Neuro (station 3) Flashcards
Genetics of myotonic dystrophy?
Dystrophia myotonica (DM) can be categorised as type 1 or 2 depending on the underling genetic defect.
⚬ DM1: expansion of CTG trinucleotide repeat sequence within DMPK gene on
chromosome 19
⚬ DM2: expansion of CCTG tetranucleotide repeat sequence within ZNF9 gene on chromosome 3
Autosomal dominant
Genetic anticipation- presents in earlier age with successive generations
At what age do you expect a patient with myotonic dystrophy to present?
DM1 usually presents in 20s–40s (DM2 later), but can be very variable depending on number of triplet repeats.
In what conditions do you see genetic anticipation?
genetic anticipation: worsening severity of the condition and earlier age of
presentation within successive generations.
Seen in DM1, Huntington’s chorea (autosomal dominant) and Friedrich’s ataxia (autosomal recessive).
Facial clinical signs of myotonic dystrophy?
• Myopathic facies: long, thin and expressionless
• Wasting of facial muscles and sternocleidomastoid
• Bilateral ptosis
• Frontal balding
• Dysarthria: due to myotonia of tongue and pharynx
Clinical signs of myotonic dystrophy in the hands?
• myotonia: ‘Grip my hand, now let go’ (may be obscured by profound weakness). ‘Screw up your eyes tightly shut, now open them’.
• wasting and weakness of distal muscles with areflexia.
• Percussion myotonia: percuss thenar eminence and watch for involuntary thumb flexion.
Additional non neurological signs in a patient with myotonic dystrophy
• Cataracts
• Cardiomyopathy, brady‐ and tachy‐arrhythmias (look for pacemaker scar)
• Diabetes (ask to dip urine)
• Testicular atrophy
• Dysphagia (ask about swallowing)
Diagnosis of myotonic dystrophy?
• Clinical features
• EMG: ‘dive‐bomber’ potentials
• Genetic testing
Mx of myotonic dystrophy
• Affected individuals die prematurely of respiratory and cardiac complications
• Weakness is major problem – no treatment
• Phenytoin may help myotonia
• Advise against general anaesthetic (high risk of respiratory/cardiac complications)
Common causes of ptosis
Clinical signs of cerebellar syndrome
Scanning dysarthria
Outstretched hands: rebound phenomenon
Face: nystagmus
UL: dysdiadochokinesia, hypotonia, hyporeflexia
LL: wide based ataxic gait
How to tell if cerebellar vermis vs hemisphere affected?
• Cerebellar vermis lesions produce an ataxic trunk and gait but the limbs are normal when tested on the bed
• Cerebellar lobe lesions produce ipsilateral cerebellar signs in the limbs
Nystagmus direction in cerebellar lesion
The fast-phase direction is TOWARDS the side of the lesion, and is maximal on looking TOWARDS the lesion.
Nystagmus in vestibular nucleus / VIII nerve lesion
fast-phase direction is AWAY FROM the side of the lesion, and is maximal on looking AWAY FROM the lesion.
Causes of cerebellar syndrome
PASTRIES
- Paraneoplastic cerebellar syndrome
- alcoholic cerebellar degeneration
- Sclerosis (MS)
- tumour (posterior fossa SOL)
- rare (Friedrich’s and ataxia telangiectasia)
- iatrogenic (phenytoin toxicity)
- Endocrine (hypothyroidism)
- Stroke (brain stem vascular event)
Cerebellar syndrome + gingival hypertrophy?
Phenytoin toxicity
Cerebellar syndrome + unkempt appearance + stigmata of liver disease?
ETOH
Cerebellar syndrome + neuropathy ?
ETOH, friedrich’s ataxia
Cerebellar syndrome + clubbing, tar stained fingers, radiotherapy burns
Bronchial carcinoma
Cerebellar syndrome + optic atrophy?
MS, friedrichs ataxia
Cerebellar syndrome + Internuclear opthalmoplegia, spasticity, female, younger age
MS
Clinical signs in multiple sclerosis?
• inspection: ataxic handshake and wheelchair
• Cranial nerves: internuclear ophthalmoplegia (frequently bilateral in MS), optic atrophy, reduced visual acuity, and any other cranial nerve palsy
• Peripheral nervous system: Upper‐motor neurone spasticity, weakness, brisk reflexes and altered sensation
• Cerebellar syndrome: ‘DANISH’
Features of internuclear ophthalmoplegia?
