Thyroid eye disease (TED) Flashcards
what is graves
- Systemic autoimmune disorder
- Hyperthyroid - px starts with having this - over acting thyroid
- Orbitopathy - eye movement disorders, swelling due to graves disease - blood tests don’t always prove
- Myxoedema (lumpy red skin) - extreme situation
- Acropachy (finger clubbing) - extreme situation
epidemiology of graves
- Prevalence of hyperthyroidism in the general population is 1.2%
- 0.7% subclinical hyperthyroidism
- 0.4% Graves’ Disease – most common etiology; note there is overlap with the subclinical group
- Graves’ Disease is more common in females (7:1 ratio)
what is normal thyroid hormone control
2 hormones produced by the Thyroid Gland
* T4 Thyroxine
* T3 Triiodothyronine
They are responsible for the metabolic regulation in all cells
Normal control
- Thyrotropin releasing hormone (TRH)is produced by the hypothalamus - sends message of how much hormone is to be produced
- Acts on the anterior pituitary gland
- Releasing thyroid stimulating hormones (TSH) - if too much produced, increases T3 AND T4 production resulting in a goitre (swelling of gland)
- TSH binds to the TSH receptors in the thyroid gland releasing Thyroid hormone
Abnormal Control
- Hyperthyroidism in Graves disease is a direct result of an Abnormal Circulating Antibody (Ab) (TSH 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
causes
→ Graves Disease
→ Thyroiditis
→ Toxic Multinodular goitre - cancerous tumor in gland
→ Toxic Thyroid nodule
→ Self administered thyroid hormones - overdose on thyroid meds
Systemic symptoms Hyperthyroid
- Weight loss
- Increased appetite
- Intolerance of heat
- Anxiety
- Tremor - never had this before/ sudden onset
- Sweating
- Increased heart rate
Systemic Symptoms Hypothyroidism
Not producing enough T3 and T4
- Weight gain
- Decreased appetite
- Intolerance of cold
- Lethargy - tired/ fatigue - can also have MG
- Hair loss
- Reduced heart rate
what is Graves Orbitopathy
enetics play a large role in the development of GO
* High levels of TSH Ab linked to severe GO
* Smoking increases the severity of GO in hyperthyroidism
→ Not all patients with hyperthyroidism develop GO
→ Approx 20% of patients develop GO prior to the diagnosis of thyroid disorder
→ 20% are diagnosed with GO at the same time as their Thyroid disorder
→ 20% develop GO 6 months after the thyrioid is diagnosed
→ 40% can develop GO more than 6 months after their hyperthyroidism
A very small percentage of patients can be Hypothyroid or Euthyroid
Anybody attending endocrinology or presenting signs/ symptoms think TED
Pathophysiology - NEED TO KNOW!!
- Acute/Active - Inflammatory Phase - used to be called wet phase
- Late/Inactive Phase - 18 months after disease has started - can be known as dry phase
active phase of ted
- Connective Tissue Inflammation
- Activation of Extraocular Muscle Fibroblasts - EOM
start to swell up can be 8-10x bigger than normal size leading to PROPTOSIS, EXOPTHALMUS - Increasing Orbital volume by differentiating into orbital fat and secreting glycosaminoglycans
- These then attract water
- Inflammatory Myopathy resulting from the Autoimmune process
Connective Tissue Inflammation symptoms
- Redness
- Mild Ocular discomfort
- Periorbital swelling
- Pain on motility - usually on elevation as pain is on opposite direction of area affected
Corneal Exposure symptoms
- Grittiness
- Photophobia
- Epiphora - over production of tears to counteract gritiness
- Reduction in vision
enlarged EOM symptoms
→ Diplopia
→ Reduced field of BSV
→ Reduced uniocular field of fixation
Typical order of limitations - MEMORISE
Will usually follow this pattern
OBLIQUES ARE NOT INVOLVED
- Inferior Rectus - unable to elevate/ pain
- Medial Rectus - unable to pull eye out to side - may have hypo and eso deviation/ pain
- Superior Rectus
- Lateral Rectus
Diplopia in opposite direction
Clinical Features
- AHP of chin elevation
- Hypophoria/tropia usually first deviation
- With/Without Head Turn - when MR affected will have head turn to move eye away from problem as cant abduct
- Enlarged Vertical fusion range - anything above 5^ - longstanding 4th or TED, if normal vertical fusion range (2-3^) then recently acquired
- Raised IOP on elevation/attempted elevation - px may have spike in IOP on direct elevation (USUALLY EXTREME CASES)
Increased Orbital Volume
- PROPTOSIS - key sign - usually one eye
- COMPRESSION ON OPTIC NERVE
- Reduced Colour Vision - colour or contrast sensitivity may be reduced before reduced VA
- Loss of vision
Muller’s muscle hyperactivity
- Upper eyelid retraction
- Lower eyelid lag
→ Upper eyelid retraction - check palpebral aperture
→ Caused by overactivity of Muller’s muscle and finally by fibrosis of the levator muscle
Upper lid lag on downgaze - not depressing at same rate as eye
Soft Tissue Inflammation types
- Periorbital swelling
- Conjunctival swelling
- Conjunctival injection
Increased Orbital Volume
- Proptosis
- Lower eyelid retraction
- Corneal exposure
- Diplopia
- Compressive Optic Neuropathy
PROPTOSIS
- Proptosis
- Exophthalmos - both eyes protruding - using ex-ophthalmometer
- Unilateral/Bilateral
- Symmetrical/Asymmetrical
Signs of Optic Nerve Compression
- Loss of VA - can be loss of color sensitivity first
- This may be due to Corneal exposure and Punctate Keratitis
- Pinhole to ensure not refractive
- Reduction in color Vision - big sign of compression on optic nerve
- Visual Field defects – paracentral/arcuate/any - can be due to rise in IOP
- RAPD – unilateral/asymmetrical - compression of ON
- Mild or no disc swelling
- Extreme cases Optic atrophy develops
- VEP – showing reduced amplitude
- CT scan- crowding of orbital apex with enlarged muscles
Active phase can last 18 months - 2 years
Need to know day of initial symptoms
Inactive Phase
Cant manage with steroids in inactive stage - can only use in active and inflammatory phase
* Cicatrical phase - can also be known as this or inactive phase
* Fibrosis and muscle contraction - become tight and fibrotic, contract, muscle cant move UP or DOWN
* Reduction in proptosis/swelling
* Corneal exposure persists due to retraction of lids - due to insufficient lid closure
CAS SCORE
EUGOGO SCORE
For initial CAS, only score items 1-7
- Spontaneous orbital pain.
- Gaze evoked orbital pain.
- Eyelid swelling that is considered to be due to active (inflammatory phase)
- Eyelid erythema
- Conjunctival redness that is considered to be due to active (inflammatory phase
- Chemosis.
- Inflammation of caruncle OR plica. Patients assessed after follow-up can be scored out of 10 by including items 8-10.
- Increase of > 2mm in proptosis.
- Decrease in uniocularocular excursion in any one direction of > 8
- Decrease of acuity equivalent to 1 Snellen line
Score of severity
- RAPD - may have optic atrophy
- Eyelid measurements
- Proptosis
- Risk of Corneal Ulceration
