Peripheral neuropathy: Types, Causes, Symptoms-NotesMed

What is peripheral neuropathy?

Peripheral neuropathy is a clinical condition of the damaged or destroyed or dysfunction of one or more nerves that results in tingling, numbness, muscle weakness, and pain in the affected site.

Neuropathies frequently start in the feet and hands, but other parts of the body rarely can be affected. Neuropathy, often known as peripheral neuropathy designates or indicates a problem within the peripheral nervous system (PNS).

The peripheral nervous system (PNS) is the network of numerous nerves present outside the brain & spinal cord. While the brain and spinal cord are a network of the central nervous system (CNS).

These two systems work together this way, the central nervous system is the central part (central station) of the body. It is the control central action in the human body, it is a hub from all trains that come and go the signals.

The peripheral nervous system (PNS) is the track that connects to the central station in the human body. The network of nerves that allow the transformation information (signal) to travel to and from the central nervous system (central station).

Neuropathy results when nerve cells (neurons) are damaged or destroyed. This disrupts the pathways of the neurons that communicate with each other and with the brain.

Neuropathy can affect one nerve (i.e. Mononeuropathy), or multiple nerve cells involved (polyneuropathy), or a combination of nerves in a certain limited area (multifocal neuropathy).

What are the types of peripheral neuropathy?

Neuropathies are classified according to the problems they cause or what is at the root of the nerve damage. They are,

Mononeuropathy

Damage to a single peripheral nerve is called mononeuropathy. It is caused by physical injuries or trauma such as from an accident is the most common cause.

Prolonged pressure on a nerve, caused by extended periods of being in a sedentary position  (such as sitting in a wheelchair or lying in bed for prolonged time), or continuous, repetitive motions, can trigger mononeuropathy.

e.g. Carpal tunnel syndrome:

It is a common type of mononeuropathy. It is known as an overuse strain injury, which occurs when the nerve that travels throughout the wrist is compressed. 

People whose work requires repeated motions with the wrist (such as assembly-line workers, physical laborers, and those people who use computer keyboards for prolonged periods of time) are at greater risk of neuropathies.

Ulnar nerve palsy: It occurs when the nerve that passes close to the surface of the skin at the elbow is damaged. And the numbness is noted in the 4th and 5th digits of the hand.

Radial nerve palsy: It is caused by injury to the nerve that runs along the underside of the upper arm and can occur with fractures of the humerus bone in the upper part of the arm.

Peroneal nerve palsy: It results when the nerves at the top of the calf on the outside of the knee are compressed of a nerve (peroneal nerve) and that leads to a condition is called “foot drop” in which it becomes difficult to lift your foot when walking as well as other purposes.

Neuropathy can affect nerves that control muscle activity in the body (motor nerves) & those that detect sensations like coldness or pain (sensory nerves).

In some clinical conditions, it can affect internal organs, like following the heart, blood vessels, bladder, or intestine.

Neuropathy that affects internal organs is called autonomic neuropathy. These are rare conditions that can cause low blood pressure or problems with sweating.

Polyneuropathy

Polyneuropathy accounts for the greatest number of peripheral neuropathy cases present in the world.

It occurs when multiple peripheral nerves involved throughout the body malfunction at the same time.

Polyneuropathy can have various types of causes present, out of some causes including exposure to certain toxins substances such as with alcohol abusers, poor nutrition (particularly vitamin B deficiency), and complications from diseases such as cancer, kidney failure, liver failure.

The most common form of polyneuropathy(chronic) is diabetic neuropathy, a condition that occurs in people with diabetes. Diabetes can also cause mononeuropathy. 

What types of peripheral nerves are present there and what do they do?

In the peripheral nervous system that contains three types of nerves, each nerve has an important role in the body that keeps the body balanced, which means the body becomes healthy and functioning properly.

• Sensory nerve:
  • The sensory nerves carry messages from five different sensory organs such as sight, hearing, smell, taste, and touch through the spinal cord to the brain.
  • For example, a sensory nerve that communicates with brain information (signal) about objects you can hold in your palm (hand), like pain, temperature, and texture.

• Motor nerve:
  • The motor nerves travel in the opposite direction of sensory nerves. They carry the information (messages) from the brain to the affected side (muscles).
  • They control body muscles how and when to contract to produce different movements. For example to move your hands away from any hot objects.

• Autonomic nerve:
  • The autonomic nerves are responsible for body functions that are directly controlled such as breathing, digestion, blood pressure, heart rate, sweating, micturition, and sexual arousal.
  • Symptoms are present depending on the type of nerves damaged or destroyed.

What does neuropathy feel like?

If neuropathy is present, the most commonly described feelings are sensations of numbness, tingling (“pins and needles”), and weakness in the affected side of the body.

Other sensations include sharp, lightning-like pain, or burning, throbbing, or stabbing pain present in the affected area of the human body.

How common is peripheral neuropathy? Who gets peripheral neuropathy?

Neuropathy is a very common neuronal abnormality. It is estimated that around 25-30% of the American people will be affected by these types of abnormalities.

This type of abnormality generally affects all ages of people; however, older peoples are at increased risk. About 8% of adults over 65 years of age reported this type of abnormality.