Diagnostic criteria for MS?
Central nervous system demyelination (plaques) causing neurological impairment that is disseminated in both time and space.
Cause of multiple sclerosis?
Unknown, but both genetic – (HLA‐DR2, interleukin‐2 and ‐7 receptors) and environmental factors (increasing incidence with increasing latitude, association with Epstein–Barr virus infection) appear to play a role.
Ix of multiple sclerosis
Clinical diagnosis plus
• CSF: oligoclonal IgG bands
• MRI: periventricular white matter plaques
• Visual evoked potentials (VEPs): delayed velocity but normal amplitude (evidence of previous optic neuritis)
Other clinical features of MS apart from neurological impairment disseminated in both space and time?
• Higher mental function: depression, occasionally euphoria
• Autonomic: urinary retention/incontinence, impotence and bowel problems
- Uthoff’s phenomenon: worsening of symptoms after a hot bath or exercise
- lhermitte’s sign: lightning pains down the spine on neck flexion due to cervical cord plaques
Treatment of MS?
multidisciplinary approach
- Nurse, physiotherapist, occupational therapist, social worker and physician.
Disease modifying treatments
• Interferon‐beta and Glatiramer reduce relapse rate but don’t affect progression. • Monoclonal antibody therapy potentially offers greater benefits; reducing disease progression and accumulated disability, e.g. Alemtuzumab (anti‐CD52) – lymphocyte depletion, Natalizumab (anti‐α4 integrin) – blocks T‐cell trafficking. Toxicity may limit their use.
Symptomatic treatments
• Methyl‐prednisolone during the acute phase may shorten the duration of the ‘attack’ but does not affect the prognosis.
• Anti‐spasmodics, e.g. Baclofen.
• Carbamazepine (for neuropathic pain)
• Laxatives and intermittent catheterization/oxybutynin for bowel and bladder disturbance
Prognosis of multiple sclerosis?
Variable: The majority will remain ambulant at 10 years.
MS and pregnancy?
• Reduced relapse rate during pregnancy
• Increased risk of relapse in postpartum period
• Safe for foetus (possibly reduced birth weight)
Clinical signs in stroke
• inspection: walking aids, nasogastric tube or PEG tube, posture (flexed upper limbs and extended lower limbs), wasted or oedematous on affected side.
• tone: spastic rigidity, ‘clasp knife’ (resistance to movement, then sudden release).
Ankles may demonstrate clonus (>4 beats).
• Power: reduced.
• Coordination: sometimes reduced. Usually impaired due to weakness but may reflect cerebellar involvement in posterior circulation stroke.
• reflexes: brisk with extensor plantars
MRC power grading?
0, none
1, flicker
2, moves with gravity neutralized
3, moves against gravity
4, reduced power against resistance
5, normal
Signs that may reveal underlying cause of stroke?
irregular pulse (AF)
blood pressure
cardiac murmurs
carotid bruits (anterior circulation stroke)
Why is frontalis spared in stroke
frontalis muscle receives bilateral supranuclear innervation and, thus, strokes that occur above the facial nucleus (i.e., cortical, subcortical, and upper pontine strokes) will spare the upper facial muscles
Stroke vs TIA definition?
• Stroke: rapid onset, focal neurological deficit due to a vascular lesion lasting > 24 hours.
• transient ischaemic attack (tia): focal neurological deficit lasting < 24 hours
Ix in suspected stroke
• Bloods: FBC, CRP/ESR (young CVA may be due to arteritis), glucose and renal function
• ECG: AF or previous infarction
• Cxr: cardiomegaly or aspiration
• Ct head: infarct or bleed, territory
• Consider echocardiogram, carotid Doppler, MRI/A/V (dissection or venous sinus thrombosis in young patient), clotting screen (thrombophilia), vasulitis screen in young CVA
Acute mx of stroke
• Thrombolysis with tPA (within 4.5 hours of acute ischaemic stroke)
+/- mechanical thrombectomy
• antiplatelet therapy
• Referral to a specialist stroke unit: multidisciplinary approach: physiotherapy,
occupational therapy, speech and language therapy and specialist stroke rehabilitation nurses
• DVT prophylaxis
Chronic management of stroke
• Carotid endarterectomy in patients who have made a good recovery, e.g. in PACS (if >70% stenosis of the ipsilateral internal carotid artery)
• Anticoagulation for cardiac thromboembolism
• Address cardiovascular risk factors
• Nursing +/− social care.
