Periorbital cellulitis and orbital infections

I. What every physician needs to know.

The classification of orbital infections is based on a five-tier system, which is as follows: Group I (periorbital cellulitis, which is also known as preseptal cellulitis), Group II (orbital cellulitis), Group III (subperiosteal abscess), Group IV (orbital abscess), and Group V (cavernous sinus thrombosis). Periorbital/preseptal cellulitis affects structures located anterior to the orbital septum, while the other four types of orbital infections occur posterior to this structure.

Periorbital/preseptal cellulitis often occurs secondary to extension of a facial/eyelid infection that developed as a result of an insect or animal bite, foreign body, or local trauma. Other causes of orbital infections include hematogenous dissemination, and spread from adjacent sites (e.g., sinusitis, which is the most common cause of orbital cellulitis). Periorbital/preseptal cellulitis is characterized by inflammation affecting the eyelids and the skin in the periorbital area, and it does not involve the orbit. If it is properly treated, then periorbital/preseptal cellulitis has an excellent prognosis.

In contrast to periorbital/preseptal cellulitis, the other types of orbital infections, that is, orbital cellulitis, subperiosteal abscess, orbital abscess and cavernous sinus thrombosis, are more severe illnesses, which can result in permanent vision loss, or in severe cases, even death. Although orbital infections occur at a higher frequency in children than in adults, their severity is usually worse in the latter population.

II. Diagnostic Confirmation: Are you sure your patient has Periorbital Cellulitis/Orbital Infections?

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A. History Part I: Pattern Recognition:

A complete ophthalmologic exam is essential for the diagnosis of an orbital infection. One of the primary objectives in performing the ophthalmologic examination is to differentiate between periorbital/preseptal cellulitis, and the other four types of orbital infections, since those in the latter category require much more aggressive management.

It should be noted that it is not possible to reliably distinguish orbital cellulitis from either subperiosteal abscess or orbital abscess based on clinical findings, that is, either a computed tomography (CT) scan or surgery is needed to make the distinction.

Common presentations for the five types of orbital infections are as follows:

1. Periorbital/preseptal cellulitis: periorbital edema (which if severe, may prevent the patient from opening his/her eyelids), periorbital erythema, eye pain. There is no evidence of orbital involvement (such as visual impairment or proptosis).

2. Orbital cellulitis: periorbital edema, fever, leukocytosis, paralysis of the eyelids, conjunctival hyperemia, eye movement limitation, dipoplia, eye pain, displacement of the globe, vision loss, chemosis and proptosis (The latter three findings are indicative of orbital involvement).

3. Subperiosteal abscess: visual impairment, directional proptosis, eye pain, chemosis. There may be decreased ability to move the globe, and pain may be elicited when the globe moves towards the abscess.

4. Orbital abscess: severe ophthalmoplegia (both internal and external), marked systemic toxicity, eye pain, marked proptosis, and the orbital apex syndrome (which is indicative of an infection in the posterior orbit). The orbital apex syndrome manifests as unilateral visual loss, ophthalmoplegia, cranial nerve VI impairment (causing sensory deficits on the forehead), and proptosis may be observed.

5. Cavernous sinus thrombosis: causes bilateral symptoms, including proptosis, eye pain, sensory deficits affecting the cornea, and bilateral orbital apex syndrome.

B. History Part 2: Prevalence:

Orbital infections are considerably more common in children than in adults. In fact, children under the age of 10 years old account for 80% of all cases of periorbital/preseptal cellulitis. Periorbital/preseptal cellulitis occurs at a much greater frequency than do the other types of orbital infections.

Predisposing factors for the development of orbital infections are:

Local trauma (e.g., animal or human bite, insect sting, scratch.
Human immunodeficiency virus (HIV) infection.
Asthma.
Nasal polyposis.
Neutropenia.
Acute sinusitis (most common etiology of orbital cellulitis).
Ophthalmologic surgery (including retinal surgery, blephaoplasty, strabismus surgery, and radial keratotomy).
Orbital trauma.
Dental infection.
Facial infection.
Dacrocystitis.
Middle ear infection.
Hordeolum.
Use of immunosuppressive drugs, including steroids.
Leukemia.
Lymphoma.
Renal transplant.
Deferoxamine therapy.
Diabetes mellitus.
History of travel to certain geographic locations increases the likelihood of a nonbacterial cause of an orbital infection.
Chalazion.

