This document discusses diabetic peripheral neuropathies and provides details about their prevalence, types, symptoms, pathophysiology, and management. It covers the following key points: 1. Diabetic neuropathies affect 30-50% of people with diabetes and include symmetric sensorimotor polyneuropathy, mononeuropathies, and radiculopathies. Symptoms range from numbness to severe pain. 2. Electrophysiological testing like EMG and NCV examine nerve conduction velocities and amplitudes to detect damage to large myelinated fibers. Changes indicate dead/dying axons. 3. The pathology of diabetic neuropathies involves metabolic and vascular mechanisms like increased sorbitol, non

1. 1
Diabetic Peripheral
Neuropathies
A clinical and electro
physiologic understanding

2. 2
Diabetic Neuropathy
General:
Prevalence – 30 to 50%
DiabCare Asia Statistics – 37%
Diabetic State is the trigger
Uncontrolled diabetes – worsens over time
Good control of diabetes - not the guarantee
for – cure, arrest, reversal

3. 3
Diabetic Peripheral Neuropathy
- 1
Major divisions
• Symmetric Sensorimotor Diabetic
polyneuropathy
• Lumbosacral plexus neuropathy
• Truncal racdiculopathies
• Diabetic mononeuropathies
Invariably associated with some autonomic
nervous system involvement and / or cranial
neuropathies

4. 4
Diabetic Peripheral Neuropathy
- 2
• Incidence of neuropathic symptoms many
times more and more sites are involved
than in non diabetic persons
• Autonomic neuropathy has diabetes as
almost the sole major cause, other than
ageing or smoking

5. 5
Diabetic Peripheral Neuropathy
- 3
• Sensory symptoms and signs distally,
numbness or paresthesia
• Ascends from toes
• Glove and Stocking anesthesia - a
phenomenon dependent on fiber length

6. 6
Diabetic Peripheral Neuropathy
- 4
• Generally or eventually symmetric,
• Initially, not infrequently, asymmetric, often
confined to single nerves
• Tear drop abdominal thoracic anesthesia,
somewhat unusual presentation, not rare

7. 7
Diabetic Peripheral Neuropathy
- 5
More severe cases –
• Paresthesia tingling and numbness,
• Dysesthesia,
• Deep, aching, severe night pains
• Paroxysmal jabbing pain
• Pain – small fiber neuropathy

8. 8
Diabetic Peripheral Neuropathy
- 6
More severe cases –
• Pain & temp loss with intact vibration and
position sense; the reflexes and power
may be normal – suggests A delta or thin,
unmyelinated fiber involvement sparing
large fibers of somatic sensation

9. 9
Diabetic Peripheral Neuropathy
- 7
Dominantly Large fiber Sensory and motor
involvement
Sensory Neuropathy – Symptoms, positive or
negative,
Loss of light touch, pain, pressure,
Post columns get involved vibration
perception, joint
position sensation is lost
Diabetic pseudotabes occurs
Large fibers intact - NCV – nearly normal

10. 10
Diabetic Peripheral Neuropathy
- 8
Dominantly Large fiber involvement –
Sensory and motor involvement
Muscle weakness
Intrinsic foot muscle - extensors and
flexors of toes, weakness, atrophy and
foot drop, foot deformities due to motor
neuropathy

11. 11
Diabetic Peripheral Neuropathy
- 9
• Once established, stays
• Exacerbates with other illnesses,
• Neuropathic joints suggestive of
autonomic neuropathy, usually accompanied by
dense sensory neuropathy and other tissue
changes, as well as altered joint structure
• Painless foot ulcers suggestive of severe
sensory neuropathy

12. 12
Diabetic Peripheral Neuropathy
- 10
• Severe painful neuropathy causes
depression
• Diabetic neuropathic cachexias
• Severe exacerbations of burning pains,
allodynia ie excessive pain sensation to
non noxious stimuli with sensory deficits,
anoxexia, weight loss, depression
• Generally recovers

13. 13
Hyperglycemic Neuropathy
• Widespread parasthesias in newly
diagnosed cases, after recovery from
ketosis
• Improve rapidly with control, could have a
different pathophysiologic basis than the
one with long term complications

