Flashcards in Neurology eye (delta) Deck (68):
Inferior obqlie action
Inferior rectus action
Medial rectus action
Superior rectus action
Retraction of eyelid
Superior oblique action
Lateral rectus action
CNs that originate from midbrain
CNs that originate from pons
CNs at cerbellopontine angle
CNs that originate at medulla
Increase in lens curvature; ciliary muscle contracts leading to relaxation of suspensory ligaments of lens
Constriction of pupils; activation of sphincter pupillae
Eye convergence medially
Signs of optic nerve dysfunction
Decrease in VA
Dyschromatopsia; red first
Visual field defects
Diminished contrast sensitivity
Systemic clinical features of MS
Motor spinal cord symptoms
Autonomic; bladder, blower and sexual dysfunction
Cerebellar; tremor + dysarthria + ataxia
L'hermitte sign; electrical shock on neck flexion
Uhthoff phenomenon; worsening of symptoms due to increase in temperature
Opthalmic features of MS?
Optic neuritis; unilateral pain exacerbated by eye movement, decreased VA (central scotoma), dyschromatopsia, RAPD
What can be seen on ix for MS?
Demyelinated plaques on MRI
Oligoclonal bands in CSF on LP
Tx for optic neuritis
IV methylprednisolone followed by PO prednisolone
What is neuromyelitis optica?
Demyelinating disorder characterized by bilateral severe optic neuritis and transverse myelitis in 3 or more vertebral columns
Causes muscle weakness, increased tone and spasm
What can be seen on investigation of neuromyelitis optica?
IgG antibody against AQP4
What is AION?
Damage to optic nerve as a result of ischaemia
Can be non-arteritic or caused by giant cell arteritis
Presentation of non-arteritic AION
Less than 50
RF: idiopathic, hypertx, diabetes, sleep apnoea, disc anomaly
Occlusion of short posterior ciliary artery
Sudden, painless, unilateral visual loss
Inferior altitudinal VF defect
Ix; BP, BG, exclude GCA
Presentation of GCA
Older than non-arteritic
GCS of short posterior ciliary artery
Sudden, painful, unilateral severe visual loss
Disc; chalky white, diffusely swollen, optic atrophy
Assoc sy; scalp tenderness, headache, jaw claudication
Ix; ESR, CRP, temporal artery biopsy
Tx; high dose IV methylprednisolone
What is papilloedema?
Optic disc swelling due to elevated ICP
Clinical features of papilloedema
Elevated ICP sy; headache (worse in morning), N+V, pulsatile tinnitus, deterioration of consciousness
Transient visual loss with a duration of seconds
Enlarged blind spot
Signs of papilloedema on fundoscopy
Hyperaemia and blurring of disc margins
Swelling and elevation of optic disc with peripapillary sphincter haemorrhage
What is horner's syndrome?
Lesion to symp pathway
Hallmarks of horner's syndrome
What causes horner's syndrome
Cavernous sinus lesion
What does a painful horner's syndrome direct you towards?
Carotid/ ICA dissection
What can be used to confirm hroner's syndrome?
Apraclonidine; will cause pupillary dilation in the horner's pupil but normal pupil will be unaffected
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
Cause of NF1
Mutation in NF1 gene on chromosome 17
Clinical features of NF1
Ophthalmic features; optic nerve glioma, bilateral lisch nodules, plexiform neurofibromas of eyelid
Cause of NF2
Mutation in NF2 gene on chromosome 22
Features of NF2
Bilateral vestibular schwannoma
What is benign essential blepharospasm?
Bilateral idiopathic condition characterized by involuntary contraction of orbicularis oris muscle
Presents in 6th decade
Diagnosis of exclusion
Tx for benign essential blepharospasm
Botulinum toxin injection
What is contained within the cavernous sinus?
ICA and CN6 pass directly through
Lateral walls; CN 3,4 and 5 (V1 and V2)
Clinical features of cavernous sinus syndrome?
Ptosis and ophthalmoplegia: compression of CN 3,4,6
Loss of corneal reflex: CN V1
Maxillary sensory loss
Horner's syndrome; internal carotid ocular sympathetics
Proptosis and periorbital swelling