Dr Robie Choudhury
Luton and Dunstable Hospital, UK
Introduction
Orbital Cellulitis is an ophthalmic emergency that requires prompt recognition and treatment to avoid potentially sight and life-threatening consequences. It is defined as an infection of the tissues posterior to the orbital septum.
It is important to differentiate it from preseptal cellulitis as orbital cellulitis requires more intensive treatment, typically necessitating admission to hospital and treatment with intravenous antibiotics.
This article will discuss the clinical features associated with orbital cellulitis, its underlying pathogenesis as well as the steps taken in managing patients with suspected orbital cellulitis.
Epidemiology
Orbital cellulitis can affect patients of all ages, but it is much more common in young children than older children or adults (1). It is less common than preseptal cellulitis (2).
Risk factors
Predisposing factors include acute sinusitis (commonly ethmoid), dacrocystitis, or dental abscesses. Amongst children, sinus disease is the most common predisposing cause (3). Trauma to the orbit or recent sinus surgery may also facilitate passage of bacteria from the sinuses to the orbit. Additionally, systemic infection can also be a risk factor for orbital infection through haematogenous spread.
Pathogenesis
Most cases of orbital cellulitis in children occur secondary to ethmoidal sinusitis or sub-periosteal abscess following an upper respiratory tract infection. The ethmoid sinuses lie in close proximity to the orbit, separated by a paper-thin layer of bone known as the lamina papyracea. This has many perforating vessels and nerves which can allow infection to spread to the orbit (4).
The orbital side of the lamina papyracea is covered by a periosteal layer known as the periorbita. Hence spread of infection from the ethmoid sinus may initially result in subperiosteal abscess formation prior to orbital spread (5).
It is believed that the higher rates of orbital cellulitis in younger children are partly due to relatively incomplete immunological development at their age (6).
The most common bacterial agents are Staphylococcus aureus and Streptococci species (6). Haemophilus influenzae is another notable cause, although there has been a sharp decline in cases since the introduction of the Hib vaccine (7). Fungal infection, especially through Mucorales and Aspergillus species have been implicated in diabetic and immunocompromised patients and are associated with a high mortality rate (8).
Clinical Presentation
Orbital cellulitis often presents with features similar to pre-septal cellulitis, including erythema and swelling of the eyelid with secondary ptosis. However, unlike pre-septal cellulitis, orbital involvement may manifest with pain on eye movement, diplopia, proptosis and ophthalmoplegia. In severe cases, the optic nerve can be affected, leading to impaired vision and RAPD (9). Additionally the patient may be systemically unwell with pyrexia and malaise.
Infection can spread via the valveless veins in the face to the cavernous sinus leading to cavernous sinus thrombosis (10). This classically presents with unilateral proptosis, ptosis, chemosis and cranial nerve palsies and may be life threatening if untreated.
Infection can also progress to the dural venous plexus and eventually the brain. This can result in intracranial complications such as meningitis, cerebritis or abscesses and may present with symptoms including severe headache, seizures or other focal neurology (11).
Investigations
In cases of suspected orbital cellulitis, baseline investigations should include blood testing for full blood count, C-reactive protein and lactate, as well as blood cultures in pyrexic patients. An endonasal swab, or swab of any purulent discharge should be taken in order to identify the possible causative agent.
An urgent contrast-enhanced CT scan of the orbits, sinuses and brain should be performed in order to assess for orbital collection and rule out any brain involvement.
Treatment
All patients suspected to have orbital cellulitis should be admitted to hospital for treatment. Management should be multidisciplinary, with input from ophthalmology, ENT, microbiology and paediatric doctors as appropriate.
Medical management consists of immediate administration of broad-spectrum intravenous antibiotics, although choice of antibiotic agent may differ according to local guidelines (12). These may be adjusted according to culture results once available. Microbiology advice should be sought especially for patients with immunocompromise.
There should be regular four hourly ocular and neuro observations to assess for progression until infection subsides.
