Download Class I Subclinical Neuropathy

Diabetic
Neuropathy
Beverly J. Mathis, D.O.
November 2007
Definition
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Complex syndrome of neurological
abnormalities caused by the
metabolic and vascular complications
of diabetes.
Class I Subclinical Neuropathy
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Abnormal electrodiagnostic tests
Decreased nerve conduction velocity
Decreased amplitude of evoked muscle or
nerve action potential
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Abnormal quantitative sensory testing
Vibratory/ warming/cooling
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Abnormal autonomic function tests
Sinus arrhythmia (beat-to-beat heart rate
variation)
Increased pupillary latency
Class II Clinical Neuropathy
Diffuse neuropathy
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Distal symmetric sensorimotor
polyneuropathy
Primarily small fiber neuropathy
Primarily large fiber neuropathy
Mixed
Class II Clinical Neuropathy
Autonomic neuropathy
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Abnormal pupillary function
Sudomotor dysfunction
Genitourinary autonomic neuropathy
Bladder dysfunction
Sexual dysfunction
Class II Clinical Neuropathy
Autonomic neuropathy
Gastrointestinal autonomic neuropathy
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Gastric atony
Gall bladder atony
Diabetic diarrhea
Hypoglycemic unawareness (adrenal
medullary neuropathy)
Classification
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Distal symmetric polyneuropathy
Individual cranial or peripheral nerve
palsies, especially cranial nerve III
Autonomic neuropathy
Thoracic and lumbar nerve root
disease
Mononeuropathy multiplex
(assymmetric involvement of
peripheral nerves
Incidence
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10-18 percent have evidence at
diagnosis of diabetes
Increases up to 41 % at 10 years
Progession and severity directly
correlates with diabetes control
Glycemic control prevents diabetic neuropathy
DCCT, NEJM 1993
Signs and Symptoms of Diabetic
Peripheral Neuropathy
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Loss of vibratory sensation and
altered proprioception reflecting
large-fiber loss
Impairment of pain, light touch and
temperature is secondary to loss of
small fibers
Complications of Peripheral
Neuropathy
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Foot ulcers due to progressive
sensory loss
Muscular Atrophy
Charcot foot with fractures,
subluxation and sclerosis of bone
Criteria for Diagnosis
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Loss of touch sensation using a
monofilament on the distal toes
Loss of vibratory sensation using a
128 Hz tuning fork at the first MCP
joint
Absent achilles reflex
Most important is to inspect the feet
for callus formation
Differential
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Vascular disease – ischemia,
vasculitis
Metabolic – thyroid disease, B12 or
B6 deficiency
Disc disease
Pathogenesis
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Metabolic –accumulation of advanced
glycosalation end products,
accumulation of sorbitol and
increased oxidative stress
Ischemic – small vessel disease
Impaired peripheral nerve repair
Prevention
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GLUCOSE CONTROL
Other risk factors though not proven
include cigarette smoking, blood
pressure control,no alcohol
consumption and lipid treatment.
Treatment of painful diabetic
neuropathy
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Tier I
Pregabalin
Duloxetine
Tier II
Tricyclics, gabapentin, oxycodone
Treatment of painful diabetic
neuropathy
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Capsaicin cream
Anticonvulsants – lamotrigine,
carbamazepine, topiramate
Anesthetic drugs – mexilitine,
lidocaine patches
Alpha-lipoic acid
Tramadol
Less studied treatments
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L carnitine
Nitro spray
NSAIDS (stay away from this one!)
TENS unit
Venlafaxine
ACE inhibitors
Aldose reductase inhibitors (too
toxic)
Autonomic neuropathy
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Orthostasis – use vasodilators and
avoid overdiuresis.
Neurogenic bladder – self cath,
suprapubic catheter
Gastroparesis – motility agents –
metoclopramide, erythromycin,
dulcolax, gastric pacemaker
Autonomic neuropathy
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Diabetic diarrhea – due to stasis,
often over treated with antimotility
agents which can make it worse
• Soluble fiber – Fibercon, metamucil
firms up the stool
• Cholestyramine, Colistid – bile resin
binders