What is neuropathic pain and how is it treated?

Pain is divided into two categories: nociceptive pain and neuropathic pain. Nociceptive pain is what everyone experiences, that is, pain detected by your sensory nerves in response to heat, chemicals, physical force or other noxious stimuli. In contrast, neuropathic pain is caused by damage or disease of your sensory nerves and affects around one in 10 people in the UK. 

Neuropathic pain is a long-term (chronic) condition that many people put up with for years before seeking treatment. It can affect any area of your body and significantly decreases your quality of life and wellbeing. This can lead to depression.

What does neuropathic pain feel like?

Neuropathic pain is often described as a burning, shooting or stabbing pain, or like an electrical shock. It can result in allodynia, where sensations that shouldn’t cause pain, do. For example, a feather-light touch, brushing your hair, the wind blowing against your skin or even your clothes moving against you.

Causes of neuropathic pain

One of the most common causes of neuropathic pain is persistent spinal pain syndrome (PSPS). This is usually triggered by spinal surgery or a spinal condition that causes the nerve roots that run alongside your spine to become compressed or pinched. This can cause neuropathic pain in the back, legs, arms and neck, depending on which part of your spine is affected.

Complex regional pain syndrome (CRPS) is another cause of neuropathic pain. The underlying cause of CRPS is unclear, however, it results in a minor injury (eg a sprained ankle, crush injury or minor fall) producing severe pain.

Other common causes of neuropathic pain include scars that form after surgery, where the pain is localised to the scarred region, and shingles ie infection of the nerves with varicella zoster virus.

Getting a diagnosis

In most cases, your doctor can diagnose neuropathic pain by taking a detailed medical history. This will involve asking you many questions, including: 

• How does your pain affect your daily life? 
• How does it feel?
• Is it always there? 
• What causes it to flare up?
• What makes it better?

Once you receive a diagnosis of neuropathic pain, you may need further investigations to identify the underlying cause eg to look for scar tissue or a pinched nerve root. 

Treating neuropathic pain

If you’re diagnosed with neuropathic pain, you will be referred to a specialist pain team. Following appropriate investigations, if surgery is not needed to resolve any underlying cause, you will be prescribed anti-neuropathic pain medication. 

These medications are different to over-the-counter painkillers, such as paracetamol and ibuprofen. They help reduce nerve activity to lessen neuropathic pain and include amitriptyline, duloxetine, pregabalin and gabapentin. Medication is successful in treating neuropathic pain in about 60–70% of cases. 

If these medications alone aren’t enough to significantly lessen your pain, you may be referred to a pain management programme. This is run by a multidisciplinary team, including physiotherapists, psychologists, nurses and doctors, who will help you learn how to cope with your pain and better manage its effects. 

If these measures are not enough to improve your quality of life, your doctor may recommend neuromodulation. 

Neuromodulation

This involves surgery to implant electrodes into your spine that send electrical impulses to your nerves and consequently mask the pain.

To be suitable for neuromodulation, you may first need treatment to get other conditions under control (eg diabetes, cardiac problems, mental health issues). Neuromodulation is not suitable if you’re taking high doses of opioids as this interferes with the chemical signals in your brain, rendering neuromodulation ineffective.

If neuromodulation is suitable, you will first undergo a trial for one to two weeks. This involves implanting the electrodes into your spine and connecting them to an external battery. Your doctor will set the device up with several programmes that you can select using a remote control.

You will be asked to keep a diary of your pain and at the end of your trial, your doctor will ask you about your experience to determine if your pain and quality of life improved (eg your sleep, mood, movements, mobility).

If your trial is successful, you will have another surgery for the full implant. The electrodes, alongside a pacemaker-like battery, will be implanted in your spine.

In the long-term, neuromodulation is successful in around three-quarters of cases and these individuals are able to taper off their pain medication. The advent of high-frequency neuromodulation also means that more people are able to find relief from their symptoms as it treats neuropathic pain originating from a wider range of areas.

Today, neuromodulation is increasingly offered to individuals with severe neuropathic pain sooner, rather than as a last line of treatment when all other approaches prove unsuccessful.