The hand that tingles at night: why it is better not to wait

The symptom that brings almost every patient in is the same: tingling in the hand that wakes them at night, above all in the thumb, index and middle fingers, forcing them to shake the hand or hang it out of the bed for relief.

It is one of the commonest consultations in hand surgery. And also one of the latest to arrive, which is the problem.

Why at night

The carpal tunnel is a narrow canal in the wrist through which the median nerve passes. When it is compressed, tingling and numbness appear and, as it progresses, loss of strength.

It is worse at night for two reasons: we sleep with the wrist bent without realising, which narrows the canal, and fluid redistributes when lying down, raising the pressure inside the tunnel. That is why it wakes you in the early hours and improves when you shake the hand, which is what moves that fluid again.

The sign that marks the line

In time come clumsiness with fine tasks — doing up a button, holding a cup, writing — and objects dropping from the hand. But the point that really divides the outlook is another: wasting of the muscle at the base of the thumb.

Compare your two open hands, looking at the fleshy mound at the base of the thumb on the palm side. If one is visibly flatter than the other, the nerve has been compressed for a long time.

While the symptoms are nocturnal and intermittent, the nerve is irritated but intact, and surgery restores function almost completely. Once there is wasting, the operation halts the progression and relieves the pain, but strength and sensation no longer return fully.

That sentence is the whole reason for this. You do not operate because it bothers you a lot: you operate before the damage is structural.

What can be tried first

In mild, recent cases there is room without surgery:

• A night splint keeping the wrist straight while you sleep. It is the most effective conservative measure of all and the easiest to abandon.
• Adjusting the activities that provoke it: vibration, repeated force, sustained flexion.
• Controlling what is associated: hypothyroidism, diabetes, rheumatoid arthritis. Pregnancy also causes it, and there it usually resolves after the birth.
• A corticosteroid injection inside the tunnel. It relieves temporarily and has diagnostic value, but it does not resolve the underlying problem.

If the symptoms persist despite that, or if there is already constant numbness or loss of strength, conservative treatment is not going to resolve it.

The surgery is small

The ligament forming the roof of the tunnel is divided and the nerve stops being compressed. Twenty to forty minutes, as a day case, under local anaesthesia. You walk out with your hand free, no splint, and move your fingers from the first day.

The night-time tingling disappears in the first days in most cases: it is the most immediate relief this surgery gives. Stitches come out at ten to twelve days. Grip strength returns between six and twelve weeks, and sensation can keep improving for months if the compression was long-standing.

What defines success is not the size of the wound but that the division is complete: an incomplete release leaves symptoms and means reoperating, and it is the commonest cause of failure.

What to know about the recovery

For weeks or months it is uncomfortable to press on the base of the palm. It is frequent, it is temporary and it does not indicate a problem. It is what limits you most at manual work: office work, one to two weeks; heavy work or tools, four to eight.