Neuropathic Pain

Question 1

What is neuropathic pain?

Answer 1

Neuropathic pain is caused by abnormal functioning of the sensory nerves delivering abnormal and painful signals to the brain.

Question 2

How can neuropathic pain present?

Answer 2

Neuropathic pain can affect a wide variety of areas with number of different causes:

• Postherpetic neuralgia from shingles is in the distribution of a dermatome and usually on the trunk
• Nerve damage from surgery
• Multiple sclerosis
• Diabetic neuralgia typically affects the feet
• Trigeminal neuralgia
• Complex Regional Pain Syndrome (CRPS)

Question 3

What are the typical features of neuropathic pain?

Answer 3

• Burning
• Tingling
• Pins and needles
• Electric shocks
• Loss of sensation to touch of the affected area

Question 4

What questionnaire is used to assess pain?

Answer 4

DN4 Questionnaire.

Question 5

Briefly describe the DN4 Questionnaire

Answer 5

This is used to assess the characteristics of the pain and examination of the affected area. They are then scored out of 10 for their pain. A score of 4 or more indicates neuropathic pain.

Question 6

Briefly describe the management of neuropathic pain

Answer 6

There are four first line treatments for neuropathic pain:

• Amitriptyline is a tricyclic antidepressant
• Duloxetine is an SNRI antidepressant
• Gabapentin is an anticonvulsant
• Pregabalin is an anticonvulsant

NICE recommend using one of these four medications to control neuropathic pain. If that does not work then stop and start an alternative and repeat this until all four have been tried.

Question 7

Other than amitriptyline, duloxetine, gabapentin and pregabalin, what other management can be offered for neuropathic pain?

Answer 7

Other options:

• Tramadol only as a rescue for short term control of flares
• Capsaicin cream (chilli pepper cream) for localised areas of pain
• Physiotherapy to maintain strength
• Psychological input to help with understanding and coping

Question 8

Briefly describe the management of trigeminal neuralgia

Answer 8

Trigeminal neuralgia is a type of neuropathic pain however NICE recommend carbamazepine as first-line for trigeminal neuralgia and if that does not work to refer to a specialist.

Question 9

Briefly describe complex regional pain syndrome

Answer 9

This is a condition where areas are affected by abnormal nerve functioning causing neuropathic pain and abnormal sensations. It is usually isolated to one limb. Often it is triggered by an injury to the area.

The area can become very painful and hypersensitive even to simple inputs such as wearing clothing. It can also intermittently swell, change colour, change temperature, flush with blood and have abnormal sweating.

Treatment is often guided by a pain specialist and is similar to other neuropathic pain.

Question 10

Briefly describe the step-up NICE guidance for managing neuropathic pain

Answer 10

NICE updated their guidance on the management of neuropathic pain in 2013:

1. First-line treatment*: amitriptyline, duloxetine, gabapentin or pregabalin
2. If the first-line drug treatment does not work try one of the other 3 drugs

In contrast to standard analgesics, drugs for neuropathic pain are typically used as monotherapy i.e. if not working then drugs should be switched, not added.

Tramadol may be used as ‘rescue therapy’ for exacerbations of neuropathic pain.

Topical capsaicin may be used for localised neuropathic pain (e.g. post-herpetic neuralgia).

Pain management clinics may be useful in patients with resistant problems.