1. Diabetic Peripheral Neuropathies
A clinical and electro physiologic understanding

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Understanding Electromyography And Nerve Conduction Velocity

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. 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. 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. 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. 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. 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. 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. 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