approach for peripheral neurology 31 may 2011

8/6/2019 Approach for Peripheral Neurology 31 May 2011

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Siwaporn Chankrachang MD

Chiang Mai University



How to Approach Peripheral

Neurology(Nerve ,Neuromuscular junction & Muscle)

31 May 2011

Siwaporn Chankrachang

Chiang Mai University



Over view

� Anatomy & physiology

�

Clinical manifestation



Anatomy of peripheral nervous system

� Cell body ± Anterior horn cell

± Sensory ganglion cell

± Autonomic ganglion cell

± Cranial nerve ganglion cell

� Nerve fiber ± Axon

± Myelin

� Sensory and autonomic end organ

� Neuromuscular junction

� Muscle



Cell body

Anterior horn cellSensory ganglion cell Autonomic ganglion cellCranial nerve ganglion cell



�Nerve fiber ±

Axon ±Myelin



ensory

&otors

*

Sen

sor

yFib

ers

**

Dia

met

er

(nm

)

Velo

city

(m/s)Functions

- Ia10-

20

50-

120

Motor: alpha motor

neurons

Sensory: muscle spindleafferents

- Ib10-

20

50-

120

Sensory: Golgi tendon

organs, touch, pressure



Sensor

y andMotoe

rs*

Sen

sor

yFib

ers

**

Dia

met

er

(nm

)

Velo

city

(m/s)Functions

A- III 2-8 10-50

Motor: Small gamma

motorneurons to

intrafusal muscle fibers

A- III 1-5 3-30Sensory: small touch,

pain, temperature fibers

Motor: small



Anatomy of peripheral nervous system



Principal components of Peripheral nervous system



Clinical syndrome

Brain

Nerve

Muscle

Spinal cord

Motor

Sensory

Reflex

ANS

NMJ



weakness

Brain

Spinal cordNerve

NMJMuscle



Peripheral nerve ±

motor, sensory, autonomic,

reflex

Root ± proximal

muscle weakness,

winging scapula

Spinal Cord ±

LMN at level ,

UMN below level ,

Suspended sensory

level

Cortex lesion ±

cortical sensation,

other cortical signs



Clinical syndrome

Neuro

Muscular Junction

Peripheral

Nerve

Muscle

Motor

Sensory

Reflex

ANS



Nerve NMJ Muscle

Motor

Sensory

Reflexes

ANS



Nerve NMJ Muscle

Motor Proximal

Distal

Focal

Sensory Pain

Numbness

Reflexes Decreased /

Normal

ANS Small fiber

ANS

Neuropathy



Nerve NMJ Muscle

Motor Proximal

Sensory Mild S/S

Reflexes Normal /

Decreased

ANS Presynaptic



Nerve NMJ Muscle

Motor Proximal

Sensory Normal

Reflexes Normal/

Decreased

ANS Normal



Distribution of weakness

Cranial musculature

Extremities

Axial musculature

Combination

� Symmetrical - Asymmetrical



Nerve NMJ Muscle

Motor Proximal

Distal

Focal

Proximal Proximal

Sensory Numbness

Pain

Cramp

Mild S/S Normal

Pain

Cramp


Normal

Normal /Decreased

Normal/

Decreased

ANS Small fiber

Presynaptic Normal



Pattern of PNS lesion

� Polyneuropathy

�

Radiculopathy� Polyradiculopathy

� Plexopathy

� Mononeuropathy

� Mononeuropathy multiplex



Nerve NMJ Muscle

Motor Proximal

Sensory Mild S/S

Reflexes Normal /

Decreased

ANS Presynaptic



Nerve NMJ Muscle

Motor Proximal

Distal

Focal

Proximal Proximal

Sensory NumbnessPain

Cramp

Mild S/S NormalPain

Cramp


Normal

Normal /Decreased

Normal/

Decreased

ANS Small fiber

Presynaptic Normal



Nerve NMJ Muscle

Motor Proximal

Distal

Focal

Proximal Proximal

Sensory Pain /crampNumbness

Mild S/S NormalPain/cramp


Normal

Normal /

Decreased

Normal/

Decreased

ANS Small fiber

ANS

Neuropathy

Presynaptic Normal



Nerve NMJ Muscle

Motor Proximal

Distal

Focal

Proximal Proximal

Sensory PainNumbness

Mild S/S Normal


Normal

Normal /

Decreased

Normal/

Decreased

ANS Small fiber

ANS

Neuropathy

Presynaptic Normal



The neuromuscular synapseRich in ion channels and associated proteins

vulnerable to antibody-mediated attacks

Voltage-gated

Potassium

channel (VGKC)

