PACES Flashcards
What does temporalis muscle wasting indicate?
consider Lower motor neurone Facial nerve (e.g. Bells palsy)
What happens when a person with myotonic dystrophy tries to shake hands with someone?
They struggle to release the grip easily
When you present in neurology, try and be anatomical in pattern detection - give examples
Symmetrical vs asymmetrical
Proximal vs distal
Pyramidal vs extrapyramidal
Why is a symmetrical finding important to note?
It suggests there is a general pathology such as a syndrome as opposed to a nerve/nerve root
In myotonic dystrophy what would you like to do to complete the exam?
cardiovascular exam check blood sugar FH EMG genetic testing
What neuro pts tend to come to exams?
Parkinsons Charcot marie tooth Myotonic dystrophy MS Peripheral neuropathy
What is associated with Myotonic dystrophy?
- Cataracts (buzz word: loss of red reflex in both eyes)
- Dysphagia (from weakness)
- Cardiac (cardiomyopathy and heart block - may need a pacemaker)
- Diabetes mellitus
- Hypogonadism (gynaecomastia/ testicular atrophy)
What investigations would you like for myotonic dystrophy?
- Lung function tests - to check for neuromuscular respiratory insufficiency
- ECG or echo (conduction block and cardiomyopathy)
- Fasting glucose for DM
- Slit lamp test for cataracts
- SALT assessment
- EMG: may show ‘dive-bomber’ potentials (this is pathopneumonic)
What cataracts do you get with myotonic dystrophy?
Christmas tree cataracts = pathopneumonic
What is the treatment for myotonia?
Phenytoin for the myotonia
but the weakness has no treatment
(avoid statins)
What type of genetic goup does myotonic dystrophy fall into?
autosomal dominant with genetic anticipation (trinucleide repeat)
What is genetic anticipation?
When a condition presents earlier and is more severe in the later generations
Conditions with genetic anticipation
Myotonic dystrophy
Huntingdon’s chroea
Freidrick’s ataxia
What are the differentials for bilateral ptosis?
- Myaesthenia gravis
- Myotonic dystrophy
- Bilateral Horner’s and bilateral 3rd nerve palsy (although these would be very rare
- congenital
- Neurosyphillis (but isn’t really seen anymore)
What is the cause for Argyll Robetson pupil?
Syphillis
Diabetes
What is an Argyll Robertson pupil?
A pupil which does not constrict when exposed to bright light but does constrict when focusing on a near object
What is the antibody against in myaesthenia gravis?
Acetylcholine receptor on the post synaptic membrane
What tumours are associated with myasthenia gravis?
Thymoma (look for on a CT scan)
Why do pts with myasethenia struggle to chew food?
It is a repeated movement
What is the treatement for myasthenia gravis?
Pyridostigmine (Ach-esterase inhibitors)
2nd line: add immunosuppression (steroids)
- consider thymectomy
What is the diagnostic test for myasthenia gravis?
The Tensilon test
What is another name for the tensilon test?
Edrophonium test
Lambert-Eaton myasthenic syndrome (LEMS)- what is the anti body against in this condition?
pre-synaptic membrane antibody to the Ca2+ receptor
LEMS is a _____ syndroem associated with ___ cancer
Paraneoplastic
small cell lung cancer
How do you differentiate between LEMS and Myasthenia gravis?
LEMS - has no eye involvement and you also get stronger the more you do something (they start of weak and get stronger)
What is the treatment for small cell lung cancer?
Poor prognosis - as there is no surgical cure, there is chemo but only extends the lifespan a few years
- this is because by the time it is detected it is often metastasised
What are the differentials for proximal myopathy?
- Diabetic amyotrophy (painful quads wasting) - will not see irl, but comes up in SBA - it is unilateral proximal myopathy
- Cushings
- Thyrotoxicosis
- Hypocalcaemia/osteomalacia - hence kidney failure can cause it as a secondary complication), vit D def (osteomalacia can cause it)
- Polymyositis
- Polymyalgia rheumatic
What blood test is important to order in any muscular pathology?
CK
What condition can be assocaited with PMR?
temporal arteritis
What signs do you get with hypocalcaemia?
CATS go numb Convulsions Arrhythmia Tetany and numbness
How can you confirm miosis in a and e?
Put some 4% eye drops and the eye fails to dilate
What are the differentials for Horner’s syndrome?
Apical lung pathology (invades the sympathetic plexus):
- Pancoast’s tumour
- Thyroid mass
- Mediastinal mass
- Cervical rib
What is the name for this:
On looking to the right, the right eye abducts normally but the left eye is unable to adduct. The right eye has a nystagmus
Intranuclear ophthalmoplegia
What is the best way to detect nystagumus in intranuclear ophthalmoplegia (INO)
Start at the point between the eyebrows to use your peripheral vision
Where is the lesion in intranuclear ophthalmoplegia?
