1. Diabetic painful neuropathy Dr. Ashok Kumar Das

2. Diabetic painful neuropathy This is a definite subset of diabetic neuropathy and requires more attention owing to its painful condition, disability and wide spectrum of clinical syndrome

3. Diabetic painful neuropathy Comprises of clinical syndromes like acute painful neuropathy, chronic sensorimotor neuropathy, proximal painful symmetrical motor neuropathy, proximal painful asymmetrical motor neuropathy (diabetic amyotrophy) painful diabetic external ophthalmoplegia, treatment induced insulin neuritis, hypoglycaemic neuritis and painful painless leg.

4. Diabetic painful neuropathy * Pain is a feature of small fiber neuropathy. The small fibers also carry autonomic impulses. * It seems logical to expect increased incidence of autonomic denervation in painful diabetic neuropathies

5. Diabetic painful neuropathy Relief of pain is of paramount importance and obligatory on the part of physician. But the state of the art of pain relief in this syndrome is far from satisfactory. Many modalities of treatment have been advocated but the arena of therapy is full of claims and counter claims.

6. Diabetic painful neuropathy * These modalities range from simple analgesic to most modern aldolase reductase inhibitors * In the national context, pain relief must be obtained by simple measures

7. Clinical types of painful diabetic neuropathy - 1 Although a rigid classification of painful diabetic neuropathy is very difficult they may be grouped under following three major categories 1. Symmetrical distal painful poly- neuropathies 2. Proximal motor neuropathies 3. Focal asymmetrical painful neuropathies

8. Clinical types of painful diabetic neuropathy - 2 Symmetrical distal painful polineuropathies may be grouped as 1. Small fibre type 2. Mixed large and small fibre type 3. Hypoglycaemic neuropathy/insulin neuritis 4. Mixed distal sensory-motor neuropathy

9. Clinical types of painful diabetic neuropathy - 3 Proximal motor neuropathies can be divided into two groups 1. Symmetrical proximal motor neuropathy 2. Asymmetrical proximal motor neuropathy - diabetic amyotrophy

10. Focal asymmetric neuropathies-1 1. Predominantly sensory: a) Intercostal Neuropathy b) Truncal neuropathy c) Thoraco-abdominal radiculopathy d) Neuropathy due to involvement of lateral cutaneous nerve of thigh

11. Focal asymmetric neuropathies-2 Predominantly motor: Mononeuritis or mononeuritis Multiplex which may include - a) Ocular neuropathy b) Femoral neuropathy c) Sciatic neuropathy d) Median neuropathy

12. Diabetic mono-neuropathies a) Isolated and multiple mononeuropathies b) Cranial moneuropathies c) Proximal motor neuropathies d) Truncal polyneuropathy

13. Distal polyneuropathies a) Acute sensory neuropathy b) Chronic sensory motor neuropathies c) Proximal motor neuropathies d) Truncal polyneuropathy

14. Symmetrical distal polyneuropathies - 1 Small fibre type: *In small fibre type neuropathy *Pain and paraesthesis, most commonly of the lower extremities are the characteristic symptoms *Pain - dull, burning, aching, lancinating, crushing and cramp-like

15. Symmetrical distal polyneuropathies - 1 Paraesthesia may manifest as a sensation of coldness, numbness, tingling or burning On exam - dysesthesia and calf tenderness

16. Symmetrical distal polyneuropathies - 3 * In addition - diminished pain and temperature perception in the lower extremity with less involvement of reflex and position and vibratory sensation * Autonomic dysfunction most prevalent

17. Diabetic neuropathic cachexia: * Outstanding symptoms - weight loss and severe pain * Emotional disturbance * Anorexia * Impotence * Mild diabetes * Simultaneous onset of diabetes and neuropathy

18. Painful-painless leg * Patient experience pain or paraesthesia * On neurological examination - pain sensation absent * Such patients are at greatest risk of painless injury to the feet

19. Hypoglycemic neuropathy / insulin neuritis * Hypoglycaemia is rare - but treatable * Usually presents symmetrical motor, sensory or mixed neuropathies of uncertain aetiology * Distal symmetrical symptoms * More common in nondiabetic patients subjected to insulin shock therapy

20. Mixed distal sensory motor neuropathies *Usually occur in middle aged and elderly with type 2 diabetes There are two entities 1. Subacute proximal neuropathy of insidious onset 2. Ischaemic mononeuropathy multiplex of acute onset

21. Focal asymmetrical diabetic neuropathy *Intercostal neuropathy *Middle aged or older patients *Present with longstanding diabetes with abrupt onset of unilateral pain *Associated with peripheral sensory neuropathy,weight loss and worsening of pain at night *Condition recovers in 3 months

22. Truncal neuropathy - 1 *Pain in the trunk *Abdominal bulge causing muscle weakness *Clinical features suggestive of malignant disease *Electromyography reveals correct diagnosis *Spontaneous and complete recovery

23. Truncal neuropathy - 2 *Most diabetic with this syndrome are in 5th or 6th decade of life *Associated with weight loss, beginning with the onset of pain *Denervation of paraspinal muscles present *Lesion is proximal, either in the nerve roots or the spinal nerves

24. Truncal neuropathy - 3 *Spinal cord compression should be excluded by appropriate investigations *Caused by ischaemic infarction of nerve *No pathological evaluation of involved intercostal nerve has been reported

25. Truncal neuropathy - 4 *Involvement of lateral cutaneous nerve may present with sensory disturbance in thigh *Usually asymmetrical without motor deficit *Recover spontaneously

26. Cranial neuropathy *With the exception of pupillary sparing,disruption of oculomotor nerve function – most frequent *Recovery usually occurs within 6-12 weeks *Lower cranial nerves can get involved. *Internuclear opthalmoplegia

27. Drugs used in painful diabetic neuropathy - 1 *Non steroidal anti inflammatory agents *Ibuprofen 600mg four times daily *Sulindac 200 mg twice daily

28. Drugs used in painful diabetic neuropathy - 2 *Carbamazepine upto 200 mg q 6h *Amitryphyline-fluphenazine combination *Gabapentin 900 mg q 8h *Whereas lignocaine and phenytoin failed to do so *Mexiteline 150 mg – 450 mg / day

29. Drugs used in painful diabetic neuropathy - 3 Tricyclic antidepressant drugs: Amitriptyline 50-150 mg at night *Nortriptyline 50-150 mg at night *Imipramine 100 mg daily *Paroxetine 40 mg daily Other drugs: Capsaicin 0.075% q 6h Fluphenazine 1 mg/day