [8], [17] For older patients, sinus surgery remains the most common surgical intervention. Recent literature suggests that the volume of subperiosteal abscess seems to be the most important criterion in determining medical versus surgical management; the volumes of abscesses needing surgery appears to be larger than the volumes of abscesses not needing surgery. In general, volumes of <1,250 mm may not need surgical intervention. [41], [42] There may be an argument regarding early drainage of an orbital abscess to prevent complications whereas early surgical intervention has the possibility of seeding the infection. [20] For practical purposes, Harris, has outlined a useful approach in the management of an orbital abscess. [20] He emphasizes on the emergent drainage for patients of any age whose visual function may be compromised. Also for the patients in whom a large orbital abscess causes discomfort, presence of superior or inferior orbital abscess, evidence of intracranial extension, involvement of frontal sinuses, and a known dental source of the infection in patients older than 9 years, urgent drainage usually within 24 hours has been recommended. [20] Wait and see approach may be indicated for patients younger than 9 years of age having medial subperiosteal abscess of modest size, for patients having no visual compromise and in those having no intracranial or frontal sinus involvement. In these patients, careful evaluation and close monitoring of their optic nerve function and the level of consciousness and mental state are necessary. When indicated, one may consider making an incision approximately 2-inch down to the periosteum at the inner quadrant of the orbit to drain these orbital abscesses. [27] Patients with suspected fungal orbital cellulitis (especially Mucormycosis), need to be treated with intravenous Amphotericin B and predisposing factors such as diabetes, acidosis and other medical conditions need to be addressed. Wide excision along with debridement of the necrotic tissue is desired. If necessary, a drain may be inserted and tissues may not need to be sutured and may be left for granulation. One may consider removal of drain when no further drainage occurs. In some cases, endoscopic approach may be utilized and has been found to be effective for the treatment subperiosteal abscess as a result of sinus infection. Some of the advantages of endoscopic surgical drainage may be the avoidance of external ethmoidectomy and associated external facial scar and an early drainage of the affected sinuses and subperosteal abscess at the same time. [27], [43] In our study [8], among the 116 radiologically confirmed orbital abscesses, 87% required drainage, and the remaining 13% required close observation until their resolution while on systemic antibiotics. Thirty-nine eyes (17.8%) had endophthal‐ mitis causing orbital cellulitis and required evisceration or enucleation. Seven orbits required exenteration and 6 infected orbital implants had to be removed. Other 6 patients had dacryo‐ cystitis that required a dacryocystorhinostomy to treat orbital cellulitis in addition to the administration of systemic antibiotics. Combined endoscopic sinus surgery with transnasal orbital abscess drainage was carried out in some of our patients with sinusitis and orbital abscess, especially in the medial orbit. [8]

### **11. Complications of orbital cellulitis**

younger than 9 years of age in whom simple infections may be suspected. Surgical option may still be exercised if clinical improvement does not occur in a timely manner and if relative afferent pupillary defect develops at any time. Further, surgical option should be considered in cases of fever not abating within 36 hours of systemic antibiotic treatment suggesting that the infection may not be responding to the choice of antibiotics being administered. Surgery should also be considered when there has been deterioration of vision despite 48 hours of appropriate antibiotic therapy and no improvement despite 72 hours of such treatment. Usually, CT-scan improvement should be expected to lag behind the clinical picture. In fact, the CT findings may worsen during the first few days of hospitalization despite successful

**Figure 11.** External photograph of an 8-year-old boy who required drainage of his right orbital abscess after failing 3 days of by systemic antibiotic treatment. CT-scan (axial and saggital cuts) showed an evidence of maxillary sinusitis

In majority of the cases, surgical intervention is indicated for significant underlying sinus disease, orbital or subperiosteal abscess, or both in the children, (Figure 11). [1], [5], [8], [17] For older patients, sinus surgery remains the most common surgical intervention. Recent literature suggests that the volume of subperiosteal abscess seems to be the most important criterion in determining medical versus surgical management; the volumes of abscesses needing surgery appears to be larger than the volumes of abscesses not needing surgery. In general, volumes of <1,250 mm may not need surgical intervention. [41], [42] There may be an argument regarding early drainage of an orbital abscess to prevent complications whereas early surgical intervention has the possibility of seeding the infection. [20] For practical purposes, Harris, has outlined a useful approach in the management of an orbital abscess. [20] He emphasizes on the emergent drainage for patients of any age whose visual function may be compromised. Also for the patients in whom a large orbital abscess causes discomfort, presence of superior or inferior orbital abscess, evidence of intracranial extension, involvement of frontal sinuses, and a known dental source of the infection in patients older than 9 years, urgent drainage usually within 24 hours has been recommended. [20] Wait and see approach may be indicated for patients younger than 9 years of age having medial subperiosteal abscess of modest size, for patients having no visual compromise and in those having no intracranial or frontal sinus involvement. In these patients, careful evaluation and close monitoring of their optic nerve function and the level of consciousness and mental state are necessary. When indicated, one may consider making an incision approximately 2-inch down to the periosteum at the inner quadrant of the orbit to drain these orbital abscesses. [27] Patients with suspected fungal orbital cellulitis (especially Mucormycosis), need to be treated with intravenous

treatment with antibiotics alone. [23]

136 Common Eye Infections

and an abscess formation in the superior orbit.

