1. Peripher al
Neuropathy

2. Peripher al Ner ve
 Myelin : Current cannot flow
 Axon : Not nerves left

3. Types of nerve fibers
Diameter Conduction Function
microns Velocity m/s
A alpha 1-20 70-110 Motor, Proprioception
beta 5-10 30-60 Touch
gama 3-6 20-30 Fusimotor, spindles
delta 2-5 20-30 Sharp pain
B <3 5-15 Autonomic, pregangl.
C <1.3 0.5-2 Slow pain
Non myelinated

4. T he Peripher al Ner vous
System
 Motor: weakness,
atrophy
 Sensory loss
 Large Fibers (position)
 Small fiber (pain)
 Reflex loss
 Autonomic symptoms
 (redness, dizziness, ED)

6. Definitions
 Neuropathy
Pathological process affecting a peripheral nerve/s
 Mononeuropathy
A single nerve affected
 Mononeuritis multiplex
Multiple mononeuropathy or Multifocal neuropathy

7. Polyneuropathy
Diffuse symmetrical disease usually
beginning peripherally
Acute/Chronic Static/Prog
Relapsing/Recovering
Motor Sensory
Sensrimotor(Mixed)
Autonomic
Demyelinating Axonal
Radiculopathy Nerve root disease

8. Mechanisms of damage
 Demyelination Myelin sheath disrupted
GBS Post Diphtheric HSMN
 Axonal degeneration Axon damage
Toxic neuropathies
 Wallerian degeneration Nerve section
 Compression Focal demyelination
Entrapment-Carpel tunnel syndrome
 Infarction Arteritis
Polyarteritis nodosa Churg-Strauss synd. DM
 Infiltration Infiltration
Leprosy Sarcoidosis

9. Classification
EXAMINATION FINDINGS
 Purely Motor or Sensory or
Sensorimotor?
 Proximal or distal? Symmetric or
asymmetric?
 Multifocal, generalized, regional?
 Upper limbs, lower limbs, neck, trunk?
TIMING
 Acute or chronic?

10. ASSOCIATED FINDINGS
Painful or painless?
Hereditary or sporadic?
ELECTRODIAGNOSIS
Axonal or demyelinating?
LABORATORY
Paraprotein present? Type?
Antibody against nerve?
CSF protein level?
HISTOLOGY
Inflammatory Cells

11. Epidemiology
 Prevalence
 ~ 2.4%
 ~ 8% in people older than 55 years
 DM is most common cause

12. Epidemiology
 Other common systemic causes
 Metabolic disorders
 Infectious agents
 Vasculitis
 Toxins
 Drugs
 Autoimmunity
 Inherited

13. Diagnosis
 Most important details to determine
 Distribution
 Duration
 Course

14. Diagnosis
 Clinical manifestations vary widely
 Altered sensation
 Pain
 Muscle weakness or atrophy
 Autonomic symptoms

15. Labor ator y Screening for
“Treatable” Neuropathy?
B12 Not truly length-dependent
Diabetes This type of neuropathy
generally a late finding
ANA, chronic disease Screen for connective tissue
screen diseases (late finding)
TSH If positive, have you proven
anything?
ESR If onset is recent
HIV Risk Factors
Review medications Big question

16. Diagnosis
 Electro diagnostic studies
 Sensitive, specific, validated
 Extension of neurologic exam
 Nerve conduction studies (NCS)
 Needle electromyography (EMG)

17. Diagnosis
 Establish distribution
 Mononeuropathy
 Mononeuropathy multiplex
 Polyneuropathy
 Determine primary pathology
 Demyelinating
 Axonal

18. Mononeuropathy
 Focal lesion involving a single nerve
 Electro diagnostic studies indispensible
 Localize site of injury
 Determine severity of lesion

19. Mononeuropathy
 Causes
 Entrapment
 Carpal tunnel syndrome is most common
 Foot drop
 Focal compression
 Trauma

20. Mononeuropathy
Multiplex
 Separate/noncontiguous involvement
 Simultaneously
 Serially
 Pattern
 Random
 Multifocal
 Frequently evolves quickly

21. Mononeuropathy
Multiplex
 Urgent assessment for vasculitis
 Polyarteritis nodosa
 Churg-Strauss disease
 Connective tissue diseases
 Rheumatoid arthritis
 Sjogren’s syndrome

22. Polyneuropathy
 Most commonly distal symmetrical
 Fiber effect is length-dependent
 Toes and soles affected first
 Associations
 Systemic diseases
 Metabolic disorders
 Exogenous toxins

23. Polyneuropathy
 Diabetes is prototype
 Chronic, sensory and motor
 Commonest in developed world
 Alcoholism is the second most common

24. Polyneuropathy
 Early symptoms
 Sensory abnormalities
 Numbness
 Burning
 Paresthesias
 Dysesthesias
 Distally predominant
 Symmetrical

25. Polyneuropathy
 Evolution is centripetal
 Symptoms spread up legs
 Sensory loss
 Dysesthesias
 Ankles jerks are depressed
 Patients have trouble walking on their heels
 Foot plantar flexion remains strong

26. Polyneuropathy
 Symptoms noticed in fingertips
 Numbness
 Dysesthesias
 Advanced picture is easily recognizable
 Stocking-glove sensory loss
 Distal muscle wasting and weakness
 Absent tendon reflexes

27. Polyneuropathy
 Sub classification
 Historical features are indispensible
 Other medical conditions
 Symptoms of systemic disease
 Recent viral or other infectious diseases
 Recent vaccinations
 Institution of new medications

28. Polyneuropathy
 Exposure to toxins
 Alcohol
 Heavy metals
 Organic solvents
 Family history
 Duration and clinical course are
helpful
 Acute = days to weeks
 Chronic = months to years

29. Laboratory
Investigations
 CBC  UREA
 SUGAR
 TFTs  B12
 Methylmalonic acid
 ESR  Homocysteine
 CRP  Folate

30. Treatment
 General
 Subtype specific
 Diabetes mellitus
 Renal insufficiency
 Hypothyroidism
 Vitamin B12 deficiency
 Systemic vasculitis

31. Treatment
 General
 Pain
 Antiepileptic drugs
 Antidepressants
 Tramadol

32. Treatment
 Preventative and palliative
 Weight reduction
 Assiduous foot care
 Good shoes
 Ankle-foot orthoses as needed
 Several organizations provide
support

33. Chronic Length Dependent
Neuropathy
 Begins in toes or feet
 Stocking distribution
 Progresses rostrally
 Tops and bottoms of
feet
 Weakness begins in
ankles when
sensation reaches
calves
Sometimes diagnosable, Never treatable?

34. Phenotype CIDP
Small Differential

35. Phenotype-MADSAM
Neur opathy
 Key DDx:
 Brachial plexopathies
 Vasculitis
mononeuropathy
multiplex
 Compression
neuropathies
 HNPP (genetic testing)

36. Multifocal Motor
Neur opathy (MMN)
 Almost always in
hands and wrists
 Pattern of weakness is
in the distribution of
individual peripheral
nerves
 i.e. severe involvement in
ulnar distribution sparing
median
 Lack of atrophy in
weak muscles
 No pathological
reflexes

37. Uncertainty
 Many cases are not easily definable
because of multiplicity of patterns
 Cases that are not clearly untreatable are
possibly treatable