Diabetic neuropathy: a question and an answer

One of the readers of my blog emailed me this query. A very good question and I wanted to reproduce it here, my answer follows.

Bree Johnson on November 28, 2008 said: Edit Link

I am very confused about whether I have diabetic neuropathy or not. I have been a diabetic for 21 years. A podiatrist confiremd recently that I have VERY good sensation in the feet & there is no evidence of neuropathy. I do not experience any numbness, pins & needles as such but I do have signficant pain at times in the my feet. The pain is largely due to a heightenend sensitivity at skin level. For example having things brush against my skin is unbearable, or putting on my shoes is also uncomfortable or walking on rough surfaces. But applying direct pressure on my feet – as in reflexology – is not painful. The podiatrist could not explain what this heightened sensitivity is due to.

I am however prone to occasional bouts of deep aching pain the feet & legs – which seems to always be the case now when I am a bit rundown & tired.

I also do have electrical type of stabbing pains that come & go – they can be quite painful stabs. Again they seem to be apparent only when rundown & tired.

Can you please offer any comments on the above? It would be greatly appreciated.

Bree

Dear Bree,

Thank you for writing in. You ask a very good question and that is what I shall attempt to answer. First at the onset let me tell you that most diabetics (especially those who have had long standing diabetes, in your case for over 21 years) shall have clinical evidence of diabetic neuropathy if one subjects them to a thorough clinical examination and electrodiagnostic testing (we use tests like nerve conduction velocities (NCV) and electromyogram (EMG) to unearth evidence of nerve damage/ neuropathy).  

Diabetes can cause different kinds of neuropathies depending upon what kind of nerves are preferentially involved:

(large nerves that carry sensations like joint sense and vibration versus smaller nerves that carry sensations of crude touch, pain and temperature)

(motor nerves that help in moving muscles and joints versus sensory nerves which carry sensation)

THE MOST COMMON NEUROPATHY THOUGH IN DIABETES IS A MIXED MOTOR SENSORY POLYNEUROPATHY WHICH USUALLY INVOLVES THE SMALL NERVES WHICH CARRY SENSATIONS LIKE PAIN, CRUDE TOUCH AND TEMPERATURE. MEANING THAT AT LEAST INITIALLY IN THE DISEASE COURSE THE MOTOR NERVES AND THE LARGE SENSORY NERVES (CARRY SENSATIONS OF VIBATION, JOINT SENSE AND POSITION SENSE) MAY BE SPARED OR AT LEAST WE DO NOT SEE EVIDENCE OF THEIR DEGENERATION ON NERVE CONDUCTION TESTING.

Patients who have small nerve fiber involvement commonly have what we refer to as allodynia and hyperpathia. What is allodynia you may ask?

Well allodynia is when a normally non-painful stimulus becomes painful. Let me explain with the aid of an example. You are lying in the bed, settling down to sleep. You pull the sheets over your bare legs. The sheets touch your legs, now they are silk sheets that is not a painful stimulus. But a patient with diabetic neuropathy may find it excruciatingly painful. THERE THAT IS ALLODYNIA.

They also have hyperpathia. What is hyperpathia? Well lets take another example. I take a pin and stab you with it. Now that is a painful stimulus and everyone shall find it so.  A normal person may say “ouch”, a patient with diabetic neuropathy though may jump out of his seat. SO HYPERPATHIA IS WHEN YOU FEEL A GREATLY EXAGGERATED PAIN SENSATION TO A PAINFUL STIMULI.

So in conclusion, it is more that likely that you have diabetic neuropathy. My advise to you would be to see a neurologist. If you do indeed have diabetic neuropathy, there are many good medicines out there that can treat the pain and more over prevent the progression of this painful and disabling condition.

Personal Regards,

Nitin Sethi, MD

Alcoholic neuropathy

Continuing with the posts on the neurological manifestations of alcoholism, I shall cover the topic of alcoholic neuropathy here. Simply put alcohol is a neurotoxin especially when it is consumed in excess. People who consume large amounts of alcohol on a chronic (daily) basis frequently develop neuropathy. It does not depend upon the kind of alcohol consumed (top of the shelf Scotch whisky Vs a cheap rum) rather it depends upon the amount and frequency of use. Patients develop a predominantly sensory neuropathy and have complaints of pain, burning, tingling, pins and needle sensation in the feet and sometimes in the finger tips. Rarely if the neuropathy is severe patients may also develop peripheral weakness (motor symptoms).

