This information is sourced from Scottish Palliative Guidelines, NICE and the MHRA
Neuropathic pain is a common complication of cancer and may be due to:
- vertebral metastases commonly from prostate, lung, bowel and breast cancer
- breast cancer brachial plexopathy
Other causes of neuropathic pain include:
- neurological illnesses such as Multiple Sclerosis
- treatment e.g. chemotherapy-induced peripheral neuropathy
- other co-morbid conditions e.g. post-herpetic neuralgia or diabetic neuropathy
Neuropathic pain is commonly found in conjunction with other types of pain.
Red flags
Always consider spinal cord compression in patients with neuropathic pain.
Key symptoms of cord compression include:
- new intractable, progressive pain, especially thoracic or lower limb
- New spinal nerve root pain may radiate down the leg (like sciatica), or the arm, or more like a band around the chest or abdomen
- Coughing, straining or weight bearing may aggravate pain
- New difficulty walking or climbing stairs; reduced power
Late signs include:
- Sensory impairment at an abdominal or thoracic level plus altered limb sensation
- Bowel or bladder disturbance; loss of sphincter control
Clinical features
- Patients often describe neuropathic pain as burning, shooting, tingling or stabbing in nature
- Altered sensation is also a symptom. Sensitivity to light touch may be reduced, increased or severe (allodynia)
- Pain may follow a dermatomal distribution
When examining always compare both sides of the body
An initial approach to treatment
- Bloods to exclude a metabolic cause e.g. B12 deficiency
- Tricyclic antidepressants e.g. Amitriptyline 10mgs at night and titrate to a total dose of 30mg daily
- Anticonvulsant e.g. Pregabalin or Gabapentin. These can be titrated, but specialist advice should be sought if titration doesn't help as sedation is a risk without benefit. Remember that Pregabalin and Gabapentin are sedative in combination with opioids
- A combination of neuropathic agent, paracetamol and weak opioid analgesics may be needed
Specialist care
If the above approaches are not working and sleep in disturbed, then specialist advice is recommended. Options include:
- Dexamethasone 6mg for 6 days (or 40mg prednisolone) with PPI cover for urgent control of neuropathic pain. This takes the pressure off the nerve
- Other anticonvulsants may be tried e.g. Oxcarbazepine 150mg BD
- Urgent MRI to inform whether further intervention is needed e.g. radiotherapy, surgery or nerve block