Orbital Cellulitis Diagnosis and Management

Orbit anatomy
Bones which make the orbit
Frontal
Zygoma
Maxillary
Nasal
Ethmoid
Lacrimal
Sphenoid

Orbital Cellulitis

Orbital cellulitis is a dangerous infectionwith potentially serious complications

It is usually caused by a bacterial infection from thesinuses (mainly ethmoid, accounting for more than 90% of all cases)

Other causes :a stye on the eyelid, recent trauma to theeyelid including bug bites, or a foreign object

Children

• In children, orbital cellulitis is usually from a sinusinfection and due to the organism Hemophilus influenzae (decrease inincidence after vaccination program implentation). 
• Other organisms are Staphlococcus aureus, Streptococcuspneumoniae, and Beta hemolytic streptococci

Pathophysiology

• Extension of infection from the periorbital structures, mostcommonly from the paranasal sinuses, but also from the face, globe, andlacrimal sac
• Direct inoculation of the orbit from trauma or surgery(orbital decompression, dacryocystorhinostomy, eyelid surgery, strabismussurgery, retinal surgery, and intraocular surgery, have been reported as the precipitating cause of orbital cellulitis)
• Hematogenous spread from bacteremia

Orbital septum

• The orbit is separated from the soft tissue of the eyelid bythe orbital septum. This is a fascial plane that is continuous with theperiosteum of the facial bones.
• The orbital septum inserts into the tarsal plate of theupper and lower eyelids.
• The orbital septum usually proves to be an effective barrierthat prevents the spread of infection from the eyelids posteriorly to theorbit.
• While preseptal cellulitis can occasionally spread to theorbital contents, it is generally a clinical entity that is distinct fromorbital cellulitis

Orbital vs. Preseptal Cellulitis

• Orbital cellulitis is infection of the soft tissues of theorbit posterior to the orbital septum, differentiating it from preseptalcellulitis, which is infection of the soft tissue of the eyelids and periocularregion anterior to the orbital septum
• Differential Diagnosis: orbital pseudotumor (inflammatory condition, responds tosteroids)

Chandler Classification

• Stage I-Inflammatory edema-Preseptal
• Stage II-Orbital cellulitis  - Postseptal
• Stage III-Subperiostal abscess
• Stage IV-Orbitalabscess
• Stage V-Complication due to posterior extension

Symptoms

• Fever, generally 102 degrees F or greater.
• Painful swelling of upper and lower lids (upper is usuallygreater).
• Eyelid appears shiny and is red or purple in color.
• Infant or child is acutely ill or toxic.
• Eye pain especially with movement.
• Decreased vision (because the lid is swollen over the eye).
• Eye bulging (forward displacement of the eye).
• Swelling of the eyelids
• General malaise.
• Restricted or painful eye movements

Complications

• Subperiostal/Orbital abscess (Chandler III-IV)
• Cavernous sinus thrombosis
• Hearing loss
• Septicemia or blood infection 
• Meningitis
• Optic nerve damage and blindeness

A male with orbitalcellulitis with proptosis, ophthalmoplegia, and edema and erythema of theeyelids

Non-surgical treatment

• IV ABx
• Antifungals (if indicated)
• Nasal decongestants (open sinus ostia)
• Duretics – DIAMOX (carbonic anhydrase inhibitor),mannitol  (reduce IOP)

Surgical Treatment

• Surgical drainage if the response to appropriate antibiotictherapy is poor within 48-72 hours or if the CT scan shows the sinuses to becompletely opacified.
• Consider orbital surgery, with or without sinusotomy, inevery case of subperiosteal or intraorbital abscess formation.
• Surgical drainage of an orbital abscess is indicated if anyof the following occurs:  decrease invision, An afferent pupillary defect. proptosis progresses despite appropriateantibiotic therapy
• The size of the abscess does not reduce on CT scan within48-72 hours after appropriate antibiotics have been administered.
• If brain abscesses develop and do not respond to antibiotictherapy, craniotomy is indicated.

How?

1. Superior orbit decompression   
2. Medial orbit decompression
3. Inferior orbit decompression
4. Lateral orbit decompression
5. Intranasal approach

Superior Orbit Decompression

• Frontal cranioitomy – unroofing of superior wall of orbit
• Titanium sheild placed to support the frontal lobe of thebrain
• High morbidity, consider only for severe cases
• Medial Orbit Decompression
• External ethmoidectomy incision  or coronal forehead approach
• External ethmoidectomy- complete ethmoid sinus resection,then orbital fat herniates into sinus defect
• Coronal incision- ethmoidectomy via a superior approach,more risk for lacrimal sac and trochlea injury  

  

Inferior Orbit Decompression

• Orbital floor blow-out fracture , but spares infraorbitalnerve
• Subcilliary eyelid incision or Caldwell-Luc incision
• Combined approach?
• Intraorbital fat herniates maxillary sinus

Lateral Orbit Decompression

• Lateral canthotomy
• Removal of lateral orbital bone posterior to the rim
• Orbital fat protrudes the newly created space
• An incision extendingfrom the lateral canthus to the area just below the inferior punctum is created4 mm to 5 mm below the lower border of the tarsal plate to avoid injury to theseptum and the canaliculus

Intranasal approach

• Decompression of medial anf medioinferior floors of orbit
• Endoscopic sinus surgery technique
• Anterior Ethmoidectomy
• Maxillary antrostomy