Neuro Flashcards
Regarding nerve conduction studies:
Which sort of lesion gives rise to slower conduction
Which sort of lesion gives rise to weaker conduction
Low velocity - Demyelinating - normal is 50m/s, severe 4m/s, effected 20-30m/s
Weaker conduction is low amplitude - axonal
Regarding cK measurement in neuromuscular disorders:
High cK is unstable muscle cell - dystrophies 1000-30,000
Lower cK is any part of the neuroaxis
Determining UMN/LMN (AntHorn/Nerve vs. NMJ/Muscular) the pattern for reflexes are:
Brisk in UMN
Decreased or absent in Ant horn/nerve
Normal or decreased in NMJ or muscle
Regarding distributions of muscular weakness with location of lesion:
Central - Hemi/Para and Distal>Proximal, cognitive signs
Ant Horn - Asymmetry/Proximal, fasiculations at rest
Nerve - Distal> Proximal, sensory symptoms
NMJ CN Involvement (ptosis/fatiguability)
Muscle Proximal > Distal (per Gower’s sign), tender, atrophied
Regarding CMT - What form is most common, what gene associated?
1:2500
Hereditary sensory/motor neuropathy
Strong association with hip dysplasia
DEMYELINATING (Slower than 38m/s)
CMT1A (60-70%)
Dominant
Gene is PMP22 duplication (find on microarray)
Axonal
CMT2
Autosomal Dominant
Severe early onset CMT3 Elevated CSF protein Extremly slow <12m/s Hypotonic Areflexic Sever De novo dominant
But also AR and XL
Same gene can cause all different phenotypes (MPZ gene mutation can cause any type)
Wide potential genes
//
Ascorbic acid held promise but no evidence with RCT
Guillane Barre Syndrome
Acute inflammatory polyneuropathy
Weakness is primary feature, may be proximal in 20% (unlike classic teaching)
Cranial nerve involvement is common - especially facial weakness
Associated pain may cause diagnostic difficulty
Beware - Respiratory failure, autonomic instability, bulbar weakness
(swallow bad, not coughing well, choking on food -> PICU for ETT (20% need respiratory support))
DDx -Tick Paralysis
Dx CSF - Raised protein by 48/24 Cytoalbuminologic disassociation (WCC is not raised) Neurophysilogy MRI - Nerve root enhancement
Miller Fisher - ataxia, areflexia, opthalmaplegia
Rx:
Support (
IVIG
Gabapentin for neuropathic pain
Chronic Inflammatory Demyelinating polyneuropathy?
Relapsing remitting or slowly progressive “GBS-like” neurologic illness
Occurs over 8/52
Rx with IVIG or PE
Rx with steroids
ADEM
ADEM
Encephalopathy
Behavioural change
Altered concious
Irritable or drowsy +++
Polysymptomatic- signs attributable to more than one neuro area
Ataxia
Cranial Nerve incl. optic neuritis - Look for afferent pupillary
Imaging
Spinal cord associated with cranial
Big fluffy asymmetric lesions
Effects deep brain matter
High dose pred (15-30mg/kg to max 1g for 5/7 then wean over 4/52 or not)
Transverse Myelitis
Spinal pathology
Central level - not just one level
May have “spinal shock”
Ix
MRI Spine (Longitudinal involvement common in kids)
To exclude urgent neurosurgical emergency (bleed or bleeding tumour)
MRI Brain for concurrent brain lesions
CSF - similar to ADEM
Additional Ix
ANA - ?1st presentation connective SLE or Sjogrens
MOG Antibodies
NMO Antibodies
Rx
Steroids
PE if severe
Aperients
70-80% good outcome
1-2/52 to walk again
Inpatient rehab
ADEM
TM
Bilateral optic neuritis
Poor vision Walking into walls Colour desaturations - ishihara plates Afferent pupillary defect - paradoxical dilation in effected eye Visual field defects, central scotoma Assess vision Assess discs
Appears as Papillodema but. Is Papilitis
Maybe normal if inflammation is more caudal
DDx Ix MRI Oligoclonal bands - abnormally high in MS Send NMO Ab Send MOG Ab
Rx
IV Steroids then 2/52 wean
If recurrent think MOG or NMO or MS (30% will have MS - especially if concurrent asymptomatic T2 lesions in brain)
If NMO +ve Ab then needs immunosuppresion (Not MS Rx)
If severe bilateral optic neuritis think MOG
If optic neuritis 30% will have MS
If single episode of ADEM 3% risk of MS
What is Multiple Sclerosis?
More than one clinical episode
OR
New lesions in time on MRI
(Dissemination in time, dissemination in place)
//
Where does demyelinating plaque land?
Optic nerve - optic neuritis
Brain stem - hemi
Acute partial transverse myelitis - sensory down one leg
Intranuclear opthalmaplegia - abnormal eye movements and vertigo
//
Do a MRI
Do paired CSF/Serum for oligoclonal bands
// Dawson’s fingers from corpus collosum
//
Steroids
Disease modifying drugs
To prevent accrual of disability
Classical
Interferon beta, beta1a and beta1b, IM or S/C, daily or second daily, or fortnightly(If PEGalated)
Kapaxon - non interferon injectable
Flu-like, Liver function, leukopaenia, injection site
Second line - more effective - immunosuppresive
Oral
Opportunistic infection incl. JC Virus,
Promising +++ incl fingolimod
Heart block, QT prolongation, first dose bradycardia in day med
Macula odema - within 6/12, so review with opthal
No live vaccines, reduced response
Must have had 2x varicella/antibodies, check hep B, booster prior
Myasthenic Syndromes that get WORSE with pyridostigmine? Mestenonn
Produces more acetylcholine via acetylcholinesterase
Downstream of tyrosine kinase 7 (DOTK 7)
Congenital Myasthenics slow channel
Myasthenia Gravis
Signs
Symptoms
Dx
Most common - Ptosis
Fatiguability, worse at night
Generalised weakness - dysphagia/dysarthyria
Dx - AchReceptor Antibodies, Repetitive nerve stimulation Elctrodecremental response
No longer stimulation with Tensinon
Respiratory and bulbar muscle weakness - DANGER ++ (With crises)
Myasthenia Gravis - Treatment
Symptom Control
MESTINON - PYRIDOSTIGMINE
Disease modifying -
Steroids
Azathioprine
Surgical
Thymectomy
Floppy baby when suspect peripheral cause (20%)
What “Single” bedside examination do you do?
CONGENITAL MYOTONIC DYSTROPHY
Floppy Baby
Triplet repeat - not seen on an exome
Examine mother! - Shake hands, can’t let go of hand
Or squeeze hand, then slow extension/abduction
