Overview

Neuropathic pain is a chronic condition that arises out of wrong signals sent by damaged or malfunctioning nerves. While diabetes is the most common cause for this condition, there are over a hundred different ailments or causes that trigger neuropathic pain. Accordingly, there are various types of neuropathic pain with unique causes and symptoms. In this article, we will explore the same, along with treatment options.

Introduction

The nervous system in human beings can be broadly divided into – the Central Nervous System (CNS) which consists of the brain and spinal cord, and the Peripheral Nervous System (PNS). The PNS consists of nerves that are distributed throughout the body, such as in the arms, legs, hands, feet and various internal organs. Pain is a natural response of the nervous system to disease or injury, in a specific part of the body. Bone(s), muscle(s) or other tissue(s) in that area may be damaged. Pain signals are sent back and forth between the concerned area and the brain. It is a signal to the human concerned, to take remedial action. This is how the normal pain mechanism works, where nerves are healthy and working as expected.

However, when there is damage to nerves, in one or more parts of the body, due to physical injury, or some bio-chemical changes happening in the body (due to various reasons), they start malfunctioning. They send pain signals even there is no need to. This results in pain, which is called Neuropathic pain. This pain can be mild to severe and is generally chronic. That is, the condition lasts for long durations of time, or is even permanent. In the latter case, treatment options aim at reducing or managing pain better, instead of eliminating it altogether. Incidentally, Neuropathic pain can affect nerves in both CNS and PNS.

Also Read: 5 Signs your Back Pain might be an Emergency

Causes

• Diabetes, the number one cause
• Alcohol abuse over a long period of time
• Facial nerve problems due to injuries
• AIDS / HIV infection
• Disorders of the CNS such as multiple sclerosis, Parkinson’s disease and stroke
• Complex regional pain syndrome, that affects an arm or leg, and occurs after a stroke, heart-attack, injury or surgery
• Shingles, a viral infection that causes painful rashes. This is followed by neuropathic pain called postherpetic neuralgia
• Chemotherapy treatment for cancer
• Radiation therapy for cancer
• Amputation of part or entire arm or leg, which causes a type of neuropathic pain called phantom pain
• Inflammation or compression of the spinal nerve
• Injuries from serious falls, motor-vehicle accidents, sporting injuries and trauma due to surgery – all these can cause nerve damage resulting in neuropathic pain
• Cancers, which can cause compression of surrounding nerves, or directly spreads to the nerves
• Hansen’s disease, commonly called as leprosy
• Auto-immune disorders such as Guillain-Barre syndrome and Lupus
• Vascular malformations and diseases in blood vessels

Symptoms

• Pain that occurs without any stimulation, also called Spontaneous pain. This is marked by shooting, stabbing, burning or electrocution-like pain; numbness tingling sensation and a ‘pins and needles’ like prickly feeling
• Evoked pain, also called allodynia: In this case, there is minor or non-painful stimuli such as cold weather, a gentle rubbing or brushing against the skin, slight pressure, brisk movement, etc.
• Hyperalgesia: Evoked pain can eventually lead to this kind of pain that occurs due to painful stimuli such as pinpricks, heat or even intensely hot weather.
• Dysesthesia: In this, the person experiences unpleasant and abnormal sensations marked by either spontaneous or evoked pain.
• Hypoalgesia: In this case, there is very less pain, in-spite of a painful stimulus
• Disturbed sleep due to pain.
• Anxiety, depression and nervous disorders

Common Types

Damage to a single nerve is called mono-neuropathy. Mono-neuropathy in multiple places in the body is called multiple mono-neuropathy. And damage to many nerves is called polyneuropathy. There are multiple types of neuropathic pain and newer ones may emerge with time, thanks to lifestyle changes. Here, we will only cover the most common ones.

1. Diabetic neuropathy

Like any other tissue in the body, nerves too require their supply of oxygenated blood. Diabetes is a condition marked by high blood-sugar levels in the body. The excess sugar causes damage to blood vessels. This results in reduced supply of oxygen and nutrients to nerves, causing impaired functioning of the nerves, and in turn – neuropathic pain.

