7. Ocular Manifestations of Systemic Disease Flashcards
Which diseases of the thyroid may cause eye pathology?
Thyroidtoxicosis (Excessive Thyroid secretion) Graves Disease (AI, IgG binds to TSH receptors, T3/4 secretion).
What are the systemic presentations of hyperthyroidism?
Diffuse thyroid enlargement Fine hand tremor Finger clubbing Pretibial myxoedema Tachycardia Atrial fibrilation
Describe the pathophysiology of the ocular manifestations of Thyroid Eye Disease?
It is an organ-specific autoimmune reaction.
Inflammation of extraoccular muscles.
Enlargement. Up to 8x.
Then they degenerate and become fibrosed = Restrictive myopathy & diplopia
Inflammatory Cellular Infiltration = Increases volume of orbital contents = Elevated IOP
What are the clinical ocular manifestations of TED?
Soft tissue involvement Lid retraction Proptosis Optic neuropathy Restrictive myopathy
What are the signs and symptoms of soft tissue involvement in TED?
SIGNS
Grittiness, lacrimation, retrobulbar discomfort
SYMPTOMS
Epibulbar hyperaemia (Red)
Periorbital swelling (Bags below/above eyes)
Chemosis (oedema of the conjunctiva)
What are the the signs of Lid Retraction?
- Dalrymple sign: lid retaraction in primary position
- Kocher sign: frightened appearance on attentive fixation
- Von Graefe sign: retarded descent of upper eye lid on downgaze-lid lag
How is proptosis categorised?
Axial
Unilateral or bilateral
Symmetrical or asymmetrical
What are the possible complications of proptosis?
Incomplete lid closure exposure keratitis or corneal ulceration
How is proptosis managed?
Systemic steroid used in rapidly, progressive & painful
Radiotherapy
Combined therapy
Surgical decompression
What is restrictive myopathy?
Ocular motility is restricted by inflammatory oedema & later by fibrosis
What is the Tx for restrictive myopathy?
Treatment is by surgery, if there is diplopia in primary or reading position
What is Optic Neuropathy?
Uncommon but serious complication
There is optic n. compression at the orbital apex by the enlarged recti
How does optic neuropathy present?
Impairment of central vision
Decreased VA, RAPD, colour vision desaturation Reduced light brightness appreciation
VF defect
What is the treatment for optic neuropathy?
Systemic steroid
Orbital decompression
What is Myasthenia Gravis?
Autoimmune disease
Antibodies mediates damage to acetylcholine receptors in striated muscle = impairment of neuromuscular conduction
There is weakness & fatigability of skeletal musculature
What are the systemic manifestations of Myasthenia Gravis?
Usually in the third decade Mostly with ptosis & diplopia Painless fatigue by exercise Worse towards the end of the day Difficult swallowing Difficult breathing is rare but serious