Don't Lose Your Nerves!

Dr. S.M.Sadikot.
Hon. Endocrinologist,
Jaslok Hospital and Research Centre,
Mumbai 400026

When the nerves are affected by diabetes, a person is said to have diabetic neuropathy. Possibly the commonest long term complication of diabetes, the biggest problem is that in many patients the signs that they have diabetic neuropathy are so subtle, that it's presence only comes to light when the patient comes with a complication caused by the nerve disorder, such as a foot ulcer, etc.

People with diabetes can develop nerve problems at any time. Significant clinical neuropathy can develop within the first 10 years after diagnosis of diabetes and the risk of developing neuropathy increases the longer a person has diabetes. Some recent studies have reported that:

Diabetic Neuropathy
  • 60 percent of patients with diabetes have some form of neuropathy, but in most cases (30 to 40 percent), there are no symptoms.
  • 30 to 40 percent of patients with diabetes have symptoms suggesting neuropathy, compared with 10 percent of people without diabetes.

To compound the difficulty of detecting it, diabetic neuropathy itself has a slow and insidious onset. Patients often say that they were at first unaware of growing numbness in their feet and hands.

But it is absolutely essential that you must have yourself tested for neuropathy, as diabetic nerve disease can lead to many serious complications.

How?

To understand this, let us briefly consider the role played by the nerves.

Tasting, smelling, seeing, hearing, thinking, dreaming, breathing, heart beating, moving, running, sleeping, laughing, singing, remembering, feeling pain or pleasure, painting, writing...you couldn't do any of these things without your nervous system!

Made up of your brain, your spinal cord, and an enormous network of nerves that thread throughout your body, it's the control center for your entire body. Your brain uses information it receives from your nerves to coordinate all of your actions and reactions. Without it, you couldn't exist!

That's how important your nervous system is.

It is the nerves which make up the peripheral nervous system which carry messages back and forth between the brain and other parts of the body.

They're the thin threads of nerve cells, called neurons that run throughout your body. Bundled together, they carry messages back and forth just the way that telephone wires do. Sensory nerves send messages to the brain and generally connect to the brain through the spinal cord inside your backbone. Motor nerves carry messages back from the brain to all the muscles and glands in your body.

Through the marvels of chemistry and a kind of electricity! Neurons are thin. Some are very small, and some can be three feet long! All are shaped somewhat like flat stars which have, to varying degrees, been pulled at each end so that they have long fingers. The fingers of one neuron almost reach to the next neuron.

When a neuron is stimulated -- by heat, cold, touch, sound vibrations or some other message -- it begins to actually generate a tiny electrical pulse. This electricity and chemical change travels the full length of the neuron. But when it gets to the end of finger-like points at the end of the neuron, it needs help getting across to the next extended finger. That's where chemicals come in. The electrical pulse in the cells triggers the release of chemicals that carry the pulse to the next cell. And so on and on till it reaches its destination. Impulses travel through the nerve network to the brain at a rate of 350 feet per second!

It takes the corporation of three system to carry out the mission of the nervous system . They are the central, the peripheral nervous systems.

The central nervous system has the responsibility for issuing nerve impulses and analyzing sensory data, and includes the brain and spinal cord.

The peripheral nervous system is responsible for carrying these nerve impulses to and from the body.

The peripheral nervous system is subdivided into the

  • Sensory-somatic Nervous System and the
  • Autonomic Nervous System

Whilst some divide the nerves in the body into the peripheral nervous system and those in the autonomic nervous system, today, most feel that that one should use the term Peripheral Nervous System for all the nerves not considered to be part of the central nervous System, and then divide these into the Sensory-Somatic Nervous System ( what has popularly been called the peripheral nervous system in the past) and the Autonomic Nervous System.

Peripheral Nervous

This helps to describe their functions better.

The somatic nervous system consists of peripheral nerve fibers that send sensory information to the central nervous system AND motor nerve fibers that project to skeletal muscle.

Somatic Nervous System

The autonomic nervous system is composed of the sympathetic and parasympathetic systems and is responsible for regulating and coordinating the functions of vital structures in the body.

Nervous System

The autonomic nervous system controls smooth muscle of the viscera (internal organs) and glands.

Internal Organs

By understanding the important role played by the nerves, one can well realize the importance of the problems that can arise when these nerves cannot function properly when damaged by diabetes.

Whilst, diabetes can affect the Central Nervous System (CNS), it is the Peripheral Nervous System (PNS) which has been the focus of diabetic neuropathy.

