Neuropathic pain is defined by the International Association for the Study of Pain (IASP) as pain arising as a direct consequence of a lesion or disease affecting the somatosensory system.¹

Clinical features²

• The discomfort is usually of a chronic nature and may be described by the patient as a burning sensation, a sharp, stabbing or shooting pain, or 'like an electric shock'.
• Other features may include:
  • Allodynia - seemingly harmless stimuli, such as light touch, provoking pain.
  • Hyperpathia - a short episode of discomfort causing prolonged severe pain.
  • Hyperalgesia - discomfort, which would otherwise be mild, being felt as severe pain. The IASP states that hyperalgesia is a psychophysical term; it is has been suggested as the umbrella term for all conditions of increased pain sensitivity. Its definition parallels that of the physiological term 'sensitisation'.²

Prevalence³

There are no accurate figures for the overall prevalence of neuropathic pain. Condition-specific figures quoted by the National Institute for Health and Clinical Excellence (NICE) are as follows:⁴

• Painful diabetic neuropathy: 16-26% of people with diabetes.
• Postherpetic neuralgia: 8-19% of people with herpes zoster when defined as pain at 1 month after rash onset (or 8% when defined as pain at 3 months after rash onset).
• Chronic pain after surgery: 10-50% for many common operations (for example, 30-50% for amputation.

Aetiology¹

Management

• The treatment of the underlying causative condition is central to the management of neuropathic pain but is outside the scope of this record. Neuropathy caused by mechanical pressure, for example, may require surgical and other interventional procedures.
• The main role of the GP in the management of neuropathic pain is in the control of symptoms where the underlying cause is medical, where the condition is of a chronic, recurring or acute self-limiting nature, or whilst awaiting specialist intervention.
• NICE recommends that the following issues be discussed with the patient:
  • Risks and benefits of pharmacological treatment.
  • The selection of a particular drug.
  • Coping strategies.
  • Non-pharmacological options, including specialist referral for psychological therapies, surgical and pain clinic interventions, etc.
• When selecting a particular medication, NICE recommends considering comorbidities, safety considerations, contra-indications, patient preference, lifestyle factors, any history of mental health problems (e.g. anxiety, depression) and existing medication history.
• Clear advice should be given about dosage instructions, preferably in writing.
• Consider overlapping old and new treatment to prevent deterioration in pain control.
• Review the patient early after starting or changing treatment.
• Review the patient regularly, covering such aspects as pain control, side-effects, effect on daily living (e.g. driving, working), mood, sleep and overall improvement.

Non-pharmacological measures

• Psychological techniques - the evidence base suggests that psychological treatment is beneficial in helping patients cope with the emotional consequences of pain but has only a weak effect on the intensity of pain itself.⁹ Studies of chronic pain management suggest that a combination of psychological, pharmacological and physical therapies, tailored to the needs of the individual patient, may be the best approach.¹⁰
• Patient education - this is often quoted as a strategy, although the evidence base is lacking.¹¹ Logic would dictate, however, that an informed patient is more able to be involved in decisions about their care, and this is certainly relevant in terms of compliance.¹²
• Electrical stimulation - interpretation of systematic trials is difficult due to differing methodologies.¹³ However, transcutaneous electrical nerve stimulation (TENS) performs consistently well compared with placebo.^14,15 NICE recommends the use of spinal cord stimulation in patients who have had chronic pain for six months (measuring at least 50 mm on a 0-100 mm visual analogue scale) despite conventional medical management (providing a prior trial of stimulation has proved to be effective).¹⁶
• Acupuncture - systematic evidence to support its use in neuropathic pain is limited.¹⁷ There is some evidence that percutaneous electrical nerve stimulation (PENS), which combines the techniques of acupuncture and TENS, may be helpful for some patients with diabetic neuropathy.¹⁸

Pharmacological measures

Diabetic neuropathy:
NICE recommends the following medication:¹⁹

• First-line: oral duloxetine (or oral amitriptyline if duloxetine is contra-indicated).
• Second-line: switch to amitriptyline or pregabalin, or combine with pregabalin (if first-line was amitriptyline, switch to, or combine with, pregabalin).

• First-line: try amitriptyline or pregabalin.
• Second-line: for patients obtaining relief from amitriptyline but unable to tolerate the side-effects, try nortriptyline or imipramine.

