Flashcards in Neurology eye (delta) Deck (68)
What is lateral medullary syndrome (wallenberg's syndrome)?
Ischaemia of lateral part of medulla due to blockage of posterior inferior cerebellar artery or vertebral artery
What are the clinical features of wallenberg's syndrome?
Damage to vestibular nucleus; vertigo, vomiting, nystagmus
Damage to descending symp tract; ipsilateral horner's
Damage to spinal trigeminal; ipsilateral loss of pain/temp and loss of corneal reflex
Damage to spinothalamic tract; contralateral loss of pain/ temp in trunk and limbs
What is adie's pupil?
Loss of postganglionic parasymp innervation to iris sphincter and ciliary muscle
What are the clinical features of adie's pupil?
Dilation and blurring on near vision
Light reflex absent or slow
What is Holmes-Adie syndrome?
Diminished or absent deep tendon reflex of lower limbs + adie's pupil +/- orthostatic hypotension
Ix for Adie's pupil
0.125% topical pilocarpine. Adie's pupil will constrict while normal pupil won't
What causes argyll robertson pupil?
What are the clinical features of argyll robertson pupil?
Bilateral, irregularly small pupils
Will NOT react to light
Will argyll robertson pupils constrict to 0.1% pilocarpine?
Causes of chiasmatic lesions?
Large pituitary adenomas
Tuberculum sellae meningioma
What visual field defects will chiasmatic optic nerve cause?lesions
What will visual field defects will lesions at the optic tracts cause?
Contralateral homonymous hemianopia
What visual field defects will lesions at the optic radiations cause?
Temporal; contralateral superior homonymous quadrantanopia
Parietal; contralateral inferior homonymous quadrantanopia
Main radiations; contralateral homonymous hemianopia
What visual field defects will lesions at the occipital cortex cause?
Contralateral homonymous hemianopia with macular sparing
Congruous homonymous macular defects if posterior head injury
Features of 3rd nerve palsy?
Abduction and depression with ophthalmoplegia
Dilated pupil and accomodation abnormality
What causes a painful 3rd nerve palsy?
Posterior communicating artery anurysm
Causes of 3rd nerve palsy?
Diabetes and hypertex; affect blood supply to nerve
Posterior communicating artery aneurysm (painful)
What is weber's syndrome?
Stroke affecting ventral midbrain; characterised by ipsilateral 3rd nerve palsy with contralateral hemiapresis
What is benedikt's syndrome?
Form of stroke affecting dorsal midbrain characterised by ipsilateral 3rd nerve palsy with contralateral tremor, ataxia or chorea (red nucleus)
Clinical features of 4th nerve palsy?
Depression of eye is limited
Compensatory head tily
Causes of 4th nerve palsy?
Clinical features of 6th nerve palsy
Horizontal double vision
Esotropia in primary position
Causes of 6th nerve palsy?
Diabetes and hypertx
Increased ICP; abducens passes over petrous tip and so can easily be squashed by increased pressure
What is the pathology of myasthenia gravis?
Autoimmune disease of ACh receptors at post-synaptic NMJ
Clinical features of myasthenia gravis
Cogan lid twitch
Fragility and weakness or muscles of facial expression and proximal limb muscles
Ix for myasthenia gravis
Ice test; ptosis imrpvoes
Antibodies; anti-ACh receptor antibody and MUSK antibody
EMG and muscle biopsy
Imagine of thorax for thymoma
Mx for myasthenia gravis?
Surgery if thymoma present
Features of myotonic dystrophy
Delayed muscular relaxation and muscle wasting
Early onset cataract
What causes myotonic dystrophy?
Trinucleotide repeat on chromosome 19