Sensory

1
Sensory Peripheral Neuropathies

• Steve Sager, MPAS, PA-C

2
Learning Objectives

• List common neuropathies
• List the common toxins which produce neuropathies
• Discuss the etiologies of common neuropathies
• Differentiate between common neuropathies
• Discuss the symptoms, signs, and treatments
• Diabetic neuropathies
• Alcoholic neuropathies
• Uremic neuropathies
• Autonomic neuropathies

3
Harrisons on Neuropathies

• The manifestations of such a disorder may be so
  bewildering and complex that it is difficult for
  a physician to know where to begin or how to
  proceed.

4
General Information

• More than 100 types of peripheral neuropathy have
  been identified
• Each has its own characteristic set of symptoms,
  pattern of development, and prognosis
• May involve sensory, motor, and/or autonomic
  nerves
• A thorough patient history is critical

5
Common Neuropathies

• Trigeminal neuralgia (tic douloureux)
• Postherpetic neuralgia
• Carpal Tunnel Syndrome
• Sciatica
• Guillain-Barré syndrome
• Peroneal Muscular Atrophy
• Diabetic Neuropathy Syndromes
• Alcoholic Neuropathy
• Uremic Neuropathy

6
Etiology of Neuropathies

• Peripheral neuropathy may be
• Inherited (C-M-T disease)
• Acquired
• Diabetes mellitus is a leading cause of
  peripheral neuropathy in the United States
• 60-70 of people with diabetes have mild to
  severe forms of nervous system damage.
• Neuropathies with no apparent cause are termed
  idiopathic

7
Etiology of Neuropathies

• Causes of acquired peripheral neuropathy include
• Physical injury (trauma) to a nerve
• Tumors (neurofibromatoses)
• Toxins
• Heavy metals
• Medications
• Infections
• Viral - HIV, EBV, HSV, CMV
• Bacterial Lyme disease

8
Etiology of Neuropathies

• Causes of acquired peripheral neuropathy include
• Kidney disease
• Autoimmune disease
• Nutritional deficiencies
• Vitamins E, B1, B6, B12, and niacin
• Alcoholism
• Thiamine deficiency
• Vascular, metabolic, and endocrine disorders

9
Symptoms of Peripheral Neuropathies

• Symptoms are related to the type of affected
  nerve and may be seen over a period of days,
  weeks, or years
• Muscle weakness is the most common symptom of
  motor nerve damage
• Sensory nerve damage causes a more complex range
  of symptoms because sensory nerves have a wider,
  more highly specialized range of functions

10
Symptoms of Peripheral Neuropathies

• Sxs of autonomic nerve damage are diverse and
  depend upon the affected organs/glands
• Autonomic nerve dysfunction can become life
  threatening and may require emergency medical
  care in cases when breathing becomes impaired or
  when the heart begins beating irregularly
• Common symptoms of autonomic nerve damage
  include
• unable to digest food easily
• an inability to sweat normally, which may lead to
  heat intolerance
• a loss of bladder control, which may cause
  infection or incontinence
• an inability to control muscles that expand or
  contract blood vessels to maintain safe blood
  pressure levels
• organ failure may occur.

11
Symptoms of Peripheral Neuropathies

• Because every peripheral nerve has a highly
  specialized function in a specific part of the
  body, a wide array of symptoms can occur when
  nerves are damaged
• Temporary numbness
• Tingling/pricking sensations (paresthesia)
• Sensitivity to touch
• Burning pain (especially at night)
• Muscle wasting
• Paralysis
• Organ or gland dysfunction

12
Symptoms of Peripheral Neuropathies
13
Radiculopathies

• Cervical due to stenosis or HNP
• Sensory sxs
• Neck, shoulder, or scapular pain increases with
  movement
• Motor sxs
• Loss of reflex based on nerve root involved
• Lumbosacral onset after heavy lifting
• Sensory sxs
• Pain in lower back, hip or buttocks /- radiation
• Increases with prolonged sitting, coughing,
  sneezing or straining
• HNP is generally unilateral
• Spondylolysis/spondylolithesis typically presents
  with bilateral sxs
• Motor sxs
• Loss of reflex
• Dx/Tx X-rays, CT/MRI, NSAIDs, bed rest, traction