• Refer to a pain specialist or a condition-specific clinic.
• Consider tramadol alone or in combination with other treatments.
• Consider topical lidocaine for people with localised pain who are unable to take oral medication.
• Avoid opioids other than tramadol until the patient has had a pain specialist review.

When to refer to a pain specialist¹⁹

This should be considered whenever there is doubt about the diagnosis of neuropathic pain, if there has been inadequate response to treatment, or if other treatments not available in primary care are required (e.g. unlicensed drugs, physical therapy such as nerve blocks, etc.).

Document references

1. Scadding J, Advances in Clinical Neuroscience and Rehabilitation 2003;3(2)
2. Pain Terminology, International Association for the Study of Pain (IASP), 2008
3. Ballester I, Banuls J, Perez-Crespo M, et al; Extragenital bullous lichen sclerosus atrophicus. Dermatol Online J. 2009 Jan 15;15(1):6. [abstract]
4. Hall GC, Carroll D, McQuay HJ; Primary care incidence and treatment of four neuropathic pain conditions: a descriptive study, 2002-2005. BMC Fam Pract. 2008 May 6;9:26. [abstract]
5. Bourne RR, Dolin PJ, Mtanda AT, et al; Epidemic optic neuropathy in primary school children in Dar es Salaam, Tanzania. Br J Ophthalmol. 1998 Mar;82(3):232-4. [abstract]
6. Byrne E, Horowitz M, Dunn DE; Strachan's syndrome 30 years after onset. Med J Aust. 1980 May 31;1(11):547-8. [abstract]
7. Neuropathy, Hereditary Sensory And Autonomic, Type I; Hsan1, Online Mendelian Inheritance in Man (OMIM)
8. Lateral Medullary Syndrome, National Institute of Neurological Diseases and Stroke
9. Eccleston C, Williams AC, Morley S; Psychological therapies for the management of chronic pain (excluding headache) Cochrane Database Syst Rev. 2009 Apr 15;(2):CD007407. [abstract]
10. Turk DC, Audette J, Levy RM, et al; Assessment and treatment of psychosocial comorbidities in patients with Mayo Clin Proc. 2010 Mar;85(3 Suppl):S42-50. [abstract]
11. Arnstein P; Chronic neuropathic pain: issues in patient education. Pain Manag Nurs. 2004 Dec;5(4 Suppl 1):34-41. [abstract]
12. Gilron I, Bailey J, Weaver DF, et al; Patients' attitudes and prior treatments in neuropathic pain: a pilot study. Pain Res Manag. 2002 Winter;7(4):199-203. [abstract]
13. Fargas-Babjak, Angelica M.D. Acupuncture, Transcutaneous Electrical Nerve Stimulation, and Laser Therapy in Chronic Pain. Clinical Journal of Pain. Etiology, Prevention, Treatment, and Disability Management of Chronic Pain. 17(4) Supplement:S105-S113, December 2001.
14. Cheing GL, Luk ML; Transcutaneous electrical nerve stimulation for neuropathic pain. J Hand Surg (Br). 2005 Feb;30(1):50-5. [abstract]
15. Bohm E; Transcutaneous electrical nerve stimulation in chronic pain after peripheral nerve injury. Acta Neurochir (Wien). 1978;40(3-4):277-83. [abstract]
16. Pain (chronic neuropathic or ischaemic) - spinal cord stimulation, NICE Technology Appraisal Guideline (October 2008); Spinal cord stimulation for chronic pain of neuropathic or ischaemic origin
17. Guidelines on the management of neuropathic pain, Clinical Resource Efficiency Support Team (February 2008)
18. Hamza MA, White PF, Craig WF, et al; Percutaneous electrical nerve stimulation: a novel analgesic therapy for diabetic neuropathic pain. Diabetes Care. 2000 Mar;23(3):365-70. [abstract]
19. Neuropathic pain - pharmacological management, NICE Clinical Guideline (March 2010); The pharmacological management of neuropathic pain in adults in non-specialist settings

Internet and further reading

• McCleane G; The pharmacological management of neuropathic pain: A review
• Richeimer S; Understanding Neuropathic Pain
• Hall GC, Carroll D, McQuay HJ; Primary care incidence and treatment of four neuropathic pain conditions: a descriptive study, 2002-2005. BMC Fam Pract. 2008 May 6;9:26. [abstract]

Acknowledgements