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Strabismus > 2 Graves Orbitopathy > Flashcards

2 Graves Orbitopathy Flashcards

1
Q

Incidence of GO

A

Women are 5x more likely to get graves than men 1994

The estimated incidence of GO is 16 women or 3 men per 100,000 individuals per year – Women approx 5X Men

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2
Q

People in UK with GO

A

Prevalence: 400 000 people in the UK with GO

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3
Q

Thyroid gland features

A

Butterfly shaped gland
Highly vascular endocrine organ
Lower neck anterior to trachea between the sternocleidomastoid muscles
Consists of densely packed follicles
Function
concentrates iodide to form thyroid hormones
Thyroid hormones synthesised and stored in the follicles

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4
Q

Thyroid hormones

A

TRH stimulates release of TSH

TSH is secreted by the anterior pituitary and stimulates secretion of

T3 – Tri-iodothyronine

T4 - Tetra­-iodothyronine (Thyroxine)

T3 & T4 secreted into bloodstream:
bound to plasma proteins then go round the body to were they are required
free form – intracellular

TRH thyroid releasing horomone
Stimulated release of t3 and t4

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5
Q

Role of thyroid hormones

GDM

A

Growth and Development

Metabolic Effects

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6
Q

Growth and development

A

rate of growth of many tissues
maturation of CNS and bones
regulation and synthesis of some respiratory enzymes

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7
Q

Metabolic effects

A

regulation of basal metabolic rate
regulation of water and ion transport
regulation of calcium and phosphorus metabolism
regulation of cholesterol and fat metabolism
regulation of nitrogen metabolism

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8
Q

Hyperthyroid- over active

A

Enlarged thyroid gland – goitre
Abnormal heart rhythms – tachycardia
Increased appetite but may have weight loss
Hand tremors
Fine brittle hair
Hyperactivity
Heat intolerance and increased perspiration – warm, moist skin
Lighter or less frequent periods
Irritability
Anxiety
Muscle weakness – upper arms and thighs

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9
Q

Females symptoms of HYPERthryoid

A

Females – less frequent periods, anxiety, muscle weakness in upper arms and thighs

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10
Q

Hypothyroid- underactive

A

Fatigue, exhaustion
Feeling run down and sluggish
Unexplained / excessive weight gain
Dry, coarse, itchy skin and hair
Slow heart rate
Feeling cold – especially in the extremities
Goitre
More frequent periods, increased menstrual flow
Difficulty concentrating – brain fog
Hoarse voice
Muscle cramps

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11
Q

Diagnostic tests

A

Blood test for TSH – (considered outside normal if lower than 0.3 or higher than 3.0)
Blood test for Thyroid-stimulating immunoglobulin (TSI)
Blood test for Anti-thyroid antibodies
Calculated free T4 index (10-20 pmol/L)
Serum T3 (2.5 – 5.3 pmol/L)

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12
Q

Hyperthyroidism management

A

Medication (Drug therapy)- thinomines, sterioids and immunosuppressents

Radioactive iodine treatment

Surgery - Thyroidectomy

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13
Q

Hyperthyroidism drug therapy

A

Thinomines (Carbimazole, Methamizole, Propylthiouracil)
- Interfere with thyroid hormone synthesis by blocking the build up of iodine. Most effective if the onset of disease within 1 year

Steroids (oral Prednisone)
- Decreases secretion of thyroid hormones and peripheral conversion of T4 and T3. Used in severe cases

Immunosuppressants (Azathioprine or Rituximab) – very rarely

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14
Q

Radioactive iodine for hyperthyroidism

A

Radioactive iodine introduced to the body and taken up by the thyroid gland. Normal cell division and function is disturbed.
- Generally used on patients over 45 years of age or in younger patients if other treatments are contraindicated.
- 20% of patients become hypothyroid within 1 year of the treatment
- Ocular symptoms have been found to worsen following this treatment (Acharya 2008)

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15
Q

Hyperthyroidism- thyroidectomy

A

Removal of most of the thyroid gland

Reduces hormone production

Post-op recurrence in 10-15% of patients

Post-op hypothyroidism in 40% of patients

Usually performed in younger patients

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16
Q

Why is medication better compared to surgery in younger patients?

A

Scar is visible so many patients don’t want this. Younger patients can improve quicker and this can be a good option because the healing is faster.

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17
Q

Hypothroidism drug therapy

A

Oral thyroxine which increases hormones in the body

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18
Q

Graves disease

A

is an autoimmune disorderthat causes hyperthyroidism. The immune systemattacks the thyroid and causes it to make more thyroid hormone than the body needs.

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19
Q

Associatied eye signs

A

Dysthyroid eye disease (DED)
Dysthyroid ophthalmopathy / orbitopathy
Endocrine ophthalmopathy
Thyroid associated ophthalmopathy (TAO)
Endocrine exophthalmos
Graves’ Orbitopathy (GO) – EUGOGO - http://www.eugogo.eu/
(EUropean Group on Graves Orbitopathy)

20
Q

Graves orbitopathy features

A

Auto-immune disease

Disease of the orbit affecting the orbital soft tissues

Closely correlated to auto-immune (systemic) thyroid disease (Graves’ Disease)

Prescence of circulating antibodies that bind and stimulate the thyroid hormone receptor (TSH) leading to hyperthyroidism and goitre.

