Periorbital and orbital cellulitis Flashcards
(14 cards)
Describe the difference in anatomy between peri-orbital and orbital cellulitis [2]
Peri-orbital cellulitis refers to infection occurring anterior to the orbital septum (pre-septal) and orbital cellulitis refers to infection occurring posterior to the orbital septum (post-septal).
- The orbital septum is a membranous sheet that forms the anterior boundary of the orbit and separates the pre-septal and post-septal space
- The septum acts as a barrier to infection.
Which tissues does orbital cellulits specifically impact? [2]
Which group is it more common in? [1]
How does it occur? [1]
Orbital cellulitis involves infection of the muscle and fat within the orbit, posterior to the orbital septum.
- It is more common in children, with the incidence reported to be 16-fold higher in children compared to adults
- Orbital cellulitis is commonly caused by a local spreading infection from acute bacterial sinusitis, typically from the paranasal sinuses
What are the clinical features of orbital cellulitis?
Erythema and swelling around the eye
Proptosis: Forward displacement or bulging of the eye (proptosis) is a cardinal sign of orbital cellulitis
Blurred vision
Painful eye movements
Change in colour vision
Fever
Reduced visual acuity and/or visual fields
Relevant afferent pupillary defect (RAPD)
Marcus-Gunn pupil
Chemosis
Bilateral eye signs of orbital cellulitis might indicate .. [1]
Bilateral eye signs may indicate cavernous sinus thrombosis.
Nausea, vomiting, headache, neck stiffness may indicate intracranial involvement.
Ix for orbital cellulitis? [1]
CT scan:
- This is typically the first-line imaging modality due to its accessibility and ability to rapidly visualise bony structures, sinuses, and soft tissue. It can effectively delineate the extent of infection and identify any associated abscesses.
What imaging would be indicated if ?cavernous sinus thrombosis [1]
MR venogram may be required to aid the diagnosis of cavernous sinus thrombosis. If meningeal signs develop, lumbar puncture is indicated.
How do you manage orbital cellulitis? [2]
Patients with orbital cellulitis require intravenous antibiotics, for seven to ten days
If an orbital collection is seen on imaging, evacuation of orbital pus or drainage of paranasal sinus pus may be required.
What is Chandler’s classification and what does it categorise?
Chandler’s classification anatomically categorises orbital complications of acute rhinosinusitis (the most common cause of orbital cellulitis).
Group 1: Pre-septal cellulitis (infection anterior to orbital septum)
Group 2: Orbital cellulitis (infection posterior to orbital septum)
Group 3: Subperiosteal abscess (pus collection between bone and periosteum)
Group 4: Intraorbital abscess (pus collection within the orbit)
Group 5: Cavernous sinus thrombosis (mural thrombus which may propagate centrally)
How do you adapt treatment according to Chandlers classification? [4]
Broadly speaking, grade 1 can be treated medically with antibiotics.
Grade 2 can also be treated medically however if there is no improvement surgical drainage should be considered.
Grade 3 and 4 can be treated surgically (drainage endoscopically or externally).
Grade 5 should be treated with anticoagulation as well as surgical drainage.
Describe ocular complications of orbital cellulitis [3]
Subperiosteal abscess:
- This is an accumulation of pus between the bone and the periosteum, often secondary to bacterial infection. It can cause proptosis, impaired ocular motility, and potentially loss of vision if not treated promptly.
Cavernous sinus thrombosis:
- This is a rare but serious complication, characterised by headache, fever, cranial nerve palsies and decreased consciousness. It results from the spread of infection from the orbit through emissary veins.
Optic neuritis:
- Inflammation of the optic nerve can lead to rapid loss of vision. Patients may present with reduced visual acuity, relative afferent pupillary defect (RAPD), or abnormal colour vision.
What are the intracranial complications of orbital cellulitis? [3]
Meningitis: This is inflammation of meninges which presents as fever, neck stiffness and altered mental status. Lumbar puncture is required for definitive diagnosis.
Brain abscess: A collection of pus within brain parenchyma resulting from contiguous spread or haematogenous dissemination. Symptoms include headache, nausea/vomiting, focal neurological deficits and seizures.
Epidural abscess: Accumulation of pus between dura mater and skull or vertebral column can lead to severe neurological deficits including paralysis.
Clinical presentation of peri-orbital cellulitis?
Eyelid redness, mild tenderness and swelling
Fever
Visual acuity and visual fields are normal, and there is no pain on eye movement
Patients with peri-orbital cellulitis are systemically well
Mx of peri-orbital cellulitis?
Paediatric patients should be urgently referred as they require empirical intravenous antibiotic treatment and daily review due to the difficulty in differentiating between orbital and peri-orbital cellulitis. Paediatric patients are often unable to give a history and can be challenging to examine.
For adult patients, oral co-amoxiclav is usually prescribed first-line (clindamycin if penicillin-allergic).
- Consider a follow-up review in 24-48 hours and safety netting advice should be provided to the patient.
