What is a carpal tunnel syndrome?
The carpal tunnel is the name given to an anatomical space situated at the wrist which holds a bundle of tendons, blood vessels and the median nerve. Carpal tunnel syndrome refers to a condition whereby the pressure within the carpal tunnel increases and irritates or compresses the median nerve. This results in tingling and numbness in the hand, in the area supplied by the median nerve, as shown in the diagram.
There are various causes of carpal tunnel syndrome including:
- Degenerative or injury related changes to the wrist joint
- Systemic conditions causing inflammatory changes at the wrist joint including rheumatoid arthritis and certain metabolic disorders
- Workplace factors including using display screen equipment or manual work involving sustained pressure on the wrist and palm
The most common symptoms are tingling and numbness in the palm of the hand involving the thumb, index, middle and adjacent half of the neighbouring ring finger. Commonly initial symptoms are mild and intermittent with tingling after repetitive activities or when the wrist is flexed (bent forward in the same direction of the palm). It is common to experience symptoms at night and classically patients will shake their hand (‘a positive flick sign’) or drop the hand over the edge of the bed to obtain relief. Fortunately, in 30% of cases symptoms will resolve with no treatment. However, if symptoms do not settle they may progress and result in weakness of function or wasting of muscle strength around the thumb.
How is carpal tunnel syndrome diagnosed?
Carpal tunnel syndrome can often be reliably diagnosed by your doctor or physiotherapist by taking a history of your condition and by conducting a physical examination. The main feature on examination is often a reproduction of symptoms when holding the wrist in sustained flexion by moving the palm of the hand towards the wrist or when tapping or pressing over the median nerve in the carpal tunnel.
X-rays and scans are not routinely required but if surgery is being considered nerve conduction studies may be requested to confirm the severity of median nerve compression.
How is carpal tunnel syndrome treated?
Many patients wish to know what they can do themselves to prevent or treat CTS. Unfortunately ,the options are rather limited but it is possible to make a few suggestions.
- Relative rest and change in aggravating activities – if you find that a particular activity reliably aggravates symptoms then it is probably worth trying to either do less of that activity or find an alternative way of doing it.
- Ergonomic changes – Carpal tunnel is often aggravated by repetitive activities or sitting with the wrist in flexion, for example when driving or at a computer. Try to find ways of changing your set up and take regular breaks from activity
- Splints – these can be obtained from your local pharmacist or on line at reasonable cost. The advice is to wear at night and when doing aggravating activities. If there is no improvement within 6 weeks it is unlikely to resolve the symptoms. Avoid wearing them all the time as the wrist may stiffen and muscles become weak
- Weight loss – If you are significantly overweight weight loss may help ease the symptoms
Corticosteroid injection therapy
If you have weakness or muscle wasting or persistent numbness then surgery is recommended. However for individuals with carpal tunnel syndrome who continue to suffer sensory (tingling and numbness) symptoms in spite a course of non-surgical management (outlined above) a corticosteroid injection can be offered as the next line of treatment. You can read more about local corticosteroid injections here.
Evidence for the effectiveness of a steroid injection is good for short term relief with evidence for more prolonged relief not as strong. A figure of 50% relief at 1 yr is a reasonable guide.
Carpal tunnel decompression surgery is an effective option for individuals who:
- Have constant sensory symptoms (numbness & tingling or pins and needles)
- Weakness or wasting of the thumb muscles
- Have significant pain or sensory symptoms which disturb sleep or daytime activities and have trialled non-surgical intervention for at least 3 months.