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Chronic Neuropathic Pain

Chronic Neuropathic PainIntroduction: Chronic neuropathic pain is common and significantly impacts the quality of life. It is essential to differentiate it from other chronic pain. Many chronic pain syndromes are characterized by a coexistence of nociceptive and neuropathic pain components. Neuropathic pain treatment is available in the form of┬ánon-steroidal anti-inflammatory drugs (NSAIDs). But, this medication doesn’t always work on patients. Thus, research is ongoing to find new medication to help relieve symptoms and improve the condition.

What Causes Chronic Neuropathic Pain?

Chronic neuropathic pain arises after damage to somatosensory nerve structures in the peripheral or central nervous system. Clinically, these syndromes are characterized by sensory deficits, persistent burning pain, shooting attacks, and evoked pain. The diagnosis for neurophysiological techniques’ typical symptoms and evidence of a nerve lesion. Four groups of substances with different pharmacological principles of action are used for treatment, which can be combined. Effective pain therapy should be initiated as early and as intensively as possible.

What are Examples of Neuropathic Pain?

Chronic neuropathic pain is common in clinical practice. It significantly impairs the patient’s quality of life and represents a major health and economic problem. Recent surveys estimate the point prevalence of neuropathic pain syndromes at up to five per cent in the general population.

Neuropathic Pain Diagnosis

Neuropathic pain syndromes are painful diabetic polyneuropathy. Postherpetic neuralgia already accounts for 13 per cent of patients in pain specialists. A neuropathic pain component can be detected in the practice of pain specialists up to 35 per cent of all pain disorders. Central neuropathic pain is estimated to occur in 30 per cent of all spinal cord injuries, 20 per cent of patients with multiple sclerosis, and 1.5 per cent of patients with stroke.

A systematic analysis of the literature from 1980 to 2006 (PubMed) was carried out to create evidence-based recommendations for diagnosis and therapy. Search terms in PubMed were “neuropathic pain, treatment algorithm”, “neuropathic pain, treatment recommendations”, or “neuropathic pain, assessment guidelines”. Furthermore, it included the author’s personal experience in the evaluation.

What is Neuropathic Pain?

Previous damage to somatosensory nerve structures is decisive for developing a neuropathic pain syndrome.

This lesion can occur in the peripheral and central nervous systems (brain and spinal cord). Various mechanical, metabolic, toxic, or inflammatory noxae can injure peripheral nerves.

Central neuropathic pain originates in a primary CNS process that can arise from disturbances throughout the neuraxis, from lesions in the spinal cord, brainstem, thalamus, subcortical structures, and cortex.

The plastic changes in the peripheral and central nervous system induced by the lesion can take on a life of their own and then become irreversible over time. A distinction from chronic pain in which the nervous system is intact – so-called nociceptive pain, for example, chronic inflammatory pain such as arthrosis, arthritis, and visceral pain – is of crucial importance since neuropathic pain requires specific therapy.

A systematic analysis of the literature from 1980 to 2006 (PubMed) was carried out to create evidence-based recommendations for diagnosis and therapy. Search terms in PubMed were “neuropathic pain, treatment algorithm”, “neuropathic pain, treatment recommendations”, or “neuropathic pain, assessment guidelines”. Furthermore, it included the author’s personal experience in the evaluation.

What is Neuropathic Pain?

Previous damage to somatosensory nerve structures is decisive for developing a neuropathic pain syndrome.

This lesion can occur in the peripheral and central nervous systems (brain and spinal cord). Various mechanical, metabolic, toxic, or inflammatory noxae can injure peripheral nerves.

Central neuropathic pain originates in a primary CNS process that can arise from disturbances throughout the neuraxis, from lesions in the spinal cord, brainstem, thalamus, subcortical structures, and cortex.

The plastic changes in the peripheral and central nervous system induced by the lesion can take on a life of their own and then become irreversible over time. A distinction from chronic pain in which the nervous system is intact – so-called nociceptive pain, for example; chronic inflammatory pain such as arthrosis, arthritis, and visceral pain – is of crucial importance since neuropathic pain requires specific therapy.

Neuropathic Pain Diagnosis

However, many chronic pain syndromes are characterized by the coexistence of nociceptive and neuropathic pain components. There is precise classification; therefore not always possible. These include many back pain syndromes in which chronic excitation of afferent nerves in joints, ligaments, and muscles (nociceptive component). It combines with compression and damage to the nerve roots due to hyperostosis, scars, or intervertebral disc tissue.

Another example is tumor pain, in which, on the one hand, intact nociceptors are stimulated by substances from the tumor. And on the other hand, the tumor itself can damage nerve tissue through direct infiltration. With these mixed forms, it is essential for therapy planning to estimate the proportion of neuropathic pain components in total pain.