Periorbital and orbital cellulitis

Question 1

What is periorbital cellulits?

Answer 1

inflammation and infection of the superficial eyelid.
“infection of tissue anterior to the orbital septum” (The orbital septum is a membranous sheet that forms the anterior border of the orbit, extending from the orbital rims (superior and inferior) and into the eyelids.)

• occurs from a superficial site of inoculation (eg. insect bite)
• May lead to orbital cellulitis.

Question 2

What is orbital cellulitis?

Answer 2

infection within the orbital soft tissues.
life-threatening emergency. It describes infection of the structures behind the orbital septum.

• Far more serious condition and warrants hospital admission.
• Commonly reflects local spread of an URTI, usually sinusitis.
• May also be due to orbital injury.

Question 3

What can cause periorbital/ orbital ceullulitis?

Answer 3

Organisms involved include Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus species, and anaerobes.

Question 4

What are the risk factors for periorbital/ orbital cellulitis?

Answer 4

• Previous sinus infection (sinusitis)
• lack of Haemophilus influenzae type b (Hib) vaccination
• Insect bite on eyelid (peri-orbital)
• Trauma
• Surgical – ocular, adnexal or sinus
• Sinus disease – ethmoidal sinusitis is the most common site of infection that spreads to the orbit
• Other facial infections – preseptal, dental abscess or dacryocystitis

Question 5

Describe the epidemiology behind periorbital/ orbital cellulitis?

Answer 5

Twice as common in children (M>F) than adults, Orbital cellulitis is less common than preseptal cellulitis, with the latter accounting for 80% of cases, mostly occurring in children under the age of 10.

Question 6

What are the presenting symptoms of periorbital/ orbital cellulitis?

Answer 6

1. Peri-Orbital Cellulitis → red, swollen, painful eye of acute onset, eyelid oedema and erythema, insect bite on eyelid
2. Orbital Cellulitis → redness and swelling around eye, severe ocular pain, visual disturbance, proptosis, pain with eye movements (ophthalmoplegia), eyelid oedema
   - Orbital Cellulitis Distinguishing Features → visual disturbance + proptosis (Bulging eyes) + pain on eye movements (ophthalmoplegia).

Question 7

What investigations are used to diagnose/ monitor periorbital/ orbital cellulitis?

Answer 7

1. CT Sinus & Orbits with Contrast → performed in all patients suspected to have orbital cellulitis. Can see inflammation of peri-orbital or orbital tissue hence helps differentiate between the two. Assess for posterior spread of the infection.
2. WBC Count, CRP → elevated
3. Blood Culture & Swab → determine causative organism

Question 8

How is periorbital/ orbital cellulitis managed?

Answer 8

1. Peri-Orbital Cellulitis → oral antibiotics (usually co-amoxiclav) and secondary care referal
2. Orbital Cellulitis → hospital admission (ENT Review) + IV antibiotics (vancomycin + cefotaxime)
   - Risk of cavernous sinus thrombosis and intracranial spread