Polyneuropathy
Polyneuropathy (PNP) — multiple lesions of peripheral nerves, which are manifested by sluggish paralysis, vegetative-vascular and trophic disorders, sensitivity disorders. In the structure of diseases of the peripheral nervous system, polyneuropathy ranks second after vertebrogenic pathology. Nevertheless, according to the severity of clinical signs and consequences, polyneuropathy is one of the most serious neurological diseases.
The content of the article:
Classification of polyneuropathies
Etiology and pathogenesis of polyneuropathies
Clinical picture of polyneuropathy
Diagnosis of polyneuropathies
Treatment of polyneuropathies
Prognosis for polyneuropathy
Polyneuropathy
This pathology is considered an interdisciplinary problem, since it is faced by doctors of different specialties, but above all neurologists. The clinical picture of polyneuropathy is characterized by a decrease in tendon reflexes, muscle atrophy and weakness, sensitivity disorders. Treatment of the disease is symptomatic and is aimed at eliminating the factors that provoked it.
Classification of polyneuropathies
According to the prevailing clinical manifestations of polyneuropathy , they are divided into the following types:
sensitive (predominant symptoms of involvement of sensitive nerves in the process);
motor (predominance of symptoms of damage to motor fibers);
vegetative (symptoms are pronounced signs of involvement of autonomic nerves in the process, which ensure the normal functioning of internal organs);
mixed (symptoms of damage to all nerves).
Depending on the distribution of the lesion, distal limb lesion and multiple mononeuropathy are distinguished. By the nature of the course, polyneuropathy can be acute (symptoms appear within a couple of days), subacute (the clinical picture is formed for a couple of weeks), chronic (the symptoms of the disease bother from a couple of months to several years).
According to the pathogenetic sign, the diseases are divided into demyelinating (myelin pathology) and axonal (primary lesion of the axial cylinder). The following types of the disease are distinguished , depending on its etiology:
hereditary (Refsum’s disease, Dejerin-Sotta syndrome, Rousey-Levy syndrome);
autoimmune (axonal type of GBS, Miller-Flesher syndrome, paraneoplastic neuropathies, paraproteinemic polyneuropathies);
metabolic (uremic polyneuropathy, diabetic polyneuropathy, hepatic polyneuropathy);
alimentary;
infectious and toxic;
toxic.
Etiology and pathogenesis of polyneuropathies
Polyneuropathy is based on metabolic (dysmetabolic), mechanical, toxic and ischemic factors that provoke similar morphological changes in the myelin sheath, connective tissue interstitium and axial cylinder. If, in addition to peripheral nerves, spinal cord roots are also included in the pathological process, in this case the disease is called polyradiculoneuropathy.
Similar intoxications can provoke polyneuropathy: lead, thallium, mercury, arsenic and alcohol. Drug-induced polyneuropathies occur in the case of treatment with antibiotics, bismuth, emetine, gold salts, isoniazid, sulfonamides, meprobamate. The causes of polyneuropathies can be different:
diffuse pathologies of connective tissue;
cryoglobulinemia;
vitamin deficiency;
vasculitis;
viral and bacterial infections;
malignant neoplasms (lymphogranulomatosis, cancer, leukemia);
diseases of internal organs (kidneys, liver, pancreas);
diseases of the endocrine glands (hyper- and hypothyroidism, diabetes, hypercorticism);
genetic defects of enzymes (porphyria).
Polyneuropathy is characterized by two pathological processes — demyelination of the nerve fiber and axon damage. Axonal polyneuropathies arise due to problems with the transport function of the axial cylinder, which leads to a disorder of the normal functioning of muscle and nerve cells. Due to violations of the trophic function of the axon, denervation changes occur in the muscles.
The process of demyelination is characterized by a violation of the saltatory conduction of the nerve impulse. This pathology is manifested by muscle weakness and a decrease in tendon reflexes. Demyelination of nerves can be triggered by autoimmune aggression, which is accompanied by the formation of antibodies to peripheral myelin protein components, exposure to exotoxins, genetic disorders.
Clinical picture of polyneuropathy
The symptoms of polyneuropathy depend on the etiology of the disease. However, it is possible to distinguish common signs for all types of the disease. All etiological factors that provoke the disease irritate nerve fibers, after which there is a violation of the functions of these nerves. The most pronounced symptoms of irritation of nerve fibers are muscle cramps (cramps), tremor (trembling of limbs), fasciculations (involuntary contractions of muscle bundles), muscle pain, paresthesia (a feeling of crawling goosebumps on the skin), increased blood pressure, tachycardia (palpitations).
