Sabtu, 10 Desember 2011

Orbital Cellulitis Diagnosis and Management

Orbit anatomy
Bones which make the orbit

    Orbital Cellulitis
    Orbital cellulitis is a dangerous infection with potentially serious complications
    It is usually caused by a bacterial infection from the sinuses (mainly ethmoid, accounting for more than 90% of all cases)
    Other causes :a stye on the eyelid, recent trauma to the eyelid including bug bites, or a foreign object

    • In children, orbital cellulitis is usually from a sinus infection and due to the organism Hemophilus influenzae (decrease in incidence after vaccination program implentation). 
    • Other organisms are Staphlococcus aureus, Streptococcus pneumoniae, and Beta hemolytic streptococci

    • Extension of infection from the periorbital structures, most commonly from the paranasal sinuses, but also from the face, globe, and lacrimal sac
    • Direct inoculation of the orbit from trauma or surgery (orbital decompression, dacryocystorhinostomy, eyelid surgery, strabismus surgery, 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 by the orbital septum. This is a fascial plane that is continuous with the periosteum of the facial bones.
    • The orbital septum inserts into the tarsal plate of the upper and lower eyelids.
    • The orbital septum usually proves to be an effective barrier that prevents the spread of infection from the eyelids posteriorly to the orbit.
    • While preseptal cellulitis can occasionally spread to the orbital contents, it is generally a clinical entity that is distinct from orbital cellulitis
    Orbital vs. Preseptal Cellulitis
    • Orbital cellulitis is infection of the soft tissues of the orbit posterior to the orbital septum, differentiating it from preseptal cellulitis, which is infection of the soft tissue of the eyelids and periocular region anterior to the orbital septum
    • Differential Diagnosis: orbital pseudotumor (inflammatory condition, responds to steroids)
    Chandler Classification
    • Stage I-Inflammatory edema-Preseptal
    • Stage II-Orbital cellulitis  - Postseptal
    • Stage III-Subperiostal abscess
    • Stage IV-Orbital abscess
    • Stage V-Complication due to posterior extension

    • Fever, generally 102 degrees F or greater.
    • Painful swelling of upper and lower lids (upper is usually greater).
    • 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
    • Subperiostal/Orbital abscess (Chandler III-IV)
    • Cavernous sinus thrombosis
    • Hearing loss
    • Septicemia or blood infection 
    • Meningitis
    • Optic nerve damage and blindeness

      A male with orbital cellulitis with proptosis, ophthalmoplegia, and edema and erythema of the eyelids

      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 antibiotic therapy is poor within 48-72 hours or if the CT scan shows the sinuses to be completely opacified.
      • Consider orbital surgery, with or without sinusotomy, in every case of subperiosteal or intraorbital abscess formation.
      • Surgical drainage of an orbital abscess is indicated if any of the following occurs:  decrease in vision, An afferent pupillary defect. proptosis progresses despite appropriate antibiotic therapy
      • The size of the abscess does not reduce on CT scan within 48-72 hours after appropriate antibiotics have been administered.
      • If brain abscesses develop and do not respond to antibiotic therapy, craniotomy is indicated.
      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 the brain
      • 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 infraorbital nerve
      • 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 extending from the lateral canthus to the area just below the inferior punctum is created 4 mm to 5 mm below the lower border of the tarsal plate to avoid injury to the septum and the canaliculus
        Intranasal approach
        • Decompression of medial anf medioinferior floors of orbit
        • Endoscopic sinus surgery technique
        • Anterior Ethmoidectomy
        • Maxillary antrostomy

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