Carpal tunnel syndrome: Much still unknown about the common condition

Lars Dahlin, consultant at Skåne University Hospital, has researched carpal tunnel syndrome.

Over half a million Swedes suffer from nerve compression in the wrist – known as carpal tunnel syndrome – a condition that causes significant pain and can negatively impact quality of life. Lars Dahlin, consultant in hand surgery at Skåne University Hospital and professor at Lund University, has now compiled all available research on the subject for the international journal Nature Reviews Disease Primers.

"Despite intensive research in the field, we do not always know why people are affected. I have treated patients and conducted research in this area for several decades, but I realise that there is still much to learn," says Lars Dahlin.

He, along with specialist doctor Malin Zimmerman at Helsingborg Hospital and four international colleagues, has compiled the latest research for the journal Nature Reviews Disease Primers to spread knowledge about a condition affecting about five percent of people in the Western world.

Carpal tunnel syndrome | Nature Reviews Disease Primers

Multiple causes

Carpal tunnel syndrome is considered a common condition and causes a reduced quality of life. The condition primarily affects middle-aged women, while men tend to develop problems later in life. Particularly at risk are people with diabetes and rheumatoid arthritis, as well as women in late pregnancy. Pregnant women often recover from their nerve compression after giving birth, but some may need medical assistance.

The most common symptoms are numbness, tingling, and weakness in the hand and fingers, as well as pain.

In the review article in Nature Reviews Disease Primers, Lars Dahlin describes several underlying causes of the condition: overuse of the wrist at work, genetic explanations, or early symptoms of diabetes and heart problems. Research also shows that carpal tunnel syndrome can be an early indicator of other diseases.

Signs of heart failure

Lars Dahlin also highlights that carpal tunnel syndrome, especially in both hands, can be an early sign of a rare and difficult-to-treat type of heart failure known as cardiac amyloidosis, where a build-up of proteins negatively affects the heart muscle.

"This is an interesting area where hand surgeons and cardiologists are working together to explore the connection. By carefully testing people with nerve compressions in both hands, healthcare can treat and prevent heart failure early," says Lars Dahlin.

Research also shows that carpal tunnel syndrome can be caused by changes in the body’s blood lipids.

Lack of guidelines

In his compilation, Lars Dahlin has noted that there are no international guidelines for treatment, despite it being a common condition. Mild symptoms may resolve on their own, with a support splint or with corticosteroid injections. More severe cases require surgery.

"Abroad, a neurophysiological exam is usually done before surgery; this is less common in Sweden, where diagnosis is based on medical history and clinical exams. There are also few scientific studies showing which surgical method is best," says Lars Dahlin.

Future research

He hopes that future research will more clearly establish the risks and factors that affect the treatment outcome for nerve compression in the wrist.

"We need to identify and treat people at risk early. We also need to understand the link between carpal tunnel syndrome and factors like high blood lipid levels better."

In short: carpal tunnel syndrome

Caused by the compression of the median nerve in the wrist, where nerve fibres to the thumb and fingers are crowded with nine flexor tendons in the narrow carpal tunnel, the roof of which is formed by a ligament.