Whilst we still do not know the exact way by which diabetes affects the nerves, everyone is agreed that having high blood glucose levels can not only damage the nerves themselves, but also affect the small blood vessels which carry nourishment to the nerves.

Damaged nerves may stop sending messages. Or they may send messages too slowly or at the wrong times.

The Sensory-Somatic nerves go from your spinal cord to your arms, hands, legs, and feet.

The Sensory-Somatic Neuropathy can be of three types and more than one type can often be present at the same time.

a) Diffuse neuropathy
b) Focal neuropathy
c) "Burning" neuropathy

Sensory Somatic

The most common type of diabetic neuropathy damages the nerves of the limbs, especially the feet. Nerves on both sides of the body are affected. Common symptoms of this kind of neuropathy are:

  • Numbness or insensitivity to pain or temperature.
  • Tingling, burning, or prickling.
  • Sharp pains or cramps.
  • Extreme sensitivity to touch, even light touch.
  • Loss of balance and coordination.

Damage to sensory-somatic nerves can make your arms, hands, legs, or feet feel numb. Also, you might not be able to feel pain, heat, or cold when you should. You may feel shooting pains or burning or tingling, like "pins and needles." These feelings are often worse at night. They can make it hard to sleep. Most of the time these feelings are on both sides of your body, like in both of your feet. But they can be on just one side.

The symptoms of diabetic neuropathy vary. Numbness and tingling in feet are often the first sign. Some people notice no symptoms, while others are severely disabled. Neuropathy may cause both pain and insensitivity to pain in the same person. Often, symptoms are slight at first, and since most nerve damage occurs over a period of years, mild cases may go unnoticed for a long time. In some people, mainly those afflicted by focal neuropathy, the onset of pain may be sudden and severe.

The damage to nerves often results in loss of reflexes and muscle weakness. The foot often becomes wider and shorter, the foot muscles get weak and the tendons in the foot get shorter. The gait may change, and foot ulcers appear as pressure is put on parts of the foot that are less protected. Because of the loss of sensation, injuries may go unnoticed and often become infected. If ulcers or foot injuries are not treated in time, the infection may involve the bone and require amputation. However, problems caused by minor injuries can usually be controlled if they are caught in time. Avoiding foot injury by wearing well-fitted shoes and examining the feet daily can help prevent amputations.

Occasionally, diabetic neuropathy appears suddenly and affects specific nerves, most often in the torso, leg, or head. Focal neuropathy may cause:

  • Pain in the front of a thigh
  • Severe pain in the lower back or pelvis
  • Pain in the chest, stomach, or flank
  • Chest or abdominal pain sometimes mistaken for angina, heart attack, or appendicitis
  • Aching behind an eye
  • Inability to focus the eye
  • Double vision
  • Paralysis on one side of the face (Bell's palsy)
  • Problems with hearing

This kind of neuropathy is unpredictable and occurs most often in older people who have mild diabetes. Although focal neuropathy can be painful, it tends to improve by itself after a period of weeks or months without causing long-term damage.

Although diabetic nerve damage usually leads to a loss of sensation in the limbs, a few patients can present with severe painful ( "burning") symptoms. 4-7% of patients with diabetes suffer chronic, often distressing symptoms of severe pain, and irritating "pins and needles" in their feet.

Why do these patients react differently to diabetic nerve damage? This question is yet to be fully answered. People with poorly controlled diabetes for a long time are more likely to get chronic painful neuropathy. However, many patients with relatively well controlled diabetes also develop it, especially if the blood glucose levels have been brought down too rapidly especially when associated with a very low calory diet.

Painful symptoms can be transient, eg less than 12 months duration. Once symptoms have persisted for more than 12 months, they are less likely to disappear on their own. Although good blood glucose control is important for many reasons, striving for very tight blood glucose control is less likely to make the painful symptoms get better when they have been present for this length of time.

Commonly reported symptoms include:

Burning Feet

Burning, feeling like the feet are on fire

Haemorrhage

Freezing, like the feet are on ice, although they feel warm to touch

Feet Knives

Stabbing, like sharp knives

Lancinating, like electric shocks

Lancinating, like electric shocks

  • Allodynia which means feeling pain from a stimulus that would not normally be painful. An example of this is wearing shoes or having bed sheets touching the feet.
  • Hyperalgaesia which means having an exaggerated response to a stimulus which is normally painful. This is often seen in response to heat.
  • A feeling of tightness or pressure around the feet.
  • Vibration or tingling sometimes described as ants crawling under the skin.