Signs of nerve dysfunction include:
muscle weakness in the legs or arms (first it develops in the muscles that are furthest from the head);
muscle atrophy (thinning);
decreased muscle tone;
hypesthesia (decreased skin sensitivity);
unsteadiness of gait while walking with eyes closed;
hypohidrosis (dry skin);
dizziness and flashing of flies before the eyes when trying to get up from a prone position, fixed pulse.
Autoimmune polyneuropathies
The acute inflammatory form of the disease occurs with a frequency of one or two cases per one hundred thousand people. It is diagnosed in men aged 20-24 and 70-74 years. It is characterized by the appearance of symmetrical weakness in the limbs. The typical course of the disease is characterized by painful sensations in the calf muscles and paresthesia (numbness and tingling sensation) in the fingers of the extremities, which are quickly replaced by sluggish paresis. In the proximal parts, hypotrophy and muscle weakness are observed, palpation reveals the soreness of nerve trunks.
The chronic form of pathology is accompanied by a slow (about two months) aggravation of motor and sensory disorders. This pathology often occurs in men (40-50 years old and over 70 years old). Its characteristic symptoms are muscle hypotension and hypotrophy in the arms and legs, hypo- or areflexia, paresthesia or numbness in the extremities. In a third of patients, the disease manifests with cramps in the calf muscles.
The vast majority of patients (about 80%) complain of vegetative and polyneuritic disorders. 20% of patients have signs of CNS damage — cerebellar, pseudobulbar, pyramidal symptoms. Sometimes the cranial nerves are also involved in the process. The chronic form of the disease has a severe course and is accompanied by serious complications, therefore, a year after its onset, half of the patients have partial or complete disability.
Inflammatory polyneuropathies
The diphtheria form of the disease is characterized by the early appearance of oculomotor disorders (mydriasis, ptosis, diplopia, limited mobility of the eyeballs, paralysis of accommodation, decreased pupillary reactions to light) and bulbar symptoms (dysphonia, dysphagia, dysarthria). One to two weeks after the onset of the disease, paresis of the extremities, predominant in the legs, becomes pronounced in its clinical picture. All these symptoms are often accompanied by manifestations of intoxication of the body.
HIV-associated polyneuropathy is accompanied by distal symmetrical weakness in all limbs. Its early symptoms are mild leg pain and numbness. In more than half of cases , the following symptoms are observed:
distal paresis in the lower extremities;
loss or decrease of achilles reflexes;
reduction of vibration, pain or temperature sensitivity.
All these symptoms appear against the background of other signs of HIV infection – fever, weight loss, lymphadenopathy.
Lyme-borrelious polyneuropathies are considered a neurological complication of the disease. Their clinical picture is represented by severe pain and paraesthesia of the extremities, which are then replaced by amyotrophy. The disease is characterized by a more severe lesion of the hands than the legs. In patients, deep reflexes may completely fall out on their hands, but achilles and knee reflexes are preserved at the same time.
Dysmetabolic polyneuropathies
It is diagnosed in 60-80% of patients who have diabetes mellitus. The early symptoms of this pathology are the development of paresthesia and dysesthesia in the distal extremities, as well as the loss of Achilles reflexes. If the disease progresses, patients begin to complain of severe leg pain, which increases at night, as well as a violation of temperature, vibration, tactile and pain sensitivity. Later, foot muscle weakness, trophic ulcers, finger deformities are added to the symptoms of the disease. This disease is characterized by vegetative disorders: cardiac arrhythmia, orthostatic hypotension, impotence, gastroparesis, sweating disorder, impaired pupillary reactions, diarrhea.
Alimentary polyneuropathy
Alimentary polyneuropathy is provoked by a lack of vitamins A, E, B. It is characterized by such manifestations as paresthesia, burning sensation, dysesthesia in the lower extremities. Achilles and knee reflexes decrease or completely fall out in patients, and amyotrophy appears in the distal parts of the arms and legs. The clinical picture of pathology also includes pathology of the heart, swelling on the legs, weight loss, orthostatic hypotension, anemia, stomatitis, cheillosis, diarrhea, dermatitis, corneal atrophy.
Alcoholic polyneuropathy
Alcoholic polyneuropathy is considered a variant of alimentary polyneuropathy. It is caused by a lack of vitamins PP, E, A and group B, which is provoked by the effect of ethanol on the body. This disease manifests itself with pain in the legs, dysesthesia, cramps. Patients have pronounced vegetative-trophic disorders: a change in skin tone, anhidrosis of the hands and feet. In the distal parts of the legs and arms, a symmetrical decrease in sensitivity is detected.