14
Toxic Neuropathies(ICD 357.7)

• Organophosphates
• Toxins/Heavy metals
• Lead
• Arsenic
• Chronic uremia
• Due to excessive levels of parathormone
• Medications (ICD 357.6)
• Antimetabolic/ChemoTx

15
Diabetic Polyneuropathies(ICD 357.2)

• Diabetes affects 6 of the population
• Vascular and neurological complications are the
  most common causes of morbidity mortality
• Neuropathy affects 25-50
• Directly related to the length of time that nerve
  fibers are exposed to hyperglycemia
• Mixed polyneuropathy
• Usually affects motor, sensory autonomic

16
Diabetic Neuropathy Syndromes

• Glucose becomes incorporated into proteins
• AGEs are formed (irreversible)
• Reactive oxidants are produced
• Cause damage to collagen structure, basement
  membrane thickening, increased inflammatory
  responses and vascular permeability

17
Diabetic Neuropathy Syndromes

• Two types
• Peripheral
• Focal
• Mononeuropathy affecting PNS or CNs
• Generalized
• Symmetric, peripheral, sensory polyneuropathy
• Insidious and progressive
• Autonomic
• May result in erectile dysfunction, gastropathy,
  or hypoglycemia
• Cardiovascular complications
• Orthostatic hypotension
• Myocardial infarction
• Malignant arrhythmia
• Sudden death

18
Diabetic Neuropathy Syndromes

• Focal or multifocal
• Occur secondary to vasculitis/ischemia
• Acute onset of pain
• Resolves spontaneously lt6 weeks
• May involve
• CN III, IV, VI, VII
• Ulnar or median nerve
• Peroneal, sural, sciatic, or femoral nerve
• Amyotrophy of proximal thigh muscles
• Diabetic truncal radiculoneuropathy

19
Diabetic Neuropathy Syndromes

• Can be detected during a routine exam
• Inspect feet for deformities and sensory loss
• Loss of ankle reflexes
• Loss of Hot/Cold sensation
• Loss of vibratory sense
• 128Hz tuning fork to hallux
• Monofilament test
• Use 10 gauge monofilament
• Charcot foot xerosis, venous distension,
  multiple
• bony deformities
• EMG and NCS confirm the diagnosis

20
Monofilament Test

• There is a risk of ulcer formation if the patient
  is unable to feel the monofilament when it is
  pressed against the foot with just enough
  pressure to bend the filament
• The patient is asked to say "yes" each time he or
  she feels the filament
• Failure to feel the filament at four of 10 sites
  is 97 percent sensitive and 83 percent specific
  for identifying loss of protective sensation

21
Diabetic Mononeuropathies

• CN III or CN VI are commonly affected
• NOT associated with pupillary abnormalities
• CTS (median neuropathy)
• Occurs in 6 of diabetics
• Acute onset of painful paresthesias in fingers
  with radiating ache to forearm
• Worse HS
• Motor weakness is progressive with thenar wasting
• Positive Phalen test and/or Tinel sign

22
Diabetic Autonomic Neuropathy

• GI-related
• Characterized by gastroparesis, nausea/emesis and
  diarrhea
• Improve overall glycemic control
• /- improvement of GI sxs with Metoclopramide
• Tx diarrhea with Clonidine QD (/- TCN)
• GU-related
• Characterized by impotence, impaired sensation to
  voiding, and retrograde ejaculation

23
Treatment ofDiabetic Neuropathy Syndromes

• Improved metabolic control is the main goal of
  treatment
• Control lipids
• Manage HTN (ACE inhibitors)
• Lifestyle intervention
• Intensive insulin therapy
• 3-4 injections QD or an insulin pump reduced
  electrophysiologic evidence by up to 64
• ASA
• Magnesium oxide 250-750mg HS

24
Treatment ofDiabetic Neuropathy Syndromes

• Analgesics
• Tramadol
• Neuromodulators
• Gabapentin
• Carbamazepine (Tegretol)
• Capsaicin
• Tx neuropathic pain rub in for 5 minutes BID
• TCAs
• Daily foot exam by patient!!!
• Use mirrors
• Annual PCP examination is required