C. History Part 3: Competing diagnoses that can mimic Periorbital Cellulitis/Orbital Infections.

Differential diagnosis for orbital infections:

Tumors (e.g., rhabomyosarcoma, retinoblastoma).
Conjunctivitis, viral or bacterial.
Periocular dermoid cyst.
Hordeolum.
Tumors (e.g., rhabdomyosarcoma, retinoblastoma).
Trauma.
Posterior scleritis.
Wegener’s granulomatosis affecting the orbit.
Orbital fractures.
Sinusitis.
Meibomian gland abscess.
Lesions from herpes simplex virus infection.
Epidural abscess.
Meningitis.
Lesions from varicella virus infection.
Allergic response.
Encephalitis.
Insect bites.
Panophthalmitis.
Contact dermatitis.
Dacrocystitis.
Dacroadenitis.

Obtaining a complete history and doing a thorough physical exam are very important for determining the most likely cause of the patient’s presenting symptoms.

The appropriate use of imaging studies, such as computed tomography (CT) scan of the orbits, sinus and head, orbital ultrasonography, or magnetic resonance imaging (MRI) is also very helpful for confirming the patient’s diagnosis.

When diagnostic uncertainty persists after doing a thorough patient interview and examination, and obtaining imaging studies, then promptly requesting consultation from an ophthalmologist, otolaryngologist, and possibly also an infectious diseases specialist, is advisable.

D. Physical Examination Findings.

Please see “A. History. Part I: Pattern recognition”

Periorbital edema (seen with all five types of orbital infections).
Periorbital erythema (seen with all five types of orbital infections).
Chemosis (most often seen with orbital cellulitis and subperiosteal abscess).
Proptosis (may be seen with all types of orbital infections, except for periorbital/preseptal cellulitis. It may be directional, in the case of subperiosteal abscess).
Vision loss (seen with all types of orbital infections, except for periorbital/preseptal cellulitis).
Paralysis of eyelids (may be seen with orbital cellulitis).
Ophthalmoplegia (may be seen with orbital abscess and cavernous sinus thrombosis).
Limited ocular movement (may be seen with subperiosteal abscess, orbital abscess, and cavernous sinus thrombosis).
Fever and leukocytosis (most commonly seen with orbital cellulitis, orbital abscess and subperiosteal abscess).
Orbital apex syndrome (seen with orbital abscess and cavernous sinus thrombosis. It will be bilateral in patients with cavernous sinus thrombosis).
Corneal hypesthesia (seen with cavernous sinus thrombosis).
Cranial nerve VI sensory deficit affecting the forehead (may be seen with orbital abscess).

E. What diagnostic tests should be performed?

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1. What laboratory studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

Complete blood count with manual differential. Leukocytosis may be less severe with periorbital/preseptal cellulitis, compared with the other types of orbital infections. However, this alone cannot reliably distinguish the type of orbital infection.
Cultures obtained from either nasal swabs or material discharged from the eye, results in a higher yield of positive cultures, in comparison with blood cultures. However, the isolated organisms may simply be from nonpathogenic flora that usually inhabit the oropharynx. Therefore, these culture results cannot be used to reliably guide the selection of antibiotic therapy.
Cultures obtained during surgical drainage of the orbital abscess or subperiosteal abscess provide the most reliable results. The most common pathogens associated with the development of orbital infections include Streptococcus pneumoniae, Staphylococcus aureus, and other species of streptococcus. Less common causes of orbital infections are anaerobes, fungi, mycobacteria, Aeromonas hydrophila, Hemophilus influenzae, Eikenella corrodens, and Pseudomonas aeruginosa.
Blood cultures have a higher yield in children than in adults. There may only be a 0 – 2% yield of positive blood cultures in adult patients with orbital cellulitis. Despite their low yield, it is recommended that blood cultures should be obtained before starting antibiotic therapy.
Lumbar puncture should be performed if meningitis is suspected.
Rapid plasma reagin (RPR) should be considered for patients who have a history of syphilis, or if the onset of symptoms was insidious.

2. What imaging studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

CT scan of the orbit, sinuses and frontal lobe should be obtained promptly for all patients who demonstrate signs of orbital involvement. Be aware that the use of intravenous contrast dye does not contribute to the diagnosis of an intraorbital infection. The CT scan can determine if the patient has sinusitis, and confirm the presence of either an orbital or subperiosteal abscess. This imaging modality can reveal the severity of inflammation affecting the orbit.
Magnetic resonance imaging (MRI) has an advantage over a CT scan in that it better detects soft tissue pathology. It may be particularly helpful in detecting cavernous sinus thrombosis. Diffusion-weighted imaging is able to confirm most cases of orbital abscess without the use of intravenous contrast dye, which is of great importance for patients who are unable to safely receive it (e.g., those who have renal insufficiency). Despite its advantages, the MRI modality is not commonly utilized, due to its lack of ready availability. In pediatric patients, the need for sedation before obtaining an MRI presents a barrier to its routine use.
Orbital ultrasonography of the orbit has some advantages over a CT scan, in that it provides greater image resolution of the orbital region. This modality may be particularly helpful for monitoring of an abscess, including those that have been drained. However, it may fail to detect an abscess that is located in a posterior location. Unfortunately, orbital ultrasonography requires specialized equipment, which is not available at most facilities. Also, the quality of the images obtained depends on the skill of the ultrasonography technician. Therefore, the use of this imaging modality is somewhat limited.

