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Orbital cellulitis is an infection of the soft tissues of the orbit posterior to the orbital septum. Infection may involve all the orbital structures, including extraocular muscles, sensory and motor nerves, and the optic nerve. Patients present with a moderate to severely inflamed painful eye, conjunctival infection, swelling of the eyelids, and chemosis (conjunctival swelling). As infection progresses, swelling increases and the eye becomes more chemotic and proptotic. Eye movement is diminished in some areas of gaze, or in severe cases, all areas of gaze (frozen globe). Patients are usually febrile and appear to be in acute distress. Orbital cellulitis may occur as a progression from preseptal cellulitis (a much more benign condition) or originate from untreated or undertreated infections of deep skin or paranasal sinuses. Causative pathogens include Streptococcus pneumoniae, nontypeable Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Streptococcus pyogenes, and anaerobes (Peptostreptococcus, Bacteroides, Fusobacterium) depending on the source of infection. Differential diagnosis includes preseptal cellulitis, idiopathic orbital inflammatory pseudotumor, thyroid orbitopathy, dacryocystitis, dacryoadenitis, and trauma with retrobulbar hemorrhage.
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Emergency Department Treatment and Disposition
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Orbital cellulitis is a true medical emergency particularly in advanced cases when extension posteriorly to the brain can occur and cause rapid deterioration in the patient’s status. Evaluate the orbit and paranasal sinuses with neuroimaging (CT scan with contrast or MRI). Admit patient and obtain prompt ear, nose, throat (ENT); infectious disease; and ophthalmologic consultations in the ED once the diagnosis of orbital cellulitis is considered. If a subperiosteal abscess is noted on imaging, refer promptly to oculoplastic surgery for possible drainage. Begin broad-spectrum intravenous (IV) antibiotics (eg, vancomycin plus either ceftriaxone or piperacillin and tazobactam [Zosyn] or sulbactam and ampicillin [Unasyn]) as soon as possible. Surgical intervention may be needed. If there is an extension posterior to the orbit, admit to ICU.
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