Neuropathic Pain: Diagnosis and Treatment
Neuropathic Pain: Diagnosis and Treatment
Medicinewise News 5 February 2018: Modified by Helen Potter FACP 22nd February 2018
Helping people with chronic pain is challenging. Imagine listening to your favourite piece of music playing softly. Then imagine the volume being turned up, louder and louder until it becomes irritating and eventually painful to the ear. The body becomes over-sensitive to the ‘music’ being sent from the body to the brain. This is neuropathic pain.
What is Neuropathic Pain?
Neuropathic pain can result from a neurological lesion or disease of the somatosensory system.
Neuropathic pain is different to nociceptive pain, or pain that is not clearly nociceptive or neuropathic, and is associated with nervous system changes such as central sensitisation (as in fibromyalgia, and chronic regional pain syndrome.
There is little to find in terms of nerve damage.
- Neuropathic pain and nociceptive pain treated differently.
- A history and a physical examination are important diagnostic prerequisites before choosing which medicine to use for effective pain management.
- The latest guidelines use the first-line medicine: Amitriptyline, duloxetine, gabapentin and pregabalin.
- Base Medicine selection on individual needs. Consideri the patient’s profile, contraindications and co-morbidities.
- Low-dose amitriptyline (Endep/Dothep) is a first-line treatment of neuropathic pain.
- It is still one of the most efficacious medicines for this type of pain.
Examples of Neuropathic Pain
- A physical examination is important to establish the link between the pain and a lesion or disease in the somatosensory system.
- Australian guidelines use a stepwise approach to build evidence for a possible, probable or definite neuropathic pain diagnosis.
- Understanding the pain and underlying pathology (neuropathic or otherwise) is important before addressing the pain with appropriate treatment strategies.
- The clinical history and examination help to confirm that the location of the pain is anatomically consistent with a neurological lesion.
- Pain descriptors that include burning, shooting, prickling, or tingling contribute towards the diagnosis of neuropathic pain.
- Pain due to radiculopathy seems more refractory than other types of pain.
Neuropathic Pain is graded as:
Neuropathic Pain Diagnosis
Neuropathic pain is a possible diagnosis if there is:
- A history suggestive of a relevant neurological lesion (like herpes zoster or a traumatic nerve injury)
- Pain descriptors are (burning, shooting, pricking and pins and needles)
- There are non-painful sensations like numbness or tingling
- A pain distribution is explainable by a lesion or disease in the somatosensory system, or typical of an underlying neuropathic disorder
A clinical examination needs to reach a ‘probable’ level of certainty. Toothpicks, brushes or cotton wool can detect sensory changes that help further differentiate neuropathic from non-neuropathic pain. Hypoalgesia to pinprick, hypoesthesia to tactile stimuli, and allodynia to brush and cold are particularly discriminant. Sensory changes should also lie within a plausible neurological distribution. (MRI) can confirm a stroke, multiple sclerosis or spinal cord injury and a skin biopsy showing reduced nerve fibre density.
Neuropathic Pain Treatment
Start treatment once probable the diagnosis of neuropathic pain is reached. Use further investigations only if these tests inform treatment.
Neuropathic Pain Medicines
The treatment of neuropathic pain remains challenging – partial pain relief is usually considered a good result. Pharmaceutical pain relief is part of a total plan for living with pain, which focuses on improving the patient’s quality of life and ability to function. Non-pharmacological treatment such as physical exercise, cognitive behavioural therapy (CBT) and meditation can help in accepting and coping with the pain.
‘There is little evidence to support the use of specific drugs in specific neuropathic pain conditions’, says Professor Siddall. ‘Usually the choice is determined by the general evidence in neuropathic pain as well as the likelihood of side effects in a particular person and the cost.’
Research recommends four medicines for treatment of neuropathic pain:
- Amitriptyline, duloxetine and gabapentin and pregabalin
- Other medicines recommended as second- or third-line options include Tramadol, lignocaine, capsaicin and botulinum toxin A.
- There is a limited role for opioids in the treatment of neuropathic pain because of safety concerns and poor evidence of long-term efficacy.
- There is little evidence that paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) are effective.
Most patients’ expectations of an analgesic medicine are something that does or doesn’t work almost immediately. Neuropathic pain analgesics, act slowly. Start low, go slow is the best way to find the balance between the analgesic benefit and the side effect burden.
Unfortunately, only partial relief is possible in many cases, and people will need support and strategies to help them understand, accept, and live with their pain.
A clear and targeted diagnosis, tackling the source of the pain where possible, and a considered treatment plan, including both pharmacological and non-pharmacological components, remain the best approaches to help people living with neuropathic pain.
Neuropathic Pain: Useful links