14. 14
Proximal Motor Neuropathy - 1
• Peaks in 6th
decade in type 2
• Diabetes mild
• Control not good
• Acute / sub acute pain
• Pelvic girdle weakness and atrophy,
illiopsoas and quadriceps, hip adductor
gluteni, namstrings
• Knees buckle, stairs difficult

15. 15
Proximal Motor Neuropathy - 2
• Sensory symptoms present.
• Commonly – paresthesias, deep aches, ↑ at
night, not relieved by rest, SLR neg.
• Unilateral, may become bilateral
• Reflexes Lower Limbs +
• Recovery usual and nearly full
• Takes 6 – 18 months
• Reassurance necessary

16. 16
Thoracic Radiculopathy: - 1
• Middle aged mild diabetics
• Acute herpes like deep ache
• Multiple segment, single, bilateral, or
unilateral
• Paresthesia, cutaneous hyper sensitivity
• Severe cases show paraspinal and
abdominal muscle weakness

17. 17
Thoracic Radiculopathy: 2
• Imagings normal
• Waste of money
• Recovers with a few months to an year
• Left sided pains disturbing as cardiac
• Pains could be as such disturbing
• Electromyography shows –
Acute denervation, insertional
hyperactivity and fibrillation potentials

18. 18
Diabetic Mononeuropathy: 3
Also called Diabetic Mononeuropathy Multiplex
Probably closure of vasa nervorum the cause
• Focal necrotic pathological changes
Or entrapment mononeuroathy, supposedly more
common in daibetes, e. g, carpal tunnel
Trauma to superficial nerves
Distal polyneuropathies can be super imposed on
Mononeuropathy multiplex

19. 19
Understanding
Electromyography
And
Nerve Conduction Velocity

20. 20
EMG and NCV - 1
• Uses surface and needle electrodes,
calculated electrical current is delivered to
the sensory and motor nerves,
• Creates action potentials in sensory and
motor nerves that are measurable
• The amplitude of these potentials is
measured by using microprocessor based
technology

21. 21
EMG and NCV - 2
• The current generated by action potentials
also carries impulses with velocities that
are measurable
• Specific changes in sensory or motor
nerves or primary muscle changes can be
detected thereby localizing diagnosis

22. 22
Electrophysiology Diagnosis - 1
EMG and NCV measure only the large
myelinated, fast conducting fibers
• Conduction velocities are indicative of the
integrity or otherwise of the individual
functioning or malfunctioning nerve fiber
• Amplitude is indicative of the fiber number
that is present and functioning,

23. 23
Electrophysiology Diagnosis - 2
Conduction velocity of a fiber depends on
fiber size,
state of myelination,
nodal and internodal length and
axonal resistance
Synchronous velocities indicate healthy fibers
Asynchronous – malfunctioning or unhealthy fibers

24. 24
Electrophysiology Diagnosis - 3
Reduction in axon number results in
reduced amplitude of action potentials
EMG measures cumulative amplitude
arising from all the functioning or firing
axons
Number is reduced due to
– Dead or dying axons
- Dying ones cause fibrillations, fasciculations

25. 25
Pathology of Peripheral Nerves
• Metabolic hypothesis:
• ↑ Sorbitol, ↓ myoinositol, ↓ ATP and 1, 3, 4 PIs
• Nonenzymatic glycation of proteins
• Abnormal flow along the nerve fibers of proteins
• Ischemic insult due to vasa nervorum closure
• Nerve hypoxia, oxidant stress
• Necrotising or simple vasculitis, angiitis

26. 26
Management of Diabetic Peripheral
Neuropathy: 1
• Hyperglycemia, (I.V. Insulin)
• Aldose reductase inhibitors
– Orlestatin, sorbinil
– Moderate to good improvement with sorbinil,
on EMG, NCV also
• Hypersensitivity with sorbinil

27. 27
Management of Painful Diabetic
Polyneuropathy: 2
• Analgesic, normoglycemia
• Phenytoin, carbomazepine – Indians feel
beeter. West not enthusiastic
• Amitryptiline 150 mg a day –
hyperesthesia helped as also depression
• Gabapentin useful, costly, high doses