Disease of Orbit: Proptosis, Orbital Fracture, and Orbital Cellulitis

Proptosis

Definition

• Proptosis refers to the abnormal forward displacement of the eyeball.
• Exophthalmos: Proptosis specifically due to thyroid eye disease.
• Normal values:
  • Adults: <20 mm
  • Difference >2 mm between eyes is significant.

Causes

1. Inflammatory: Orbital cellulitis, thyroid eye disease (Graves' ophthalmopathy)
2. Neoplastic: Orbital lymphoma, optic nerve glioma, meningioma
3. Trauma: Orbital fracture with hemorrhage
4. Vascular: Carotid-cavernous fistula, orbital varix
5. Infectious: Orbital cellulitis, fungal infections (e.g., mucormycosis)
6. Congenital: Craniofacial syndromes (e.g., Crouzon syndrome)

Signs and Symptoms

• Forward protrusion of the eye
• Diplopia (double vision)
• Pain or tenderness
• Chemosis (conjunctival swelling)
• Decreased visual acuity
• Restriction of eye movements
• Exposure keratopathy

Investigations

• Clinical Examination: Hertel exophthalmometry, ocular motility assessment
• Imaging:
  • CT scan of orbit (trauma, infection, tumor)
  • MRI orbit (soft tissue details, tumors)
• Laboratory Tests: Thyroid function tests (if thyroid eye disease suspected)
• Biopsy: If a neoplastic lesion is suspected

Treatment and Management

• Emergency:
  • Immediate surgical decompression if optic nerve compression
• Specific Management:
  • Thyroid eye disease: Corticosteroids (Prednisolone), radiotherapy, orbital decompression surgery
  • Infective causes: Broad-spectrum IV antibiotics (e.g., Ceftriaxone, Vancomycin), antifungals if fungal cause
  • Neoplastic: Surgical excision, radiotherapy, chemotherapy depending on tumor type
• Supportive care: Lubricating eye drops, eyelid taping at night, management of underlying cause

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Orbital Fracture

Definition

• Fracture involving the bony orbit, commonly affecting the orbital floor (blowout fracture).

Causes

• Blunt trauma to the orbit (sports injury, motor vehicle accidents, falls)

Signs and Symptoms

• Periorbital swelling and bruising
• Enophthalmos (posterior displacement of the globe)
• Diplopia (especially on upward gaze)
• Hypoesthesia over the cheek (infraorbital nerve involvement)
• Subconjunctival hemorrhage
• Orbital emphysema (air in soft tissue from sinus fracture)

Investigations

• Imaging:
  • CT scan (gold standard for assessing orbital fractures)
• Ophthalmic Evaluation:
  • Visual acuity and field testing
  • Intraocular pressure measurement
  • Assessment for globe rupture

Treatment and Management

• Initial Care:

  • Ice packs, head elevation
  • Avoid nose blowing (risk of orbital emphysema)

• Medical Management:

  • Prophylactic antibiotics (e.g., Amoxicillin-clavulanate)
  • Nasal decongestants

• Surgical Intervention:

  • Indications: Enophthalmos >2 mm, persistent diplopia, large fracture size
  • Repair with implants (titanium mesh, porous polyethylene)

• Follow-up:

  • Monitor for late complications (orbital fibrosis, persistent diplopia)

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Orbital Cellulitis

Definition

• Infection of the soft tissues of the orbit posterior to the orbital septum.
• A potentially sight- and life-threatening emergency.

Causes

1. Bacterial Infections (common):
   • Staphylococcus aureus, Streptococcus species
2. Sinusitis: Especially ethmoidal sinusitis
3. Trauma: Orbital fractures, foreign bodies
4. Hematogenous spread: From distant infections
5. Post-surgical: Orbital or sinus surgery

Signs and Symptoms

• Painful eye movements
• Proptosis
• Eyelid swelling and erythema
• Ophthalmoplegia (paralysis of ocular muscles)
• Decreased vision
• Fever, malaise
• Chemosis

Investigations

• Blood Tests: CBC (elevated WBC), blood cultures
• Imaging:
  • CT scan with contrast (to differentiate from preseptal cellulitis, abscess formation)
• Microbiology:
  • Culture of blood or pus if available

Treatment and Management

• Hospitalization: Essential for IV antibiotics and monitoring
• Medical Therapy:
  • Broad-spectrum IV antibiotics:
    • Vancomycin + Ceftriaxone or Cefotaxime
    • Consider Metronidazole if anaerobic infection suspected
• Surgical Intervention:
  • Abscess drainage if orbital abscess present
• Supportive Care:
  • Analgesics, antipyretics
  • Frequent ophthalmic assessment
• Complications to Monitor:
  • Vision loss
  • Cavernous sinus thrombosis
  • Meningitis

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Key Points for Medical Exams

• Proptosis: Differentiate between unilateral (orbital cellulitis, tumors) and bilateral (thyroid eye disease) causes.
• Orbital Fracture: CT orbit is diagnostic; surgical repair if functional or cosmetic indications arise.
• Orbital Cellulitis: Always consider it an emergency; requires IV antibiotics and sometimes surgical drainage.