Polyneuropathies of critical conditions
Polyneuropathies of critical conditions occur due to severe injuries, infections or intoxication of the body. Such conditions are characterized by multiple organ failure. Pronounced signs of the disease are considered to be the early appearance of muscle weakness and contractures in the distal parts of the arms and legs, loss of deep reflexes, lack of independent breathing after the cessation of ventilation, which is not due to cardiovascular or pulmonary pathology.
Hereditary polyneuropathies
Polyneuropathy, which has a hereditary etiology, usually manifests itself in patients aged 10-16 years. This disease is characterized by the following triad of symptoms: violation of surface types of sensitivity, atrophy of the hands and feet, hypo- or areflexia. Patients also have deformity of the feet.
Diagnosis of polyneuropathies
Diagnosis of polyneuropathy begins with the collection of anamnesis of the disease and patient complaints. Namely, the doctor should ask the patient how long ago the first symptoms of the disease appeared, in particular muscle weakness, numbness of the skin and others, how often he drinks alcohol, whether his relatives were ill with this disease, whether he has diabetes. The doctor also asks the patient if his activity is related to the use of chemicals, especially heavy metal salts and gasoline.
At the next stage of diagnosis, a thorough neurological examination is carried out to detect signs of neurological pathology: muscle weakness, areas of numbness of the skin, violation of skin trophic. Blood tests are necessarily carried out to identify all kinds of toxins, determine protein products and glucose levels.
For an accurate diagnosis, a neurologist may additionally prescribe an electroneuromyography. This technique is necessary to identify signs of nerve damage and assess the speed of the pulse along the nerve fibers. A nerve biopsy is performed, which involves examining a piece of nerves that is taken from the patient with a special needle. Additionally, you may also need to consult an endocrinologist and a therapist.
Treatment of polyneuropathies
The tactics of treatment of polyneuropathy is chosen depending on its etiology. For the treatment of a hereditary disease, symptomatic therapy is chosen, aimed at eliminating the most pronounced signs of pathology that worsen the patient’s quality of life. The goal of the autoimmune form of polyneuropathy is to achieve remission. Treatment of alcoholic, diabetic and uremic polyneuropathies is reduced to slowing down the course of the disease and eliminating its symptoms.
An important place in the treatment of all types of polyneuropathy is occupied by physical therapy, which allows you to prevent the appearance of contractures and maintain muscle tone in normal. If the patient has respiratory disorders, he is shown a ventilator. Effective medical treatment of polyneuropathy, which would allow to get rid of it forever, does not exist today. Therefore, doctors prescribe supportive therapy aimed at reducing the severity of the symptoms of the disease.
Treatment of porphyritic polyneuropathy involves the appointment of glucose, symptomatic and painkillers to the patient.
For the treatment of chronic inflammatory demyelinating polyneuropathy, membrane plasmapheresis (a method of purifying the patient’s blood outside his body) is used. If this technique has proved ineffective, in this case the doctor prescribes glucocorticosteroids. After the start of therapy, the patient’s condition improves after 25-30 days. After two months of treatment, you can begin to reduce the dose of the drug.
In addition to the neurologist, an endocrinologist takes an important part in the treatment of diabetic polyneuropathy. The goal of treatment is to gradually reduce blood sugar levels. To eliminate the intense pain that the patient suffers from, drugs such as gabapentin, pregabalin, carbamazepine, lamotrigine are prescribed.
Therapy of uremic polyneuropathy involves correction of the level of uremic toxins in the blood due to kidney transplantation or programmed hemodialysis.
The success of the treatment of toxic polyneuropathy depends on how quickly the patient’s contact with the toxic substance is stopped. If the disease has become a consequence of taking medications, its treatment should begin with a reduction in their dosage. Timely administration of antitoxic serum will help prevent the aggravation of diphtheria polyneuropathy with a confirmed diagnosis of diphtheria.
Prognosis for polyneuropathy
Patients diagnosed with chronic inflammatory demyelinating polyneuropathy have a favorable prognosis for health. The mortality rate of patients with this diagnosis is very low. However, it is impossible to completely cure the pathology, so treatment involves the elimination of its symptoms. Immunosuppressive therapy allows to achieve remission of the disease in more than 90% of cases. However, it must be remembered that the disease polyneuropathy is accompanied by numerous complications.
Hereditary polyneuropathy progresses very slowly, so its treatment is difficult, and the prognosis for patients is unfavorable. Nevertheless, many patients manage to adapt and learn to live with their diseases. A favorable prognosis for diabetic polyneuropathy is possible only if it is treated in a timely manner. Usually doctors manage to normalize the patient’s condition. Only in the later stages of polyneuropathy, the patient may complain of severe pain syndrome. The prognosis for the life of a patient with uremic polyneuropathy depends on the severity of chronic renal failure.
