Test 32  (Thyroid eye disease)

1. Thyroid eye disease is exacerbated by:

a. radio-iodine treatment of hyperthyroidism

b. development of hypothyroidism after treatment of 
    hyperthyroidism

c. smoking

d. male sex

e. presence of diabetes mellitus
 

Answer
a.T   b.T   c.T   d.T   e.F

2. Upper eyelid retraction in thyroid eye disease is caused by:

a. adrenergic stimulation of the Muller's muscle

b. superior oblique muscle fibrosis

c. inferior rectus fibrosis

d. fibrosis of the levator

e. fatty infiltration of the levator
 

Answer
a.T   b.F   c.T  d.T  e.F
Fibrosis of the levator leads to secondary overaction of superior rectus/levator complex.

3. Thyroid eye disease:

a. is seen in 40% of patients with Graves' disease

b. does not occur in Hashimoto's thyroiditis

c. is not a feature of thyroid cancer

d. tends to peak 6 months from onset

e. usually cease to be active 18 months after onset
 

Answera.T  b.F  c.T  d.T  e.T
Thyroid eye disease occurs in 3% of patients with Hashimoto's thyroiditis. 

4. The following are true about the radiological features of 
    thyroid eye disease:

a. inferior and lateral recti are the two extraocular muscles 
    most often involved

b. the tendon of the affected muscle is not involved

c. medial rectus enlargement is more likely than inferior
    rectus enlargement in causing compressive optic 
    neuropathy

d. oedema of the extraocular muscle is best diagnosis with
    B-scan

e. STIR-sequence MRI is useful in assessing the activity of
    thyroid eye disease

Answer
a.F   b.T  c.T  d.F  e.T
Inferior rectus is the most common involved followed 
by medial rectus. Medial rectus being closer to the optic nerve is the most likely to cause optic nerve compression. STIR (short-tau inversion recovery) sequence MRI is useful in assessing the activity of thyroid eye disease radiologically by showing the amount of muscle oedema.

 

5. The following are true about thyroid eye disease:

          a. the orbital tissue is infiltrated by B cells during 
              the active phase

b. when performing orbital decompression for 
    optic neuropathy, the medial wall should be 
    removed

c. lacrimal gland enlargement is common

d. bicoronal flap is the best approach for orbital 
    decompression

e. diplopia is a common complication of orbital 
    decompression
 

Answer
a.F   b.T  c.F  d.F  e.T
The orbital tissue is infiltrated by T cells during the active phase. Lacrimal gland prolapsed is common; enlargement is rare. Bicoronal flap is rarely used use nowadays for orbital decompression.

 

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