Features of total anterior circulation stroke
• Hemiplegia (contra‐lateral to the lesion)
• Homonomous hemianopia (contra‐lateral to the lesion)
• Higher cortical dysfunction, e.g. dysphasia, dyspraxia and neglect
Features of partial anterior circulation stroke
2/3 of
• Hemiplegia (contra‐lateral to the lesion)
• Homonomous hemianopia (contra‐lateral to the lesion)
• Higher cortical dysfunction, e.g. dysphasia, dyspraxia and neglect
Dominant parietal lobe cortical signs
• Dysphasia: receptive, expressive or global
• gerstmann’s syndrome
⚬ Dysgraphia, dyslexia and dyscalculia
⚬ L‐R disorientation
⚬ Finger agnosia
Non dominant parietal lobe stroke signs
• Dressing and constructional apraxia
• Spatial neglect
Either
• Sensory and visual inattention
• Astereognosis
• Graphaesthesia
Features of lateral medullary syndrome?
Clinical signs of spastic legs?
• Wheelchair and walking sticks (disuse atrophy and contractures may be present if chronic)
• Increased tone and ankle clonus
• Generalized weakness
• Hyper‐reflexia and extensor plantars
• Gait: ‘scissoring’
additional signs
• Examine for a sensory level suggestive of a spinal lesion
• Look at the back for scars or spinal deformity
• Search for features of multiple sclerosis, e.g. cerebellar signs, fundoscopy for optic
atrophy
• Ask about bladder symptoms and note the presence or absence of urinary catheter.
Offer to test anal tone
Causes of spastic legs?
Common:
• Multiple sclerosis
• Spinal cord compression/cervical myelopathy
• Trauma
• Motor neurone disease (no sensory signs)
Other Causes
• Anterior spinal artery thrombosis: dissociated sensory loss with preservation of dorsal columns
• Syringomyelia: with typical upper limb signs
• Hereditary spastic paraplegia: stiffness exceeds weakness, positive family history
• Subacute combined degeneration of the cord: absent reflexes with upgoing plantars
• Friedreich’s ataxia
• Parasagittal falx meningioma
Some causes of cord compression?
⚬ Disc prolapse (above L1/2)
⚬ Malignancy
⚬ Infection: abscess or TB
⚬ Trauma: # vertebra
Mx cord compression?
⚬ Urgent surgical decompression
⚬ Consider steroids and radiotherapy (for a malignant cause)
Lower limb dermatomes
Lower limbs which action to test which spinal root
What is syringomyelia?
Syringomyelia is caused by a progressively expanding fluid filled cavity (syrinx) within the cervical cord, typically spanning several levels.
What structures does a syringomyelia affect?
Syrinx expands ventrally affecting:
1 Decussating spinothalamic neurones producing segmental pain and temperature loss at the level of the syrinx.
2 Anterior horn cells producing segmental lower motor neurone weakness at the level of the syrinx.
3 Corticospinal tract producing upper motor neurone weakness below the level of the syrinx.
It usually spares the dorsal columns 4 (proprioception).
Syringomyelia associated with?
Arnold–Chiari malformation and spina bifida
Clinical signs of Syringomyelia?
• Weakness and wasting of small muscles of the hand
• Loss of reflexes in the upper limbs
• Dissociated sensory loss in upper limbs and chest: loss of pain and temperature sensation (spinothalamic) with preservation of joint position and vibration sense (dorsal columns)
• Scars from painless burns
• Charcot joints: elbow and shoulder
additional signs
• Pyramidal weakness in lower limbs with upgoing (extensor) plantars
• Kyphoscoliosis is common
• Horner’s syndrome
• If syrinx extends into brain stem (syringobulbia) there may be cerebellar and lower cranial nerve signs
What is a Charcot joint
Painless deformity and destruction of a joint with new bone formation following repeated minor trauma secondary to loss of pain sensation
Causes of Charcot joint?
⚬ Tabes dorsalis: hip and knee
⚬ Diabetes: foot and ankle
⚬ Syringomyelia: elbow and shoulder
Treatment of Charcot joint
bisphosphonates can help
Cervical roots - power and reflexes
What is motor neuron disease
MND is a progressive disease of unknown aetiology
• There is axonal degeneration of upper and lower motor neurones
Types of motor neuron disease
• amyotrophic lateral sclerosis (50%): affecting the cortico‐spinal tracts predominantly producing spastic paraparesis or tetraparesis.
