Peri-orbital cellulitis Flashcards
What is periorbital cellulitis?
Infection of the peri-orbital soft tissue
Which age group does peri-orbital cellulitis tend to affect?
0-15yo
Peak incidence <10yo
Describe the seasonal variation of peri-orbital cellulitis
Bi-modal
Late winter/early spring
What causes peri-orbital sinusitis
URTI Paranasal sinusitis - Contiguous spread from surrounding periorbital structures Dacrocytis Dental infections Endophthalmitis Infection - impetigo Foreign bodies Insect bites Eyelid problems - chalazion and hordeola Iatrogenic - eye and oral procedures
Name the two forms of peri-orbital cellulitis
Pre-septal (anterior to septum)
Post-septal (posterior to septum)
What divides the two forms of peri-orbital cellulitis?
Orbital septum
What is the orbital septum?
Thin, fibrous, multilaminated structure that attaches peripherally to the periosteum of the orbital margin to form the arcus marginalis
Which sinusitis is the most common cause of peri-orbital cellulitis in neonates and why?
Ethmoidal
Have not yet formed their frontal sinuses
When do the frontal sinuses develop?
Age 7
Why does peri-orbital cellulitis happen more in young children?
Thin dehiscent bone surface of their lamina papyracea and increased diplopic venous supply in comparison to adults
Incomplete immunological development
What used to be the most common organism causing peri-orbital cellulitis before the vaccine?
Haemophilus influenzae type B (Hib)
What is the most common organism which now causes peri-orbital cellulitis?
Staphylococcus aureus
streptococcus pneumoniae and other URTI causing bacteria
Give the common clinical presentation of pre-septal peri-orbital cellulitis
Eyelid oedema and erythema
Absence of orbital signs
What causes the oedema in peri-orbital cellulitis?
Impedance of drainage through ethmoid vessels
List some orbital signs of orbital cellulitis
Proptosis Ophthalmoplegia Decreased visual acuity Loss of red colour vision Chemosis (swelling of conjunctiva) Painful diplopia
What classification is used for peri-orbital cellulitis?
Chandler classification
Describe the chandler classification
Type 1 - pre-septal cellulitis - confined to eyelid
Type 2 - post septal, orbital cellulitis - extends to orbital tissue
Type 3 - Subperiosteal abscess - abscess forms deep to the periosteum of the orbit
Type 4 - Intra-orbital abscess - collection of pus inside the muscle cone
Type 5 - cavernous sinus thrombosis - Infection in the cavernous sinus
Which cranial nerves are involved in cavernous sinus thrombosis?
3rd
5th
6th
How is per-orbital cellulitis diagnosed?
History - preceding URTI or sinusitis
Examination - vital signs, anterior rhinoscopy (nasal mucosa and middle meatus), dentition, ophthalmic examination (eye movement, visual acuity, pupillary response, tonometry, anterior segment bio microscopy, ophthalmoscopy), neurological examination
Swab discharge for MC&S
Sepsis screen - FBC, CRP, Blood cultures, U&Es, ABG and lactate
CT or MRI - visualise extent and abscesses
What are some differentials of peri-orbital cellulitis?
Vesicles of herpes zoster opthalmicus
Erythematous irritation of contact dermatitis
Raised, dry plaques of atopic dermatitis
Stye
Chalazion
Blepharitis
Dacryocysitis (infection of lacrimal sac)
How is mild pre-septal cellulitis treated?
Outpatient
Oral empiric broad spectrum ABX
How is moderate/severe post-septal cellulitis treated?
Hospital admission
IV broad spectrum ABX - Gram positive and negative cover
Nasal decongestants
Steroid nasal drops
Nasal douching
Urgent drainage if intracranial complications
What are the complications of peri-orbital cellulitis?
Loss of vision Abscess formation Cavernous sinus thrombosis Encephalomeningitis Sepsis
