The Nervous system is one of the most important organ systems in the body, as this is what controls and manages signaling or communication throughout the body. The Central Nervous System (CNS) which consists of the brain and spinal cord is the main ‘control room’ from which signals are sent and received to and from nerves in the Peripheral Nervous System (PNS). The PNS consists of nerves distributed throughout the body – in the arms and legs, face and sense organs, and internal organs as well.
Needless to say, a healthy Nervous system is indispensable for proper functioning of organs, proper responses from our limbs, sense organs and face. Damage to one or more nerves anywhere in the network can impair the concerned function. Like any other part of the body, the nerves too are vulnerable to damage – either temporarily, or permanent, and the condition is called Neuropathy. Neuropathy is a complex condition with both short and long-term consequences. That is why, it’s important to be aware of it, so that timely medical help can be provided.
Types of Nerves
There are 3 types of nerves and neuropathy in each type brings its own set of symptoms.
- Autonomic nerves: These manage the internal organs. That is, all our involuntary or partly-voluntary activities of our body such as temperature regulation, blood pressure, digestion, heart rate, etc., are all controlled by these nerves.
- Motor nerves: As the name implies, these nerves manage all our voluntary activities involving our arms, legs, movements and muscles in various parts of the body, by relaying signals back and forth from CNS to our muscles.
- Sensory nerves: These are responsible for sensation and sense organs, hence the name. The signals from the skin and sense organs are relayed back and forth between them and the CNS. This is what helps us feel pain, heat, cold, taste, vision, smell, hearing etc.
Symptoms of Nerve Damage
Depending on which of the above type of nerves are damaged, the symptoms are different.
Autonomic Neuropathy
- Problems with sweating – too less sweating (anhidrosis) or excessive sweating (hyperhidrosis)
- Inability to sense pain in the chest caused by angina or heart attack
- Problem in swallowing
- Constipation and diarrhea
- Nausea, belching and bloated feeling in the stomach
- Intoleranceto heat
- Dry eyes and mouth
- Problems with blood pressure. For example, low BP that causes the person to faint upon standing
- Lightheadedness
- Urinary or bowel incontinence (problem in control)
- Sexual dysfunction
Motor Neuropathy
- Muscle problems: cramps, twitching, wasting or shrinking leading to muscle atrophy
- Twitching in different parts of the body, also known as fasciculation
- Muscle weakness and weakness in general – small tasks such as buttoning a shirt becomes difficult now
- Paralysis
- Muscle atrophy
Sensory Neuropathy
- Pain–burning, sharp, shooting, stabbing or excessive pain from even small things such as touch, and which gets worse at night
- Sensitivity, burning sensation, tingling or prickly feeling all over the body, called as ‘pins and needles’
- Numbness
- Issues with positional awareness
- Problems with balance and coordination
- Reducing sensation of touch, impact orvibration
- Increased pain or the opposite – not able to feel any pain
- Inability to detect changes in ambient heat or cold
Specific examples of Neuropathy
- Diabetic neuropathy: excess blood-sugar increases the risk of atherosclerosis in small arteries which carry blood to nerves, thereby reducing oxygen supply to the nerves and hence neuropathy in them. Quite a common condition.
- Post-herpetic neuralgia: Shingles is a viral infection that leaves rashes all over the body. After the rashes disappear, there is neuropathy for several months.
- Ulnar nerve palsy: Ulnar nerve in the hand helps us move our forearm, elbow and some of the fingers. An injury to the elbow can cause neuropathy in the same, which restricts hand movement.
- Carpal tunnel syndrome: Repetitive stress on the wrist and lower palm, as from typing on a keyboard, causes compression of nerves in the wrist.
- Peroneal nerve palsy: Peroneal nerve, also called fibular nerve, is an important nerve in the lower leg. Compression of this nerve causes neuropathy, thereby making leg movements painful.
- Bell’s palsy: A neuropathy in the nerves of the face, causing weakness or paralysis on one side of the face.
Causes of Neuropathy
There are over 100 different neuropathies diagnosed till date and more may emerge with time. The causes for the same are also quite varied. It is not possible to cover all those causes, so the most common ones are given here:
- Diabetes: as described above
- Autoimmune diseases: Includes multiple sclerosis, Guillain-Barré syndrome, rheumatoid arthritis, systemic lupus erythematosus (SLE), inflammatory bowel disease, Sjogren’s syndrome and chronic inflammatory demyelinating polyneuropathy.