• Progressive muscular atrophy (25%): affecting anterior horn cells predominantly producing wasting, fasciculation and weakness. Best prognosis.
• Progressive bulbar palsy (25%): affecting lower cranial nerves and suprabulbar nuclei producing speech and swallow problems. worst prognosis.
Ix of Motor neuron disease?
• Clinical diagnosis
• Emg: fasciculation
• MRI (brain and spine): excludes the main differential diagnoses of cervical cord compression and myelopathy and brain stem lesions
Mx of motor neuron disease
• Supportive, e.g. PEG feeding and NIPPV
• Multidisciplinary approach to care
• Riluzole (glutamate antagonist): slows disease progression by an average of 3 months but does not improve function or quality of life and is costly
Prognosis of motor neuron disease
• Most die within 3 years of diagnosis from bronchopneumonia and respiratory failure. Some disease variants may survive longer.
• Worst if elderly at onset, female and with bulbar involvement.
Causes of generalised wasting of hand muscles?
anterior horn cell
⚬ MND
⚬ Syringomyelia
⚬ Cervical cord compression
⚬ Polio
Brachial plexus:
⚬ Cervical rib
⚬ Pancoast’s tumour
⚬ Trauma
Peripheral nerve:
⚬ Combined median and ulnar nerve lesions
⚬ Peripheral neuropathy
muscle
⚬ Disuse atrophy, e.g. rheumatoid arthritis
What is fasciculation?
Visible muscle twitching at rest
Causes of fasciculations
axonal loss results in the surviving axons recruiting and innervating more
myofibrils than usual resulting in large motor units
Fasciculations commonly seen in?
MND, syringomyelia
Clinical signs of Parkinson’s disease?
• Expressionless face with an absence of spontaneous movements.
• Coarse, pill‐rolling, 3–5 Hz tremor. Characteristically asymmetrical.
• Bradykinesia (demonstrated by asking patient to repeatedly oppose each digit onto thumb in quick succession).
• Cogwheel rigidity at wrists (enhanced by synkinesis – simultaneous movement of the other limb (tap opposite hand on knee, or wave arm up and down) ).
• Gait is shuffling and festinant. Absence of arm swinging – often asymmetrical.
• Speech is slow, faint and monotonous.
in addition
• BP looking for evidence of multisystem atrophy: Parkinsonism with postural
hypotension, cerebellar and pyramidal signs.
• Test vertical eye movements (up and down) for evidence of progressive
supranuclear palsy.
• Dementia and Parkinsonism: lewy‐body dementia.
• Ask for a medication history
Causes of Parkinsonism?
- Parkinson’s disease (idiopathic)
- Parkinson plus syndromes:
Multisystem atrophy (Shy–Drager)
Progressive supranuclear palsy (Steele–Richardson–Olszewski)
Corticobasal degeneration; unilateral Parkinsonian signs - Drug‐induced, particularly phenothiazines
- Anoxic brain damage
- Post‐encephalitis
- MPTP toxicity (‘frozen addict syndrome’)
Pathophysiology of Parkinson’s disease
Degeneration of the dopaminergic neurones between the substantia nigra and basal ganglia.
Treatment options for Parkinson’s disease?
• l‐Dopa with a peripheral Dopa‐decarboxylase inhibitor, e.g. Madopar/co‐beneldopa:
⚬ Problems with nausea and dyskinesia
⚬ Effects wear off after a few years so generally delay treatment as long as possible
⚬ End‐of‐dose effect and on/off motor fluctuation may be reduced by modified release preparations
• Dopamine agonists, e.g. Pergolide:
⚬ Use in younger patients: less side effects (nausea and hallucinations) and save l‐Dopa until necessary
⚬ apomorpine (also dopamine agonist) given as an SC injection or infusion; rescue therapy for patients with severe ‘off’ periods
• mao‐B inhibitor, e.g. Selegiline, inhibit the breakdown of dopamine
• anti‐cholinergics, can reduce tremor, particularly drug‐induced
• Comt inhibitors, e.g. Entacapone, inhibit peripheral breakdown of l‐Dopa thus
reducing motor fluctuations
• amantadine, increases dopamine release
• Surgery; deep‐brain stimulation (to either the subthalamic nucleus or globus pallidus)
> helps symptoms
Causes of tremor?