Voltage-

gated Calcium

channel (VGCC )

Acetyl choline

receptor (AChR)

acetylcholine

Voltage-gated

Sodiumchannel

Muscle pecifickinases (MUSK

rapsyn

Blood brain barrier



Characteristic signs in M gravis



Test for Fatiguability



Enhancing test



Give diagnosis



It¶s fun to hidehahahaaaa



Describe Abnormal Findings



Botulism exotoxin actionBotulism exotoxin action



High rate stimulation

Ach quantaReleased byCa++ which was

previously blockedby toxin becomesmore important

> 10 Hz



Repetitive nerve stimulation test 2 weeks after

30 stimulation

30 HZ



Syndromes with Neuropathy &

Myopathy

� Hereditary

±Debrancher deficiency

±Lamin A/C mutations

± Congenital muscular dystrophy: Merosin

deficiency

±

Marinesco-Sjögren ± Mitochondrial: MNGIE Syndrome

±Tyrosinemia



Periodic paralysis

� Symmetric weakness that reverses within 1 day

± Asymmetrical weakness may occur due to excessive utilization

± No respiratory failure

± Periodic attack is very common

± Attack may related to over exercise or high carbohydrate intake

± Normal CSF and CK

± Associated with hyperthyroidism in young oriental male

±Associated with renal tubular acidosis in north-eastern Thailand

± Positive family history may occur



Guillain-Barré syndrome

±

Symmetric weakness ±Generalized areflexia

±Distal tingling with little sensory loss

± Extraocular weakness

± Respiratory failure

± Elevated cerebrospinal fluid (CSF) protein

± Anteccdent infection



"Classic" Guillain-Barré syndrome

C linical features

� Onset ±Weakness: Most often

symptomatic in legs ±Pain: Low back & legs

±

Paresthesias: Distal




� Cranial Nerves (70%)

±VII

� Symmetric:

Occurs early in parallel withweakness

� Asymmetric

±Occurs later in disease course

±Other weakness may be stable or improving

± Extra-ocular: Overlap with Miller-Fisher

± Tongue: Symmetric; Common (50%)




� Tendon reflex loss

± Early in most (70%) but not all patients

± Progressive reduction during 1st week

± Distribution: Ankles most frequently lost;

