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
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
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