What is Orbital Cellulitis (Eye Infection)?
Orbital cellulitis is a serious infection that affects the muscle and fat within the eye socket, also known as the orbit. It’s important to note that this infection doesn’t impact the eye itself. While this condition can affect individuals at any age, it tends to be more common in children.
Many different organisms can cause orbital cellulitis, including different types of bacteria, fungi, and other microbes. The most frequent culprits are bacteria called Staphylococcus aureus and Streptococci. However, other rare cases involve bacteria like Aeromonas hydrophila, Pseudomonas aeruginosa, and Eikenella corrodens. Certain types of fungi can also lead to dangerous infections. In patients with weakened immune systems, specific infections to consider include mucormycosis and invasive aspergillosis, which can be life-threatening.
Diagnosis of orbital cellulitis largely depends on the physical symptoms observed during a clinical examination. These symptoms often include ophthalmoplegia, which is pain with eye movement, and proptosis, a condition where the eye seems to protrude from the orbit. Eyelid swelling may also be common. To confirm this diagnosis, imaging tests like CT scans or MRI may be used. However, because of potential radiation risks, guidelines exist to ensure safe and necessary use of imaging tests, especially in children.
Treatment for orbital cellulitis usually involves antibiotics and other support therapies. Experts like ophthalmologists and otolaryngologists are often consulted for proper examination, and in some cases, surgery may be necessary. If the condition is not promptly diagnosed and treated, it can progress and spread to nearby areas, leading to significant complications such as vision loss or spread of the infection into the skull. The prescribed antibiotics aim to be effective against a range of bacteria, and may also include treatments for anaerobic bacteria or fungi in certain circumstances. Pain relief using NSAIDs and acetaminophen may also be part of the treatment plan.
What Causes Orbital Cellulitis (Eye Infection)?
- Infections in the teeth, middle ear, or face
- Dacryocystitis, an infection of the tear sac
- Injuries to the eye, like a fracture or something getting stuck there
- Certain types of eye surgery, like corrective surgery for crossed eyes (strabismus), eyelid surgery (blepharoplasty), cornea reshaping surgery (radial keratotomy), and retinal surgery
- Anaesthesia given around the eyeball
- An infected mucocele, a mucus-filled cyst, that eats into the eye socket
- Weakened immune system
Risk Factors and Frequency for Orbital Cellulitis (Eye Infection)
Orbital cellulitis is typically found in younger children. However, it is less common in older children and adults.
Signs and Symptoms of Orbital Cellulitis (Eye Infection)
Orbital cellulitis is a condition that typically presents with certain telltale signs. These include pain when moving the eyes, bulging of the eyes, and difficulty controlling eye movements, which may result in double vision. Swelling of the conjunctiva, a membrane that covers the front of the eye, is also common, though it can occasionally occur with preseptal cellulitis, another eye condition. People with orbital cellulitis often have a fever and elevated levels of white blood cells, specifically neutrophils. Redness of the eyelid may also be present, but not always.
- Pain with eye movements
- Bulging of the eyes
- Difficulty controlling eye movements resulting in double vision
- Swelling of the conjunctiva
- Fever
- Elevated white blood cells, specifically neutrophils
- Possible redness of the eyelid
Testing for Orbital Cellulitis (Eye Infection)
If you’re suspected to have orbital cellulitis, a type of eye infection, your doctor will first perform a physical examination. It’s crucial to see both an eye specialist (ophthalmologist) to test your visual sharpness and eye movements and an ear, nose, and throat specialist (otolaryngologist) for signs of sinus inflammation, which could be related.
Part of the process usually involves some laboratory tests as well. Even though they might not always provide clear answers, blood samples may be taken to test for common bacteria, fungi, or mycobacteria before starting antibiotic treatment.
To aid in the diagnosis further, doctors will also turn to imaging tools such as a computed tomography (CT) scan or magnetic resonance imaging (MRI). These machines visualize the soft tissues around your eye and can help detect if the disease is spreading. The MRI tends to offer superior images, but CT scans are used more commonly, partly because MRIs may not be as accessible.
