The unpleasant sensation of numbness, tingling, burning, stinging or coldness of the skin, which is more common in the extremities, is called paresthesia or numbness of the feet or hands.
Leg numbness – neurological causes
Vitamin E, B1, B6, B12 and niacin deficiency
Some viral and bacterial infections
Leg numbness – orthopaedic causes
Foot numbness – endocrine causes
Causes of numbness in feet
Among the causes frequently involved in numbness of the feet are:
- Vicious postures – the main cause favoring the development of lower limb numbness is the adoption of vicious postures during the night or during daily activities, which involve prolonged sedentary sitting in the “leg over leg” position or with a pelvic limb flexed under the seat. Postural defects cause compression of the various nerve roots serving the lower limbs and promote the development of temporary, benign numbness, which remits spontaneously without treatment.
- Inadequate footwear and “leg over leg” position – in the case of the lower limbs, paresthesia is more frequently seen on the lateral aspect of the calf, caused by temporary compression of the fibular nerve when adopting the leg over leg position. Wearing inappropriate footwear that constricts and limits the movement of the foot or high heels is another cause of pelvic limb paresthesia.
- Medical treatments – certain therapies involving chemotherapy, tuberculostatic, antiepileptics or antibiotics may have as an adverse effect in some patients, the appearance of paresthesia in the upper and lower limbs.
- Chronic diseases – in certain situations, however, numbness in the legs may be a secondary manifestation of a chronically progressive disease such as diabetic neuropathy or may be due to lumbar disc disease which compresses certain nerve roots with emergence at this level.
- Neuronal lesions – neuronal lesions caused by trauma or repetitive stress or viral and bacterial infections are other causes of lower limb paresthesia.
Leg numbness – neurological causes
Lower limb stiffness due to diabetic causes is called diabetic neuropathy and is a peripheral nerve dysfunction generated by hyperglycemic values that occur in patients with uncontrolled diabetes. Diabetic neuropathy is the most common complication of diabetes mellitus, being a pathology with irreversible evolution and a major impact on the patient’s quality of life.
Peripheral nerve damage occurs after prolonged exposure (years) to elevated blood glucose levels, and the symptoms of paresthesia may occur late in the course of the disease, at intervals ranging from a few years to 20 years.
The risk factors involved in the acceleration of pathological processes that eventually lead to lower limb paresthesia in chronic diabetics are:
- Obesity
- Hypertension
- Hypercholesterolemia
- Diabetic nephropathy
- Smoking
- Excessive alcohol consumption.
The pathological processes that lead to nerve damage in chronic diabetics are varied and include, besides the direct harmful action of glucose and its metabolites on nerve pathways, secondary vascular damage, with the appearance of neuronal metabolic imbalances.
Lower limb paresthesia due to diabetes gradually sets in as the disease progresses, is accompanied by altered integumentary perception of hot/cold, decreased muscle strength, difficulty maintaining postural balance and, finally, integumentary trophic changes represented by soft tissue ulcerations and infections with necrosis and risk of sepsis.
Vitamin E, B1, B6, B12 and niacin deficiency
Vitamin E, B1, B6, B12 and niacin deficiency is another cause of numbness of the feet and hands, along with sensory disturbances and difficulty concentrating.
B-complex vitamins are essential exogenous nutrients (cannot be synthesized by the body) that support the proper functioning of the nervous system by ensuring myelin synthesis.
Vitamin E is another exogenous compound that protects the nervous system from the damaging action of free radicals due to its powerful antioxidant role.
Alcoholic polyneuropathy
Alcoholic polyneuropathy is a neurological disorder that involves damage to peripheral nerves through chronic and increased consumption of alcohol, together with nutritional deficiency. In most cases, alcoholism is accompanied by severe eating disorders that result in poor nutritional status through insufficient nutrient intake.
Alcohol abuse affects the gastrointestinal mucosa and reduces the absorption of food-derived vitamins, accentuating nutritional deficiencies that lead to polyneuropathy manifested by numbness in the pelvic limbs.
The deficient nutritional status of alcoholics deprives the body of cofactors necessary for optimal glucose metabolism and energy production. The energy deficit is also felt at the neuronal level, through the appearance of demyelination of peripheral nerves, which causes damage to nerve cells and the appearance of paresthesia of the lower limbs.