Biceps most frequently spared

± Spared reflexes all during disease course

suggests another diagnosis



Motor neuron diseases

Amyotrophic lateral sclerosis

± asymmetric weakness proximal or distal

± Weakness with atrophy and fasciculations

± Upper motor neuron signs ± Preservation of reflexes unless severe weakness

Spinal muscular atrophy

± Symmetrical weakness

± Associated features� Kenedy syndrome

± gynecomastia, diabetes

� Madras pattern ± Deafness



Neuromuscular Junction Disease

� Myasthenia gravis

� Lambert-Eaton myasthenic

syndrome

� Congenital myasthenic syndrome

� Drug-induced myasthenicsyndrome

Classification of Myasthenia gravis and Congenital



Acquired NMJ disorders Congenial and familial

Myasthenia gravis Congenital Myasthenic Syndrome

Sero Positive Pre synaptic

Anti AChR Positive CMS with episodic apnea

Anti MuSK Positive Paucity of synaptic vescicles

Drug induced (pencillamine) Simulating Lambert Eaton

MGwith Thymoma Synaptic

Neonatal MG AChE deficiency

Sero Negative Post synaptic

AChR Negative Kinetic abnormalities with

Normal, reduced or

Increased AChR MuSK,Rapsyn,Agarin,

Plectin mutations

Classification of Myasthenia gravis and Congenital

myasthenic syndrome



Distinctive Features Myasthenia Gr avis Congenital Myasthenic

Syndr ome

Familial occurrence Extremely r are(2-5%) Common

Pattern of inheritance Mostly Autosomal recessive

Consanguinity Favours diagnosis

Age of onset Unknown below 2 years,except

tr ansient neonatal myasthenia

gr avis

Neonatal period to adulthood

S pontaneous remission Can occur Does not occur

Association of other autommune disease Favours diagnosis Not seen

Char acteristic facial a ppear ance a part

f r om ptosis

Nil Elongated face,

pr ongnathism,high arched

palate

Response to immuno modulatory

treatment

Positive Nil

Differentiating features of Myasthenia gravis and Congenital Myasthenic syndrome



Selection of diagnostic tests based on clinical features




Bedside

Test

Sensitivity,%

Edx Test

(muscle)

Sensitivity

%Immunologi

c

Sensitivity,%

Ocular Distribution

of Weakness

Edrophoni

um

60-95 SFEMG

(facial)

90 AChR-Ab 50

Ice pack

89

Oropharyn

geal.

None RNS

(limb/crania

l)

60 AChR-Ab 85

SFEMG

(limb/facial) 99 MuSK-Ab(if above

negative)

40-50




Distribution

of Weakness

Bedsid

e Test

Sensitivity

,%

Edx Test

(muscle)

Sensitivity,

%

Immunol

ogic

Sensiti

vity,%

Generalized

(hyporeflexia,

autonomic

signs),suspect

LEMS

None RNS(hand)

SFEMG

(limb)

98

100

VGCC-Ab 90

Suspect

botulism

None RNS(limb) ? None

Suspect CMS None RNS(limb) ? None*

Edx,electrodiagnostic;SFEMG,singlr-fiber electromyography;AChR-Ab,acetlcholine receptor antibody;RNS,repetitive

nerve stimulation;MuSK-Ab,muscle-specific receptor tyrosine kinase antibody;MG, myasthrnia

gravis;LEMS,Lambert-Eaton myasthenic syndrome;VGCC-Ab, voltage-gated calcium channel

antibody;CMS,congenital myasthenic syndrome.

*Muscle biopsy

MGFA li i l l iti ti f th i i



Jaretzki et al Neurology 2000Class I-Ocular

Class II-Mild general

IIa-Predominantly limb/axial muscles

IIb-Predominantly oropharyngeal/respiratory musclesClass III-Moderate general

IIIa- Predominantly limb/axial muscles

IIIb- Predominantly oropharyngeal/respiratory muscles

ClassIV- Severe generalIVa- Predominantly limb/axial musclesIVb- oropharyngeal/respiratory muscles (feeding tube)

MGFA clinical classitication of myasthenia gravis



Myasthenia gravis: treatment recommendattions

1st Line Mestinon Mestinon

Prednisone Prednisone

Thymectomy Thymectomy

2 nd Line Azathioprine Azathioprine

Myocphenolate mofetil Cyclosporine

Cyclosporine IVIg

3 rd Line IVIg Myocphenolate mofetil

Plasmapheresis Plasmapheresis

4 th Line Tacrolimus

5 th Line Rituximab cyclophophamide

BeforeBefore 20072007

M th i i t t t d tti




1st Line Mestinon Mestinon

Prednisone Prednisone

Thymectomy Thymectomy

2 nd Line Azathioprine Azathioprine

Myocphenolate

mofetil

Cyclosporine

Cyclosporine IVIg


M th i i t t t d tti




3 rd Line IVIg Myocphenolate mofetil

Plasmapheresis Plasmapheresis

4 th Line Tacrolimus

5 th Line Rituximab cyclophophamide


MGF A : M gravis FoundationMGF A : M gravis Foundation of Americaof America



History



Pain testing (1)



Sensory testing (2)



Reflexes



Q uestion

� Where is the lesion?