• resting tremor: Parkinson’s disease
• Postural tremor (worse with arms outstretched):
⚬ Benign essential tremor (50% familial) improves with EtOH
⚬ Anxiety
⚬ Thyrotoxicosis
⚬ Metabolic: CO2 and hepatic encephalopathy
⚬ Alcohol
• intention tremor: seen in cerebellar disease
Most common types of Hereditary sensory motor neuropathy? HSMN
Aka Charcot Marie tooth
Most common types are I (demyelinating) and II (axonal)
Clinical signs of hereditary sensory motor neuropathy e.g Charcot Marie tooth disease, peroneal muscular atrophy?
• Wasting of distal lower limb muscles with preservation of the thigh muscle bulk (inverted champagne bottle appearance)
• Pes cavus (seen also in Friedreich’s ataxia)
• Weakness of ankle dorsi‐flexion and toe extension
• Variable degree of stocking distribution sensory loss (usually mild)
• Gait is high stepping (due to foot drop) and stamping (absent proprioception)
• Wasting of hand muscles
• Palpable lateral popliteal nerve
Causes of predominantly sensory peripheral neuropathy
• Diabetes mellitus
• Alcohol
• Drugs, e.g. isoniazid and vincristine
• Vitamin deficiency, e.g. B12 and B1
Causes of predominantly motor peripheral neuropathy
• Guillain–Barré and botulism present acutely
• Lead toxicity
• Porphyria
• HSMN
Causes of mononeuritis multiplex
• Diabetes mellitus
• Connective tissue disease, e.g. SLE and rheumatoid arthritis
• Vasculitis, e.g. polyarteritis nodosa and Churg–Strauss
• Infection, e.g. HIV
• Malignancy
inheritance pattern of Friedreich’s ataxia?
autosomal recessive
onset and prognosis for Friedreich’s ataxia?
onset during teenage years,
survival rarely exceeds 20 years from diagnosis
signs of Friedreich’s ataxia?
- Young adult, wheelchair (or ataxic gait)
- Pes cavus
- Bilateral cerebellar ataxia (ataxic hand shake + other arm signs, dysarthria, nystagmus)
- Leg wasting with absent reflexes and bilateral upgoing plantars
- Posterior column signs (loss of vibration and joint position sense)
other signs
* Kyphoscoliosis
* Optic atrophy (30%)
* High‐arched palate
* Sensorineural deafness (10%)
* Listen for murmur of HOCM
* Ask to dip urine (10% develop diabetes)
what heart condition is Friedreich’s ataxia associated with?
HOCM
Causes of extensor plantars with absent knee reflexes?
- Friedreich’s ataxia
- Subacute combined degeneration of the cord
- Motor neurone disease
- Taboparesis (syphilis)
- Conus medullaris lesions
- Combined upper and lower pathology, e.g. cervical spondylosis with peripheral
neuropathy
what is bell’s phenomenon?
eyeball rolls upwards on attempted eye closure
signs of facial nerve palsy
- Unilateral facial droop, absent nasolabial fold and forehead creases
- Inability to raise the eyebrows (frontalis), screw the eyes up (orbicularis oculi) or smile
(orbicularis oris)
facial nerve palsy + parotid mass/scar?
parotid tumour, trauma to neck/face
facial nerve palsy + VIII, V nerve involvement + cerebellar signs?
lesion at cerebellopontine angle e.g. acoustic neuroma
Facial nerve and VIII nerve palsy?
lesion at internal acoustic meatus/ facial canal
e.g. cholesteatoma, abscess
facial nerve palsy and long tract signs?
lesion might be at level of pons
(where facial nerve exits)
e.g. MS, stroke
Causes of isolated facial nerve palsy?
commonest: Bell’s palsy
- Herpes zoster (Ramsay Hunt syndrome)
- Mononeuropathy due to diabetes, sarcoidosis or Lyme disease
- Tumour/Trauma
- MS/ stroke
features of Bell’s palsy?
- rapid onset (1-2 days)
- HSV 1 has been implicated
- induced swelling and compression of the nerve within the facial canal causes demyelination and temporary conduction block
treatment of Bell’s palsy?
prednisolone commenced within 72h of onset improves outcomes + aciclovir if severe (as HSV1 has been implicated)
eye protection: artificical tears, tape eye closed at night
prognosis of bell’s palsy?
