What is diabetic polyneuropathy?

Diabetic polyneuropathy (DPN) is a complication of diabetes mellitus characterized by progressive death of nerve fibers, which leads to loss of nerves, increased sensitivity, and the development of foot ulcers. Diabetes mellitus (DM) is one of the leading non-communicable diseases of mankind. According to the World Health Organization, more than 422 million people (1-4% of the population) suffer from diabetes mellitus worldwide, and 7-10% at the age of 65 and older. Risk factors for development are obesity, low physical activity, hyperlipidemia (abnormally elevated lipid levels), arterial hypertension, impaired glucose tolerance, heredity for diabetes mellitus, gestational diabetes in history.

Elevated blood sugar levels cause damage to the peripheral nervous system, which manifests itself in the development of diabetic neuropathy. The initial damage is mainly the long nerve fibers that provide innervation (connection with the central nervous system) of the distal parts of the lower extremities since they are especially sensitive. This explains the clinical picture of the predominant lesion of the feet. 

Symptoms of diabetic polyneuropathy

In the early stages of DPN, patients may complain of numbness, tingling, paresthesia, burning, cutting pains in the legs, which intensify in the afternoon and often cause sleep disturbances.

In the later stages of the disease, thin nerve fibers are involved in the pathological process, which is manifested by the occurrence of hyperalgesia or allodynia. Hyperalgesia is characterized by increased sensitivity to pain from stimuli that, in a healthy person, cause a slight pain reaction (for example, a blunt needle prick). Allodynia – the appearance of pain in response to irritation, which is not normally accompanied by them (touching a blanket, a piece of cotton wool, a brush).

Movement disorders. Over time, as diabetic polyneuropathy progresses, appear movement disorders such as muscle weakness and atrophy. In some patients in later stages, the characteristic symptom is extensor paralysis of the foot, as a result of which they cannot stand on the heels. When walking, a pathological gait is revealed – steppage. The speed and likelihood of the development of motor symptoms depend on many factors: both on glycemic control and on concomitant pathologies. 

Chronic diabetic polyneuropathy is characterized by an irreversible progressive course, and acute polyneuropathy is a reversible condition in which the pain syndrome stops over time.

Diagnostics of the diabetic polyneuropathy

In the diagnosis of diabetic polyneuropathy, its early detection is important. In the future, this will improve the quality of life of patients and prevent early disability. Diagnosis in DPN consists of taking anamnesis, high-quality clinical examination, and the use of modern instrumental examination methods.

Despite the wide possibility and availability of neurophysiological examination methods, special attention is paid to clinical examination. Do not forget that the absence of symptoms does not mean the absence of neuropathy – often DPN may be asymptomatic in the early stages. An important role at the preclinical or early clinical stages is played by specific, screening tests that exist to detect early manifestations of diabetic polyneuropathy:

• Study of vibration sensitivity using a graduated tuning fork at 128 Hz, which is applied to the bony part of the distal phalanx of the big toe and the inner ankle.
• Tactile sensitivity studies using monofilament. To perform the test, place the instruments perpendicular to the surface to be examined (the area of the back of the toes, the area of the inner ankles, shins, knees). When touching the skin, the working monofilament should normally bend, which indicates a reaction. Lack of response indicates decreased sensitivity.
• Using scales to determine polyneuropathy. There are special scales for assessing the strength of the muscles of the feet, the Achilles reflex and pain assessment – NISS-LL (neuropathy impairment score in the lower limbs) and for determining the degree of pain, numbness and paresthesia – TSS (assessment of general symptoms). 

Treatment of diabetic polyneuropathy

It should be noted that for the successful treatment of polyneuropathy, it is very important to maintain blood sugar at a normal level, although this does not guarantee that the disease will not develop, since there are other risk factors: age, smoking, alcohol, obesity, duration of the disease.

With diabetic polyneuropathy, it is very important to regularly examine the feet and prevent possible damage to the skin of the feet. To do this, you must wear only comfortable shoes, do not walk barefoot on the floor, and if skin lesions (even calluses) appear, consult a doctor or take medications that he prescribed in case of damage, injury, or cuts. Dry skin of the limbs must be treated with special creams.

At the first symptoms of polyneuropathy, you should consult a doctor for a comprehensive examination. You should know that damaged nerve fibers cannot be repaired, therefore it is very important to diagnose and begin treatment in a timely manner. As for drug treatment methods, complexes of B vitamins, thioctic acid, antihypoxic drugs are now actively used. Physiotherapy procedures are widely used. All these drugs and procedures should be prescribed only by an experienced doctor. 

Forecast. Prevention of  diabetic polyneuropathy

Acute polyneuropathy is a reversible condition. In chronic diabetic polyneuropathy, degenerative changes cannot be restored. The goal of treatment, in this case, is to improve the quality of life and prevent complications. In the process of the development of diseases, the patient loses the ability to work.

The basis for the prevention of DPN is early detection and correction of diabetes mellitus with glycemic control, especially for insulin-independent type 2 diabetes mellitus. If the patient already has clinical manifestations of diabetic polyneuropathy, it is necessary to take measures to prevent complications and disability, which imply the following:

• correction of glycemic levels;
• correction of concomitant diseases (especially arterial hypertension and hypercholesterolemia);
• weight loss;
• rejection of bad habits;
• adequate physical activity.

Prevention of diabetic foot and purulent-necrotic complications of diabetes includes mandatory thorough care of the skin of the feet, correct selection of shoes, and regular examination of the feet for the appearance of abrasions or swelling.