Orbital infection

Orbital infection can be a commonly encountered entity.

It is important to differentiate between orbital and periorbital cellulitis, as this has therapeutic and prognostic implications:

  • periorbital cellulitis (preseptal cellulitis) is limited to the soft tissues anterior to the orbital septum 1
    • often managed with oral antibiotics
  • orbital cellulitis (post-septal cellulitis) extends posterior to the orbital septum 1
    • more serious condition requiring hospitalisation and parental antibiotics
    • complications such as intraorbital abscess formation may require surgical intervention

Orbital infections represent more than half of primary orbital disease processes 2. These infections typically present in children and yound adults but can affect any age group.

  • proptosis
  • painful ophthalmoplegia
  • chemosis
  • reduced visual acuity

Periorbital cellulitis often results from contiguous spread of an infection of the face, teeth, or ocular adnexa. Orbital cellulitis typically results from extension of a paranasal sinusitis infection 1.

Urgent imaging is indicated to assess the anatomic extent of disease, including postseptal, cavernous sinus and intracranial involvement; evaluate for sources of contiguous spread, such as with sinusitis or trauma; and identify orbital abscesses that require exploration and drainage 3.  CT is the imaging investigation of choice as it is:

  • readily available at all hours and quick
  • ideal for assessing for underlying sinus disease
  • will identify a subperiosteal reaction or intracranial extension
Periorbital cellulitis

Diffuse soft-tissue thickening and areas of enhancement anterior to the orbital septum are seen on periorbital cellulitis. It is very difficult to differentiate between preseptal oedema and periorbital cellulitis on CT 4.

Orbital cellulitis
  • poor definition of orbital planes
  • inflammatory stranding in the intraconal fat
  • intraconal or extraconal soft tissue mass
  • oedema of the extraocular muscles
  • intra-orbital abscess
  • subperiosteal abscess

Rarely performed, as not usually necessary or will not add anything to the assessment.  It will identify like CT a subperiosteal abscess and appear:

  • T1: low signal
  • T2: high signal
  • DWI/ADC: diffusion restricton
  • T1 + C: rim enhancement

Periorbital cellulitis is treated with oral antibiotic therapy. Orbital cellulitis is treated with intravenous antibiotic therapy. However, if a subperiosteal abscess is present, surgical drainage may be necessary 1.


Complications of orbital cellulitis include 1:

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Article information

rID: 14849
System: Head & Neck
Sections: Gamuts, Pathology
Synonyms or Alternate Spellings:
  • Periorbital cellulitis
  • Preseptal cellulitis
  • Orbital infections
  • Orbital cellulitis
  • Peri-orbital cellulitis
  • Post-septal cellulitis

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Cases and figures

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    Increased attenua...
    Case 1: orbital and peri-orbial cellulitis
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    Case 2: sub-periosteal abscess
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    Case 3: dacryocystitis 
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    Case 4: complicated periorbital cellulitis
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    Case 5
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    Case 6: with subperiosteal collection
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    Case 7: with subperiosteal abscess
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    Case 8: preseptal periorbital cellulitis
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