Periorbital & orbital cellulitis

Question 1

Define orbital cellulitis

Answer 1

Infection within the orbital soft tissues with associated dysfunction and is usually due to underlying bacterial sinusitis

Question 2

Define peri-orbital cellulitis

Answer 2

Inflammation and infection of the superficial eyelid, usually from a superficial source. Inflammation remains confined to the soft tissue layers superficial to the orbital septum and ocular function remains intact

Question 3

What is the aetiology of Periorbital & orbital cellulitis

Answer 3

Pathogens: Staph. aureus, Staph. epidermidis, Streptococcus species, anaerobes

Source:
Paranasal sinus infection
Dental abscess
Orbital injury
Fracture
Dacrocystitis
Endophthalmitis
Haematogenous spread

DKA or immunosuppression → fungal infection (mucormycosis or invasive aspergillosis)

Question 4

What are the risk factors for Periorbital & orbital cellulitis

Answer 4

Male children
Previous sinus infection (sinusitis)
Lack of Hib vaccination
Skin infection
Recent dental infection or dental work
Orbital fracture
Foreign body in eye/orbit

(The bony orbit is thin, and is penetrated by many small nerves, vessels, and minute defects (Zuckerkandl dehiscences). This predisposes the area to the spread of infection from adjacent sinuses. Septic thrombophlebitis affecting the valveless veins that bridge the orbit and the sinuses also facilitate the spread of infection. There are no lymphatics in the orbit to serve as a carrier of infection)

Question 5

What investigations should be done for Periorbital & orbital cellulitis

Answer 5

Bedside: complete ophthalmological examination (visual acuity + RAPD), NPA/conjunctival swab for microbiology (+ve)
Bloods: FBC, blood culture
Other:
- CT/MRI sinus and orbits + contrast: Inflammation of peri-orbital or orbital tissue; sub-periosteal abscess (commonly superomedial or inferomedial); sinusitis

Question 6

What are the symptoms and signs of orbital cellulitis

Answer 6

Painful or limited ocular movement
± reduced visual acuity or loss of vision (11%)
Diplopia
Proptosis
Headache, Malaise
Recent sinus infection

Question 7

What are the symptoms and signs of Periorbital cellulitis

Question 8

What is the management for peri-orbital cellulitis

Answer 8

Mild: outpatient treatment with empirical oral antibiotic therapy e.g. co-amoxiclav + clindamycin

Moderate-severe: Admit
IV Abx: high-dose ceftriaxone (prevents posterior spread → orbital cellulitis) for 2-5 days

Question 9

What is the management for peri-orbital cellulitis with abscess

Answer 9

Abscess <1cmx0.4cm AND no visual compromise → medical management
Abscess → surgical drainage

Question 10

What is the management for orbital cellulitis

Answer 10

Admit
Refer to ophthalmology
Empirical IV Abx
± empirical antifungal therapy (amphotericin B deoxycholate)
± nasal decongestant
± Lateral canthotomy and cantholysis may be required to reduce intra-ocular pressure before orbitotomy can be performed if there is visual loss at presentation
± orbitotomy and surgical drainage of orbital abscess

Question 11

What are the complications of Periorbital & orbital cellulitis

Answer 11

Abscess formation (sub-periosteal, orbital, epidural)
Ocular empyema
Meningitis
Cavernous sinus thrombosis (papilloedema, neuro signs, visual loss, muscle paresis)
Ocular compartment syndrome

Question 12

What is the prognosis for Periorbital & orbital cellulitis

Answer 12

Pre-orbital:
- Excellent prognosis
- Clinical improvement seen within 24-48 hours

Orbital:
- Lag time of 24-48h between imitation of antibiotics and clinical response
- Prompt and proper antibiotic treatment and drainage of sinusitis is critical to avoid progression to sub-periosteal orbital abscess, epidural abscess, and meningitis.

Question 13

What is the difference between pre and post septal cellulitis

Answer 13

Pre-septal: infection from the conjunctive or eyelids
post-septal: infection from the frontal or ethmoid sinuses