Diabetic neuropathy is a specific lesion of the peripheral nervous system caused by dysmetabolic processes in diabetes mellitus. Disease is manifested by impaired sensitivity (paresthesia, numbness of the extremities), autonomic dysfunction (tachycardia, hypotension, dysphagia, diarrhea, anhidrosis), genitourinary disorders, etc. In diabetic neuropathy, the functioning of the endocrine, nervous, cardiac, digestive, and urinary systems is examined. Treatment includes insulin therapy, the use of neurotropic drugs, antioxidants, the appointment of symptomatic therapy, acupuncture.
Meaning
Diabetic neuropathy (DN) is one of the most frequent complications of diabetes mellitus, detected in 30-50% of patients. Pathology is spoken of in the presence of signs of peripheral nerve damage in persons with diabetes mellitus, excluding other causes of nervous system dysfunction. DN is characterized by impaired nerve conduction, sensitivity, disorders of the somatic and/or autonomic nervous system. Due to the multiplicity of clinical manifestations, DN has to be faced by specialists in the field of endocrinology, neurology, gastroenterology, podiatry.
Causes
Diabetic neuropathy refers to metabolic polyneuropathies. A special role in the pathogenesis of DN belongs to neurovascular factors – microangiopathies that disrupt the blood supply to the nerves. Multiple metabolic disorders developing against this background eventually lead to edema of the nervous tissue, disruption of metabolic processes in nerve fibers, disruption of nerve impulses, increased oxidative stress, the development of autoimmune complexes and, ultimately, to atrophy of nerve fibers.
Factors of increased risk of DN are:
- age;
- duration of diabetes;
- uncontrolled hyperglycemia;
- arterial hypertension;
- hyperlipidemia;
- fatness;
- smoking.
Classification
Depending on the topography, peripheral neuropathy is distinguished with the predominant involvement of spinal nerves in the pathological process and autonomous neuropathy – in violation of the innervation of internal organs. According to the post-syndrome classification of DN, there are:
I. Generalized symmetric polyneuropathy syndrome:
- With a predominant lesion of the sensory nerves (sensory neuropathy)
- With a predominant lesion of the motor nerves (motor neuropathy)
- With a combined lesion of the sensory and motor nerves (sensorimotor neuropathy)
- Hyperglycemic neuropathy.
II. Syndrome of autonomic (autonomic) DN:
- Cardiovascular
- Gastrointestinal
- Urogenital
- Respiratory
- Sudomotornaya
III. Syndrome of focal or multifocal DN:
- Cranial neuropathy
- Tunnel neuropathy
- Amyotrophy
- Radiculoneuropathy/plexopathy
- Chronic inflammatory demyelinating polyneuropathy (CIDP).
A number of authors distinguish central neuropathy and its following forms: diabetic encephalopathy (encephalomyelopathy), acute vascular brain disorders (stroke), acute mental disorders caused by decompensation of metabolism.
According to the clinical classification, taking into account the manifestations of DN, there are several stages of the process:
1. Subclinical neuropathy.
2. Clinical neuropathy:
- chronic pain form
- acute pain form
- pain-free form in combination with a decrease or complete loss of sensitivity
3. The stage of late complications (neuropathic deformity of the feet, diabetic foot, etc.).
Diabetic neuropathy symptoms
Peripheral polyneuropathy
Peripheral polyneuropathy is characterized by the development of a complex of motor and sensory disorders, which are most pronounced on the part of the extremities. Diabetic neuropathy is manifested by burning, numbness, tingling of the skin; pain in the toes and feet, fingers of the hands; short-term muscle cramps.
Insensitivity to temperature stimuli, hypersensitivity to touch, even to very light ones, may develop. These symptoms tend to worsen at night. Diabetic neuropathy is accompanied by muscle weakness, weakening or loss of reflexes, which leads to a change in gait and impaired coordination of movements. Debilitating pains and paresthesia lead to insomnia, loss of appetite, weight loss, depression of the mental state of patients – depression.
Late complications of peripheral diabetic neuropathy may be ulcerative defects of the foot, hammer-like deformity of the toes, collapse of the arch of the foot. Peripheral polyneuropathy quite often precedes the neuropathic form of diabetic foot syndrome.
Autonomous neuropathy
Autonomous DN can develop and proceed in the form of cardiovascular, gastrointestinal, urogenital, sudomotor, respiratory, etc. forms characterized by impaired functions of individual organs or entire systems.
The cardiovascular form of diabetic neuropathy can develop already in the first 3-5 years of the course of diabetes mellitus. It is manifested by tachycardia at rest, orthostatic hypotension, ECG changes (prolongation of the QT interval), an increased risk of pain-free myocardial ischemia and infarction.
