Orbital Cellulitis

SIGNS AND SYMPTOMS
The patient with orbital cellulitis may be of any age or sex. There will be noticeable lid edema and redness, distention, proptosis, and significant pain upon palpation. Additionally, there will be diplopia from extraocular motility limitations. There typically will be a precipitating factor such as penetrating lid trauma, mucormycosis, orbital medial wall blow-out fracture, severe lid infectious disease, bite wounds, meningitis, sinusitis and sinus infection, septicemia, ketoacidosis, or dental abscess. Vision loss and an afferent pupil defect may often be present. The patient will also be systemically ill and have a fever.


PATHOPHYSIOLOGY
Orbital cellulitis results from microbial infection with subsequent inflammation of the post-septal aspect of the eyelids. The most common routes of infection are from adjacent sinuses or teeth, and direct inoculation through penetrating lid injury. Common organisms include Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae in children. There is significant potential morbidity and even mortality as a post-septal lid infection can spread through a valveless venous system leading to cavernous sinus thrombosis, meningitis, intracranial infection, and septicemia.

Inflammatory proptosis develops due to intraorbital abscesses of mucopurulent material. Ophthalmoplegia develops as a result of toxic myopathy and soft tissue edema. Vision loss will occur due to intraorbital increase in pressure from the mucopurulent abscess, compressing the optic nerve.

MANAGEMENT
Differentiate orbital cellulitis from pre-septal cellulitis so as to recognize a medical emergency. There are many superficial similarities between the two diseases, namely lid edema and redness, and pronounced pain upon palpation. However, orbital cellulitis manifests proptosis and extraocular muscle restriction, whereas pre-septal cellulitis does not. Also, patients with orbital cellulitis have fever and typically manifest decreased vision; these features are not present in pre-septal cellulitis.

Often, the degree of proptosis in orbital cellulitis cannot be readily appreciated due to the extreme lid edema. For this reason, CT scans are necessary, not only to identify orbital abscesses, but also to ascertain precipitating sinus involvement.

There is no place for topical or oral antibiotic therapy in the management of orbital cellulitis. Optimal management involves immediate consultation with and referral to a primary care physician, pediatrician, or infectious disease specialist. This is especially important with children as the potential for mortality is great. The patient needs immediate hospitalization with in-patient parenteral antibiosis.

CLINICAL PEARLS

When encountering a suspected orbital cellulitis, look for precipitating factors such as sinus infection, bite wounds, dental abscess, and penetrating injury.
Orbital cellulitis is a medical emergency and requires in-patient care.
Patients with orbital cellulitis are systemically ill. The presence of fever is highly diagnostic of post-septal orbital cellulitis. Patients who are (tentatively) diagnosed with pre-septal cellulitis should be educated about the seriousness of the development of fever.
Post-septal orbital cellulitis will have motility restriction whereas pre-septal cellulitis will not.