F. Over-utilized or “wasted” diagnostic tests associated with this diagnosis.

There are no commonly ordered “useless” tests, since even blood cultures, which typically have a low yield in adults, are recommended prior to starting antibiotic therapy.

III. Default Management.

Perform physical examination, which includes an evaluation for ocular motility and visual impairment. This will help to determine if the patient more likely has periorbital/preseptal cellulitis, or one of the other more serious types of orbital infections.
Obtain CBC.
Obtain blood cultures (prior to giving the first dose of antibiotics), as well as cultures of nasal swab and eye discharge.
Outpatient antibiotic therapy can be considered for adult patients who have mild periorbital/preseptal cellulitis, if there is no evidence of systemic toxicity (such as fever, tachycardia, or leukocytosis). A 7 to 10-day course of oral antibiotics is recommended for periorbital/preseptal cellulitis. However, intravenous antibiotics will need to be initiated if the patient’s clinical status does not improve within 24 hours after starting oral antibiotics.
An orbital, sinus, and head CT scan should be obtained for patients who have suspected orbital involvement (e.g., due to the presence of visual impairment or proptosis). A CT scan is also recommended when it is not possible to reliably determine a patient’s visual acuity, due to his or her inability to provide accurate information (e.g., a child less than 1 year old.)
Promptly initiate appropriate intravenous antibiotic therapy, in patients who have orbital cellulitis, subperiosteal abscess, orbital abscess, or cavernous sinus thrombosis, since failure to do so may result in permanent visual impairment. These patients should receive Vancomycin (which is necessary due to concern about the high prevalence of methicillin-resistant Staphylococcus aureus), and one of the following: Cefotaxime, Ticarcillin-clavulanate, Piperacillin-tazobactam, Ampicillin-sulbactam, or Ceftriaxone. Penicillin or cephalosporin-allergic patients should receive Vancomycin plus either Levaquin or Ciprofloxacin.
Surgical drainage of a subperiosteal abscess or orbital abscess is often essential for adequate treatment, that is, in addition to intravenous antibiotics. If there is evidence of optic nerve damage, then this indicates the need for emergent surgical drainage of the abscess. For small abscesses, intravenous antibiotics alone, that is, without surgical drainage may be adequate for treatment.
Nasal decongestants can be initiated to decrease nasal congestion.

A. Immediate management.

Appropriate intravenous antibiotic therapy must be initiated in the emergency room, to decrease the likelihood of permanent vision loss or death.

B. Physical Examination Tips to Guide Management.

The following should be monitored for a patient with an orbital infection:

Appearance of the affected eye. Periorbital edema and erythema are expected to significantly improve over a period of a few days.
Visual acuity.
Pupillary abnormalities.
Persistence of fever.
Mental status changes.

C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.

A CBC may be obtained once daily, until the leukocytosis resolves. As long as the patient’s clinical status continues to improve, then there is no need to obtain additional CBCs subsequently.

D. Long-term management.

Once a 2 to 3-week course of appropriate oral antibiotic therapy has been completed, then the orbital infection will have been adequately treated. Thus, there is no need for long-term management of this diagnosis.

E. Common Pitfalls and Side-Effects of Management.

It is important to select appropriate antibiotics, which provide coverage for the most likely pathogen(s) causing the orbital infection.

If clinical deterioration occurs despite the administration of appropriate antibiotic therapy, then orbital surgery is indicated.

The adult doses for appropriate intravenous antibiotics are as follows:

Vancomycin 15 mg/kg IV q 12 hours (for coverage of MRSA) which must be given with one of the following antibiotics:

Cefotaxime 2 g IV q 4 hours

Piperacillin-tazobactam 4.5 g IV q 6 hours

Ampicillin-sulbactam 3 g IV q 6 hours

Ticarcillin-clavulanate 3.1 g IV q 4 hours

Ceftriaxone 2 g IV q 12 hours

When the patient’s clinical condition has improved, so that a change to oral antibiotics can be made, then the following choices are appropriate. Adult doses are indicated:

Levofloxacin 750 mg PO daily OR Amoxicillin-clavulanate 875 mg PO twice daily

If there is concern about MRSA, then Linezolid 600 mg PO twice daily should be added to the regimen.

The patient must complete a 2 – 3 week course of oral antibiotics.

IV. Management with Co-Morbidities.

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