In the medial longitudinal fasciculus
What is normal in Intranuclear ophthalmoplegia?
Convergence - the eye can look inwards
What is the most likely cause of Intranuclear ophthalmoplesia?
MS - lesion in the medial longitudinal fasiculus (a stroke could also cause it if the stroke location affects the (MLF)
What eye conditions are associated with MS?
INO
Optic nerve damage
What are the signs of optic nerve damage?
Central scotoma
RAPD (relative afferent pupillary defect)
Colour and visual acuity loss
optic atrophy
What is a central scotoma?
A blind spot that covers the centre of ones vision
What is the eponymous name for a RAPD?
Marcus gun
What are the DDx for RAPD?
Optic neuritis
Total retinal detachment
In INO is the nystagmus in the affected or the normal eye?
The normal eye
What is Lhermittee’s phenomenon?
Electric shocks going down their back when they bend their neck forwards
What is Uthoff’s phenomenon?
Heat making the neuro symptoms worse
What is this phenomenon? -
Heat making the neuro symptoms worse
Lhermitte’s
What is this pneumenon?
Electric shocks going down their back when they bend their neck forwards
Uthoff’s
What causes Uthoff’s phenomenon?
Neurological condution is reduced at higher temps
In demyelination - the problem is the speed of conduction, so it get exacerbated in heat
What are DDx for demyelination?
- HIV
- CIDP (chronic inflammatory demyelinating polyneuropathy)
- multiple myeloma
- MGUS
- Charcot Marie Tooth (type 1 and 3 are demyelinating)
What is chronic inflammatory demyelinating polyneuropathy a fancy name for?
Chronic Guillaine barre syndrome
Why does a patient with a 3rd nerve eye palsy need urgent CT angiogram of the brain?
Because a cause is Posterior communicating artery aneurysm (PCAA) - the posterior communicating artery runs right next to the 3rd nerve
What is Trousseau’s sign?
For hypocalcaemia- when you inflate the BP cuff, they get a painful contraction of the MCP joint on the same side as well as ADduction of the thumb
What is Webber syndrome?
3rd nerve palsy on one side and hemiplegia on the other side - it is caused by a midbrain infarct or bleed
What artery is involved with Webber’s syndrome?
The posterior cerebral artery
also near the 3rd cranial nerve nucleus
Which fracture in the brain causes rhinorrhoea and why?
Basal skull fracture - you get CSF leaking from the nose
How can you tell between a surgical or medical third nerve palsy?
surgical - the pupil is blown
Why does a surgical 3N palsy cause the pupil to be blown?
The entire nerve is compressed
as well as the parasympathetic fibres which run alongside the 3rd CN are affected - the cause of this could be an aneurysm for example and hence is a surgical
(the pupil wall also not respond to light and accommodation and the eye will be down and out)
What are the causes of a medical 3rd nerve palsy?
Mononeuritis multiplex - caused by Diabetes or HTN
(mononeuritis multiplex means inflammation of a single nerve)
- MS/demyelination can also causes a mononeuritis multiplex
- mass lesion or compression along the route/course of the nerve
Why can the pupil still constrict in a medical cause of 3N palsy?
In medical causes it is the vascular supply of the nerve which is affected but the parasympathetic occulomotor fibres have their own blood supply and so may be spared- the pupil can still react to light and accommodation but will be down and out
which 3N palsy is more likely to have a complete ptosis (rather than a partial one? - surgical or medical?
Surgical (complete compression of the nerve, hence dilated pupil and complete ptosis)
What are causes for dilated pupil 3N palsy (i.e. a surgical 3N palsy?
tumour
dissection
Posterior communicating artery aneurysm- this is the classic cause (PCAA)
How can you describe a 3N palsy in PACES terms?
the globe is down and out in the primary position
Why is it important to find out when the diplopia (double vision) is the worst?
If it is complex ophthalmoplegia with multiple muscle groups involved it can help work out the differential
If someone has diplopia and you cover up the affected eye, which of the two images should disappear?
The outer image of the two
If someone has a 3rd nerve palsy what investigations are good to check?
- the BP
- the capillary glucose
- examine for 4th N palsy
- if the pupil is dilated - then CT scan and angiography
If someone has a medical 3N palsy what is the management?
conservative - self-resolving in 3 months, can give them prism glasses in then mean time (to correct the double vision)
What is the job of the 4th cranial nerve?
to move the eye down and in
think - trying to read a book
Which cranial nerves does cavernous sinus syndrome invovle?
III
IV
V1 (first division of the 5th nerve)
VI
When should you consider cavernous sinus syndrome?
