580 likes | 1.23k Views
EYES IN FINALS. SHORTS TAGGED ON TO NEURO EXAM TINY PROPORTION OF THE MARKS Can make you look really clever RELAX. Neuro -ophthalmology for finals. Tom Marjot. To do…. Pupillary abnormalities Horners syndrome Eye movements and Ophthalmoplegia Visual field defects Special cases
E N D
EYES IN FINALS • SHORTS • TAGGED ON TO NEURO EXAM • TINY PROPORTION OF THE MARKS • Can make you look really clever • RELAX
Neuro-ophthalmology for finals Tom Marjot
To do… • Pupillary abnormalities • Horners syndrome • Eye movements and Ophthalmoplegia • Visual field defects • Special cases • Multiple Sclerosis • Myasthenia gravis • Cerebellar disease
Pupillary abnormalities Relative Afferent Pupillary Defect Rehearse! – come up with your own script “Stimulation of the normal eye produces full constriction of both pupils – both direct and consensal reflexes are intact” “Subsequent stimulation of the affected eye causes dilatation of both the pupils” “This is because the consensual pathway from the normal eye (which is now in darkness) is stronger than the afferent pathway from the pathological eye”
Relative Afferent Pupillary Defect …“These findings are consistent with a RAPD…otherwise known as a Marcus Gunn Pupil” REMEMBER: If you pick up a pen-torch in finals it is synonymous with “I am looking for a RAPD” Difference in pupil size in all other pathologies (Horners, oculomotor palsy, brainstem herniation) will NOT require a pen torch. ….. When I shine a light in the eye does the pupil dilate?
“What are the causes of RAPD?......” “Disorders of the optic nerve Or Disorders of the Retina … I would therefore like to perform fundoscopy Optic nerve: Optic neuritis/atrophy – Multiple Sclerosis Retina: Retinal detachment, retinal vein or artery occlusion, severe diabetic retinopathy “RAPD there must be a difference in the extent of the disease between the two eyes”
RAPD • Have a script • Pen-torch = RAPD = does pupil dilate when I shine a light? • Afferent pathway involves - nerve or retinal • Offer fundoscopy
Unequal pupils A starting point: • Don’t need a pen-torch • Look carefully • Smaller = ‘miotic’ Larger = ‘mydriatic’ • Unequal = “Anisocoria”
“The patient has marked anisocoria with a left miotic pupil” “The is also a visible (partial) left sided …………..Ptosis” “This gives the impression of apparent enophthalmos” “These findings would be consistent with a left Horners Syndrome”
So you’ve landed at Horner's Syndrome (Correctly) • Now sit and wait for the questions or you can be proactive. • Remember your differentials • You have discovered and commented on a ptosis • State that you would like to check for ophthalmoplegia (eye movements) because Myasthenia gravis and Oculomotor nerve pasyalso give a ptosis. • No opthalmoplegia and given the clearly miotic left pupil – Horner’s Syndrome. Silly because impossible to accurately clinically determine but important for exams ……… Pattern of ANHIDROSIS
ANHIDROSIS 1 3 More peripheral the lesion the less sweating is affected 1 - Face, arm and trunk 2 – Face 3 – Not affected 2
Unilateral ptosis Horners syndrome III nerve Palsy Myasthenia Gravis Bilateral ptosis Myasthenia Gravis 1 Central or Peripheral lesions Horner’s Central Demyelination Tumour Peripheral Pancoast tumour Cervical rib Neck/cardiothoracic surgery 3 2
Heterochromia Associated with congenital Horners
Horner’s Syndrome • Ptosis + miosis • Remember ptosis differentials and check eye movements • Causes can be central or peripheral
“The patient has a complete left sided ptosis” “There is also marked aniscocoria with a mydriatic pupil on the left” “There is a left divergent stabismus at rest…. With the eye fixed in a down and out position” “These findings would be consistent with a left III cranial nerve lesion” • LevatorPalpebraeSuperioris – CNIII • Mullers Muscle - Sympathetic “Due to pupillary involvment this could be said to be a ‘surgical’ III nerve palsy” Superior Oblique - IV Lateral Rectus - VI Unilateral ptosis Horners syndrome III nerve Palsy Myasthenia Gravis
Surgical External compressive lesion impinging on parasympathetic fibres which run very superficially in the nerve trunk • Tumour • Haemorrhage • Aneurysm – (Posterior Communicating Artery Aneursym) Medical • Diabetes Anatomically Brainstem: Tumour, infarct haemorrhage, demyelination Cavernous sinus lesion: Tumour, thrombosis Superior orbital fissure: Trauma
Oculomotor Nerve Palsy • Ptosis +/- mydriasis • Divergent strabismus at rest • Opthalmoplegia • Medical vs Surgical may help you list causes
Cavernous Sinus A large channel of venous blood creating a cavity bordered by the sphenoid bone and the temporal bone of the skull Get out of jail card when pushed for causes of Cranial nerve lesions Tumours, thrombosis, aneurysms, infections Oculomotor (III) Trochlea (IV) Ophthalmic nerve (V1) Maxillary nerve (V2) Abducens (VI) Internal carotid artery carrying sympathetic plexus Horner’s
IV and VI Nerve Superior Oblique - IV Lateral Rectus - VI Don’t effect pupil Don’t effect eyelid
VI Nerve Palsy “The patient has a convergent strabismus on the right at rest” Failure to Abduct the eye “Pupils are equal, no ptosis” Superior Oblique - IV Lateral Rectus - VI Abducens only job
VI (Abducens) Nerve Palsy ? Right convergent strabismus. “There is diplopia maximal on right lateral gaze ” (towards the affected side) (because you are trying to move the eye outwards with a non-functioning lateral rectus muscle) Outmost image comes from the affected eye Covering the right eye removes the outer most image
VI Nerve Palsy • Only innervates Lateral Rectus so can move eye outwards • Convergent strabismus at rest • Diplopia towards affected side • Outermost image comes from affected eye
IV Nerve Palsy • RARE and Unlikely for finals Trauma is most common Superior oblique – IN and DOWN Therefore in a palsy eye appears higher.
