Periorbital (Preseptal) vs Orbital Cellulitis

Periorbital (Preseptal) Cellulitis

Pathology

• Infection anterior to the orbital septum (i.e., eyelid and surrounding tissues, not the orbit itself).

• Usually from local spread (sinusitis, dacryocystitis, eyelid or lacrimal infections, trauma).

• Common pathogens: Staphylococcus aureus, Streptococcus pyogenes, Haemophilus influenzae (in unimmunised).

Clinical Features

• Eyelid swelling, erythema, warmth

• No vision symptoms: Normal visual acuity, no proptosis, no painful eye movements

• Usually less severe than orbital cellulitis, but can progress if untreated.

Management

1. Assess for Orbital Signs

   • Blurred vision, proptosis, painful eye movements → suggests orbital involvement

2. Antibiotics

   • If systemic symptoms, high-risk scenario (e.g., <5 years unimmunised, sinusitis present):

     • Amoxicillin + Clavulanic Acid 875/125 mg BD x 7 days

   • Otherwise mild cases:

     • Flucloxacillin or Cephalexin 12.5 mg/kg QID x 7 days (adult doses typically fluclox 500 mg QID or cephalexin 500 mg QID)

3. Follow-Up

   • Review in 48 hrs. If no improvement or orbital symptoms develop, urgent ED referral.

Orbital (Post-Septal) Cellulitis

Pathology

• Infection posterior to the orbital septum.

• Commonly spreads from ethmoidal sinusitis; also can progress from untreated periorbital cellulitis.

• Highest risk in young children (<4 years) because of thin sinus walls.

Clinical Features

• Vision Changes: Blurred vision, diplopia

• Pain with Eye Movement, headache

• Proptosis, chemosis, conjunctival injection

• Fever may be present but can be mild or absent.

Management

1. Urgent Referral to ED

   • This is an emergency due to risk of vision loss, intracranial abscess, or cavernous sinus thrombosis.

2. IV Antibiotics

   • Typically Ceftriaxone + Flucloxacillin.

   • If MRSA suspected: consider vancomycin.

   • Add metronidazole if anaerobes (e.g., from sinus or dental source) are suspected.

3. Imaging

   • CT orbit/sinuses to identify abscess, orbital involvement, or complications (e.g., cavernous sinus thrombosis).

4. If Delayed Transfer (Rural)

   • Start IV antibiotics (e.g. ceftriaxone), arrange retrieval.

Notes

• Orbital cellulitis is an emergency; can lead to permanent vision loss or intracranial spread.

• Prompt management of ethmoidal sinusitis is crucial to prevent progression.

• Blood cultures in severe or non-responsive cases.

• Distinguishing Factor: Normal visual acuity and no pain on eye movement typically indicates periorbitalcellulitis; changes in vision, proptosis, or painful eye movements point to orbital cellulitis.