Neuropathic pain

Pain is directly caused by damage to the somatosensory system or disease. The disease can be caused by injury to peripheral nerves, posterior roots of the spinal cord, spinal cord and above central nerves caused by trauma and/or disease.

Causes and common diseases:

Age, gender, the intensity of pain, emotional and cognitive abilities, etc. indicate that the formation of chronic pain is the result of a combination of multiple factors, not simply caused by neurological damage.

Differential diagnosis:

1. Greater occipital neuralgia:

Refers to paroxysmal or persistent pain within the distribution range of the greater occipital nerve (posterior occipital region), which can also be exacerbated on the basis of persistent pain. The clinical manifestations are acupuncture-like, knife-cutting or burning-like pain on one or both sides of the posterior occiput or both sides. The patient does not dare to turn his head when it is painful, and the head and neck are sometimes in a straightened state. On physical examination, there is tenderness at the exit of the greater nerve, and the distribution area of the greater occipital nerve (C2-3) from the top of the ear to the hairline hyperalgesia or hypoalgesia.

2. Sciatica:

Refers to sciatic neuropathy, a group of pain symptoms that occur along the sciatic nerve pathway, namely the waist, buttocks, back of the thigh, posterior and lateral calf, and lateral foot. The sciatic nerve is the main nerve trunk that innervates the lower limbs. Sciatica refers to pain in the sciatic nerve pathway and its distribution area (buttocks, back of the thigh, back of the calf, and outside of the foot).

3. Intercostal neuralgia:

Refers to the frequent pain that occurs in one or several intercostal areas, with episodic aggravation. Primary intercostal neuralgia is rare, and secondary ones are mostly related to viral infection, toxin stimulation, mechanical damage and foreign body compression. The pain is mostly tingling or burning, and it is distributed along the intercostal nerves. When intercostal neuralgia occurs, the pain is seen from back to front, radiating in a semicircular shape along with the corresponding intercostal space; the pain is tingling or burning. Pain worsens when coughing, deep breathing, or sneezing. The pain is mostly on one nerve on one side.

Physical examination:

The standard examination of patients with neuropathic pain should include the following aspects: touch, acupuncture, compression, cold stimulation, thermal stimulation, tremor and "total". Responses to these stimuli are classified as normal, decreased or increased pain sensation. Stimulus-induced (positive) pain is divided into hyperalgesia and pain paresthesia and is classified according to whether the stimulus is dynamic or static. The tactile sensation can be assessed by gently stimulating the skin with cotton, acupuncture sensation can be assessed by stimulating the skin with sharp needles, deep pain sensation can be assessed by gently pressing muscles and joints, and cold and hot sensations can be assessed by measuring the response to warm stimulation. The response of the tuning fork is evaluated for tremor.

Treatment principles:

(1) Drug treatment:

The choice of medication for neuropathic pain should be based on the basic pathogenesis of each patient. The drugs used to treat chronic neuropathic pain mainly include anticonvulsants, tricyclic antidepressants, N-methyl-D-aspartate (NMDA) antagonists, ion channel blockers, and non-steroidal antidepressants. Inflammatory drugs (NSAID), local anesthetics, capsaicin receptor blockers, antihypertensive drugs, morphine drugs and GABA receptor agonists, etc. In recent years, some new types of drugs have emerged, such as gabapentin and anti-tumor drugs.

(2) Neuromodulation:

The neuromodulation method of stimulating the spinal cord or cerebral motor cortex by placing electrodes in the epidural space or cerebral cortex has gradually been widely used to treat intractable central and peripheral neuropathic pain. The principle of this method is to appropriately stimulate the target nerve that can produce pain through electrodes, thereby producing a numb sensation to cover the painful area, so as to achieve the purpose of pain relief. Clinical indications: neuropathic pain (such as back surgery syndrome, radiculopathy, chronic regional pain syndrome and peripheral nerve injury), ischemic pain (such as peripheral vascular disease and angina), seizures, Parkinson's syndrome-related movement disorders (such as tremor, paralysis, rigidity, and movement disorders) and other dysfunctions. The main methods of neuromodulation are spinal cord stimulation (SCS) and cerebral motor cortex stimulation (MCS).

神经性疼痛 神經性疼痛

躯体感觉系统的损害或疾病直接导致的疼痛。本病可由外伤和（或）疾病致末梢神经、脊髓后根、脊髓及其以上中枢神经某些部位损伤而引发。