Paresthesia is the sensation of tingling and numbness in the extremities, often accompanied by a temporary loss of sensation. This phenomenon occurs when compression or irritation of a nerve interferes with its ability to transmit signals to the brain.
“When, for example, we cross our legs for a long time, we are compressing the nerves and they stop properly transmitting signals; if blood flow decreases, it makes the nerve work worse; when nerve signals are altered, the information received by the brain is distorted and causes tingling, numbness or strange sensations such as loss of sensitivity,” he explained to EFE Health Carlos Bastida, head of the Locomotor System group of the Spanish Society of General and Family Physicians (SEMG).
Common causes of paresthesia
Maintaining forced positions, such as crossing your legs, can compress nerves and blood vessels, affecting blood flow and causing a tingling sensation.
Bastida points out that, when the nerve recovers blood flow, there is a sudden neuronal reactivation, which sends “thousands of diverse signals” to the brain at the same time: heat, touch and pressure. Then, the brain does not know how to interpret them and translates the message as punctures, electric currents or tingling. “As the nerve stabilizes, the tingling disappears and full and normal sensitivity is recovered,” he says.
In extreme cases, such as “Saturday night palsy,” compression of a radial nerve can result in temporary weakness in the affected extremity. The permanence of the compression can also cause actual damage to the nerve.
Prevention and practical advice
It is advisable to change your position every half hour to avoid nerve compression and maintain good blood circulation.
It is advisable to maintain good posture both when sleeping and when sitting, to reduce the risk of experiencing the sensation of a numb limb.
Specifically, there are certain warning signs that we must take into account:
- If the joint is asleep, we change posture, but after a few minutes we do not recover mobility in model.
- If we notice loss of strength in the limb.
- When the area is cold or changes color – pale or bluish.
- If the tingling does not go away and lasts for several hours or days.
Certain signs that indicate the need for medical evaluation should be taken into account, such as persistent tingling, loss of strength in the limb or changes in skin color. It is important to seek care if symptoms are recurrent or prolonged, as they may be indicative of more serious problems.
Underlying conditions causing chronic paresthesia
Chronic paresthesia is usually a symptom of a disease or damage to the nervous system, rather than an isolated problem. Below are the most common medical conditions that can cause it chronically, grouped by categories.
Neurological diseases of the CNS
- Multiple sclerosis: inflammation and demyelination of nerve fibers in the brain and spinal cord often cause paresthesias in the arms, legs or trunk.
- Stroke and cerebrovascular accidents: injury to sensitive areas of the brain can produce persistent tingling, often on only one side of the body.
- Encephalitis, transverse myelitis, aneurysms or brain tumors: these conditions compress or inflame the CNS and may be associated with localized paresthesias.
Neuropathies and radiculopathies
- Peripheral neuropathy (especially diabetic): Type 1 and 2 diabetes progressively damages peripheral nerves, causing tingling in the feet and hands (“gloves and socks”).
- Radiculopathy (due to herniated disc, canal stenosis, and so on.): compression of nerve roots in the spine (cervical or lumbar) causes paresthesia in the arms or legs, depending on the level affected.
- Carpal tunnel syndrome and other nerve compressions: Entrapped nerves in the wrists, elbows or ankles can cause chronic tingling in the hands or feet.
Autoimmune and systemic diseases
- Rheumatoid arthritis and systemic lupus erythematosus: they can inflame joints and peripheral nerves, promoting paresthesia.
- Endocrine-metabolic diseases: hypothyroidism, poorly controlled diabetes, and chronic kidney or liver disorders can damage nerve fibers.
- Fibromyalgia and some connective tissue diseases are also associated with diffuse or localized paresthesias.
Infections, vitamin deficiencies and toxins
- Infections: HIV, Lyme disease, shingles and others can cause chronic neuropathy with tingling.
- Vitamin deficiency: lack of B1, B6, B12, folate or vitamin E is related to sensory neuropathy and paresthesias.
- Toxic: chronic alcohol, chemotherapy, heavy metals or certain medications can damage nerves reversibly or permanently.
Other common causes
- Toxic habits and malnutrition: chronic alcohol abuse, diets poor in micronutrients and smoking increase the risk of peripheral neuropathy.
- Injuries from repeated movements or trauma: prolonged nerve compression (due to work, sports or surgery) can leave chronic paresthesias.
If you have chronic paresthesia, a neurological evaluation (clinical history, physical examination, analysis and, if necessary, neuroimaging or neuroconduction studies) is advisable to identify the underlying cause and treat it specifically.
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