• Clinical science

Orbital disorders

Summary

The orbital cavity (eye socket) is the bony cavity that encloses the bulb and accessory organs of the eye, including the ocular muscles, lacrimal glands, nerves, vessels, and retrobulbar adipose tissue. Diseases of the orbital cavity include Graves ophthalmopathy, orbital cellulitis, rhabdomyosarcoma, and lacrimal sac disorders. Typical symptoms associated with these diseases include exophthalmos and diplopia. Treatment differs according to the underlying disease and includes conservative measures (antibiotics), surgery, radiotherapy, and chemotherapy.

Disorders of the lacrimal system are discussed in a separate learning card.

Graves ophthalmopathy

  • Definition: Graves ophthalmopathy or orbitopathy (GO) (also known as thyroid-associated orbitopathy or ophthalmopathy, TAO) is an autoimmune condition that is generally associated with Graves disease
  • Etiology
  • Epidemiology
    • Sex: >
    • Risk factors; : family history of Graves disease and tobacco smoking
  • Pathophysiology
    • TSH autoantibodies are present in the orbital cavity; (eye socket) → bind TSH receptor antigen (autoimmune reaction) on cells; lymphocytic infiltration into the orbital tissues → inflammation and release of cytokines from CD4+ T cells stimulates fibroblasts to secrete glycosaminoglycans (hyaluronic acid), which also pulls water into the interstitial space (osmotic effect); expansion of retro-orbital tissue due to increased fluid in extraocular muscles, lymphocytic infiltration, and adipogenesis
  • Clinical features
    • Exophthalmos : can be unilateral or bilateral, often asymmetric. Retropulsion (palpation of the globe while the eyelid is closed) enable adequate examination.
    • Ocular motility disturbances
    • Lid retraction, also known as “thyroid stare”
      • Retraction of the upper eyelid with visible sclera
      • Lagophthalmos keratitis (occurs with insufficient blinking)
    • Conjunctival injection and chemosis
    • Ocular discomfort (pain or pressure)
    • Patient may be hyperthyroid, euthyroid, or hypothyroid.
  • Diagnosis
  • Treatment
    • Principles
      • This is a self-limiting disease, but intervention may be necessary because of severe symptoms or risk of complications.
      • Goals of therapy include treatment of hyperthyroidism, smoking cessation, eye protection, and decreasing inflammation.
      • Radioiodine therapy may initially worsen the appearance and symptoms of the disease, while surgery and thioamides do not affect the disease.
      • If radioiodine therapy is used, steroids are recommended before and after treatment.
    • Mild disease
    • Moderate to severe inflammation, nonresponders, or threatened/manifested vision loss: high-dose IV steroids
      • If response is good: consider orbital radiation
      • If no response after 48–72 hours → surgical decompression while on steroids

References:[1][2][3][4]

Orbital and preseptal cellulitis

Orbital cellulitis Preseptal cellulitis
Definition
  • An infection of the orbital contents, such as the fat and extraocular muscles
  • Posterior to the orbital septum
  • The eye globe is not affected.
  • An infection of the eyelid and periorbital soft tissues without involvement of the orbital contents
  • Anterior to the orbital septum
  • The eye globe is not affected.
Etiology
  • Complication of upper respiratory tract infection, most commonly due to bacterial rhinosinusitis
  • Other causes include:
    • Acute dacryocystitis
    • Local trauma to the surrounding tissues of the face and eyelids
    • Insect or animal bites
    • Ophthalmic surgery
Epidemiology
  • More common in children than adults
Clinical features
  • Proptosis and ophthalmoplegia are the cardinal signs.
  • Fever and malaise
  • Reduced vision: diplopia, afferent pupil defect, dyschromatopsia
  • Other clinical features include:
  • Necrotic areas in the nares and/or oral cavity in immunocompromised patients with maximally and/or ethmoid sinusitis should raise suspicion for mucormycosis.
Diagnosis
  • Primarily a clinical diagnosis
  • Laboratory tests: leukocytosis; positive blood and tissue fluid cultures
  • CT scan: confirm diagnosis and look for complications, e.g., orbital abscess or intracranial extension
  • Primarily a clinical diagnosis
  • Laboratory tests: leukocytosis; blood cultures are generally unnecessary
  • CT scan: only eyelid swelling apparent
Treatment
Complications Although preseptal cellulitis can cause severe complications, these are rare, which is why the condition is rarely life-threatening.

Reduced vision, diplopia, ophthalmoplegia, and proptosis are typical features of orbital cellulitis. They do not occur in preseptal cellulitis!

References:[5][6][7][8][9][10]

Rhabdomyosarcoma

  • Definition: malignant mesenchymal tumor of primitive skeletal muscle cells (rhabdomyoblasts) that have failed to fully differentiate
  • Epidemiology
    • Most common soft tissue sarcoma and malignant orbital tumor in children
    • Primarily occurs in the first decade of life.
  • Clinical features
    • Frequently in the orbital cavity; , but can also be in the head and neck, urogenital region , or extremities
    • Minimally painful, rapidly increasing, gross swelling
    • Orbital rhabdomyosarcoma
      • Growing orbital mass that may be painful and have potential hemorrhage
      • Proptosis or dysconjugate gaze
  • Diagnosis
    • Open or core needle biopsy for light microscopy to look for rhabdomyoblasts (confirm the presence of rhabdomyosarcoma)
  • Treatment
    • Surgery (complete excision) if a functional and cosmetic result is possible
    • Combination of radiation and chemotherapy following a diagnostic biopsy if complete excision is not feasible
  • Prognosis: more favorable for localized tumors of the orbit , and less favorable for metastatic disease

References:[11][12][13][14][15]