What is neuropathic pain?
Neuropathic Pain is defined by the International Association for the Study of Pain (IASP) as the pain caused by damage or disease of the Somatosensory Nervous System in the:
- Peripheral Nervous System (peripheral neuropathic pain)
- Central Nervous System (central neuropathic pain)
The peripheral neuropathic pain is caused by a primary damage to the peripheral nervous system. The causes of peripheral neuropathic pain include:
- Diabetic neuropathy
- Radiculopathy (low back pain)
- Herpes zoster infection (postherpetic neuralgia)
- Surgical Injury (post-traumatic and post-operative pain)
- Malignancy - cancer (cancer pain)
- Acute and chronic inflammatory demyelinating polyradiculopathies
- Alcoholic polyneuropathy
- Polyneuropathy due to chemotherapy
- Neuropathies due to compression of peripheral nerves
- Nerve compression caused by a tumor
- Metastatic inflammation of the nerve plexus
- Trigeminal neuralgia
The central neuropathic pain derives from the Central Nervous System. The causes of central neuropathic pain include:
- Cerebrovascular Accident - stroke
- Spinal cord injury
- Multiple sclerosis
- Pain related to Parkinson's disease
Neuropathic pain is a clinical symptom that requires the presence of a clear damage or disease that meets specific neurological diagnostic criteria.
How often does Neuropathic Pain occur?
Neuropathic pain is very common, resulting from studies at international level showing a prevalence of 7%.
Painful diabetic peripheral neuropathy and postherpetic neuralgia are two of the most common types of neuropathic pain. It is estimated that 11-26% of patients with diabetes develop painful diabetic peripheral neuropathy. Among patients with chronic back pain, an estimated 37% experiences neuropathic pain. Neuropathic pain occurs in one third of patients with cancer, affects 8% of patients after stroke and 75% of patients with spinal cord injury.
What do we find during the examination?
Patients usually have a "paradoxical" sensory perception of pain as the predominant symptom accompanied by reduced sensations caused by the damage. The co-existence of signs of hypersensitivity and insensitivity is common to neurological disorders. Instead, pain as a subjective aesthetic symptom is not visible, it is difficult to measure it and includes psychological and emotional components.
The neuropathic pain syndrome usually consists of a combination:
- negative symptoms such as loss of sensation, hypoesthesia and numbness.
- positive symptoms such as dysesthesia, paresthesia and pain.
Symptoms are described by the patient as stinging, burning, prickling, numb or a sensation of electric shock.
May be:
Continuous or intermittent.
Induced or stimulated by a stimulus (i.e., occurring in response to a stimulus, in an exaggerated manner)
Hyperalgesia: Excessive pain
Allodynia: pain from stimuli that would not normally cause pain.
Paresthesia: Pathological sensation often described as "numbness" and it is not unpleasant.
Dysesthesia: Pathological sensation often described as "numbness" and it is always unpleasant.
Hyperpathia: A painful symptom characterized by a pathological painful reaction to a stimulus, especially a recurring one.
What other conditions are associated with neuropathic pain?
Patients with neuropathic pain often have:
- Sleep disorders
- Anxiety
- Depression
How to diagnose neuropathic pain?
A detailed patient’s medical history, a complete neurological assessment and, if necessary, hematological, biochemical and imaging tests are required. Our goal is to.
- Identify the neuropathic pain
- Locate the injury
- Diagnose the disease
- Assess the operational limitations caused by the pain
- Assess the psychological state of the patient
- Assess any disorders such as insomnia, anxiety, depression, chronic fatigue, various socio-environmental factors, etc.
- Assess any changes in skin color and temperature
- Examine if there is edema (swelling) of the extremities
What are the therapeutic options?
It is worth noting that the treatment of Neuropathic Pain is a challenge for the scientific community, as it is a field that in the recent years has been investigated in order for neurologists to fully understand the underlying mechanisms of pain induction and why its treatment requires individualization. Depending on the type of the disease, there are the options of oral medication, invasive injection therapies and the latest invasive neurostimulation therapies. Most important, however, remains the correct diagnosis and personalization of the treatment that in all cases should consider not only the type of the condition but also the particular characteristics of each patient.