Firstly it is important to determine if the pain is due to diabetes or some other cause. People with pain should have a thorough assessment.

    Pain due to diabetes is usually:
  • present in both feet
  • of equal severity in each
  • often, but not always, worse at night

If the pain is in one foot only, it is likely from another cause such as arthritis, spinal problems, other neuropathies or peripheral vascular disease, which should be investigated by your doctor.

Painful diabetic neuropathy is not easy to treat, but many options are available and it would be best to discuss these options with your doctor and choose those which may be the best for you. It is important to understand that for some people, several treatments may need to be tried or used in combination to achieve acceptable symptom relief.

Autonomic nerves go from your spinal cord to your lungs, heart, stomach, intestines, bladder, and sex organs.

Diabetic autonomy neuropathy produces changes in many processes and systems, although all the organs may not be affected at the same time or to the same degree.

Autonomic nerves
Cardiovascular System

Autonomic neuropathy can affect the cardiovascular system, which controls the circulation of blood throughout the body. Damage to this system interferes with the nerve impulses from various parts of the body that signal the need for blood and regulate blood pressure and heart rate. Damage to these nerves makes your blood move too slowly to keep your blood pressure steady when you change position. When you go from lying down to standing up or when you exercise a lot, the sudden changes in blood pressure can make you dizzy.As a result, blood pressure may drop sharply after sitting or standing, causing a person to feel dizzy or light-headed, or even to faint (orthostatic hypotension).

Neuropathy that affects the cardiovascular system may also affect the perception of pain from heart disease. People may not experience angina as a warning sign of heart disease or may suffer painless heart attacks. It may also raise the risk of a heart attack during general anesthesia.

Autonomic neuropathy most often affects the organs that control urination and sexual function. Nerve damage can prevent the bladder from emptying completely, so bacteria grow more easily in the urinary tract (bladder and kidneys). When the nerves of the bladder are damaged, a person may have difficulty knowing when the bladder is full or controlling it, resulting in urinary incontinence.

Urination Response

The nerve damage and circulatory problems of diabetes can also lead to a gradual loss of sexual response in both men and women, although sex drive is unchanged. A man may be unable to have erections or may reach sexual climax without ejaculating normally.

Sexual Response

Damage to these nerves prevents a woman's vagina from getting wet when she wants to have sex. A woman might also have less feeling around her vagina.

Autonomic neuropathy can affect digestion. Nerve damage can cause the stomach to empty too slowly, a disorder called gastric stasis. When the condition is severe (gastroparesis), a person can have persistent nausea and vomiting, bloating, and loss of appetite. When nerves to the stomach are damaged, the muscles of the stomach do not work well and food may stay in the stomach too long. Gastroparesis makes it hard to keep blood sugar under control, and levels tend to fluctuate greatly with this condition. If nerves in the esophagus are involved, swallowing may be difficult. Nerve damage to the bowels can cause constipation or frequent diarrhea, especially at night. Problems with the digestive system often lead to weight loss.

Autonomic neuropathy can hinder the body's normal response to low blood sugar or hypoglycemia, which makes it difficult to recognize and treat an insulin reaction. Some people take diabetes medicines that can accidentally make their blood sugar too low. Damage to the autonomic nerves can make it hard for them to feel the symptoms of hypoglycemia, which is the medical name for low blood sugar.

This kind of damage is more likely to happen if you have had diabetes for a long time. It can also happen if your blood sugar has been too low very often.

Autonomic neuropathy can affect the nerves that control sweating. Sometimes, nerve damage interferes with the activity of the sweat glands, making it difficult for the body to regulate its temperature. Other times, the result can be profuse sweating at night or while eating (gustatory sweating).

How do I know I have diabetic neuropathy?

You may have diabetic neuropathy if you have any of the following:
  • Pain in your legs
  • Numbness in your feet and toes
  • A feeling of lightheadedness that causes you to fall
  • Diarrhea or constipation
  • Failure to get erections (in men)

Tell your doctor right away if you get any of these signs.

Many of you may have no symptoms or these may be so minor that you may not pay attention to them. It is therefore, so necessary to have a regular checkup done with your doctor so that the presence of diabetic nerve damage can be diagnosed early. As an example, insensitive feet can be diagnosed at the earliest and steps taken to avoid major complications such as foot ulcers!

Although many of you will get some degree of diabetic nerve damage, it can be kept at a level which does not interfere with your daily life and routine. There is no need to be afraid of diabetic neuropathy.

Don't lose your nerve and your nerves won't let you down!