25
Diabetic Autonomic Neuropathy

• Avoid medications that can cause syncope
• Alpha-blockers, anti-HTN, antidepressants
• Frequent accuchecks
• Maintain adequate hydration
• Minimize cardiac-related AN
• Monitor for orthostatic hypotension
• Increased risk of sudden death/silent ischemia
• Improve mgmt of glucose, lipids, and HTN
• Use ACE inhibitors

26
Diabetic Neuropathy Syndromes

• Foot ulceration and amputation are the most
  common consequences
• Risk factors for amputation
• Poor glycemic control
• Alcohol abuse
• Obesity
• Loss of protective sensation
• Altered biomechanics/foot deformities
• Diagnosis gt10 years
• Gender
• Peripheral vascular disease

27
Neuropathy Disability Score
28
Alcoholic Polyneuropathy(ICD 357.5)

• Establish Dx of alcohol abuse
• Preoccupation
• Increased tolerance
• Drinking alone
• Use as a medication
• Blackouts
• Physical/Social/Family issue
• CAGE questionnaire
• ? Vitamin deficiency

29
Alcoholic Polyneuropathy

• Wernicke-Korsakoff syndrome
• CNS injury related to thiamine deficiency
• Nystagmus, ataxia, confusion, EOM paralysis
• Peripheral polyneuropathy
• Earliest symptom of chronic alcoholism
• Mostly sensory with /- motor involvement
• Burning sensation in feet
• Dementia due to cerebral atrophy
• Cerebellar degeneration truncal ataxia
• Myopathy proximal muscle wasting
• Hepatic encephalopathy
• Altered consciousness/lethargy
• Ataxia/dysarthria/asterixis

30
Alcoholic Polyneuropathy

• Delirium Tremens (DTs)
• Alcohol withdrawal syndrome
• Occurs 72-96 hours after cessation
• Often fatal
• Similar to withdrawal from barbiturates/benzos
• Mild tremors seizures
• Jittery and easily startled
• Hallucinations
• Autonomic hyperactivity

31
Alcoholic Polyneuropathy

• Seizures are common
• Generalized (Rum fits)
• Occur 12-48 hours after decreased ETOH intake
• Focal
• Occur during periods of intoxication
• Tx
• Supportive (diet, vitamins, etc.)
• Librium
• Diazepam
• Thiamine (50mg IV and 50mg IM QD)

32
Uremic Neuropathy (Uremia)(ICD 357.4)

• Presents with altered mental status
• Variable
• Irritability
• Difficulty concentrating
• Psychosis
• May have convulsions
• Secondary to acidosis, hypokalemia, hyponatremia
• Often occurs postdialysis/postdiuresis
• Most patients with BUNgt60 have EEG changes
• R/O infection and subdural hematoma

33
Uremic Neuropathy

• Additional (late) symptoms
• Peripheral neuropathy
• Restless leg syndrome
• Burning paresthesias of the feet
• Sensory loss in digits
• Asterixis
• Fasciculations
• Myoclonus
• Muscle cramps
• Amaurosis
• Cerebral emboli
• Dementia

34
Autonomic Neuropathies

• Parasympathetic neuropathies typically involve
  the cranial nerves or sacral nerves
• Sympathetic neuropathies involve the medulla
  oblongata, spinal cord, or sympathetic ganglia
• Both involve receptors in the smooth muscles and
  glands

35
Clinical Manifestations of Autonomic Neuropathies

• Sudden death
• Tremors
• Hyperthermia
• Altered sweating
• Tachycardia
• Orthostatic hypotension
• Syncope
• Gastroparesis
• GU dysfunction

36
Conditions Associated with Autonomic Neuropathies

• Poisoning
• Atropine
• Anticholinesterase inhibitors
• Horners syndrome
• Oculosympathetic paralysis
• Ptosis
• Miosis
• Anhidrosis
• Shy-Dragger syndrome
• Progressive autonomic failure
• Multiple system atrophy
• Progressive and fatal