If there is 3rd and 4th nerve palsy
How can you check for a 4th nerve palsy in a patient who has a 3rd nerve palsy?,
Ask the patient to look down and you will notice the eye adduct slightly (by looking at the capillaries of the inner eye and noticing that they move into the eye socket
In a simple 4th nerve palsy in what position will the eye be?
Up and out (in the primary position)
If someone has a 3n Palsy why is it so important to check for a 4th nerve palsy too?
to make sure there is nothing in the cavernous sinus
What does ‘It’s a 4th nerve palsy…. Look away!’ - help you to remember?
The pateint will have a head tilt AWAY from the side of the 4th nerve (away from the affected side)
In a 4th nerve palsy, when will the diplopia be worst?
when they look down and in (depress and adduction) - i.e. when trying to read a book or trying to walk down stairs
- it is worst at this point because the action of the 4th nerve is to look down and in and they are unable to (which is why the eye is up and out in the primary positon)
What is the most common cause of 4th nerve palsy and why?
Trauma this is because the fourth nerve runs along the tentorium along the base of the skull
What are causes of 4th nerve palsy?
Trauma
mononeuritis multiplex
Congenital
What are the causes of mononeutritis multiplex?
Diabetes
HTN
MS
Infection - Lyme disease, syphillis
Autoimmune disorders - small vessel vasculitis (e.g. polyarteritis nodosua), SLE, RA
Malignancy- haematological malignancy or anitbodies from paraneoplastic syndromes
How can you detect a 6th nerve palsy
When they look to the side, the affected eye cannot look laterally
e.g. upon looking right, the right eye cannot loow to the right
What are the most common causes of 6th Nerve palsy?
HTN and DM
What is a false localising sign?
6th nerve is the longest intracranial nerve and so anything which raises the intracranial pressure , the 6th nerve will feel the stretch first - this could Mean that a 6th nerve palsy on the right side does not necessarily mean the issue was on the right (e.g. It could be a tumour on the left causing raised intracranial pressure and that just happens to develop a right-sided 6th nerve palsy)
What should you do once a 6th nerve palsy has been detected?
- Examine CN 7 and 8 for nerve palsys and examine the cerebellar system -to check for cerebellarpontine angle tumour (CPA)
- Fundoscopy - check for papilloedema (sign of raised ICP)
What is the cerebellar pontine angle and why is it important ?
It is space where the 6th nerve runs through and is there is a tumour there it can cause a 6th nerve palsy
What are the DDx for a 6th nerve palsy?
DM and HTN ICP Demyelination (MS) Mass Vascular
Why is the forehead spared in an Upper motor neurone cause of facial nerve palsy?
Because both hemispheres a supply nerve to the facial muscles (in the top half of the face)
What is Bell’s phenomenon?
The eyes rolling up when you ask the patient to close them (this is seen in Bells palsy (LMN facial palsy)
Why do patients with facial nerve get hyperacusis
Strapedius muscle reduces vibration to protect from loud noises- if it is not working then patients get hyperacusis
Which part of taste does the facial nerve supply?
Anterior 2/3rds
What are the causes of facial nerve palsy?
- Viral/idiopathic
- Damage to the nerve - facial trauma
- Infection (herpes Zoster)
- Compression/ mass lesion e.g. Parotic tumour/ tumour in the cerebellarpointine angle
- Otitis media (check ear with otoscope)
- Forceps delivery (trauma)
What is the most common cause of an UMN facial nerve palsy?
Stroke
Why do facial nerve palsy patients require referral to ENT?
To rule out cholesteatoma and acoustic neuroma (MRI brain)
What is the management of LMN facial palsy?
Self-limiting - recovery in 6 months
Eye drops and patch (because or corneal irritation or corneal scarring)
Steroids (if presented within 72 hours)
Referral to ENT surgeon for further assessment
What is the first sign of a cerebellarpointine angle lesion?
loss of corneal reflex
What are the signs of cerebellarpontine lesion?
- loss of corneal reflex
- failure to ABduct eye (6th nerve palsy)
- sensorineural hearing loss (8th nerve)
- Facial sensation loss
- Cerebellar signs
the nerves involved = 5 to 8
What are the complications of facial nerve palsy?
Synkinesis of facial muscles
crocodile tears phenomena
What is synkinesis?
Wrong muscle groups activated
-if you want to close your eyes, you might clench your jaw instead
What is crocodile tears phenomena?
When they are eating, instead of salivating, they cry because the facial nerve has healed badly
What are the features of MS in PACES?
- Hemiplegia - similar to stroke
- Female
- Catheterised
- Eye signs
- Cerebellar signs
- Ataxic (unable to to hell-toe walk)
- UMN signs - pyramidal weakness (flexors stronger in the arms and in the legs extensors stronger) and brisk reflexes
- Dorsal column disease- reduced vibration, proprioception, Romberg’s positive