Table of Contents
Definition of Periorbital and Orbital Cellulitis
Orbital cellulitis is an infectious inflammation of the tissue posterior to the orbital septum. Orbital fat, muscles, and even bony structures can be involved. Periorbital cellulitis differs from orbital cellulitis, the infected tissues are anterior to the orbital septum.
|Orbital cellulitis||Periorbital cellulitis|
|Include Gram-positives, Gram-negatives, anaerobes||Usually GAS or staph|
|Requires broad-spectrum antibiotics||Treat with narrow-spectrum antibiotics|
|Vision risk||Rarely spreads into the eye if treated|
Epidemiology of Periorbital and Orbital Cellulitis
Periorbital cellulitis is a more common condition when compared to orbital cellulitis, but the morbidity and complications of orbital cellulitis are more severe. Periorbital and orbital cellulitis are more common in children, with periorbital cellulitis occurring most often in children 5 to 10 years of age.
Periorbital cellulitis initiates superficially, whereas orbital cellulitis starts deeper in the septum of the orbit. A possible predisposing factor is paranasal sinusitis. Patients typically have an extension of a paranasal or dental infection. Other possible risk factors include trauma, insect bites, and skin infections of the eyelid.
The most common risk factor for the two infections is similar, that being an infection that is often a direct extension of infected paranasal sinuses. In orbital cellulitis, however, eye surgery or trauma plays a significant role in predisposition to the condition. Metastatic spread of infection from other areas can also cause either condition.
Pathophysiology of Periorbital and Orbital Cellulitis
Patients can develop periorbital cellulitis due to a direct extension of infected paranasal sinuses to tissues anterior to the orbital septum. Spread of the infection in soft tissues such as the skin, subcutaneous fat, and eye adnexa is also common. Certain conditions such as dacryocystitis, sinusitis, and recent trauma or surgery to the eyelid or the eye itself can cause periorbital cellulitis.
Orbital cellulitis can result from direct hematogenous spread of causative organisms, especially in patients with diabetes or in immunocompromised individuals. Patients can also develop the condition as a complication of direct extension of an infection from the paranasal sinuses separated by a partition of bone only. In one series, almost all patients with orbital cellulitis had some form of paranasal sinusitis. The infection is severe and extensive.
Patients can also develop the condition as a complication of eye surgery and direct inoculation of the eye with causative organisms. People with diabetes and other immunocompromised patients are at risk for orbital cellulitis as a complication from trauma to the eye, orbital bone fractures, or surgery to the eye. Orbital cellulitis can spread to cause cavernous sinus thrombosis, cerebral abscess, and meningitis.
Historically, the most common etiology of orbital and periorbital cellulitis was Haemophilus influenzae type b. Since the wide-spread introduction of H. influenzae vaccination, the organism is less likely to cause orbital cellulitis. Currently, the most commonly identified organisms in children with periorbital cellulitis are Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus. Staphylococcus aureus and Streptococcus pneumoniae are also commonly identified in cases of orbital cellulitis. Patients who develop periorbital cellulitis present to the clinic complaining of a swollen eyelid due to eyelid edema, warmth, redness or discoloration of the eye and eyelid with or without fever, but with no protrusion of the eye.
Visual examination reveals normal visual acuity with intact ocular movement and no proptosis. Patients who develop orbital cellulitis are usually unable to move their eyes due to severe pain. Visual acuity might be impaired, and eye protrusion is common. Eyelid edema and redness can also be seen in orbital cellulitis, similar to periorbital cellulitis. In both conditions, patients might describe a recent history of upper respiratory tract infection or sinusitis. Patient history is essential for excluding other risk factors such as eye surgery or trauma to the orbit.
|Eyelid swelling, redness, discharge||Yes||Yes|
|Normal pupil response||Yes||Yes|
|Abnormal eye movement||Common||No|
|Pain with eye movements||Usually||No|
Diagnostic Workup for Periorbital and Orbital Cellulitis
As part of the evaluation of the patient presenting with periorbital or orbital cellulitis, a full ophthalmologic examination should be conducted. Visual acuity, pupillary response, intraocular pressure with tonometry, and ophthalmoscopy should be normal in patients with periorbital cellulitis, but might be impaired in patients with orbital cellulitis. Ophthalmoscopy can show optic nerve edema and posterior segment venous engorgement in patients with orbital cellulitis.
Imaging is essential in evaluating a patient presenting with possible orbital cellulitis. Magnetic resonance imaging (MRI) of the orbit can reveal soft tissue involvement, multiple loculations of the posterior segment of the eye, and signs of endophthalmitis. A computed tomography scan (CT) of the orbital bone can show orbital bone fractures, a possible risk factor for orbital cellulitis due to trauma. MRI is preferred to a CT scan if there is cavernous sinus thrombosis. Possible indications for orbital imaging include young age, significant periorbital edema, presence of fever, severe eye pain on movement, and presence of focal neurological signs. Focal neurological signs suggest spread of the infection to the central nervous system.
Blood cultures enable selection of the best antibiotic based on the microorganism detected. Lumbar puncture can be performed if meningitis is suspected.
Treatment of Periorbital and Orbital Cellulitis
Treatment options for periorbital and orbital cellulitis can either be medical or surgical. Medical management of periorbital cellulitis includes administration of adequate antibiotic therapy to treat the infection and limit its spread. Patients with mild periorbital cellulitis who are older than one year of age can be treated in an outpatient setting with oral antibiotics. Antibiotics of choice should cover the most commonly implicated organisms, Staphylococcus aureus and Streptococcus spp.
Patients who have severe periorbital cellulitis or those who do not respond to oral antibiotic therapy should be admitted to the hospital for intravenous antibiotic therapy. Infants younger than one year of age who present with periorbital cellulitis should be treated in an inpatient setting regardless of the severity of the condition.
Those who develop orbital cellulitis should always be treated in an inpatient setting with intravenous antibiotics. Patients suspected to have methicillin-resistant S. aureus should receive intravenous vancomycin. Combination therapy with intravenous cefotaxime, metronidazole, or clindamycin is usually indicated in cases of orbital cellulitis to cover Gram-negative organisms and anaerobes.
Intranasal corticosteroids are indicated in cases of chronic sinusitis to facilitate nasal drainage. Treatment of sinusitis in cases of orbital cellulitis was found to provide an improved outcome especially in case of subperiosteal abscesses.
Surgical intervention in patients with periorbital cellulitis is rarely needed and is only indicated in the case of the following:
- Impairment of vision
- Suspicion of pus formation or presence of foreign body
- Evaluation of orbital or large subperiosteal abscess by imaging
- Failure of antibiotics to resolve the infection
Patients who develop abscesses might need open drainage of the periorbital abscess. Patients with orbital cellulitis are more likely to require surgical intervention to remove foreign bodies, bony fragments in case of orbital trauma, drain abscesses, or to remove an infected eye globe to avoid extension to other adjacent structures such as the central nervous system.
|Oral antibiotics usually sufficient||Unasyn|
|Ceftriaxone and vancomycin if severe or eye-threatening|
|Cephalexin or clindamycin if allergic||MRI scan for abscess|
|Surgery if drainable abscess|
|Nose drops for sinuses (saline, α-agonist)|