21
Q

Risks factors of GO

A

Genetic
Environmental e.g.
Smoking and stress
Immune factors

22
Q

GO ages affected men and women

A

Affects 16/100000 women
3/100000 men

Affects women ages 45-50
Affects men ages 50-55

23
Q

Smoking and GO

A

Smoking gives a 7-8 more likely chance of getting this including vaping

24
Q

Hyperthyroidism frequency

A

90% common in clinic

Patients hyperthyroid without eye signs = 50-60%
80-90% have EOM changes on CT imaging not visible only on CT e.g. swelling

25
Q

Hypothroidism frequency

A

3-5%

26
Q

Euthyroid

A

5% Sensitivity of detection

27
Q

Phases of GO

A

According to Rundles curve

Active phase first 3 years- clinical features develop
Inactive phase- 3 years on more well managed

28
Q

Active phase/ wet findings

A

Eyes are painful and red
Can last around 3 years
Most clinical features at this time

29
Q

History/ signs of GO

A

Lid retraction (90-98%)
Lid lag – von Graefe’s sign
Exophthalmos (proptosis)
Lid oedema
Periorbital oedema
Epiphora (watery eyes)
Visual loss – Dysthyroid optic neuropathy DON ~5%
Chemosis (swelling of eye lids)
Strabismus – Eso/ Hypo
AHP
Thyroid disease
Photophobia

29
Q

Inactive phase/ dry findings

A

Eyes are white
Painless, restrictive myopathy may be present
Better managed

30
Q

Vertical muscles

A

The vertically oriented procerus muscle makes the greatest contribution to the formation of horizontal glabellar furrows, the corrugator supercilii muscles produce the vertical rhytids.

31
Q

Lid position in GO

A

Can affect upper, low lid and palpebral apeture.

Schlera can show on the top
Can be asymmetric

32
Q

Use of measuring lid retraction

A

Useful to do in each visit to measure any changes in the retraction
Gives indication as to the level of control

33
Q

Method of measuring lid retraction

A

Position patient’s head correctly
Ask patient to fixate on target positioned at their eye level and in the distance.
Ask patient to relax as much as possible to record the minimum amount of retraction for that patient (i.e. Müller’s muscle as relaxed as possible).
Observer holds vertical clear plastic ruler near to visual axis without touching eyelashes
Observer should consistently use only one of their eyes, and on same horizontal level as patient’s eye.
For patients with manifest strabismus, the contralateral visual axis is occluded prior to measurement.
Record in mm

34
Q

Instrument to measure proptosis/ exophthalmos

A

Hetel mirror exopthalmometer

Normal ranges vary based on ethnicity

35
Q

Normal exophthalmos measurement

A

12-21mm Caucasian males
12-20mm Caucasian females
12-24mm African males
12-23mm African females

36
Q

Exophthalmos features

A

Usually bilateral
Asymmetric
Unilateral ?
Normal
exophthalmometry >22mm or
asymmetry greater than 3mm

37
Q

Lid lag

A

common GO symptom where eyelids take longer to come down
https://www.youtube.com/watch?v=WHOOKbVYeE0

38
Q

Lid oedema/ periorbital oedema

A

Swelling around the eye

39
Q

Chemosis and Conjunctival Injection

A

Chemosis is a sign of eye irritation. The outer surface of the eye (conjunctiva) may look like a big blister. It can also look like it has fluid in it. When severe, the tissue swells so much that you can’t close your eyes properly.

40
Q

Graves orbitopathy features

A

Extraocular muscles swollen

Lids most obvious changes

Sight optic nerve gets damaged

41
Q

EOM’s in the active phase

A

Cellular infiltration with glycosaminoglycans (GAGs) and osmotic inhibition of water
This leads to EOMs becoming up to 8-10x enlarged
May compress ON leading to visual loss
Subsequent degeneration of muscle fibres leads to fibrosis resulting in restriced motility and diplopia

This phase tends to settle within 3 years- earlier the management the better the outcome

EOMS get x10 larger

42
Q

EOMs in dry phase

A

Muscle fibres become distorted, contracted and damaged due to fibrosis
Eyes are white and quiet
Painless when moving eyes , restrictive myopathy may be present

43
Q

Expected ocular movements summary

A

Limitation
Reversal
Hypometric Saccades
Cog wheel pursuit- - no smooth pursuit
Fatigue in ocular movements
Pain
Retraction
Bilateral involvement can be
asymmetric

44
Q

Order of EOM involvement

A

IR
MR
SR, LR
SO, IO (Thacker et al 2005)
Vertical, horizontal and torsional diplopia
Swelling of EOM results in restriction: if IR affected then pt unable to elevate as eye becomes tethered down

44
Q

SUMMARY of GO

A

GO is an autoimmune condition diagnosed by blood tests along with clinical history and assessment
MRI scans can aid diagnosis
Patients are usually hyperthyroid, but can be hypothyroid or euthyroid
Management of thyroid levels in an important first step in treatment
Multiple distinctive eye signs
Can result in painful eye movements if within active phase, diplopia or visual loss
Upgaze typically affected first

Strabismus (46 decks)

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