70-80% make full recovery, substantial minority have persistent facial weakness
more common in pregnancy, outcome may also be worse
causes of bilateral facial palsy?
- Guillain Barre
- Myasthenia gravis
- Bilateral Bell’s palsy
- Sarcoidosis
- Lyme disease
pathophysiology of myasthenia gravis?
Anti‐nicotinic acetylcholine receptor (anti‐AChR) antibodies affect motor
end‐plate neurotransmission
associated conditions of myasthenia gravis?
other autoimmune diseases, e.g. diabetes mellitus, rheumatoid arthritis,
thyrotoxicosis, SLE and thymomas
clinical signs of myasthenia gravis
- Bilateral ptosis (worse on sustained upward gaze)
- Complicated bilateral extra‐ocular muscle palsies
- Myasthenic snarl (on attempting to smile)
- Nasal speech, palatal weakness and poor swallow (bulbar involvement)
- Demonstrate proximal muscle weakness in the upper limbs and fatiguability. The
reflexes are normal - Look for sternotomy scars (thymectomy)
- State that you would like to assess respiratory muscle function (FVC)
Ix of myasthenia gravis?
For diagnosis:
* Anti‐AChR antibodies positive in 90% of cases
* Anti‐MuSK (muscle‐specific kinase) antibodies often positive if anti‐AChR negative
* EMG: decremented response to a titanic train of impulses
* Edrophonium (Tensilon) test: an acetylcholine esterase inhibitor increases the concentration of ACh at the motor end plate and hence improves the muscle weakness. Can cause heart block and even asystole.
Others
* CT or MRI of the mediastinum (thymoma in 10%)
* TFTs (Grave’s present in 5%)
treatment of myasthenia gravis?
acute:
* IV immunoglobulin or plasmapheresis (if severe)
Chronic:
* Acetylcholine esterase inhibitor, e.g. pyridostigmine
* Immunosuppression: steroids and azathioprine
* Thymectomy is beneficial even if the patient does not have a thymoma (usually young females)
causes of bilateral ptosis?
- Congenital
- Senile
- Myasthenia gravis
- Myotonic dystrophy
- Mitochondrial cytopathies, e.g. Kearns–Sayre syndrome
- Bilateral Horner’s syndrome
causes of bilateral extra-ocular palsies?
- Myasthenia gravis
- Graves’ disease
- Mitochondrial cytopathies, e.g. Kearns–Sayre syndrome
- Miller–Fisher variant of Guillain–Barré syndrome
- Cavernous sinus pathology
features of Lambert Eaton Myasthenic syndrome?
- Diminished reflexes that become brisker after exercise
- Lower limb girdle weakness (unlike myasthenia gravis)
- Associated with malignancy, e.g. small‐cell lung cancer
antibodies associated with lambert eaton myasthenic syndrome?
Antibodies block pre‐synaptic calcium channels
EMG finding of Lambert Eaton Myasthenic Syndrome?
EMG shows a ‘second wind’ phenomenon on repetitive stimulation
Central Retinal Vein Occlusion
Clinical features:
* Flame haemorrhages +++ radiating out from a swollen disc
* Engorged tortuous veins
* Cotton wool spots
features of central retinal revin occlusion on fundoscopy?
- Flame haemorrhages +++ radiating out from a swollen disc
- Engorged tortuous veins
- Cotton wool spots
- Cause: look for diabetic or hypertensive changes (visible in branch retinal vein
occlusion) - Effect: Rubeosis iridis causes secondary glaucoma (in central retinal vein occlusion),
visual loss or field defect.
> rubeosis iridis, is when, blood vessels develop on the anterior surface of the iris in response to retinal ischemia.
Causes of Central Retinal Vein occlusion?
- Hypertension
- Hyperglycaemia: diabetes mellitus
- Hyperviscocity: Waldenström’s macroglobulinaemia or myeloma
- High intraocular pressure: glaucoma
Central Retinal Artery Occlusion
Clinical signs of Central retinal artery occlusion?
- Pale, milky fundus with thread‐like arterioles
- ± Cherry red macula (choroidal blood supply)
- Cause: AF (irregular pulse) or carotid stenosis (bruit)
- Effect: optic atrophy and blind (white stick)
Note that branch retinal artery occlusion will have a field defect opposite to the quadrant of affected retina
causes of central retinal artery occlusion?