Any intracranial complications should be discussed with neurosurgical and microbiology teams. Drainage of orbital or paranasal sinus pus may be necessary if there is no response to antibiotic therapy or rapid deterioration in symptoms. Other features which would warrant surgical intervention include evidence of optic nerve compromise, clinical deterioration in spite of 48 hours of intravenous antibiotics, or suspicion of anaerobic infection on CT.
Patients may be discharged with oral antibiotics once swelling has resolved and pyrexia is settled (12).
Conclusion
Though potentially life and sight-threatening, orbital cellulitis often carries an excellent prognosis if identified and treated early. It is important for clinicians to be able to recognise the clinical features associated with it and commence treatment at the earliest opportunity.
References
- Iftikhar M, Junaid N, Lemus M, Mallick ZN, Mina SA, Hannan U, et al. Epidemiology of Primary Ophthalmic Inpatient Admissions in the United States. Am J Ophthalmol [Internet]. 2018 Jan 1;185:101–9. Available from: https://pubmed.ncbi.nlm.nih.gov/29101007/
- Botting AM, McIntosh D, Mahadevan M. Paediatric pre- and post-septal peri-orbital infections are different diseases. A retrospective review of 262 cases. Int J Pediatr Otorhinolaryngol [Internet]. 2008 Mar;72(3):377–83. Available from: https://pubmed.ncbi.nlm.nih.gov/18191234/
- Chaudhry IA, Shamsi FA, Elzaridi E, Al-Rashed W, Al-Amri A, Al-Anezi F, et al. Outcome of Treated Orbital Cellulitis in a Tertiary Eye Care Center in the Middle East. Ophthalmology. 2007 Feb 1;114(2):345–54.
- Jain A, Rubin PAD. Orbital cellulitis in children. Int Ophthalmol Clin. 2001;41(4):71–86.
- Soon VTE. Pediatric subperiosteal orbital abscess secondary to acute sinusitis: A 5-year review. Am J Otolaryngol – Head Neck Med Surg. 2011 Jan 1;32(1):62–8.
- Ferguson MP, McNab AA. Current treatment and outcome in orbital cellulitis. Aust N Z J Ophthalmol [Internet]. 1999;27(6):375–9. Available from: https://pubmed.ncbi.nlm.nih.gov/10641894/
- Ambati BK, Ambati J, Azar N, Stratton L, Schmidt E V. Periorbital and orbital cellulitis before and after the advent of Haemophilus influenzae type B vaccination. Ophthalmology [Internet]. 2000;107(8):1450–3. Available from: https://pubmed.ncbi.nlm.nih.gov/10919886/
- Trief D, Gray ST, Jakobiec FA, Durand ML, Fay A, Freitag SK, et al. Invasive fungal disease of the sinus and orbit: A comparison between mucormycosis and Aspergillus. Br J Ophthalmol [Internet]. 2016 Feb 1;100(2):184–8. Available from: https://bjo.bmj.com/content/100/2/184
- Patt BS, Manning SC. Blindness Resulting from Orbital Complications of Sinusitis. Otolaryngol Neck Surg [Internet]. 1991;104(6):789–95. Available from: https://pubmed.ncbi.nlm.nih.gov/1908969/
- Ebright JR, Pace MT, Niazi AF. Septic thrombosis of the cavernous sinuses [Internet]. Vol. 161, Archives of Internal Medicine. American Medical Association; 2001. p. 2671–6. Available from: https://jamanetwork.com/
- Kombogiorgas D, Seth R, Athwal R, Modha J, Singh J. Suppurative intracranial complications of sinusitis in adolescence. Single institute experience and review of literature. Br J Neurosurg [Internet]. 2007 Dec;21(6):603–9. Available from: https://pubmed.ncbi.nlm.nih.gov/18071989/
- Ball S, Arthur O, Powell S, Carrie S. Orbital cellulitis management guideline – for adults & paeds. ENT UK; 2017.