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Pins and needles  
 'Pins and needles' (paraesthesia) is a sensation of uncomfortable
tingling or prickling, usually felt in the hands or feet. The affected area
is sometimes said to have 'fallen asleep'. A common cause is leaning or
lying awkwardly on a limb, which either presses against the nerves or
reduces the blood supply to the local area. Changing position quickly
restores normal feeling. Any numbness is soon replaced by the tingling and
prickling sensation, as the nerves start sending messages again to the
brain and spinal cord. In some cases, pins and needles are caused by nerve
damage or certain disorders of the central nervous system. Always see your
doctor if you experience frequent or persistent bouts of pins and needles.

Symptoms
The symptoms of pins and needles include:

Hands and feet are usually affected
Initial numbness and heaviness
Prickling and tingling sensation on the skin
Return of normal feeling a few minutes after changing position.
A range of causes
Pins and needles can be caused by a wide range of events and conditions,
including:
Pressure on nerves
Reduced blood supply
Nerve injury
Hyperventilation or breathing excessively
The effect of toxic substances on the nerves, such as alcohol or lead
Certain medications
Diabetes
Multiple sclerosis
Hypothyroidism (underactive thyroid gland)
Transient Ischaemic Attack (TIA)
Stroke.
Pressure-related pins and needles
The peripheral nerves of the body send information back to the brain and
spinal cord. When a sensory nerve is pressed by a cramped or awkward
position, its functioning starts to falter. In time, the affected limb
'falls asleep', which means the sensory messages are blocked. Once pressure
is taken off the nerve, functioning resumes. The uncomfortable prickling
sensation is caused by the resumption of pain messages from nerves to the
brain. Other nerves, such as those that provide information on temperature,
take a little longer to recover.

Pinched nerve
Nerves can be pinched by bones and other tissue. Some examples include:
Carpal tunnel syndrome - the main nerve that services the hand runs through
a ring of wrist bones. Inflamed and swollen tendon membranes reduce the
amount of room inside the wrist and squash the nerve. Symptoms include pins
and needles, pain and weakness.
Cervical nerve root irritation - nerves in the neck exit the spinal cord
via small holes between the vertebrae. These small holes can be narrowed by
inflammation, trauma or outgrowths of bone tissue (bone spurs). The nerves
are compressed, causing pins and needles and, sometimes, referred pain into
the arms.
Sciatica - the legs and feet are serviced by the sciatic nerve, which
starts as four nerve roots between the vertebrae of the lower back. Each
vertebra is cushioned by discs of cartilage. A prolapsed or 'slipped' disc
bulges out and presses against one of the roots of the sciatic nerve,
causing pins and needles and referred pain down the leg.
Neuritis
Neuritis is inflammation of the nerves. Some of the causes include:
Alcohol - chronic overconsumption of alcohol can be toxic to nerves and
cause a condition called peripheral neuropathy, characterised by pins and
needles.
Guillain-Barre syndrome - thought to be triggered by some kinds of viral
infection.
Pernicious anaemia - causes a vitamin B12 deficiency that affects the
functioning of the spinal cord.
Nerve disease
Nerve disease, or neuropathy, is characterised by the lack of sensory
information to the brain due to damage of the sensory nerves. For example,
a person with neuropathy may not experience pain to the normal degree, if
at all. Conditions that may damage the sensory nerves include:
Severed spinal cord
Diabetes
Charcot-Marie-Tooth inherited neuropathy
Exposure to certain drugs and heavy metals, such as lead
Chronic overconsumption of alcohol.
Seek medical advice
The occasional bout of pins and needles is a harmless event. However,
chronic pins and needles can be symptomatic of some other underlying
disorder. Always see your doctor for a thorough medical investigation if
you experience persistent or frequent episodes of numbness or pins and
needles.

Treatment options
Treatment depends on the cause. For example, carpal tunnel syndrome may be
treated with rest, splinting and medications such as anti-inflammatory and
diuretic drugs. A nerve pinched by bone or some other tissue may need
chiropractic or physiotherapy, or perhaps surgery to ease the pressure and
allow full nerve functioning to resume. Underlying conditions such as
diabetes need to be properly controlled to ease associated symptoms,
including pins and needles. The symptoms of nerve inflammation and damage
caused by chronic overconsumption of alcohol generally improve once the
person stops drinking.

Where to get help
Your doctor.
Things to remember
'Pins and needles' is a sensation of uncomfortable tingling or prickling,
usually felt in the hands or feet.
A common cause is leaning awkwardly on a limb, which presses against the
nerves.
Persistent pins and needles may be symptomatic of more serious conditions,
such as nerve disease or nerve inflammation.
Always see your doctor if you experience persistent or frequent episodes of
pins and needles