Diabetic painful neuropathy

Dr. Ashok Kumar Das

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

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 .

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

Diabetic painful neuropathy

Relief of pain is of paramount importance andobligatory on the part of physician.But the state of the art of pain relief in thissyndrome is far from satisfactory. Many modalities of treatment have beenadvocated but the arena of therapy is full ofclaims and counter claims.

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

Clinical types of painful diabetic neuropathy - 1

Although a rigid classification of painfuldiabetic neuropathy is very difficult they maybe grouped under following three majorcategories1. Symmetrical distal painful poly- neuropathies2. Proximal motor neuropathies 3. Focal asymmetrical painful neuropathies

Clinical types of painful diabetic neuropathy - 2

Symmetrical distal painful polineuropathiesmay be grouped as

1. Small fibre type2. Mixed large and small fibre type3. Hypoglycaemic neuropathy/insulin neuritis4. Mixed distal sensory-motor neuropathy

Clinical types of painful diabetic neuropathy - 3

Proximal motor neuropathies can be dividedinto two groups

1. Symmetrical proximal motor neuropathy2. Asymmetrical proximal motor neuropathy

- diabetic amyotrophy

Focal asymmetric neuropathies-1

1. Predominantly sensory:

a) Intercostal Neuropathyb) Truncal neuropathyc) Thoraco-abdominal radiculopathyd) Neuropathy due to involvement of lateral cutaneous nerve of thigh

Focal asymmetric neuropathies-2

Predominantly motor:Mononeuritis or mononeuritis Multiplex which may include -a) Ocular neuropathyb) Femoral neuropathyc) Sciatic neuropathyd) Median neuropathy

Diabetic mono-neuropathies

a) Isolated and multiple mononeuropathiesb) Cranial moneuropathiesc) Proximal motor neuropathiesd) Truncal polyneuropathy

Distal polyneuropathies

a) Acute sensory neuropathyb) Chronic sensory motor neuropathiesc) Proximal motor neuropathiesd) Truncal polyneuropathy

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

Symmetrical distal polyneuropathies - 1

Paraesthesia may manifest as a sensation ofcoldness, numbness, tingling or burning

On exam - dysesthesia and calf tenderness

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

Diabetic neuropathic cachexia:

* Outstanding symptoms - weight loss and severe pain

* Emotional disturbance* Anorexia* Impotence * Mild diabetes * Simultaneous onset of diabetes and

neuropathy

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

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

Mixed distal sensory motor neuropathies

* Usually occur in middle aged and elderly with type 2 diabetes

There are two entities1. Subacute proximal neuropathy of insidious

onset2. Ischaemic mononeuropathy multiplex of

acute onset

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

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

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

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

Truncal neuropathy - 4

* Involvement of lateral cutaneous nerve may present with sensory disturbance in thigh

* Usually asymmetrical without motor deficit* Recover spontaneously

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

Drugs used in painful diabetic neuropathy - 1

* Non steroidal anti inflammatory agents * Ibuprofen 600mg four times daily* Sulindac 200 mg twice daily

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

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 6hFluphenazine 1 mg/day