- Embolic: carotid plaque rupture or cardiac mural thrombus
> Treatment: aspirin, anti‐coagulation and endarterectomy - giant cell arteritis: tender scalp and pulseless temporal arteries
> treatment: high‐dose steroid urgently, check ESR and arrange temporal artery biopsy to confirm diagnosis
Retinitis pigmentosa
Peripheral retina ‘bone spicule pigmentation’, which follows the veins and spares the macula.
Optic atrophy due to neuronal loss (consecutive).
clinical signs of retinitis pigmentosa?
- White stick and braille book (registered blind)
- Reduced peripheral field of vision (tunnel vision)
- Fundoscopy:
- Peripheral retina ‘bone spicule pigmentation’, which follows the veins and spares the macula.
- Optic atrophy due to neuronal loss (consecutive).
- Association: cataract (absent red reflex)
clinical signs to search for underlying cause of retinitis pigmentosa?
- ataxic: Friedreich’s ataxia, abetalipoproteinaemia, Refsum’s disease, Kearns–Sayre syndrome
- Deafness (hearing‐aid/white stick with red stripes): Refsum’s disease, Kearns– Sayre syndrome, Usher’s disease
- ophthalmoplegia/ptosis and permanent pacemaker: Kearns–Sayre syndrome
- Polydactyly: Laurence–Moon–Biedl syndrome
- icthyosis: Refsum’s disease
what is retinitis pigmentosa?
Inherited form of retinal degeneration characterized by loss of photo receptors
causes of retinitis pigmentosa?
- Congenital: often autosomal recessive inheritance, 15% due to rhodopsin pigment mutations
- Acquired: post‐inflammatory retinitis
prognosis of retinitis pigmentosa?
- Progressive loss of vision due to retinal degeneration. Begins with reduced night vision. Most are registered blind at 40 years, with central visual loss in the seventh decade
- No treatment although vitamin A may slow disease progression
causes of tunnel vision?
- Papilloedema
- Glaucoma
- Choroidoretinitis
- Migraine
- Hysteria
fundoscopy findings of age related macular degeneration?
- Wet (neovascular and exudative) or dry (non‐neovascular, atrophic and non‐exudative)
Macular changes:
⚬ Drusen (extracellular material)
⚬ Geographic atrophy
⚬ Fibrosis
⚬ Neovascularization (wet)
risk factors for age related macular degeneration?
- Age, white race, family history and smoking
- Wet AMD have a higher incidence of coronary heart disease and stroke
treatment of age related macular degeneration?
- Ophthalmology referral
- Wet AMD may be treated by intravitreal injections of anti‐VEGF (though can increase
cerebrovascular and cardiovascular risk)
prognosis of age related macular degeneration?
Majority of patients progress to blindness in the affected eye within 2 years of diagnosis
what is relative afferent pupillary defect?
dilatation of the pupil on moving the light source from the normal eye (consensual reflex) to the abnormal eye (direct reflex)
Clinical signs of optic atrophy?
- RAPD
- Fundoscopy: disc pallor
- look for cause of optic atrophy
what clinical signs may suggest underlying cause of optic atrophy?
Fundoscopy:
* glaucoma (cupping of the disc)
* retinitis pigmentosa
* Central retinal artery occlusion
* frontal brain tumour: foster–kennedy syndrome (papilloedema in one eye due to
raised intercranial pressure and optic atrophy in the other due to direct compression by the tumour)
From end of the bed
* Cerebellar signs, e.g. nystagmus: multiple sclerosis (internuclear ophthalmoplegia), friedreich’s ataxia (scoliosis and pes cavus)
* Large bossed skull: Paget’s disease (hearing aid)
* Argyll–Robertson pupil: tertiary syphilis
causes of optic atrophy?
PALE DISCS
Pressure: tumour, glaucoma and Paget’s
Ataxia: Friedreich’s ataxia
LEber’s Hereditary Optic Neuropathy
Diet: ↓B12, Degenerative: retinitis pigmentosa
Ischaemia: central retinal artery occlusion
Syphilis and other infections, e.g. CMV and toxoplasmosis
Cyanide and other toxins, e.g. alcohol, lead and tobacco
Sclerosis: MS
*most commonly pressure cause
Down and out pupil with ptosis?
Cranial nerve 3 palsy
Down and out pupil with normal rather than dilated pupil?
