### 1. Introduction: Neuropathic pain is a debilitating form of chronic pain. Learn more about it in this storyboard.(navigate through the storyboard by clicking on the panels in this top row).

Imagine having a pain that has been described as being ‘Worse than death’. A pain that may feel like your ‘skin is on fire’, and at the same time the painful area may be ‘numb’. In some cases even the lightest of touches, such as your clothes on your skin, may be excruciatingly painful. This is what it can feel like to have neuropathic pain.

This storyboard will introduce you to this unusual type of chronic pain and its treatment.

Navigation: Every section of the storyboard consists of an interactive plot on the left (try it out by hovering your mouse arrow over the adjacent plot), and a text panel on the right. The text panel expands on the question stated in the numbered navigation panel above, and provides a legend for the figure. The figure provides illustrative data that complements the text.

##### Interactive plot: What does neuropathic pain feel like?.

The plot shows the relative frequency of terms used by 89 individuals with various causes of nervous system injury (e.g., traumatic nerve injury, post-herpetic neuralgia, polyneuropathies, stroke pain; block size is proportional to frequency). ‘Burning’ was the most commonly used term, but most patients use several terms to describe their pain1.

Created by: painblogR

### 2. How common is neuropathic pain? Neuropathic pain is estimated to affect 7 to 10% of adults globally; that’s between 518 to 740 million people2.

Neuropathic pain is caused by damage to the sensory pathways and structures of the nervous system. This damage may occur as a result of physical trauma (e.g., motor vehicle accidents, war-related trauma to combatants and non-combatants, surgery), or as a secondary consequence of other medical conditions (e.g., diabetes mellitus, HIV, malnutrition, stroke, tumours) and their treatments (e.g., cancer chemotherapy).

##### Interactive plot: Prevalence of neuropathic pain in the general population

The centre horizontal lines show the reported prevalence of neuropathic pain. The boxes show the bootstrap 95% confidence interval of the prevalence (10,000 resamples), and the whiskers show the maximum and minimum values obtained from the resampling. The dashed line shows the bootstrap mean across all six studies (n = 38,422), and line & fill colour quantifies the sample size.

(Click the flag to access the related PubMed entry)

Created by: painblogR

### 3. Are we winning the war on neuropathic pain? No. The burden of neuropathic pain is likely to increase in the future, with developing countries being worst affected.

Two persistent global trends are an aging population3 and the rising prevalence of diabetes mellitus4. Both these factors are major risks for neuropathic pain, and mean that neuropathic pain is likely to increase in prevalence and importance in the future.

Developing countries have the highest rates of increase in population aging and cases of diabetes mellitus. Moreover, these countries face a greater burden of disease from other common causes of neuropathic pain such as trauma, HIV/AIDS, and leprosy than do developed countries5. Thus, more poorly resourced nations are likely to increasingly shoulder a disproportionate share of the global burden of neuropathic pain.

##### Interactive plot: Estimated and projected global burden of diabetes mellitus and painful diabetic polyneuropathy

Estimated number of cases of diabetes mellitus (blue) and painful diabetic polyneuropathy (DPN) (orange) between 1985 and 2013. Projected number of cases up to 2035 are highlighted in the grey block6. The number of DPN cases is based on estimates of between 10 and 20% of diabetics developing a painful neuropathy7.

Created by: painblogR

### 4. Why does neuropathic pain matter? Neuropathic pain has a significant adverse impact on life, health and function; even more so than other causes of chronic pain8.

Neuropathic pain has a significant adverse impact on all measured aspects of life, health and function. This impact is greater than the impact of chronic, non-neuropathic pain, even when adjusting for pain intensity8. In one study, 17% of people reporting neuropathic pain rated their quality of life as ‘worse than death’, according to the validated EQ5D health-related quality of life measure9. The average quality of life scores in the presence of neuropathic pain are comparable to those with severe depression, with poorly-controlled diabetes mellitus, and after recent myocardial infarction8.

### 5. Do we have effective medicines? Neuropathic pain can be difficult to treat, but there are specific classes of drugs with proven efficacy in managing the pain10.

A recent GRADE assessment of pharmacological treatments for neuropathic pain recommended10:

• FIRST LINE: Tricyclic antidepressants (e.g., amitriptyline), serotonin and noradrenaline reuptake inhibitors (duloxetine, venlafaxine), and $$\alpha2\delta$$-calcium channel ligands (gabapentin, pregabalin).

• SECOND LINE: Tramadol, 5% lidocaine patches $$^\dagger$$, 8% capsaicin patches $$^\dagger$$.

• THIRD LINE: Strong opioids (e.g., morphine and oxycodone), and botulinium toxin A $$^\dagger$$.

$$\dagger$$: Recommended for neuropathic pain of peripheral origin only