Overview

Orbital cellulitis is a serious bacterial infection that affects the tissues surrounding the eye, particularly within the eye socket (orbit). This condition involves inflammation of the fat and muscles located behind the eye, and it can lead to severe complications if not treated promptly. Orbital cellulitis most commonly occurs in children but can affect adults as well. It often develops as a complication of sinus infections, particularly involving the ethmoid sinuses, which are located near the eyes. Prompt medical attention is crucial as orbital cellulitis can threaten vision and, in severe cases, become life-threatening if the infection spreads to the brain or bloodstream.

Causes

Orbital cellulitis is primarily caused by bacterial infections that spread to the orbital tissues. The most common causes include:

• Sinus infections (sinusitis): The most frequent cause, particularly ethmoid sinusitis, which is adjacent to the orbit.
• Trauma: Direct injury to the area around the eye or penetration injuries can introduce bacteria into the orbital tissues.
• Insect or animal bites: These can lead to localized infection that spreads to the orbit.
• Post-surgical infection: Infections following eye surgery or procedures involving the nose or sinuses.
• Dental infections: Severe dental abscesses or gum infections can rarely spread to the orbit.
• Skin infections: Conditions such as facial cellulitis or infected eyelid (preseptal cellulitis) can progress to orbital cellulitis if left untreated.

The most common bacteria responsible include Staphylococcus aureus (including MRSA), Streptococcus species, and Haemophilus influenzae (especially in unvaccinated children).

Symptoms

Orbital cellulitis presents with a range of symptoms that affect both the eye and surrounding structures. Common symptoms include:

• Swelling of the eyelids: Significant puffiness and redness around the eye.
• Redness of the eye and surrounding skin: The skin over the affected area appears red and inflamed.
• Eye pain: Pain, especially when moving the eye or applying pressure.
• Proptosis (bulging eye): The infected eye may protrude forward due to swelling behind the eye.
• Restricted eye movement: Difficulty moving the eye in certain directions, sometimes accompanied by double vision.
• Fever: High temperature is common, especially in children.
• Decreased vision: Blurred or reduced vision may occur in more severe cases.
• General malaise: Fatigue and feeling unwell may accompany the local symptoms.

Diagnosis

Diagnosis of orbital cellulitis requires a thorough clinical evaluation and imaging studies to confirm the extent of the infection. The diagnostic steps typically include:

• Medical history: Evaluation of recent sinus infections, trauma, or other local infections.
• Physical examination: Detailed examination of the eye, eyelids, and surrounding facial structures, including checking for pain on eye movement and visual acuity.
• Blood tests: Complete blood count (CBC) often shows elevated white blood cells indicating infection.
• Imaging studies:
  • CT scan of the orbits and sinuses: The most commonly used imaging method to assess the spread of infection and any abscess formation.
  • MRI scan: May be used in complicated cases to provide more detailed soft tissue imaging.
• Blood cultures: Performed to identify the bacteria responsible, especially if the infection spreads systemically.

Treatment

Orbital cellulitis is a medical emergency that requires prompt and aggressive treatment to prevent complications:

• Hospital admission: Most patients, especially children, are admitted to the hospital for close monitoring and treatment.
• Intravenous (IV) antibiotics: Broad-spectrum antibiotics are started immediately to target the most common bacteria. The choice may be adjusted once culture results are available.
• Surgical drainage: If an abscess is present, surgery may be required to drain the pus and relieve pressure within the orbit.
• Treatment of underlying cause: Addressing any sinus infection, dental abscess, or skin infection contributing to the condition.
• Supportive care: Pain management, antipyretics (fever reducers), and hydration support.
• Oral antibiotics: After initial IV treatment, patients are usually switched to oral antibiotics for several days to complete the treatment course.

Prognosis

With early diagnosis and appropriate treatment, the prognosis of orbital cellulitis is generally good, and most patients recover fully without permanent damage. However, delayed or inadequate treatment can lead to serious complications such as:

• Vision loss: Due to optic nerve involvement or corneal damage.
• Brain abscess or meningitis: The infection can spread to the brain, resulting in life-threatening complications.
• Cavernous sinus thrombosis: A rare but severe condition where infection spreads to a large vein in the brain, causing blood clots.

Timely medical intervention significantly reduces the risk of these complications. Follow-up care with an ophthalmologist and possibly an ENT specialist is often recommended to ensure complete recovery and prevent recurrences.