Carpal Tunnel Syndrome
Carpal tunnel syndrome occurs when the median nerve is compressed at the wrist as it passes through the carpal tunnel.
It commonly causes numbness, tingling or pins and needles in the thumb, index, middle and part of the ring finger. Symptoms are often worse at night or early in the morning.
What does carpal tunnel syndrome feel like?
Common symptoms include:
- Numbness or tingling in the thumb, index, middle or ring fingers
- Pins and needles or an “ants crawling” sensation at the fingertips
- Symptoms that wake you from sleep
- Early morning numbness or discomfort
- Difficulty with fine movements or pinching
- A feeling of weakness in the hand
- Dropping objects
When compression becomes more severe, patients may develop weakness of the muscles at the base of the thumb.
Some patients also describe an aching or pulling discomfort extending into the forearm, arm or even towards the shoulder.
Is every numb hand caused by carpal tunnel syndrome?
No.
Carpal tunnel syndrome is very common, but not every episode of hand numbness is carpal tunnel syndrome.
The median nerve can also become compressed higher in the forearm, such as in pronator syndrome or lacertus syndrome.
Other peripheral nerves, the cervical spine and more proximal conditions involving the brachial plexus may also produce hand numbness.
It is also possible to have more than one nerve compression at the same time.
In my clinical practice, I therefore assess the whole upper limb rather than concentrating only on the wrist when the symptoms suggest more than an isolated carpal tunnel problem.
How is carpal tunnel syndrome diagnosed?
Carpal tunnel syndrome is primarily a clinical diagnosis based on the pattern of symptoms and physical examination.
During examination, I look at the distribution of numbness, hand strength and any muscle wasting.
Provocative tests I commonly use include Phalen’s test and direct compression over the carpal tunnel, often referred to as Durkan’s compression test.
Tinel’s sign may also be helpful in some patients.
A nerve conduction study is not required to make the diagnosis in every patient.
I may request one when I want to assess the severity of nerve dysfunction, when there is weakness or muscle wasting, or when the symptoms suggest that more than one condition may be present.
Depending on the pattern of symptoms, other investigations may occasionally be required to assess other possible sites of nerve compression, including the cervical spine or proximal upper limb.
Importantly, an investigation should always be interpreted together with the patient’s symptoms and examination findings.
A normal nerve conduction study does not necessarily mean that a patient has no clinically relevant nerve compression.
How is carpal tunnel syndrome treated?
Treatment depends on the severity and duration of symptoms and whether weakness or muscle wasting has developed.
For mild or relatively recent symptoms, treatment may include:
- Activity and lifestyle modification
- Night splinting
- Physiotherapy and appropriate exercises
- Medication for symptom control
- Corticosteroid injection in selected patients
Corticosteroid injection can provide short-term symptom relief, but it does not provide reliable long-term improvement in carpal tunnel syndrome.
When symptoms are persistent or severe, or when there is significant weakness, muscle wasting or substantial nerve dysfunction, carpal tunnel release surgery may be considered.
Treatment should be tailored to the individual rather than based on the diagnosis alone.
When should I seek assessment?
Consider medical assessment if numbness repeatedly wakes you at night, becomes increasingly frequent, affects your ability to use the hand, or is associated with weakness or dropping objects.
Visible wasting of the muscles at the base of the thumb should be assessed promptly.