Systemic disease and the eye Flashcards
(136 cards)
What is the most common of all systemic diseases in eye clinics?
diabetes mellitus
What forms of sight impairment registration is diabetes a major cause of?
Both blind (severely sight impaired) and partial sighted (sight-impaired) registration in people under 65
What is a key endocrine disease associated with eye disease?
Graves’ disease - form of hypERthyroidism
What is ophthalmic Graves’ disease?
Clinical changes of Graves’ disease in the eye/orbit but clinically and biochemically euthyroid
What (briefly) is the physiology underlying Graves’ disease of the eye?
Immunologically mediated disease in which circulating auto-antibodies attack structures of the orbit and extra-ocular muscles
What is the key effect of Graves’ disease on the eye?
Inflammation of orbital and periorbital tissues
What are 5 EYE symptoms that a patient with Graves’ disease may present with?
- Exophthalmos (aka proptosis)
- Grossly swollen extra-ocular muscles –> restricted eye movements
- Lid retraction
- Lid lag
- Blindness
What causes exophthalmos/proptosis in Graves’ disease?
inflamed tissue in orbit (extra-ocular fat or peri-orbital muscles) forces the globe forwards; the orbit is an enclosed space, so the only direction for expansion is forwards.
Which extra-ocular muscles are particular affected by gross swelling in Graves’ disease?
medial and inferior recti
What is a consequence of the grossly swollen extra-ocular muscles?
Restricted eye movements
What is lid retraction?
Abnormally raised position of upper lid
What is lid lag?
Delayed following of upper lid as patient looks down
What are 2 things that can cause blindness in
- Optic nerve damage
2. Corneal perforation
What can cause optic nerve damage leading to blindness in Graves’ disease?
inflamed tissue in the orbit which compresses the nerve (irreparable)
What can cause corneal perforation leading to blindness in Graves’ disease?
eyelids and tear film provide barrier to surface of globe; when pushed forwards, lids can’t completely close –> drying, increased risk of infection, thinning and eventual perforation of the cornea
Where do the upper eyelids normally come down to (that is disrupted in graves’ disease: retraction)?
Normally rests just over the upper part of the cornea, covers the superior limbus (junction between cornea and sclera) - in Graves’ disease, can see continuous rim of sclera round cornea (see image)
What causes restricted eye movements in Graves’ disease?
Inflammation of infra-orbital and peri-ocular tissues, restricting movement of the globe
Look at an MRI of the orbit in Graves’ disease - how can the extra-ocular muscles be identified? What will be abnormal?
4 petal like structures = extra-ocular muscles just posterior to the globe. Grossly enlarged due to circulating auto-antibodies
Why can anything in neurology cause ophthalmic disease?
ophthalmology comprises the eye and visual system, and one third of the brain is devoted to the visual system –> any lesion that interferes with the visual pathways may present to an ophthalmologist
What are 8 neurological conditions with big implications for the eyes?
- CNIII palsy
- CNIV palsy
- CNVI palsy
- Horner’s syndrome
- Multiple sclerosis –> optic neuritis
- Myasthenia gravis
- Myotonic dystrophy
What are the three key symptoms of Horner’s syndrome, plus three additional symptoms?
- meiosis (small pupil), non-reactive pupil, anisocoria (different sized pupils)
- ptosis
- anhydrosis
- eye sunken back into socket
- facial flushing
- inability to completely close or open eye
What causes Horner’s syndrome?
Disruption in the pathway in the sympathetic nervous system i.e. compression of sympathetic chain (from hypothalamus to face and neck)
What are 3 points at which the cause of Horner’s syndrome can occur? Give examples for each.
- First order neuron: arises at hypothalamus –> through brainstem to upper spinal cord. [stroke, tumour, syringomyelia]
- Second order neuron: upper spinal cord, across upper thorax and into neck [Pancoast’s tumour in lung apex, schannoma, aortic disease]
- Third order neuron: neck to facial skin, muscles of eyelids and iris [base of skull tumour/ infection, cluster headaches/migraines, carotid artery dissection]
What 2 ocular symptoms will there be in myasthenia gravis?
Ptosis, ocular motility problems