High Risk Low Prevalence: Orbital Cellulitis

Orbital cellulitis is a postseptal infection that can threaten vision and spread intracranially, while preseptal cellulitis is a different anatomic disease with far lower morbidity. In a painful red eye, sinus or dental symptoms plus orbital red flags should push CT imaging and urgent specialty involvement.

Orbital vs Preseptal Cellulitis

• Postseptal anatomy matters: Orbital cellulitis occurs behind the orbital septum, involving the orbital contents and optic nerve drainage pathways, which is why missed disease can progress to cavernous sinus thrombosis or intracranial abscess.
• Sinus and dental sources: Sinusitis is the most common cause of orbital cellulitis, especially ethmoid disease in younger children, but dental infection and trauma are important alternative sources clinicians should actively seek.
• Clinical red flag findings: Pain with eye movement, ophthalmoplegia, vision change, RAPD, diplopia that resolves when the affected eye is closed, and proptosis are the bedside findings that should make orbital cellulitis rise fast on the differential.
• Subtle proptosis bedside check: A top-down look over the patient's forehead can reveal mild proptosis that is easy to miss straight on. That exam pearl is worth hearing in the episode.
• Kids carry higher burden: Orbital cellulitis is about 10 times more common in children than adults, and winter or spring presentations fit the URI-driven epidemiology without lowering concern in adults.

Diagnosis and Early Management

• CT is first-line imaging: CT brain and orbits with and without contrast is the go-to test when orbital cellulitis is suspected, with MRI reserved for persistent concern when CT is nondiagnostic.
• Labs do not decide: CRP, ESR, leukocytosis, and even blood cultures cannot rule in or rule out orbital cellulitis; blood cultures are positive in only about 3% of cases.
• Intraocular pressure check: When orbital red flags are present, measure intraocular pressure to screen for ocular compartment syndrome, a rarer but vision-threatening complication that changes urgency immediately.
• Early consultant involvement: These patients need prompt ophthalmology involvement because some require surgical drainage, and neurosurgery may enter the picture when there is intracranial extension.
• Empiric antibiotic targets: Initial therapy should cover staphylococci, streptococci, and anaerobes; vancomycin plus a broad beta-lactam is a common starting point, with regimen nuances we get into in the chapter.
• Steroids are not proven: A 2021 Cochrane review found no clear improvement in visual acuity preservation, day-3 pain, or IV antibiotic duration with corticosteroids in orbital cellulitis.

References:

1. Tsirouki T, Dastiridou AI, Ibánez Flores N, et al. Orbital cellulitis. Surv Ophthalmol. 2018;63(4):534-553.  PMID: 29248536
2. Williams KJ, Allen RC. Paediatric orbital and periorbital infections. Curr Opin Ophthalmol. 2019;30(5):349-355. PMID: 31261188
3. Gordon AA, Phelps PO. Management of preseptal and orbital cellulitis for the primary care physician. Dis Mon. 2020;66(10):101044.  PMID: 32622679
4. Fanella S, Singer A, Embree J. Presentation and management of pediatric orbital cellulitis. Can J Infect Dis Med Microbiol. 2011;22(3):97-100.  PMID: 22942886
5. Kornelsen E, Mahant S, Parkin P, et al. Corticosteroids for periorbital and orbital cellulitis. Cochrane Database Syst Rev. 2021;4(4):CD013535. Published 2021 Apr 28.  PMID: 33908631
6. McCallum E, Keren S, Lapira M, Norris JH. Orbital Compartment Syndrome: An Update With Review Of The Literature. Clin Ophthalmol. 2019;13:2189-2194. Published 2019 Nov 7.  PMID: 31806931
7. Ebright JR, Pace MT, Niazi AF. Septic thrombosis of the cavernous sinuses. Arch Intern Med. 2001;161(22):2671-2676.  PMID: 11732931