Medical cause of CNIII palsy
Surgical causes often impinge on the superficially located papillary fibres running in the III nerve
‘Surgical’ causes of CN III palsy?
Communicating artery aneurysm (posterior)
Cavernous sinus pathology: thrombosis, tumour or fistula (IV, V and VI may also be affected)
Cerebral uncus herniation
‘Medical’ causes of cranial nerve 3 palsy?
mononeuritis multiplex, e.g. DM
Midbrain demyelination (MS)
Midbrain infarct ie. Webers
Migraine
Argyll Robertson pupil
Clinical signs of Argyll Robertson pupil?
- Offer to look for sensory ataxia (tabes dorsalis)
causes of argyll robertson pupil
Usually a manifestation of quaternary syphilis, but it may also be caused by diabetes mellitus
ix for quarternary syphilis
TPHA (Treponema Pallidum Hemagglutination Assay) or FTA (fluorescent treponemal antibody), which remain positive for the duration of the illness
tx of quarternary syphilis
penicillin
clinical features of CNIII palsy?
some surgical causes of CNIII palsy?
- Communicating artery aneurysm (posterior)
- Cavernous sinus pathology: thrombosis, tumour or fistula (IV, V and VI may also be affected)
- Cerebral uncus herniation
‘medical’ causes of CNIII palsy? ie. pupil may not be affected
- mononeuritis multiplex, e.g. DM
- midbrain infarction: Weber’s
- midbrain demyelination (MS)
signs of Holmes-Adie pupil
what to tell patient about holmes-adie pupil?
A benign condition that is more common in females. Reassure the patient that nothing is wrong.
examination in Horner’s syndrome
Types of Neurofibromatosis?
Both autosomal dominant
- Type I (chromosome 17) is the classical peripheral form
- Type II (chromosome 22) is central and presents with bilateral acoustic neuromas and sensi‐neural deafness rather than skin lesions
Neurofibromatosis associated with?
• Phaeochromocytoma (2%)
• Renal artery stenosis (2%)
Complications of neurofibromatosis
• Epilepsy
• Sarcomatous change (5%)
• Scoliosis (5%)
• Mental retardation (10%)
Causes of enlarged nerves and peripheral neuropathy?
• Neurofibromatosis
• Leprosy
• Amyloidosis
• Acromegaly
• Refsum’s disease
Clinical features of neurofibromatosis?
• Cutaneous neurofibromas: two or more
• Café au lait patches: six or more, >15 mm diameter in adults
• Axillary freckling
• Lisch nodules: melanocytic hamartomas of the iris
• Blood pressure: hypertension (associated with renal artery stenosis and phaeochromocytoma)
• Examine the chest: fine crackles (honeycomb lung and fibrosis)
• Neuropathy with enlarged palpable nerves
• Visual acuity: optic glioma/compression
Features/ clinical signs of tuberous sclerosis
Skin
• Facial (perinasal: butterfly distribution) adenoma sebaceum (angiofibromata)
• Periungual fibromas (hands and feet)
• Shagreen patch: roughened, leathery skin over the lumbar region
• Ash leaf macules: depigmented macules on trunk (fluoresce with UV/Wood’s light)
Lungs
• Cystic lung disease
Abdo
• Renal enlargement caused by polycystic kidneys and/or renal angiomyolipomata
• Transplanted kidney
• Dialysis fistulae
Eyes
• Retinal phakomas (dense white patches) in 50%
CNS
• Mental retardation may occur
• Seizures
• Signs of anti‐epileptic treatment, e.g. phenytoin: gum hypertrophy and hirsuitism
Ix in tuberous sclerosis
• Skull films: ‘railroad track’ calcification
• CT/MRI head: tuberous masses in cerebral cortex (often calcify)
• Echo and abdominal ultrasound: hamartomas and renal cysts
Renal manifestations of tuberous sclerosis
• Include renal angiomyolipomas, renal cysts and renal cell carcinoma
• The genes for tuberous sclerosis and ADPKD are contiguous on chromosome 16, hence some mutations lead to both conditions
• Renal failure may result from cystic disease, or parenchymal destruction by massive angiomyolipomas
Autosomal dominant condition (TSC1 on chromosome 9, TSC2 on chromosome 16) with variable penetrance
• 80% have epilepsy (majority present in childhood; but adult presentation also seen)
• Cognitive defects in 50%
Tuberous sclerosis