More specific imaging scans, like MRI or CT venography (tests that visualize blood vessels), might be used if orbital cellulitis complications are suspected. If a patient shows signs such as eye protrusion, pain or limitation in eye movement, double vision, swelling beyond the eyelid, or other serious symptoms, they’re likely to undergo a contrast-enhanced CT scan. The same goes for patients who are very young, anyone showing signs of central nervous system involvement, or those not showing improvement from standard treatments within 24 to 48 hours.
When examining CT scan results, doctors often look for signs of inflammation on components around the eye, fat stranding (a kind of inflammation), or forward displacement of the eyeball. Additionally, they’ll check for evidence of sinus inflammation, particularly around the ethmoid sinuses. Sometimes, low-density collections can be seen in the scans, suggesting complications such as subperiosteal abscesses and orbital abscesses – these are pockets of infection.
Treatment Options for Orbital Cellulitis (Eye Infection)
Uncomplicated orbital cellulitis, an infection of the eye socket, can generally be treated with antibiotics. The drugs are specially chosen to fight common bacteria that cause the infection, as it can be hard to get reliable culture results without performing surgery. Antibiotics should be continued until every sign of orbital cellulitis is gone. Usually, the patient will need to be on antibiotics for 2-3 weeks, but if severe sinusitis is present, this period could be extended to 4 weeks.
Typical antibiotic treatments for people with normal kidney function may be given intravenously and include drugs such as Vancomycin for MRSA, a type of tough-to-treat bacteria, and others such as Ceftriaxone, Cefotaxime, Ampicillin-sulbactam, Piperacillin-tazobactam, and Metronidazole. Dosing will depend on patient age and specific conditions. Other drugs that can fight MRSA include daptomycin, linezolid, and telavancin, but these are not commonly used for eye socket or brain infections. Vancomycin is the go-to tool against MRSA in eye socket infections as long as the patient isn’t allergic.
If the patient is allergic to common antibiotics like penicillins and/or cephalosporins, a combination of vancomycin plus either Ciprofloxacin or Levofloxacin can be used. The exact dose depends on the patient’s age and method of drug delivery.
Although there are no controlled trials on the ideal length of treatment for orbital cellulitis, it appears reasonable to switch to oral therapy once the infection shows signs of clearing up; this typically happens within the first 3 to 5 days for uncomplicated cases. The choice of antibiotic for oral therapy will depend on the culture results, but could include Clindamycin, Trimethoprim-Sulfamethoxazole, Amoxicillin, Amoxicillin-clavulanic, Cefpodoxime, or Cefdinir.
Surgery may be needed if the infection has spread to the brain, if antibiotics are not working, if vision becomes worse or if there are pupil changes, if there’s an abscess present, especially one greater than 10mm in diameter, or if the patient is thought to have a fungal or mycobacterial infection of the eye socket. If the patient doesn’t show improvement within 24-48 hours then surgical drainage may be performed. This can be carried out both through the eye socket or endoscopically.
What else can Orbital Cellulitis (Eye Infection) be?
- Immediate problems caused by Sarcoidosis
- An eye infection due to Adenovirus
- An abnormal connection between the carotid artery and the cavernous sinus
- A rare disease involving an overproduction of cells, called Langerhans cell histiocytosis
- A condition where inflammation affects the eye’s orbit, known as Orbital Inflammatory Syndrome
- A rare and dangerous fungal infection in children, known as Pediatric Mucormycosis
- A type of eye cancer in children, known as Retinoblastoma
- Bleeding into the space at the back of the eye, referred to as Retrobulbar haemorrhage
- A condition in which sickle cell disease affects the eye’s orbit, known as Sickle cell orbitopathy
- A condition where the thyroid gland causes eye problems, known as Thyroid Ophthalmopathy
- The harmful effects of the venom from the Widow Spider
