Neuropathic Pain
Learn more about common pain conditions, their development, and the pain mechanism.
Overview
There are various types of pain. Besides inflammatory pain, known as nociceptive pain, where tissue damage occurs and inflammatory mediators (cytokines) activate pain nerve fibers, neuropathic pain is the second most common type. 7-10% of all pain is neuropathic pain. Different subtypes are described based on various characteristics, such as neuropathic and neuralgic pain. Neuropathic pain results from damage or dysfunction of the nervous system. These pains can have different causes and vary in their intensity and nature.
Causes
Neuropathic pain can be caused by various factors. These include metabolic factors (e.g., diabetes – diabetic polyneuropathy), injuries or trauma, surgeries, infections (e.g., shingles – postherpetic neuralgia, HIV), autoimmune diseases (e.g., multiple sclerosis), tumors, medical treatments such as chemotherapy or radiation therapy, or long-term exposure to toxins or chemicals (often occupational).
Symptoms
The symptoms of neuropathic pain can vary widely, but typically include burning, cramping, stabbing, tearing, or electrifying sensations, along with neuropathic positive symptoms such as tingling-electrifying dysesthesias, hypersensitivity to light touches (allodynia), or increased pain sensitivity to mild pain stimuli. Neuropathic negative symptoms include a lack of or reduced sensory perceptions, such as numbness to touch, temperature, or vibration, and in severe cases, muscle weakness or paralysis.
Diagnosis
Diagnosing neuropathic pain often requires a thorough medical history, physical and neurological examination, and possibly additional tests such as nerve conduction studies or imaging. Targeted diagnostic nerve blocks, usually guided by ultrasound, can help identify the site of nerve injury.
Treatment
The treatment of neuropathic pain aims to address the underlying cause, if possible, and simultaneously relieve pain. Medication therapy primarily relies on antineuropathic agents, also known as antineuropathic co-analgesics, which act directly on the nerves. ‘Normal’ painkillers, such as NSAIDs, paracetamol, and metamizole, are not effective. Opioids are only slightly effective to not effective at all and are therefore not recommended. Neuropathic pain medications are used off-label, meaning outside their initial approved indication. There are two main groups from which all antineuropathic co-analgesics originate: antidepressants (tricyclics and SSNRIs) and anticonvulsants (antiepileptics). Medication can only treat the symptom of pain and its intensity. Simultaneous physiotherapy or occupational therapy is essential to maintain or improve the function of the body part affected by nerve injury. Additionally, similar to spinal pain, targeted, mostly ultrasound-guided nerve blocks (nerve infiltrations) can relieve pain. Acupuncture and other alternative treatment approaches, as well as lifestyle changes, regular exercise, and stress management, can also help. For several years, neuromodulative procedures such as pulsed radiofrequency treatment of the nerve, peripheral nerve stimulation, and spinal cord stimulation have been used with very good results.
Prognosis
The prognosis for neuropathic pain varies depending on the underlying cause and the effectiveness of treatment strategies. While some individuals may experience significant relief with appropriate treatment, others may continue to suffer from chronic pain. An early and comprehensive treatment approach can improve outcomes and quality of life for many patients.