Although less common, major complications related to orbital cellulitis and abscess can occur. Even after the successful treatment of such infections, permanent visual loss or loss of function of the vital structures may remain. Ferguson [1] reported no visual function loss among their patients after resolution of their infections. Only one of their patients from the pediatric age group had proptosis on follow-up; one had ophthalmoplegia and one had recollection of the abscess. One of their adult patients developed presumed meningitis and another adult patient required enucleation. In rare circumstances, the microorganism may cause necrotizing eyelid disease often referred as necrotizing fasciitis. [3], [44]- [46] This may progress to systemic manifestations including the potentially fatal toxic streptococcus syndrome, characterized by multi-organ failure. [44], [46] These complications can occur in the absence of antecedent health problems or history of trauma. [3], [45], [46] The virulence of this organism is related to the production of M proteins and exotoxins A and B. [47] These proteins act as super-antigens in vitro and mediate tissue necrosis by causing massive release of cytokines such as tumor necrosis factor and interleukins.

#### **12. Visual loss in orbital cellulitis**

Permanent loss of vision has been noted as a complication of orbital infection and up to one fifth of patients with orbital inflammation had blindness in the pre-antibiotic era. [2] Now, al‐ though permanent loss of vision resulting from orbital inflammation is unusual it can still oc‐ cur, (Figure 12). [8], [25], [26] Patt [26] reported 38 patients with orbital cellulitis and resultant permanent vision loss one of which progressed to no light perception vision. Loss of vision with orbital inflammation may result from optic neuritis as a reaction to adjacent or nearby in‐ fection, ischemia due to thrombophlebitis along valveless orbital veins, or compressive/pres‐ sure ischemia possibly resulting in central artery/occlusion, (Figure 12). [22], [26] Permanent irreversible visual loss may occur in cases with orbital and subperiosteal abscess despite early intervention. In a survey of 46 cases with confirmed diagnosis of orbital and subperiosteal ab‐ scess in which visual results were reported, permanent loss of vision occurred in 15% of the cases. [48] Blindness was attributed to the central retinal artery occlusion in 4, optic atrophy in 2 of hese patients. Permanent visual loss in orbital cellulitis probably has a vascular cause, whereas partial vision loss that respond to antibiotic therapy and drainage procedures may be due to inflammatory infiltrates or presence of compressive optic neuropathy. [21] It is be‐ lieved that the confinement of the optic nerve in the orbital apex area and within its bony ca‐ nal along with its proximity to the posterior ethmoid and sphenoid sinuses may further highlight the importance of the these factors in the exacerbation of posterior orbital celluliltis. Physcians need to be aware that patients with sinusitis and associated orbital cellulitis may be at risk for developing severe vision deficit requiring timely intervention. In a review of 148 pa‐ tients with orbital abscess from 13 series reported by Hornblass [15], 3 patients had evidence of no light perception vision.

Clinical examination by itself may not exactly delineate the nature of orbital inflammatory processes, clinicians may have to rely on imaging studies to select potential surgical candi‐ dates. Despite availability of modern CT-Scan and MRI studies, the physician stil needs to re‐ ly on the clinical progression of the inflammation based on vision, pupillary fuction, and assessment of ocular motility. Patt and Manning [26], reported 4 patients with vision loss due to orbital cellulitis and in each of these cases had CT-scan readings of "no definite abscess" contributing to the delay in diagnosis of orbital abscess, with a resultant delay in surgical drainage.

Ethmoidal sinuses are separated from the orbital cavity by the lamina papyracea and anterior and posterior ethmoidal foramina serve as additional connections that may allow infection to gain access from ethmoidal air cells to the orbital cavity, (Figure 5). Periorbita in this area is loosely attached to bone and may be elevated by a purulent collection, resulting in subperios‐ teal abscess. Acute visual loss due to sinusitis may either be secondary to complications of or‐ bital cellulitis or may be seen as a part of orbital apex syndrome. orbital cellulitis or as a part of the orbital apex syndrome. [27] Two cases of acute visual loss have been reported by El-Sayed and Muhaimeid [49], as a complication of orbital cellulitis due to sinusitis. One of these pa‐ tients had dramatic improvement in vision from hand motion to normal vision after systemic antibiotic treatment of pansinusitis and associated orbital cellulitis. The second patient, (a 10 year old girl), achieved normal visual acuity from no light perception after only surgical inter‐ vention by exploration of sphenoid and ethmoid sinuses along-with intravenous antibiotic administration. Three cases of sphenoethmoiditis with minimal signs of orbital inflammation causing permanent loss of vision have been reported by Slavin and Glaser. [48] These authors suggested the use of term "posterior orbital cellulitis" for such cases and defined it as a clini‐ cal syndrome in which early severe visual loss overshadows or precedes accompanying in‐ flammatory orbital signs. Acute blindness may also result from orbital infarction syndrome.

Orbital infarction syndrome is a disorder that may take place secondary to different mech‐ anisms which may include acute perfusion failure like common carotid artery occlusion, systemic vasculitis such as giant-cell arteritis, or as a result of orbital cellulitis with vasculi‐ tis such as Mucormycosis. In some of these cases, vision loss can be permanent due to reti‐ nal or optic nerve damag. [50] According to our experience in a developing country, most patients with sinusitis and orbital abscess presented late in the course of their disease. [8] Most patients with refractory or complicated subperiosteal abscesses have been older chil‐ dren or adults. In one of the largest studies reported, among the 159 patients with orbital complications of sinusitis, 4 had permanent blindness. [26] All 4 had surgically confirmed subperiosteal abscess, and all were older than 15 years of age. In another study, among the 13 patients with intracranial abscess extension from sinusitis or orbital abscesses, 2 pa‐ tients were 9 to 14 years of age and 11 were older than 15 years of age. [7] In our study of orbital cellulitis, visual acuity improved in 16.1% and worsened in 6.2%, including 4.3% that sustained complete loss of vision. We attributed the permanent loss of vision to the delay in diagnosis and intervention. [8]
