Orbital Cellulitis
On this page
Direct answer
Orbital cellulitis is infection of the soft tissues behind the orbital septum, nearly always spreading from adjacent ethmoid sinusitis through the paper-thin lamina papyracea, and it is an admission emergency because it threatens sight through optic neuropathy and life through cavernous sinus thrombosis and meningitis. Preseptal cellulitis spares the orbit: no proptosis, eye movements are full and vision is normal. Chandler's classification stages the spread — preseptal cellulitis, orbital cellulitis, subperiosteal abscess, orbital abscess and cavernous sinus thrombosis. Contrast-enhanced computed tomography of the orbits and sinuses defines any abscess; management is intravenous antibiotics, with surgical drainage when an abscess is significant, the eye deteriorates, or 24 to 48 hours of medical therapy fail.
What you must remember
- The orbital septum is the diagnostic divide: preseptal (periorbital) cellulitis means swollen, red lids with normal vision, full motility and no proptosis; orbital cellulitis adds proptosis, painful restricted movement, chemosis, and — the signs of danger — reduced vision, colour desaturation or a relative afferent pupillary defect.
- Chandler classification: group I preseptal cellulitis; group II orbital cellulitis; group III subperiosteal abscess; group IV orbital abscess; group V cavernous sinus thrombosis — the exam expects all five in order.
- Sources: ethmoid sinusitis dominates in children (lamina papyracea), then dental infection, facial trauma, dacryocystitis and post-surgical wounds; organisms include Staphylococcus aureus, Streptococcus pyogenes and, in the unvaccinated or very young, Haemophilus influenzae.
- Imaging trigger: any orbital sign, failure to improve within 24–48 hours of intravenous antibiotics, or suspicion of intracranial spread — contrast CT of orbits and paranasal sinuses; blood cultures before antibiotics where possible.
- Medical management: admit, intravenous antibiotics covering gram-positives and anaerobes (for example ceftriaxone or ampicillin–sulbactam with metronidazole, adding vancomycin where methicillin-resistant Staphylococcus aureus is likely), nasal decongestants, elevation and analgesia.
- Small medial subperiosteal abscesses in children under about nine years, without visual loss, often resolve on intravenous antibiotics — but any large collection, frontal location, deterioration or visual compromise goes to drainage (endoscopic sinus surgery or external approach).
- Cavernous sinus thrombosis: the catastrophe — bilateral orbital findings, progressive ophthalmoplegia involving cranial nerves three, four, six and the ophthalmic and maxillary divisions of five, meningism, high swinging fever; needs prolonged intravenous antibiotics and intensive care.
- Complications to declare on every review: optic neuropathy, corneal exposure, abscess extension, meningitis, brain abscess and orbital apex or cavernous sinus involvement; serial vision and pupil checks are the monitoring tools.
A boy whose eyelids swelled overnight
An eight-year-old with a week of coryza wakes with swollen, red, tender right upper and lower lids and a fever. The resident's discipline is to look past the lids: visual acuity is 6/12 (was 6/6), the globe is proptotic on Hertel exophthalmometry, upgaze and lateral gaze are painful and limited, the conjunctiva is chemosed, and red colour desaturation is present — these findings cross the septum and make it orbital cellulitis, not a simple lid infection. Contrast CT of orbits and sinuses shows right ethmoid opacification with a medial subperiosteal collection. He is admitted, cultured, and started on intravenous ceftriaxone with metronidazole and nasal decongestants. At 24 hours vision and motility are the daily scoreboard: a small medial abscess in a child his age may resolve on antibiotics alone, but any fall in acuity, rising proptosis, spread of ophthalmoplegia or general deterioration triggers drainage of the abscess and the ethmoid by the ENT surgeon. Had both eyes swollen progressively with meningism and cranial nerve palsies, the discussion would jump to Chandler group V — cavernous sinus thrombosis — with prolonged antibiotics and intensive-care monitoring.
Where students slip
The common error is upgrading every red swollen lid to "cellulitis of the orbit" — or worse, downgrading a true orbital case to preseptal because the lids dominate the picture; proptosis, painful restricted movement and vision or pupil change are the findings that force the orbital label and the scan. Under-requesting CT kills time, and so does persisting with antibiotics beyond 48 blind hours when drainage is indicated. The Chandler order (preseptal, orbital, subperiosteal, orbital abscess, cavernous sinus) is a guaranteed one-liner in Indian postgraduate examinations.
Frequently asked questions
Which features separate orbital from preseptal cellulitis?
Proptosis, painful restricted ocular motility, chemosis, and visual compromise (acuity, colour vision or a relative afferent pupillary defect) indicate postseptal orbital involvement; preseptal disease is confined to the lids.
List the Chandler classification groups.
Group I preseptal cellulitis, group II orbital cellulitis, group III subperiosteal abscess, group IV orbital abscess, group V cavernous sinus thrombosis.
What is the commonest source and organism set in orbital cellulitis?
Ethmoid sinusitis crossing the lamina papyracea, seeding Staphylococcus aureus and streptococci; Haemophilus influenzae is considered in the very young and unimmunised, anaerobes in dental origin.
When can a subperiosteal abscess still be managed medically?
A small medial collection in a young child (commonly under nine years) without visual loss or significant ophthalmoplegia, with close inpatient monitoring and readiness to drain on deterioration.
What signs suggest cavernous sinus thrombosis?
Bilateral proptosis and chemosis, ophthalmoplegia of cranial nerves three, four and six with trigeminal sensory loss, meningism and a high swinging fever — an intensive-care emergency.
Which investigation is first when orbital cellulitis is suspected?
Contrast-enhanced computed tomography of the orbits and paranasal sinuses, staged for abscess and intracranial extension, obtained alongside immediate intravenous antibiotics.