Case
An eight-year-old boy with marked periorbital erythema and oedema with proptosis in his right eye is brought in by his anxious mother.
A week earlier he briefly complained of nasal pain and three days later the inflammation in his eye had started to develop. The swelling and redness had become dramatically worse in the past day or so and the boy started complaining of pain when he moved his eye. Visual acuity was 6/6 in his left eye but he could only count fingers using the right eye. He also had diplopia, extensive hyperaemia of the conjunctiva and purulent nasal discharge. His temperature was 38.5°C and he felt and looked very unwell.
His GP immediately transferred him to the emergency eye care service with suspected orbital or preseptal cellulitis.
A CT scan confirmed a diagnosis of orbital cellulitis, his leucocyte count was 20x109/l and cultures were positive for Haemophilus influenzae. He was immediately started on IV cefotaxime for 10 days followed by oral antibiotics for a further two weeks. He made a good recovery, although visual acuity remained slightly reduced at 5/6 in his left eye.
The problem
Orbital cellulitis is a potentially life-threatening ophthalmic emergency characterised by infection of the soft tissues behind the orbital septum.1 Preseptal cellulitis is a more common and far less serious infection, anterior to the orbital septum. The most common cause is – as in this case – extension of an infection from the periorbital structures, usually the paranasal sinuses. But it can also come from the face, the globe, the lacrimal sac and occasionally from a dental infection or as a result of direct infection of the orbit from trauma.
The organisms most commonly responsible are Staphylococcus aureus, Streptococcus pnuemoniae, Haemophilus influenzae and anaerobes.2
Both conditions are more common in children – orbital cellulitis more frequently affects seven- to 12-year-olds, while 80% of patients with preseptal cellulitis are under 10 and most are younger than five.
Features
- Rapid onset of erythema and swelling with severe pain associated with blurred vision with or without diplopia.
- Fever, headache and systemic malaise.
- Visual acuity is usually reduced in the affected eye.
- Possible proptosis, which may be obscured by lid swelling but is usually lateral and downward.
- Restricted and painful eye movement.
- Key differentiating signs are that preseptal cellulitis is associated with similar symptoms but an absence of proptosis, pain and restriction of ocular movement.
Differential diagnosis
- Orbital/preseptal cellulitis
- Chalazion
- Allergic lid swelling
- Severe viral conjunctivitis
- Erysipelas
- Other orbital conditions such as thyroid eye disease, orbital tumours/pseudotumours, orbital vasculitis
- Insect bites or angioedema
- Cavernous sinus thrombosis (on CT following referral).
Referral
- Suspected orbital cellulitis is an emergency and needs urgent referral.
- Delay in treatment may cause blindness and progression to life-threatening sequelae such as brain abscess, meningitis or cavernous sinus thrombosis.
Management
- IV broad-spectrum antibiotics should be started immediately.
- Typically, IV antibiotics are continued for one to two weeks, followed by oral antibiotics for a further two to three weeks.
- Surgical drainage is considered if the response to antibiotic therapy is poor after 72 hours or if CT shows drainable fluid collection.
Dr Mark Llewellyn is a consultant ophthalmologist at the Powys Teaching Health Board in Brecon, Wales
References
1 Nageswaran S, Woods CR, Benjamin DK Jr et al. Orbital cellulitis in children. Pediatr Infect Dis J 2006;
25:695-9
2 McKinley SH, Yen MT, Miller AM et al. Microbiology of paediatric orbital cellulitis. Am J Ophthalmol 2007;
144:497-501