Alcoholic neuropathy is also thought to be not entirely due to alcohol, rather it is a nutritional neuropathy and occurs due to lack of essential nutrients and vitamins in the marginal diets of alcoholics. It is uncertain whether the neuropathy would develop in an alcoholic who supplements his diet with essential nutrients and vitamins. Alcoholic neuropathy is more commonly seen in patients who have other neuropathic conditions like diabetes. In this subgroup of patients, alcohol acts as an additional neurotoxin and makes the neuropathy worse. The same principle applies to cancer patients been treated with neurotoxic chemotherapy medications or an HIV patient been treated with neurotoxic antiretroviral medications.

Thus the message is simple.

Drink alcohol in moderation applies to all of us.

People who have diabetes should avoid alcohol if possible or if that is not possible consume as little.

Patients been treated with neurotoxic medications should also avoid alcohol.

Supplement your diet with at least one to two tablets of a good multivitamin every day.

Alcoholic neuropathy is treated much the same as any other neuropathy (see my post on diabetic neuropathy http://braindiseases.info)

Nitin Sethi, MD

Neuropathy presenting features

Neuropathy presenting features

So what are the signs and symptoms of someone with a neuropathic condition:

Sensory neuropathies present with the following signs and symptoms:

1) Numbness in the arms or legs ( a clue to neuropathy is that the signs and symptoms are usually symmetrical and start distally. For example the patient may complain of numbness in both legs or hands initially in the toes and the fingertips. As the disease progresses this numbness also moves more proximally reaching to the ankles, shin and the arms).

The patient may not complain of numbess rather may use words like ” my legs feel dead” or “my hands burn” to describe his symtoms.

2) Pins and needles sensation in the arms and legs: people with neuropathy have what doctors call paresthesias or abnormal sensations.  They may complain of feeling pins and needles , electric shocks or at times as if their skin is been touched with a feather.

They have allodynia (a non-noxious stimuli feels noxious meaning that if I touch you with a feather you may feel as if I am boring a sharp pin into your skin) and hyperalgesia (meaning that they have an increased sensitivity to pain).

3) Patients with neuropathy may present with skin changes. This is most commonly noted on the skin overlying the shin and feet. The skin is shiny and atrophic, the overlying hair are sparse or completely lost. At times people may develop non-healing ulcers of the feet which may get infected and even gangrenous. This condition is commonly seen in diabetic patients with severe neuropathy (diabetic foot).

4) If a patient has a large fiber neuropathy, he may complain of difficulty with balance especially at night or when his eyes are closed. They feel as if they are walking on cotton wool.

5) Patients may present with ulcers or burns in their hands: this is because as they are not able to detect the sensations of heat etc they may touch something hot like a gas stove and get burnt.

 

 

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Neuropathy

Neuropathy

In this section we shall discuss neuropathies. This is a vast topic and I shall try to make it simple. First lets start with the basics. What is neuropathy? Neuropathy refers to disease and dysfunction of the nerves.  There are different types of nerves in the human body: some nerves supply the muscles of the head, face and neck example the facial nerve supplies the muscles of the face ( it is this nerve which helps you to smile or frown).  Another  example is the auditory nerve which helps you to hear. These nerves which supply the muscles of the head and face are referred to as Cranial Nerves.

Apart from the cranial nerves there are other nerves which supply the muscles of the arms and legs and carry sensations of pain, temperature, pressure, joint sense, vibration and light touch. As these nerves supply the muscles in the periphery of the body they are referred to as peripheral nerves. Peripheral nerves are of three types:

1) Motor nerves : nerves which carry out motor functions example closing and unclosing your fist , walking etc

2) Sensory nerves: nerves which carry sensation of pain, temperature, touch, joint sense, vibration and position sense from the periphery back to the brain.

3) Mixed nerves: nerves which carry out both the above functions.

Neuropathies can thus be of different types based on which type of nerve is involved by the disease process. So you can have a motor neuropathy, a sensory neuropathy and a mixed motor-sensory neuropathy.

Another way to classify neuropathies is on the basis of the size of the nerve fibers involved. Pain, temperature and crude touch is carried by small sized nerve fibers and hence neuropathy of the small sized sensory nerves is referred to as small fiber neuropathy. Vibration, position sense and joint sense are carried by larger diameter nerve fibers and hence neuropathy of larger diameter nerve fibers is referred to as large fiber neuropathy.

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