IV Nerve Palsy • RARE and Unlikely for finals Trauma is most common Superior oblique – IN and DOWN Therefore in a palsy eye appears higher.
IV Nerve Palsy • Rare. Trauma. • Eye higher • Head tilt to opposite side.
MONONEURITIS MULTIPLEX • Get out of jail card for nerve lesions • Simultaneous or sequential involvement of individual non-contiguous nerves WARDSPLC Wegeners AIDS/Amyloid Rheumatoid Diabetes Sarcoid Polyarteritisnodosa Leprosy Cancer Diabetes Vasculitis Rheumatoid IIIrd nerve palsy “What are the causes?” Surgical: Tumour Aneurysm Haemorrhage Medical: Diabetes …Mononeuritis multiplex
MONONEURITIS MULTIPLEX • Get out of jail card for nerve lesions • Simultaneous or sequential involvement of individual non-contiguous nerves WARDSPLC Wegeners AIDS/Amyloid Rheumatoid Diabetes Sarcoid Polyarteritisnodosa Leprosy Cancer Diabetes Vasculitis Rheumatoid Foot drop…. “What are the causes?” “Common peroneal nerve lesion (L5/S1)” External compression (cast) Trauma (head of fibula) Motor Neurone disease Charcot Marie Tooth …Mononeuritis multiplex”
VISUAL FIELDS Arcuatescotoma Glaucoma Age related macular degeneration Retinitis pigmentosa Migraine
Bitemporal Hemianopia • Common for finals • Easy to detect “Represent a lesion at the optic chiasm” • Pituitary tumour
↓TSH ↓T4
Bitemporal Hemianopia • Common for finals • Easy to detect “Represent a lesion at the optic chiasm” • Pituitary tumour • Craniopharyngioma • Menigioma/Glioma
Pituitary tumour Craniopharyngioma
From Hemiparesis to Homoymous Hemianopia One of the most likely Neuro cases Start with PRONATOR DRIFT Be patient Ask if Right or Left Handed
Diagnosed Hemiparesis Stroke MS Tumour
Diagnosed Hemiparesis Stroke MS Tumour BAMFORD Classification of Stroke Hemiparesis Hemianopia Loss Higher functioning x3 = TOTAL ANTERIOR CEREBRAL INFARCT X2 = PARTIAL ANTERIOR CEREBRAL INFARCT Dead @ 1 Year 60% 16%
PICK UP A PEN TORCH “Im looking for an RAPD” Hemiparesis + RAPD ………………………………….. MULTIPLE SCLEROSIS
“What are the causes RAPD?......” “Disorders of the optic nerve Or Disorders of the Retina … I would therefore like to perform fundoscopy Optic nerve: Optic neuritis/atrophy – Multiple Sclerosis Retina: Retinal detachment, retinal vein or artery occlusion, severe diabetic retinopathy “RAPD there must be a difference in the extent of the disease between the two eyes”
SPECIAL CASES MULTIPLE SCLEROSIS
Multiple Sclerosis, Multiple Eye Signs • RAPD – optic neuritis/atrophy • Ophthalmoplegia – any individual muscle or combination • Nystagmus (cerebellar involvement) • Internuclearopthalmoplegia (INO)
InternuclearOphthalmoplegia Medial Longitudinal Fasciculus • III VI • VI III Medial Longitudinal Fasciculus
InternuclearOphthalmoplegia Medial Longitudinal Fasciculus • III VI • VI III Medial Longitudinal Fasciculus Right sided INO Bad eye fails to ADduct Nystagmus
InternuclearOphthalmoplegia Medial Longitudinal Fasciculus • III VI • VI III Medial Longitudinal Fasciculus Bilateral INO Failure to ADduct in both eyes with contralateral nystagmus = MS
SPECIAL CASES Myasthenia Gravis
Ptosis Accentuated by upgaze Opthalmoplegia Variable and complex “Intra-saccadic fatigue” Pupils not involved Unilateral ptosis Horners syndrome III nerve Palsy Myasthenia Gravis Bilateral ptosis Myasthenia Gravis 15% pure ocularMyasthenia Gravis (more likely to be seronegative) 85% generalized Myasthenia Gravis
Cerebellar eye signs 1 - HORIZONTAL NYSTAGMUS FAST (saccade) Towards side of lesion 2 - BROKEN PERSUIT3 - ABNORMAL SACCADES