Week 6 - Thyroid Eye Disease/Graves Disease

Question 1

What is Graves Disease?

Answer 1

• Systemic autoimmune disorder
• Hyperthyroid
• Orbitopathy
• Myxoedema (lumpy red skin)
• Acropachy (finger clubbing)

Question 2

What is the epidemiology of Graves Disease?

Answer 2

•Prevalence of hyperthyroidism in the general population is 1.2%
- 0.7% subclinical hyperthyroidism
- 0.4% Graves’ Disease - most common aetiology; note there is overlap with the subclinical group

• Graves’ Disease is more common in females (7:1 ratio)

Question 3

What is normal thyroid hormone control?

Answer 3

• 2 hormones produced by the Thyroid Gland
• T4 Thyroxine
• T3 Triiodothyronine

• They are responsible for metabolic regulation in all cells

Question 4

How does the normal thyroid system work?

Answer 4

• Thyrotropin releasing hormone (TRH)is produced by the hypothalamus

• Acts on the anterior pituitary gland

• Releasing thyroid stimulating hormones (TSH)

• TSH binds to the TSH receptors in the thyroid gland releasing Thyroid hormone

Question 5

What is abnormal control of thyroid system?

Answer 5

• Hyperthyroidism in Graves disease is a direct result of an Abnormal Circulating Antibody (Ab) (ISH receptor AB)
• This targets the TSH receptor and mimics the effect of normal TSH resulting in overstimulation of the Thyroid gland

• Goitre - swelling of the gland may occur

• Over production of T4 and T3

Question 6

What are some causes of an abnormal thyroid?

Answer 6

• Graves disease
• Thydoiditis
• Toxic multi modular goitre
• Toxic thyroid nodule
• Self administered thyroid hormones

Question 7

What is Graves Orbitopathy risk factors?

Answer 7

• Genetics are role in the development of GO
• High levels of TSH Ab linked to severe GO
• Smoking increases severity of GO in hyperthyroidism

Question 8

Graves orbitopathy statistics:-

Answer 8

• Not all patients with hyperthyroidism develop GO
• 20% patients develop GO prior to diagnosis, 20% are diagnosed with GO at the same time as, 20% develop GO 6 months after the thyroid is diagnosed
• 40% can develop GO more than 6 months after their hyperthyroidism. Very small percentage of patients can be Hypothyroid or Euthyroid

Question 9

Types of Graves Orbitopathy?

Answer 9

•Acute/ Active Inflammatory Phase

• Late/Inactive Phase

Question 10

What is the active phase?

Answer 10

• Connective Tissue Inflammation
• Activation of Extraocular Muscle Fibroblasts
• Inflammatory Myopathy resulting from the Autoimmune process

• Increasing Orbital volume by differentiating into orbital fat and secreting glycosaminoglycans.
• These then attract water

Question 11

What are signs/symptoms of connective tissue inflammation?

Answer 11

• Redness
• Mild ocular discomfort
• Periorbital swelling
• Pain on motility

Question 12

What signs appear with corneal exposure?

Answer 12

• Gritty
• Photophobia
• Epiphora
• Reduction in vision

Question 13

What does enlarged EOM’s cause?

Answer 13

• Diplopia
• Reduced field of BSV
• Reduced uniocular field of fixation

Question 14

What order of muscles are usually affected first?

Answer 14

• Inferior rectus
• Medial rectus
• Superior Rectus
• Lateral Rectus

Question 15

Which order of signs/symptoms in AHP and phorias present in graves disease? (order most likely)

Answer 15

• AHP of chin elevation
• Hypophoria/ tropia usually first deviation
• With /Without Head Turn
• Enlarged vertical fusion range
• Raised IOP on elevation/attempted elevation

Question 16

What does increased posterior orbital volume cause?

Answer 16

• Proptosis causes:
• Compression of optic nerve
- Reduced colour vision
- vision loss

Question 17

What is mullers muscle hyperactivity?

Answer 17

• Upper eyelid retraction
- Caused by overactivity of Muller’s muscle and finally by fibrosis of the levator muscle
- Upper lid lag on downgaze
• Lower eyelid lag

Question 18

What are signs of soft tissue inflammation?

Answer 18

• Periorbital swelling
• Conjunctival swelling
• Conjunctival injection

Question 19

What are signs/symptoms of increased orbital volume??

Answer 19

• Proptosis
• Lower eyelid retraction
• Corneal exposure
• Diplopia
• compressive optic neuropathy

Question 20

What is proptosis?

Answer 20

• Proptosis
• Exopthalmos
• Unilateral/bilateral
• Symmetrical/ Asymmetrical

Question 21

What are signs of optic nerve compression?

Answer 21

• Loss of VA
- This may be due to Corneal exposure and Punctate Keratitis
- Pinhole to ensure not refractive
• Reduction in Colour Vision
• Visual Field defects - paracentral/arcuate/ any
• RAPD - unilatera/ asymmetricall compression

• Mild or no disc swelling
• Extreme cases Optic atrophy develops
• VEP - showing reduced amplitude
CT scan- crowding of orbital apex with enlarged muscles

Question 22

How does graves disease present in its inactive phase?

Answer 22

• Cicatrical phase
• Fibrosis and muscle contraction
• Reduction in proposis /swelling
Corneal exposure persists due to retraction of lids

Question 23

What are some systemic symptoms of an hyperthyroidism?

Answer 23

• Weight loss
• Increased appetite
• Intolerance of heat
• Anxiety
• Tremor
• Sweating
• Increased heart rate

Question 24

What are systemic symptoms of hypothyroidism?

Answer 24

• Weight gain
• Decreased appetite
• Intolerance of cold
• Lethargy
• Hair loss
• Reduced heart rate