Paresthesias of the lower extremities are one of the variants of a sensitivity disorder. This condition is characterized by sensations of tingling, crawling ants, numbness. Passing paresthesia of the extremities, as a rule, is caused by a direct mechanical type of irritation of the nerve, which lies superficially. This irritation includes shock or pressure. In addition, paresthesia of the lower extremities may occur due to temporary disturbances in the blood supply. This, in turn, provokes a change in the conduct of nerve impulses. Such conditions often occur during sleep and when in an uncomfortable position.
Chronic paresthesia of the lower extremities are often symptoms of lesions in various areas of the nervous system. These include disorders of the primary type: tumor and infectious lesions, autoimmune and neurodegenerative processes, and others. Conditions can also occur against the background of secondary lesions and are complications of existing diseases. So, paresthesias of the lower extremities are observed with alcoholic polyneuropathy, a deficiency of certain vitamins, metabolic disorders (with diabetes, for example), atherosclerosis.
One of the known forms of the condition is considered to be a numbness of the tongue, lip, or chin that persists for a long time.
The defeat of bundles of nerve fibers occurs with radiculitis. This disease is among the most common lesions of the nervous peripheral system. Damage to the spinal roots in radiculitis is a consequence of a spinal disease (osteochondrosis). In this case, there is a decrease in the elasticity of the intervertebral cartilaginous discs, resulting in compression of the roots. As a result, there are sensations of numbness, pain.
Paresthesia may relate to the structure of vegetative-vascular paroxysm. As a rule, it occurs in the form of headache or heartache, facial flushing, palpitations. At the same time, blood pressure and temperature increase, the pulse quickens, chills begin. In some cases, the patient experiences causeless fear. Others are characterized by general weakness, darkening in the eyes, nausea, dizziness, sweating, and a decrease in blood pressure and heart rate. Attacks can last from a few minutes to three hours. In many cases, they go away without therapy.
An exacerbation of vegetative-vascular dystonia is accompanied by cooling of the extremities. They also become moist and purplish-cyanotic. Paresthesias in the hands are manifested by numbness in the fingers, a feeling of crawling ants, tingling. In some cases, the patient feels pain. At the same time, sensitivity to the effects of cold is significantly increased, the limbs look very pale. After an attack, the patient may experience general malaise and a feeling of weakness for several days.
Long-term paresthesia can be caused by ischemic lesion in the cortical representation of sensitivity or thalamocortical afferent pathways. Numbness of the extremities can develop both against the background of transistor ischemic attacks, and during associated migraine.
Paresthesia may not have clear boundaries and have a burning character. In most cases, such conditions arise due to focal lesions of the spinothalamic pathways or thalamus. Paresthesias of the angle of the mouth and hand, which arise as a result of damage to the parietal lobe or thalamus, are considered characteristic. In addition, conditions can develop acutely against the background of hemorrhage in areas of the medial loop.
The main diagnostic symptom includes antigiokeratomas in the navel, pubis and knees from dark red to brown in color with a bluish tint.