2. Peripheral neuropathy

As the name implies, this type of pain affects nerves in the PNS, such as those in arms, hands, legs and feet.

Also Read: Painkillers for Acute and Chronic Pain

3. Focal neuropathy

As the names implies, here the damage is to a single nerve located in the head, arms, legs or torso. This can cause double-vision, pain and sudden weakness in different parts of the body including the front of the thigh. Bell’s palsy is one such type of focal neuropathy, and is marked by sudden weakness or paralysis in one side of the face.

4. Autonomic neuropathy

As the name implies, this affects the Autonomous Nervous System that controls or regulate the functioning of internal organs of various body-systems (circulatory/digestive/respiratory/excretory). Depending on which body-system is affected, this condition shows different symptoms.

5. Proximal neuropathy

A rare type of neuropathy. Here, nerves in the hip, thigh or buttock in one side of the body are affected. The condition can cause severe pain, muscle loss, weight loss and difficulty in movement.

6. Phantom limb syndrome

Nearly 80% of people with a missing limb (whether entire or part of the limb is missing) experience this condition. The nerves near the amputated end may be damaged due to amputation. They malfunction and send pain signals to the brain and spinal cord. The pain is frequent in the 6 months following surgery and reduces over the years.

7. Compression mononeuropathy

As the name implies, there is damage to a single nerve caused by compression injuries, or even a blood-vessel disease. The narrowed blood-vessels results in reduced blood-flow to the nerves causing this condition. The nerves passing over a joint may get compressed due to injury or a particular movement that is repeated (due to occupation, or wrong habits of movement). The best example of this is Carpal tunnel syndrome, where the median nerve gets compressed at the wrist. This is marked by numbness, swelling and tingling sensation in the fingers while using the hands or sleeping.

8. Thoracic or lumbar radiculopathy

Here, nerves in one or both sides of the chest, or abdominal wall, are affected. It is common in people with type-2 diabetes. However, it is not serious and the patient recovers with time.

9. Trigeminal neuralgia

An incident of stroke or Multiple Sclerosis or a surgery in the face can compress or damage the trigeminal nerve in the head. Symptoms include intense pain in the face which makes even everyday activities such like washing the face and brushing the teeth painful.

Also Read: Why does Bone Pain get worse at night?

Treatment options

Medication

• Non-steroidal anti-inflammatory drugs or NSAIDs – basically OTC painkillers
• Topical pain-relievers (applied on the skin) such as capsaicin creams, lidocaine patches, and other ointments or creams
• Anti-convulsants, or anti-seizure drugs, such as Gabapentinoids
• Anti-depressants including tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors (SNRIs)
• Nerve-blocks: These are steroids, pain-killers or other medication that can tame misbehaving nerves

Implantable device: Using an invasive surgery, a device is implanted in the brain. This sends out electrical signals to the concerned nerve and helps correct the wrong signals.

Transcutaneous Electrical Nerve Stimulation (TENS): Here, an electrode is stuck on the skin above the affected nerves. Then the TENS machine sends out small electrical signals through the electrode. This stimulates the concerned nerves and blocks out wrong signals. This helps relax the muscles and ease the pain.

Percutaneous Electrical Nerve Stimulation (PENS): Similar to TENS. But here, the electrode is put under the skin using a needle.

Alternative therapies: such as acupuncture, massage therapy, relaxation therapy and physiotherapy.

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem and Bengaluru, the hospital also renders adult and pediatric trauma care.

Chennai – 044 4000 6000 • Trichy – Cantonment – 0431 4077777 • Trichy – Heartcity – 0431 4003500 • Trichy – Tennur – 0431 4022555 • Hosur – 04344 272727 • Salem – 0427 2677777 • Tirunelveli – 0462 4006000 • Bengaluru – 080 6801 6801

NOTE: Take medications only when prescribed by your doctors, self-medication must be avoided under any circumstances.

Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals

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