1.Nerve2.Neuromuscular lesion

3.Muscle



Syndrome in peripheral nerve

Weakness

Muscle painDecreased muscle tone

Decreased deep tendon reflex



S t i l i l t



Symmetrical involvement

Neuropathic skin changePain & Numb

Decreased reflexes



Motor

predomi

nate

Less

sensorys/s

Plexopathy



Mononeuropathy

Multiple mononeuropathy /

mononeuropathy multiplex



Radiculopathy



Dorsal scapular to rhomboid

Long thoracic nerve to seratus anterior



Motor

predomi

nate

Less

sensorys/s

Plexopathy



Muscles to test

for brachial plexuslesion

1. Supraspinatous

2. Infraspinatous

3. Pectoraris major

4. Pectoraris minor

5. Subscapularis

6. latissimus dorsi

1 and2

3

3 and 4

56



Mononeuropathy

Multiple mononeuropathy /

mononeuropathy multiplex



Median N.

M di N



Median N.

APBFPB

OpponenLumbrical 1&2

Pronator Teres

Flexor Carpi Radialis

Palmaris LongusFlexer Digitor um superficialis

Flexer digitor um

prof undus

Flexer pollicislongus

Anterior

interosseous

nerve

Median N



Median N.

APBFPB

OpponenLumbrical 1&2

Flexer digitor um prof undusFlexer pollicis longus

Anterior

interosseous

nerve



Sensory Changes in Median Nerve lesion



Ulnar Nerve



N & M l



Nerve & MuscleMedian Thumb and thenar eminence

Ulnar Little finger and hypothenar

eminence

Radial Wrist-drop

Femoral (weak hip flexion

& knee extension)

Peroneal Foot-drop

Sciatic Weak gastrocnemius

Nerve NMJ Muscle



Motor

Sensory NumbnessPain

Cramp

MildS

/S

Normal /Pain

Cramp

Reflexes

ANS



S t



Sensory symptoms

Pain� Nerve

� Muscle

� NMJ

Pain (1)



Pain (1)

�I nflammatory process ±Inflammatory myopathies

� Systemic connective tissue disease

� Childhood dermatomyositis ±Muscle infections

�Viral myositis

� Pyomyositis� Toxoplasmosis

� Trichinosis

P i (2)



Pain (2)

� Denervation muscle painsymmetrical or asymmetricle withweakness

±Guillain Barre syndrome

±Acute anterior horn cell disease�

� Rhabdomyolysis ± Metabolic disorder

Pain (3)



Pain (3)

InfectionsViral & post-viral syndromes

Brucellosis; Leptospirosis;

Falciparum malariaSystemic connective tissue

disorders: S jögren's

Drugs & ToxinsPolyneuropathy: Small fiber

Cramp



Cramp� Nerve

Motor system disorders� Amyotrophic Lateral Sclerosis

�

Motor neuropathies� Hereditary motor neuron disorders

Other denervation� S

pinal stenosis� Polyneuropathies

Cramp



Cramp� Nerve

Spontaneous activity syndromes� Episodic ataxia 1 (EA1)

� Neuromyotonia (Isaac's syndrome)

� Stiffman syndrome

� Cramp-fasciculation syndromes

� Muscle ± Becker muscular dystrophy

± Type II muscle fiber predominance

Fasiculations



F asiculations� Along the course of the axon� Causes

±Benign

� Common in gastrocnemius

� Normal strength

� Exacerbated by exercise, hyperventilation &

tension� May be associated with tendency to cramp

Fasiculations 2



F asiculations 2

±Motor neuron disorders & Motorneuropathies

±

Metabolic disorders:Hyperparathyroid; Hyperthyroid;Hypomagnesemia

±

Pharmacologic� Anti-Cholinesterase; Caffeine;

Theophylline; Terbutaline; Lithium

Primary reflexes



Primary reflexes

1. Ankle jerk S1 Gastrocnemius

2. Knee jerk L2,L3,L4 Quadriceps

3. Biceps C5,C6 Biceps

4. Triceps C7,C8 Triceps

Root & muscle



Root & muscle

C5 Deltoid

C5 Infraspinatus

C5,C6 Biceps

C6 Extensor carpi radialis &

ulnaris

C7 Extensors digitor um &

triceps

C8,T1 Inetrossei and lumbricals

Root & muscle



Root & muscle

L2,L3,L4 Quadriceps & iliopsoas

L5 Anterior tibial andextensor hallucis

S1 Gastrocnemius



C5



C6



C6

C7



C7

T1

Nerve & Muscle



Nerve & MuscleMedian Thumb and thenar eminence

Ulnar Little finger and hypothenar

eminence

Radial Wrist-drop

Femoral Absent knee jerk (weak hip

flexion & knee extension)

