DOM Morning Report Peripheral Neuropathy

							Peripheral Neuropathy




  Dr. Sunil J. Panjwani M.D.
  Associate Professor in Medicine,
  Medical College, Bhavnagar.
 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
Peripheral Nerve




 Myelin   : Current cannot flow
 Axon     : Not nerves left
The Peripheral Nervous System
                Motor: weakness,
                 atrophy
                Sensory loss
                  Large Fibers
                   (position)
                  Small fiber (pain)
                Reflex loss
                Autonomic
                 symptoms
                  (redness,
                   dizziness, ED)
  Mechanisms of damage
 Demyelination            Myelin sheath disrupted
  GBS        Post Diphtheric           HSMN
 Axonal degeneration             Axon damage
  Toxic neuropathies
 Wallerian degeneration Nerve section Both
 Compression       Focal demyelination
  Entrapment-Carpel tunnel syndrome
 Infarction       Arteritis
  Polyarteritis nodosa     Churg-Strauss synd.   DM
 Infiltration     Infiltration
  Leprosy    Sarcoidosis
                 Definitions
 Neuropathy
Pathological process affecting a peripheral nerve/s
 Mononeuropathy
A single nerve affected
 Mononeuritis multiplex
Multiple mononeuropathy or Multifocal neuropathy
 Polyneuropathy
Diffuse symmetrical disease usually beginning peripherally
Acute/Chronic   Static/Prog.    Relapsing/Recovering
Motor Sensory      Sensrimotor(Mixed)     Autonomic
Demyelinating      Axonal
 Radiculopathy           Nerve root disease
Classification FINDINGS
         EXAMINATION
      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?
             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
Objectives

  To learn a logical/sequential approach

  To know the types and etiologies

  To understand the treatment
Background

  Common problem
  Logical/sequential approach necessary
    Variable presentation and disparate causes
    Evaluation and management
Background

  Categorized by subtype and etiology
    Clinical findings
    Electro diagnostic tests
    Laboratory investigations
  Classification allows rational assessment
    Prognosis
    Treatment options
Epidemiology

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

  Other common systemic causes
      Metabolic disorders
      Infectious agents
      Vasculitis
      Toxins
      Drugs
      Autoimmunity
      Inherited
Diagnosis

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

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

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

   Establish distribution
     Mononeuropathy
     Mononeuropathy multiplex
     Polyneuropathy
   Determine primary pathology
     Demyelinating
     Axonal
Mononeuropathy

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

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

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

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

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

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

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

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

  CBC         UREA
  SUGAR
  TFTs        B12
                 Methylmalonic acid
  ESR           Homocysteine

  CRP         Folate
Treatment

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

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

    Preventative and palliative
      Weight reduction
      Assiduous foot care
      Good shoes
      Ankle-foot orthoses as needed
  Several organizations provide
   support
  Objectives Revisited
 Approach
   History              Laboratory
     Distribution        evaluation
     Duration             CBC
     Course               SUGAR
                           TFTs
   Physical exam
                           UREA
     Sensation
                           B12
     Strength
   Electrodx studies
     NCS
     EMG
  Objectives Revisited

 Subtypes
   Mononeuropathy         Polyneuropathy
     Entrapment             DM
     Focal compression      Toxin
     Trauma
   Mononeuropathy
    multiplex
     DM
     Vasculitis
  Objectives Revisited

 Treatment
   General            Specific
     Pain control       DM
     Preventative/      Renal
                          insufficiency
      Palliative
                         Vasculitis
                         B12 deficiency
                         Hypothyroidism
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?
Phenotype CIDP




        Small Differential
Phenotype-MADSAM
Neuropathy
 Key DDx:
   Brachial plexopathies
   Vasculitis
    mononeuropathy
    multiplex
   Compression
    neuropathies
   HNPP (genetic testing)
Multifocal Motor
Neuropathy (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
Uncertainty

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