Www.plymouthdiabetes.org.uk/ Diabetic Neuropathy Patrick English Diabetes Consultant Derriford Hospital

www.plymouthdiabetes.org.uk/

Diabetic Neuropathy

Patrick English

Diabetes Consultant

Derriford Hospital


Outline

Size and costs of the problem Pathology/pathophysiology Risk factors Presentations Diagnosis Prevention and Treatment Algorithm/NICE


Size and cost Prevalence: 22.7% T1DM, 32.1%

T2DM USA: 17% of costs of treating diabetic

complications (approx $300 per patient per year)

UK: £13 million p.a on diabetic foot complications

1900 patients with painful diabetic neuropathy in Derriford Catchment

435 requiring at least 2nd line agent for pain

1. Young MJ, Boulton AJ, MacLeod AF, Williams DR, Sonksen PH. Diabetologia 1993;36(2):150-4.

2. Caro, J. J., A. J. Ward, et al. (2002). Diabetes Care 25(3): 476-81.


Pathology

Axonal loss, focal demyelination & regeneration

conduction velocity and sensory thresholds


Pathophysiology-biochemical and vascular factors


Risk Factors

Glycaemic control-DCCT with age: 5% 20-29 years, 44.2% 70-79

years > 50% T2DM >60 years of age with duration of diabetes: 20.8% <

5years, 36.8%>10 years Smoking Microalbuminuria Height ? Nutritional factors


Presentations

3 types of neuropathy:

1. Progress steadily with increasing duration of diabetes and associated with other diabetic complications-common

2. Acute onset with resolution over period of months-rare

3. Pressure palsies


Presentations

Diffuse symmetrical sensorimotor polyneuropathy

Predominantly sensory Predominantly feet pain and temperature sensation Parasthesiae and numbness Neurogenic pain/allodynia Neuropathic oedema Wasting occurs only if severe


Diffuse symmetrical sensorimotor polyneuropathy

Problems: Pain and oedema Diabetic foot ulceration

Present in 80% of foot ulcers Principle cause in 39% of ulcers Partly responsible in 36% of ulcers




Autonomic Neuropathy Closely associated with

sensorimotor neuropathy Signs are common if looked for

(40% subjects have abnormal CVS tests) but symptoms are rare (<1%)

Affects the response to hypos but not awareness

If symptoms: mortality=30-50% over 10 years



Diffuse Small Fibre Neuropathy

T1DM Young, ♀ > ♂ Selective damage to small nerve

fibres Pain and temp lost but LT retained Symptomatic autonomic

neuropathy, Charcot arthropathy and foot ulcers

? autoimmune



Mononeuropathies

Acute ? Secondary to ischaemia Pain and weakness (severe) Resolve over months

Amyotrophy (Older ♂>♀) 3rd nerve 6th nerve Truncal radiculopathies

Diabetic Amyotrophy



Insulin Neuritis

Acute & diffuse May be painful Follows improvement of blood

glucose control ?steal phenomenon


Acute diffuse painful neuropathy Not related to duration of diabetes or

complications Association with marked weight loss severe burning/shooting pain, “electric

shocks”, allodynia Resolve spontaneously, usually with

weight gain, 6-8 months. Some 2 years. Does not relapse Signs may be lacking and dissociated

from symptoms


Pressure Palsies

susceptibility to pressure damage

Limited joint mobility (soft tissue)

Carpal tunnel Ulnar nerve Lateral popliteal nerve


DiagnosisAnnual review Enquire annually for:· Painful neuropathy· Loss of sensation· Erectile impotence Note duration of DM, treatment,

complications & weight Ask about other manifestations of

autonomic neuropathy if:· Other complications are present· Anaesthesia is contemplated· Blood glucose control is erratic

DiagnosisExamine: For evidence of peripheral

neuropathy annually LT

OR if new symptoms Vibration LT ?Thermal thresholds ?Pain For postural hypotension if

symptoms of autonomic neuropathy


Examination-ANS

Ewing’s batteryAbnormal results common Valsalva-expiration for 15 secs against 40

mmHg. Rest 1 min then repeatx2. Avoid in proliferative retinopathy. RR max : RR min>1.21 =Normal, <1.20 =

abnormal. HR increase on standing

RR 30:15 ratio > 1.04 HR at max overshoot or 15 seconds

15bpm (abnormal if<12)


Ewing’s battery

HR variation during deep breathing (6 breaths per minute) Max-min > 15bpm (<10 is

abnormal) Postural BP-2 mins after standing

Fall< 10mmHg normal >30 mmHg abnormal


Diagnosis

Consider differential diagnoses HSMN Ethanol B12/folate Malignancy Renal failure Drugs AI disease Cord problems Leprosy


Prevention

Control DCCT (1995)

Tight control-3% neuropathy at 5 years Conventional-10%

UKPDS (1998) Tight control (HbA1c 7%)-31.2%

neuropathy at 15 years Conventional (HbA1c 7.9%)-51.7% P=0.005 No protective effect seen for BP control


Prevention

Aldose reductase inhibitors Gamma Linoleic Acid Vasodilators-ACE? AGE inhibitors Antioxidants NGFs ? Smoking cessation, ? BP

reduction

Treatment-Painful neuropathyGeneral Measures

Improve glycaemic controlExclude or treat other contributory factors•Alcohol excess•Vitamin B12 deficiency/Folate•UraemiaSimple analgesia-NSAID/ParacetamolExplanation, empathy and reassurance

Choose drugs according to dominant symptoms

Burning pain

Tricyclics

Anticonvulsants

Duloxetine

Lancinating pain

Tricyclics

Anticonvulsants

Duloxetine

Other symptomsAllodynia•Plastic film•Leg cradle at nightRestless legs•RopinirolePainful Cramps•Quinine sulphate

NICE CG 87

May 2009


Treatment -ANS

Postural hypotension Fludrocortisone NSAIDs Compression stockings Elevate the head of the bed


Treatment -ANS

Bladder Manual SP pressure ISC ? Anticholinesterase Cyclical antibiotics if recurrent infections

Sweating ?clonidine

Erectile dysfunction


Treatment -ANS

Gastroparesis Improve glycaemic control Prokinetic drugs

Metoclopramide, domperidone, cisapride, erythromycin (250 mg tds)

Octreotide? If severeadmit for IV fluids, IV drugs NG tube IV/jejunal

feedingDiarrhoea Codeine/loperamide/diphenoxylate Clonidine or octreotide Treat bacterial overgrowth (oxytet/erythromycin) if

suspected/present

Any questions?

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Www.plymouthdiabetes.org.uk/ Diabetic Neuropathy Patrick English Diabetes Consultant Derriford Hospital