Neuropathic Pain Associated with Diabetic Peripheral Neuropathy.

1. Neuropathic Pain Associated with Diabetic Peripheral Neuropathy. Saad Cyril Naaman, MD, MS Assistant Clinical Professor @Wayne State Medical School Assistant Professor Beaumont Oakland University

2. Objectives To understand the etiology, pathogenesis of the disease To discuss the management of pDPN.

3. Assessing Diabetic Nerve Pain American Diabetes Ass. recommends screening for DPN in all patients at diagnosis and annually thereafter. About 23.6 Million people in USA have diabetes both diagnosed and undiagnosed. 60%-70% have diabetic neuropathy 1 out 4 patients with diabetes have pDPN. 8 out of 10 patients with pDPN report moderate to severe pain A survey showed that nearly 50% of diagnosed diabetic patients have not discussed diabetic nerve pain or its symptoms with their physician. Even if glucose level are under control their chronic pDPN associated pain might not be.

4. Sensory Nerve damage“Stock & Glove”“Typically in pDPN small fibers are affectec first” Small Fibers Pain amplification and heyperalgesia Loss of sensitivity , later Autonomic symptoms Predisposes to diabetic foot disease Elctrophysiology may not detect nerve damage Large Fibers Sensory & motor fibers Loss of vibration Feet usually affected first Deep seated gnawing and aching pain Muscle wasting Usually detected by NCS/EMG

5. Diagnosis of Neuropathy NCS/Electromyography Skin Biopsy: Quantification of intraepidermal nerve fiber (IENF) density is lower than normal. Quantitative Sudomotor Axon Reflex Testing (QSART)

6. The Role of Neuroplasticity/Central Sensitization Neuronal plasticity are the changes in neuron function, chemical profile or structure as a result of painful stimulation and nerve damage Neuropathic pain is pain felt in absence of nociceptor stimulation resulting from lesion or disease in nervous system. Amplified pain perception results from changes in pain processing in CNS Pain amplification is characterized by hyperalgesia and allodynia Understanding Central sensitization in spinal cord and CNS is helping in the management of neuropathic pain

7. Diabetic Neuropathy Distal symmetric polyneuropathy is the most common form Involves small & large fibers Keep in mind the differential diagnosis e.g entrapment/compression neuropathies

8. Establish realistic goals : therapies typically do not result in complete resolution of symptoms Medication dosage tailored to the individual Goal of treatment is symptom resolution. Try to use the lowest effective dose.

9. Management of pDPN Medications: OTC TCAs SSRIs Opioids FDA approved meds Neurontin Lyrica Cymbalta

10. New AAN Guidelines on Painful Diabetic NeuropathyApril 2011 2200 papers were reviewed on pDPN 463 were relevant Strong Evidence (Level A ): Pregabalin Moderate evidence (Level B) Anticonvulsants: gabapentin should be considered Aniconvalsaant: lamotrigine and lacosamide should not be considered Antidepressants: duloxetine should be considered Opioids: are to be considered. Weak Evidence (Level C): weak evidence adding venlafaxine to neurontin Insufficient evidence (level U): vitamins, topiramate, impramine