- Infections: Viral or bacterial infections such as HIV, shingles, Lyme disease, chickenpox, leprosy,herpes, West Nile virus,syphilis, Epstein-Barr virus and Hepatitis C
- Cancer: When cancerous tissues press on nerves, they can cause nerve pain in the short-term and neuropathy in the long run. Examples include lymphoma and multiple myeloma. So also, treatment for cancer such as chemotherapy and radiation in some cases can cause nerve pain and neuropathy in some people.
- Compression and trauma: Anything that causes nerves to be pinched, compressed, torn, pulled, twisted or cut can cause nerve pain and neuropathy. Examples includes falls, motor vehicle accidents, carpal tunnel syndrome, fractures and sporting injuries. Even the plaster or cast that is put for fractures can cause compression and hence neuropathy.
- Medicine side-effects: Drugs used to treat HIV, medication given as a part of cancer treatment (chemotherapy), and radiation can cause neuropathy
- Alcohol abuse: This deprives the body of minerals and vitamins such as thiamine, E, B1, B12, B6and niacin causing neuropathy eventually.
- Toxic substances: Ingesting or inhaling vapors of toxic metals like mercury, arsenic and lead, industrial chemicals and solvents, at the workplace, can cause serious neuropathy.
- Motor neuron diseases: Diseases that affect the motor nerves can cause motor neuropathy. Examples include amyotrophic lateral sclerosis (ALS) or ALS or Lou Gehrig’s disease.
- Nutritional deficiencies. Deficiencies of certain vitamins such as B6 and B12 or folate can trigger neuropathy eventually. These deficiencies may be due to the diet, alcohol abuse or gastric surgery.
- Various diseases: Chronic kidney disease or CKD causes an imbalance of salts and chemicals in the body which triggers peripheral neuropathy. So also liver disorders, hypothyroidism and monoclonal gammopathy is known to cause neuropathy.
- Blood circulation issues: These can be due to diabetes, smoking, vasculitis, blood-clots, inflammation and other blood vessel disorders.
- Inherited conditions: This includes Fabry disease, Familial amyloidosis, Charcot-Marie-Tooth (CMT) disease and metachromatic leukodystrophy.
- Idiopathic neuropathy: Where the cause is not clearly known
Investigations
Neuropathy is diagnosed using physical examination, genetic testing, tests such as needle electromyography (EMG), nerve conduction velocity (NCV), Electro-diagnostic assessment (EDX), tissue biopsy and imaging tests such as CT or MRI scan.
Nerve conduction velocity (NCV) test – also called a nerve conduction study (NCS) — measures how fast an electrical impulse moves through your nerve. NCV can identify nerve damage.
An illustration of a nerve conduction velocity test: During the test, your nerve is stimulated, usually with electrode patches attached to your skin. Two electrodes are placed on the skin over your nerve. One electrode stimulates your nerve with a very mild electrical impulse. The other electrode records it. The resulting electrical activity is recorded by another electrode. This is repeated for each nerve being tested.
The speed is then calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes.
Nerve biopsy: Nerve biopsy is the removal of a small piece of a nerve for examination.
Nerve biopsy may be done to help diagnose:
- Axon degeneration (destruction of the axon portion of the nerve cell)
- Damage to the small nerves
- Demyelination (destruction of parts of the myelin sheath covering the nerve)
- Inflammatory nerve conditions (neuropathies)
- Nerve biopsy is usually done to look for inflammation that could be damaging the nerve.
Treatment for Nerve Damage
Treatment options are a mix of medication and therapy.
- Self-care: Includes monitoring and maintaining blood-sugar levels for diabetics
- Alternative therapies such as Acupuncture, Meditation, Biofeedback and Hypnosis to relieve pain and stress
- A diet-plan to correct nutritional deficiencies
- Changing or stopping medication that causes nerve damage
- Physical therapy
- Mechanical aids such as splints, braces, casts and specially-designed shoes. These help relieve compression, nerve misalignment, nerve pain, muscle weakness, and improve stability.
- Surgery for compression and trauma related neuropathies
- Medications for curing autoimmune conditions
- Pain relievers
- Tricyclic antidepressants
- Anti-seizure drugs
- Capsaicin cream
- Antioxidant vitamins
- Electrical nerve stimulation such as TENS (Transcutaneous electronic nerve stimulation)
- Lifestyle changes such as quitting smoking and alcohol, exercising regularly and consuming a healthy diet and managing stress better.
Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals
NOTE: Take medications only when prescribed by your doctors, self-medication must be avoided under any circumstances.
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, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.
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