Peroneal Foot-dropSciatic Pain down lateral thigh

and leg , absent ankle jerk

Deep tendon reflexes 1




� Reflexes are lost before weakness ±Demyelinating neuropathies

±Loss of large myelinated sensoryaxons: Ankle reflexes lost early

� Reflexes are lost with weakness ±

Reflexes are generally lost inproportion to weakness inpolyneuropathy





� Preserved after weakness in myopathy

� lost proximally in muscular dystrophies orsevere proximal myopathy

� hyper-reflexia in myasthenia gravis� hypo-reflexia in myasthenic syndrome

� Ankle reflexes preserved in porphyria

Nerve NMJ Muscle



Motor

Sensory


Fasciculation/Normal

Normal / may

be increased

and may bedecreased

Normal/

Decreased

ANS

How to get Diagnosis ?



How to get Diagnosis ?

History taking

Physical examinationLab investigations

History (1)



History (1)Course ±Acute: Days to Weeks

±Subacute : Weeks to months

±Chronic: Months to Years

±Episodic

History (2)



History (2)Age at onset Pediatric: Neonatal; Childhood

Adult: 20 to 60 years;Geriatric

Hereditary: family history or examination of relatives

Physical examination



Physical examination

� Motor� Sensory

� Reflexes� ANS

Clinical

Syndrome

Onset

progression

locationHistory of

Clinical syndrome



Clinical syndrome

� Acute generalized weakness

� Subacute generalized weakness

� Acute or sunacute or chronic

focal S/S

� Relapsing� Fluctuating

Acute generalized weakness



� GBS� Neuromuscular junction diseases

� Food-borne botulism

� Acute necrotizing myopathy

� Acute poliomyelitis syndrome

� Periodic paralysis

Subacute or chronic generalized

k



weakness

� Motor neuron diseases

� Chronic demyelinating

polyneuropathy� Neuromuscular junction diseases

� Myopathies

Acute or subacute or chronic



weakness or numbness

limited to one limb

Radiculopathy ,

Plexopathy

Compressive neuropathy

Mononeuritis multiplex

RELAPSING deficit



RELAPSING deficit ± I

mmune mediated disease� CIDP

± Hereditary

� Neuropathy Liability to Pressure Palsy

� Brachial Plexopathy

� Porphyria

Fluctuation

Myasthenic syndrome

I nvestigations



g

in

P eripheral nerve disease

Types of Investigations



Where is the

lesion ?

What is the

lesion ?

Objectives



Objectives� localization

�Function components

�Physiology

�Pathology�Follow up

Investigation of



Peripheral nerveNerve

& MuscleBiopsy

�NCV

�EMG

MRI

MRI



MRI

� painless.

� identify axonal damage

� identify a lesion site

Magnetic resonance imaging of

human peripheral nerve disease



human peripheral nerve disease



Motor conduction velocity



CV = distance / time

Median nerve

Sensory conduction velocity



Ulnar nerve



Pathology



Pathology

� Segmental demyelination

� Wallerain degeneration

� Axonal degeneration



Segmental demyelination



�

destr uction of the myelinsheath leaving the axon intact,

� Although axonal degeneration may

also be present in demyelinatingneuropathies

� and secondary primary segmental

demyelination may be seen in axonaldegeneration.

Pathological diagnosis



g g

3 major pathologicalprocesses

� axonal degeneration,� segmental demyelination,

� neuronopathy.



Wallerian type degenrtation



Pathology



gy



Chronic inflammatory neuropathy. Patchy loss of myelinated fibres ina fascicle of the sural nerve (Semi-thin resin section, toluidine blue).

The lower rectangle is an area with a significant loss of large

myelinated fibres. There are several other thinly myelinated and

entirely demyelinated fibres. The upper rectangle is a more densely

populated area.



� V asculitis and severe axonal neuropathy in a peripheral nerve. CD68

immunohistochemical staining tovisualize digestion chambers and macrophage in the acutely degenerating nerve.

approach for peripheral neurology 31 may 2011

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