Neurology - neuropathic pain

Question 1

Causes of neuropathic pain

Answer 1

Postherpetic neuralgia from shingles (in the distribution of a dermatome)

Multiple sclerosis

Diabetic neuralgia (typically the feet)

Trigeminal neuralgia

Nerve damage from surgery

Disc herniation or degenerative joint

Cancer

Complex regional pain syndrome (CRPS)

Question 2

Typical features of neuropathic pain

Answer 2

Burning
Tingling
Pins and needles
Electric shocks
Loss of sensation to touch

Question 3

How can neuropathic pain be assessed?

Answer 3

DN4 questionnaire

Score of 4 or more indicates neuropathic pain

Question 4

Management of neuropathic pain

Answer 4

First line agents:

• Amitriptyline - TCA
• Duloxetine - SNRI antidepressant
• Gabapentin is an anticonvulsant
• Pregabalin is an anticonvulsant

Question 5

First line for neuropathic pain in trigeminal neuralgia

Answer 5

Carbamazepine

Question 6

What is Complex regional pain syndrome (CRPS)?

Answer 6

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.