Quelle peut être la cause de vos fourmillements ?

What are pins and needles?

If you've woken up with a numb, tingling feeling down your arm or in your legs and feet, having lain on the couch for hours then you've experienced pins and needles - or paraesthesia, to give it its medical name.

While it can be annoying, it usually goes away after some light movement to get the blood flowing.

Qu'est-ce qui provoque les fourmillements ?

Dr Daniel Fenton, medical director, London Doctors Clinic, says: "Pins and needles are caused by many different reasons - it happens when your nerves send signals to the brain.

"Pins and needles are usually caused by pressure on a nerve due to sitting or lying awkwardly. They do not last for long and stop when pressure on the nerve is released by repositioning."

Pins and needles are down to the co-existence between nerves and blood vessels. These nerves, made up of living cells, are serviced by blood vessels - known as vasa nervorum - which bring oxygen and nutrients to them. By the same measure, nerves, which can change the diameter of vessels, are needed to make sure the right amount of blood reaches our organs.

So, when the nerves or blood vessels are compressed, it is more difficult to send impulses back to the central nervous system - the spinal cord and brain. The brain then interprets these abnormal signals as pins and needles.

De quoi les fourmillements peuvent-ils être le signe ?

Occasionally, pins and needles can be the symptom of something much more serious. Sudden trauma or long term injuries can also contribute towards nerve damage, as can conditions such as diabetes and alcohol misuse.

Fenton says: "If pins and needles happen more frequently, without a clear reason or with other symptoms, it can indicate other underlying conditions. A nerve can have pressure placed on it due to anatomical problems such as back problems or thickening of surrounding tissue."

Deficiencies

Imbalances or deficiencies in certain minerals and vitamins such as vitamin B12 can cause pins and needles as they can play important roles in maintaining the health of the nerves.

Autoimmune diseases

Fenton also says some autoimmune diseases - such as lupus, and rheumatoid arthritis - that can be responsible for neuropathy, can lead to the body’s normal defence systems incorrectly attacking its own cells, including nerves.

Back injuries

Pins and needles in part of your bottom, leg or foot can be a sign of pressure on a nerve, caused by a prolapsed or 'slipped' disc - the best known example is sciatica.

In rare cases, this can be accompanied by numbness in the area around your bottom, weakness in one or both legs and/or problems with bladder or bowel function. This complication, known as cauda equina syndrome, is a medical emergency.

Accident vasculaire cérébral

Pins and needles on one side are rarely the only sign of stroke, but it's important to be aware of the signs. These include weakness on one half of the face or body, difficulty speaking, or finding the right words - seek emergency help if you might be affected.

Affections neurologiques

Les fourmillements et les engourdissements dans différentes parties du corps sont également l'un des premiers symptômes les plus courants de la sclérose en plaques (SEP).

"Les maladies neurologiques telles que la sclérose en plaques, qui est une affection de la gaine des nerfs, peuvent provoquer des fourmillements inexpliqués", explique M. Fenton.

Carpel tunnel syndrome

Pins and needles are sometimes linked to carpal tunnel syndrome - when the median nerve is squeezed as it passes through the wrist, producing numbness and tingling.