<unk>  is an inflammation of the deep, soft tissue cells surrounding the eye, posterior to the orbital septum. This inflammation can occur by means of extension of an adjacent infection, by direct inoculation through traumatic or iatrogenic pathways, or by hematogenous spread from a distant infected site.<unk>  most commonly occurs from typical bacterial infections. In some cases, mycobacteria or mycosis may be implicated. The most common underlying condition is ethmoid sinusitis. Children are more commonly affected by<unk>  than adults.<unk>  has a higher incidence in the winter months and follows the seasonal patterns of sinusitis and upper respiratory tract infections. The most commonly reported pathogens are Staphylococcus aureus, Streptococcus spp. and Haemophilus influenzae. MRSA must be considered as a potential cause and is correlated with geographic prevalence. A positive history of  fever, proptosis, eyelid edema and erythema, diplopia, and painful or restricted ocular movements is highly suggestive of<unk> .<unk>  must be differentiated from various conditions which affect the eye and present similarly, such as periorbital cellulitis, cavernous sinus thrombosis, and orbital or periorbital neoplasia. Both CT and MRI of the head may be used as gold standard diagnostic imaging modalities. The most common risk factors for<unk>  include acute or chronic ethmoid sinusitis, upper respiratory tract infection, and recent ocular or periocular procedures or infections. If left untreated,<unk>  may result in blindness in 20% of patients and death in 17%. Serious complications can develop as a result of<unk> , such as abscess, orbital compartment syndrome, intracranial extension of infection, and septic shock. Although<unk>  is an ophthalmologic emergency, the prognosis is good if prompt medical treatment is received. The mainstay of therapy for<unk>  involves prompt intravenous antimicrobial therapy. Surgery may be necessary if medical therapy is ineffective, if there is intracranial extension of the disease, or in the presence of abscesses. Effective measures for the primary prevention of<unk>  include prompt, appropriate, and aggressive treatment of adjacent infections.
Orbital cellulitis
Periorbital cellulitis
Corneal ulcer
Blepharitis
Labyrinthitis
Lacrimal gland tumor
Cavernous sinus thrombosis
Endophthalmitis