Other than age, in the United States, some other common risk factors include diabetes, metabolic syndrome (high cholesterol, high blood pressure, obesity, diabetes), and heavy alcohol consumption.

People in certain professions such as those that require repetitive motions have a greater chance of developing a single nerve damaged or destroyed (mononeuropathy) from trauma (car accident, falling, etc.) or compression of nerves.

Neuropathy is present in the following average percentage according to research:

• 60 to 70% of people have diabetes.

• 30 to 40 % of people receive chemotherapy for the treatment of cancer.

• 30% of people have HIV infection.

How quickly does neuropathy chance to develop?

Some peripheral neuropathies develop slowly over and over a period of time months to years while some other develops rapidly and continues to get worse. There are more than 100 types of neuropathies present and each type can develop differently and have different symptoms.

The way these clinical conditions progress and how quickly symptoms start can vary greatly depending on the type of nerves or nerves damaged and the underlying cause of that condition. There are numerous causes that are present but diabetes is the major common cause in the world and the United States. The common causes include trauma, chemotherapy, alcoholism, autoimmune disease, and other infections.

What are the common causes of peripheral neuropathy?

Neuropathy is not caused by a single disease. Many clinical conditions and events that impact health can causes neuropathy, some common causes are,

• Diabetes:
  • The most common cause worldwide and in the United States. In the United States about 60 to 70 % of people who have diabetes experience neuropathy.
  • Diabetes is the most frequent cause of small fiber neuropathy, which causes painful burning sensations in your hands and feet.

• Trauma:
  • Injuries from various conditions like falls, compression of the nerves because of repetitive stress, car accidents, fracture of different sports activities can change neuropathy.

• Autoimmune disease and infections:
  • Guillain-Barre’s syndrome
  • Systemic lupus erythematosus (SLE)
  • Rheumatoid arthritis
  • Sjogren’s syndrome and other chronic inflammatory demyelinating polyneuropathies are common causes of neuropathy.
  • Common infections include;
    • Chickenpox
    • Shigella
    • HIV virus
    • Syphilis
    • Lyme disease
    • Leprosy
    • Herpes
    • West Nile virus
    • Epstein-Barr virus
    • Hepatitis C

• Other health abnormalities:
  • Neuropathy can be present from
    • Liver abnormalities
    • Kidney disorder
    • Hypothyroidism
    • Multiple myeloma
    • Lymphoma
    • Monoclonal gammopathy.

• Antibiotics:
  • Some antibiotics such as some anti seizures drugs and some HIV drugs are other common causes of neuropathy.
  • Cancer chemotherapy, radiation can damage peripheral nerves that lead to neuropathy.

• Toxic substances:
  • Exposures to toxic substances like heavy metals lead and mercury and other industrial chemicals especially solvents can affect nerve function.

• Vascular disorder:
  • Due to inflammation, blood clots, or other blood vessels disorder that leads to the cause of neuropathy.
  • Decreased blood flow deprives the nerve cells of oxygen, causing nerve damage or destruction.
  • The vascular disorder most commonly caused by vasculitis, smoking, and diabetes.

• Poor nutrition or abnormal vitamin levels and alcoholism:
  • The proper amounts of vitamins E, B1, B6, B12, and niacin are important for well nerve functioning.
  • Chronic alcohol consumer people, which typically results in a lack of a well-rounded diet, robs the body of thiamine and other essential nutrients needed for well nerve functioning.
  • Alcohol is directly toxic to the peripheral nerve.

• Inherited disorder:
  • Charcot-Marie-Tooth (CMT) disease is the most common cause of hereditary neuropathy.
  • Charcot-Marie-Tooth (CMT) causes weakness in the foot and lower leg muscles and can also affect muscle present in the hands.
  • Familial amyloidosis, Fabry disease, and metachromatic leukodystrophy are other common examples of inherited disorders that can cause neuropathy.

• Unknown causes are known as Idiopathic: Sometimes Unknown causes may be present in some cases.

Signs & Symptoms

Symptoms depend on the type and location of nerve involvement. Symptoms that can appear suddenly are called acute neuropathy or develop after a long period of time called chronic neuropathy.

Common signs and symptoms include the following;

• Tingling (“pins and needles”) or numbness:
  • Specially present in the hands and feet and sensations can be spread to the arms and legs.

• Sharp, burning, throbbing, stabbing, or electric pain, etc.

• Changes in sensation; severe pain at night, inability to feel pain, pressure, temperature or touch, etc. Sometimes extreme sensitivity to touch.

• Falling, loss of body coordination.

• Not able to feel any objects or things in your feet and hands: example note feel when you can wear gloves and socks.

• Muscles weakness, difficulty in walking, or moving arms or legs.

• Muscles twitching, cramps, and spasms.

• Paralysis: Loss of muscle control, loss of muscle tone, or dropping.

• Low blood pressure or abnormal heart rate causes dizziness when standing up, fainting, or lightheadedness.

• Sweating too much is not related to temperature.

• Frequent urination (in bladder problem).

• Bloating
• Nausea
• Vomiting
• Diarrhea
• Constipation

• Sexual dysfunctions
• Weight loss, etc.

 

Treatment of peripheral neuropathy