The gastrointestinal form of DN is characterized by gustatory hypersalivation, esophageal dyskinesia, profound disorders of the motor evacuation function of the stomach (gastroparesis), the development of pathological gastro-esophageal reflux (dysphagia, heartburn, esophagitis). Patients with diabetes mellitus often have hypo-acid gastritis, gastric ulcer associated with Helicobacter pylori; the risk of gallbladder dyskinesia and gallstone disease is increased. Intestinal damage in diabetic neuropathy is accompanied by a violation of peristalsis with the development of dysbiosis, watery diarrhea, steatorrhea, constipation, fecal incontinence. On the part of the liver, fatty hepatosis is often detected.
In the urogenital form of autonomous diabetic neuropathy, the tone of the bladder and ureters is disturbed, which may be accompanied by a delay in urination or urinary incontinence. Patients with diabetes mellitus are prone to developing urinary infections (cystitis, pyelonephritis). Men may complain of erectile dysfunction, violation of testicular pain innervation; women – vaginal dryness, anorgasmia.
Sudomotor disorders in diabetic neuropathy are characterized by distal hypo– and anhidrosis (decreased sweating of the feet and palms) with the development of compensatory central hyperhidrosis, especially during meals and at night. The respiratory form of diabetic neuropathy occurs with episodes of apnea, hyperventilation of the lungs, and a decrease in surfactant production. Diabetic neuropathy often develops diplopia, symptomatic hemeralopia, thermoregulation disorders, asymptomatic hypoglycemia, “diabetic cachexia” – progressive exhaustion.
Diagnostics
The diagnostic algorithm depends on the form of diabetic neuropathy. At the initial consultation, anamnesis and complaints about changes from the cardiovascular, digestive, respiratory, genitourinary, and visual systems are carefully analyzed. In patients with diabetic neuropathy, it is necessary to determine the level of glucose, insulin, C-peptide, glycosylated hemoglobin in the blood; study of pulsation in peripheral arteries, measurement of blood pressure; examination of the lower extremities for deformities, fungal lesions, corns.
Depending on the manifestations in the diagnosis of diabetic neuropathy, in addition to the endocrinologist and diabetologist, other specialists may participate – cardiologist, gastroenterologist, neurologist, ophthalmologist, podologist. The primary examination of the cardiovascular system consists of ECG, cardiovascular tests (Valsalva test, orthostatic test, etc.), EchoCG; determination of cholesterol and lipoproteins.
Neurological examination for diabetic neuropathy includes electrophysiological studies: electromyography, electroneurography, evoked potentials. Reflexes and various types of sensory sensitivity are evaluated: tactile using a monofilament; vibrational – using a tuning fork; temperature – by touching a cold or warm object; pain – by tingling the skin with the blunt side of the needle; proprioceptive – using a stability test in the Romberg pose. Calf nerve biopsy and skin biopsy are resorted to in atypical forms of diabetic neuropathy.
Gastroenterological examination in diabetic neuropathy involves abdominal ultrasound, EGDS, stomach radiography, examination of the passage of barium through the small intestine, tests for helicobacter. In case of complaints from the urinary system, urinalysis is examined, ultrasound of the kidneys, bladder is performed (including ultrasound with the determination of residual urine), cystoscopy, intravenous urography, electromyography of the bladder muscles, etc.
Diabetic neuropathy treatment
Treatment of diabetic neuropathy is carried out consistently and in stages. Effective therapy of diabetic neuropathy is impossible without achieving compensation for diabetes mellitus. For this purpose, insulin or tablet antidiabetic drugs are prescribed, glucose levels are monitored. As part of an integrated approach to the treatment of diabetic neuropathy, it is necessary to develop an optimal diet and exercise regime, reduce excess body weight, maintain normal blood pressure levels.
During the main course, the intake of neurotropic vitamins (group B), antioxidants (alpha-lipoic acid, vitamin E), trace elements (Mg and Zn preparations) is indicated. With the painful form of diabetic neuropathy, it is advisable to prescribe analgesics, anticonvulsants.
Physiotherapeutic methods of treatment are useful: electrical stimulation of nerves, magnetotherapy, laser therapy, light therapy; acupuncture, physical therapy. With diabetic neuropathy, particularly careful foot care is necessary: wearing comfortable (according to indications – orthopedic) shoes; performing a medical pedicure, foot baths, moistening the feet, etc. Treatment of autonomous forms of diabetic neuropathy is carried out taking into account the developed syndrome.
Prognosis and prevention
Early detection of DN (both peripheral and autonomous) is the key to a favorable prognosis and improvement of the quality of life of patients. The initial stages of diabetic neuropathy can be reversible by achieving stable compensation for diabetes mellitus. Complicated diabetic neuropathy is a leading risk factor for pain-free myocardial infarctions, cardiac arrhythmias, non-traumatic amputations of the lower extremities.
In order to prevent DN, constant monitoring of blood sugar levels, timely correction of treatment, regular monitoring by a diabetologist and other specialists is necessary.