37
Conditions Associated with Autonomic Neuropathies

• Pheochromocytoma
• Tumors arising from chromaffin cells in the
  sympathetic nervous system
• Release Epinephrine and NE into circulation
• Cause autonomic hyperactivity
• Paroxysmal hypertension
• Diaphoresis
• Flushing
• Tachycardia
• Anxiety
• Test blood/urine for catecholamines,
  metanephrines and vanillylmandelic acid (VMA)

38
Assessment of PossibleAutonomic Neuropathies

• Orthostatic VS
• ECG
• Look for R-R variability
• Tilt test
• Cold pressor test
• Sweat provocation

39
Treatment of Neuropathies

• Several classes of drugs have recently proved
  helpful to many patients suffering from more
  severe forms of chronic neuropathic pain
• Antiepileptic drugs
• Phenytoin (Dilantin)
• Carbamazepine (Tegretol)
• Some classes of antidepressants (Tricyclics)
• Gabapentin (Neurontin)
• Mexiletine (Mexitil)
• developed to correct irregular heart rhythms
• sometimes associated with severe side effects

40
Treatment of Neuropathies

• Neuropathic pain is often difficult to control
• Use smallest effective dose and titrate
• Mild pain may sometimes be alleviated by OTC
  analgesics
• Limit narcotic use
• Corticosteroids may help reduce inflammation
• Injections of local anesthetics such as lidocaine
  or topical patches containing lidocaine may
  relieve more intractable pain
• In the most severe cases, doctors can surgically
  destroy nerves
• The results are often temporary and the procedure
  can lead to complications.

41
Information Resources

• Neuropathy Association60 East 42nd StreetSuite
  942New York, NY   10165-0999http//www.neuropath
  y.orgTel 212-692-0662 800-247-6968Fax
  212-692-0668
• National Chronic Pain Outreach Association
  (NCPOA)P.O. Box 274Millboro, VA  
  24460http//www.chronicpain.orgTel
  540-862-9437Fax [phone]
• American Chronic Pain Association (ACPA)P.O. Box
  850Rocklin, CA   95677-0850http//www.theacpa.or
  gTel 916-632-0922 800-533-3231Fax [phone]

42
Information Resources

• Charcot-Marie-Tooth Association (CMTA)2700
  Chestnut ParkwayChester, PA   19013-4867http//w
  ww.charcot-marie-tooth.orgTel 610-499-9264
  800-606-CMTA (2682)Fax [phone]
• American Pain Foundation201 North Charles
  StreetSuite 710Baltimore, MD  
  21201-4111http//www.painfoundation.orgTel
  888-615-PAIN (7246) 410-783-7292Fax
  410-385-1832
• National Foundation for the Treatment of
  PainP.O. Box 70045Houston, TX  
  77270http//www.paincare.orgTel
  713-862-9332Fax [phone]

43
Summary

• List common neuropathies
• Etiologies of common neuropathies
• Differentiate between common neuropathies
• Discuss treatment options for common neuropathies
• List the common toxins which produce neuropathies
• Symptoms, signs, and treatments of
• Guillain-Barré syndrome
• Peroneal Muscular Atrophy
• Diabetic neuropathies
• Alcoholic neuropathies
• Uremic neuropathies
• Autonomic neuropathies

44
Summary

• Diabetes mellitus is a leading cause of
  peripheral neuropathy in the United States
• Diabetic Neuropathy Syndromes
• Vascular and neurological complications are the
  most common causes of morbidity mortality
• Foot ulceration and amputation are the most
  common consequences
• CTS (median neuropathy) occurs in 6
• Improved metabolic control is the main goal of
  treatment
• Daily foot exam by patient is essential

45
Summary

• Alcoholic Neuropathy
• Peripheral polyneuropathy is the earliest symptom
  of chronic alcoholism
• Wernicke-Korsakoff syndrome results from CNS
  injury related to thiamine deficiency
• Seizures are common
• Uremic Neuropathy
• Presents with altered mental status
• Often occurs postdialysis/postdiuresis

46
Summary

• Autonomic neuropathies affect receptors in the
  smooth muscles and glands
• Clinical manifestations of autonomic neuropathies
  include sudden death, hyperthermia, altered
  sweating, orthostatic hypotension, and
  gastroparesis
• Neuropathic pain is difficult to control