EYE Flashcards
What is the orbital septum?
A thin, fibrous membrane that serves as a barrier between the superficial lids and the orbit.
Where is peri-orbital cellulitis?
Infection occurring anterior to the orbital septum
Where is orbital cellulitis?
Infection occurring posterior to the orbital septum
Orbital septum function?
Barrier to infection
Describe orbital cellulitis
Orbital cellulitis involves infection of the muscle and fat within the orbit, posterior to the orbital septum. It is more common in children. It is a serious sight-threatening condition.
Aetiology of orbital cellulitus?
Orbital cellulitis is commonly caused by a local spreading infection from acute bacterial sinusitis, typically from the paranasal sinuses.
Less common causes = extension of peri-orbital cellulitis, haematogenous spread, orbit trauma (e.g. dog bite), or contiguous spread from the face or teeth from recent surgery or dental infection.
Symptoms of orbital cellulitis
-erythema and swelling around the eye
-blurred vision
-painful eye movements
-change in colour vision
-fever
Clinical finding in orbital cellulitis
-severe eye redness and swelling
-fever
-painful eye movements
-reduced visual acuity and/or visual fields
-proptosis (protrusion of the eyeball)
-relevant afferent pupillary defect (RAPD): Marcus-Gunn pupil (unequal pupillary response to light)
-chemosis (oedema of the conjunctiva)
-altered colour vision (red-green tends to be the first colours lost)
Investigations for orbital cellulitis
-FBC- wcc, particularly neutrophilia
-CRP
-Lactate- may be raised if septic
-Blood cultures
-Microscopy, culture and sensitivity swabs of the conjunctiva and nasopharyns
-CT orbit, sinuses and brain
-MR venogram may be required to aid the diagnosis of cavernous sinus thrombosis.
-If meningeal signs develop, lumbar puncture is indicated.
Medical management for orbital cellulitis
Intravenous antibiotics for 7-10 days with results from microbiology investigations
Surgical management of orbital cellulitis
If an orbital collection is seen on imaging, evacuation of orbital pus or drainage of the paranasal sinus pus may be required.
Most common cause of orbital cellulitis
acute rhinosinisitis
What is Chandlers classification?
Chandler’s classification anatomically categorises orbital complications of acute rhinosinusitis
Complication of orbital cellulitis
-cavernous sinus thrombosis
-loss of vision
-intracerebral abscess
-meningitis
-death (rarely)
Which is more common, orbital or peri-orbital cellulitis?
Peri-orbital cellulitis is much more common and less serious than orbital cellulitis.
