Fact-sheet: Graves disease of orbit


Updated on 06/23/2020 at 9:37 AM

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Definition

Dysthyroid orbitopathy is an autoimmune disease associated with thyroid disorders.

It occurs in a context of thyroid dysfunction (hyperthyroidism 80%, euthyroidism 10%, Hypothyroidism 10%)

Moderate and severe forms progress in two stages: an inflammatory stage followed by a sequelar stage. The course involves a dynamic phase with flares and remissions followed by stabilization of the lesions.

Exophthalmos is often subsequent to the initiation of antithyroid treatment, particularly iodine-131.

Clinical features

Exophthalmos

Upper eyelid retraction, present in 90 to 98% of patients

Fatty infiltration of the eyelids

Diplopia

Inflammatory signs: deep orbital pain, redness of the conjunctiva, caruncle, and eyelids, and edema of the eyelids and conjunctiva. Worsening of exophthalmos and oculomotor disorders also indicate inflammatory activity.

Laboratory findings

The laboratory work-up confirms the diagnosis of Graves disease of orbit.

T3 and T4 levels are elevated and TSH is suppressed.

TRAb levels are elevated. Their level correlates with the activity of dysthyroid orbitopathy.

CT

CT examination quantifies exophthalmos (Grade I, II, or III)

  • Grade I: more than 2/3 of the globe lies anterior to the bicanthal line
  • Grade II: the bicanthal line is tangent to the posterior pole of the globe
  • Grade III: the entire globe lies anterior to the bicanthal line)

Muscle hypertrophy

MRI

Indicated to assess:

-> Inflammation, degree of muscle fibrosis: inflammatory (iso- to hypointense T1/hyperintense T2) or fibrotic (isointense T1/hypointense T2)

-> Status of the orbital apex

-> Muscle and intraorbital fat volume, defining four semiologic patterns:

  • I: mild increase in muscle volume
  • II: marked increase in muscle volume predominating at the apex: compressive form
  • III: increased fat volume with slender, thin, stretched muscles: fatty form
  • IV: increased muscle and fat volume: mixed form

-> Signs of optic nerve compromise

Management

Multidisciplinary and complex management: prolonged corticosteroid therapy

If failure: consider radiotherapy or immunosuppressive treatment