The neurological symptoms of alcoholic polyneuropathy include, in addition to numbness of the legs, pain and motor weakness with a tendency to progress centrally. Alcoholic paresthesia manifests symmetrically in both lower limbs and includes numbness and heat intolerance.
Guillain Barre Syndrome
Guillain-Barre Syndrome is an autoimmune inflammatory disease of the peripheral nervous system that evolves with paresthesia, rapid onset muscle weakness and paralysis of the lower and upper limbs.
The risk factors involved in the development of Guillain-Barre syndrome are multiple, but viral and bacterial infections are the most common causes that induce the development of this autoimmune pathology.
Restless legs syndrome
Restless legs syndrome (Willis Ekbom disease) is a sensorimotor neurological disorder that alters the quality of life of the patient through fatigue caused by sleep disturbances.
Clinically, restless legs syndrome is manifested by an imperative need to move the legs and a feeling of discomfort in the lower limbs represented by paresthesia (tingling, burning, stinging, restlessness), temporarily improved by movement, with exacerbation during night rest.
Some viral and bacterial infections
Viral infections with Epstein Barr, Herpes simplex, HIV-AIDS, Cytomegalovirus or bacterial infections may cause encephalitis in some patients, favoring the appearance of numbness in the lower and/or upper limbs.
Leg numbness – orthopedic causes
Leg numbness can be caused by some orthopedic conditions such as lumbar hernia, paresthesia, peroneal nerve palsy,
Lumbar herniation is a debilitating condition that is due to compression of a vertebral ligament by a herniated disc and damage to the nearby nerve root. Lumbar disc disease frequently occurs between L4-L5 and L5-S1, causing pain of varying intensity along the pelvic limb, distal paresthesia and functional impotence.
Fibular nerve palsy is the most common peripheral nerve disorder of the lower limb causing paresthesia. The peroneal nerve can be injured by compression from bone tumors or schwannomas, ganglion cysts or lipomas, incarceration, ischemia or direct trauma, prolonged wearing of a plaster cast, by adoption of vicious positions or dislocation of the patella. Risk factors predisposing to fibular nerve trauma and lower limb numbness are poor nutritional status, alcoholic liver disease and asthenic conformation.
Foot numbness – endocrine causes
Primary hyperaldosteronism or Conn’s disease is an endocrine dysfunction caused by hypersecretion of aldosterone in the adrenal glands. Aldosterone is involved in maintaining the body’s water and electrolyte balance by retaining sodium and water at the expense of potassium and magnesium. Along with temporary paresthesia in the limbs, Conn’s disease evolves with neuromuscular excitability, cramps, and muscle weakness due to hypotassemia and hypomagnesaemia.
Peripheral arterial disease
Peripheral arterial disease or peripheral arteriopathy obliterans a pathology whose manifestations are caused by the reduction of blood volume in the tissues of the lower limbs. The most common cause of peripheral arterial disease is atherosclerosis, with the formation of endovascular atheromas leading to ischemia of the pelvic limbs.
The main manifestations of peripheral arterial disease include pain at rest in the lower limbs, coldness and numbness in the feet and toes, decreased muscle strength, decreased functionality and decreased ability to maintain postural balance.
If you are experiencing distressing symptoms, see your doctor for a specialist consultation.
Prevention and monitoring of medical conditions reduce the risk of complications and aggressive treatment of the body.
References:
- Alcoholic polyneuropathy, Robert W. Shields – https://onlinelibrary.wiley.com/doi/abs/10.1002/mus.880080302
- Deficiency of Vitamin B-Complex and Its Relation with Body Disorders, Muhammad Farhan Sarwar, Muhammad Haroon Sarwar – https://www.google.co.uk/books/edition/Deficiency_of_Vitamin_B_Complex_and_Its/OeMd0AEACAAJ?hl=ro
- Peripheral arterial disease, Kenneth Ouriel – https://www.sciencedirect.com/science/article/abs/pii/S0140673601063516
- Restless legs syndrome, K. Ekbom, J. Ulfberg, Journal of Internal Medicine – https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2796.2009.02159.x
