Orbital cellulitis


Orbital cellulitis is inflammation of eye tissues behind the orbital septum. It is most commonly caused by an acute spread of infection into the eye socket from either the adjacent sinuses or through the blood. It may also occur after trauma. When it affects the rear of the eye, it is known as retro-orbital cellulitis.
It should not be confused with periorbital cellulitis, which refers to cellulitis anterior to the septum.
Without proper treatment, orbital cellulitis may lead to serious consequences, including permanent loss of vision or even death.

Signs and symptoms

Orbital cellulitis commonly presents with painful eye movement, sudden vision loss, chemosis, bulging of the infected eye, and limited eye movement. Along with these symptoms, patients typically have redness and swelling of the eyelid, pain, discharge, inability to open the eye, occasional fever and lethargy.

Complications

Complications include hearing loss, blood infection, meningitis, cavernous sinus thrombosis, cerebral abscess, and blindness. It is possible that children experience more severe complications due to their immature immune system and because they have thinner orbital bones, which makes the infection easier to spread.

Causes

Orbital cellulitis occurs commonly from bacterial infection spread via the paranasal sinuses, usually from a previous sinus infection. Other ways in which orbital cellulitis may occur are from blood stream infections or from eyelid skin infections. Upper respiratory infection, sinus infection, trauma to the eye, ocular or periocular infection, and systemic infection all increase one's risk of orbital cellulitis.
Staphylococcus aureus, Haemophilus influenzae B, Moraxella catarrhalis, Streptococcus pneumoniae, and beta-hemolytic streptococci are bacteria that can be responsible for orbital cellulitis.
Risk factors for the development of orbital cellulitis include, but are not limited to:
Early diagnosis of orbital cellulitis is urgent, and it involves a complete and thorough physical examination. Common presenting signs include: a protruding eye, eyelid edema, eye pain, vision loss, inability to move the eye completely, and fever. It is important to correlate physical findings with patient history and reported symptoms.
CT scan and MRI of the orbits are two imaging modalities that are commonly used to aid in the diagnosis and monitoring of orbital cellulitis, as they can provide detailed images that can show the extent of inflammation along with possible abscess location, size, and involvement of surrounding structures. Ultrasound has also been used as an imaging modality in the past, but it cannot provide the same level of detail as CT or MRI.
Blood cultures, electrolytes, and a complete blood count with differential showing elevated white blood cell count is a useful laboratory test that may aid in diagnosis.

Differential Diagnosis

A variety of pathologies and diseases can present similarly to orbital cellulitis, including:
Immediate treatment is very important, and it typically involves intravenous antibiotics in the hospital and frequent observation. Several lab tests should be ordered, including a complete blood count, differential, and blood culture.
Although orbital cellulitis is considered an ophthalmic emergency, the prognosis is good if prompt medical treatment is received.

Death and blindness rates without treatment

Bacterial infections of the orbit have long been associated with a risk of devastating outcomes and intracranial spread.
The natural course of the disease, as documented by Gamble, in the pre-antibiotic era,
resulted in death in 17% of patients and permanent blindness in 20%.

Epidemiology

Orbital cellulitis is an uncommon medical condition, with the reported rates being much higher among the pediatric population compared to the adult population. One study reported that children are approximately 16 times more likely to suffer from orbital cellulitis compared to adults. It is twice as common among male children compared to female children. Some studies reported that orbital cellulitis follows a seasonal pattern, with the highest rates occurring during the fall and winter, which coincides with the higher rates of sinus infection during the colder months.