Carpal Tunnel Syndrome - Home Management Part 1 - Introduction
Carpal Tunnel Syndrome is a Median Nerve neropathy that causes pain, paresthesia, numbness and/or tingling sensation in the distribution of Median Nerve due to its compression at the wrist as it passes from the forearm to the hand through the Carpal Tunnel. Anything that decreases the amount of space in the Carpal Tunnel or anything that increases the amount of tissue in the Carpal Tunnel or anything that increases the sensitivity of the Median Nerve can lead to the Carpal Tunnel Syndrome.
Brief Anatomy of the wrist
The bones of the wrist are called the Carpal bones and they are 8 in number. They are arranged in two rows, the proximal row and the distal row, 4 in each row. The Carpal bones of the proximal row are the Scaphoid, the Lunate, the Triquetral and the Pisiform. The Carpal bones of the distal row are the Trapezium, the Trapezoid, the Capitate and the Hamate. The bones of the proximal row articulate with the lower end of radius and articular disc of the inferior radio-ulnar Joint, proximally. Distally, they articulate with the proximal surfaces of the Carpal bones of the distal row except the Pisiform.Carpal bones of the distal row articulate with the metacarpal bones.
What is Carpal Tunnel?
Carpal Tunnel is a fibro osseous tunnel,the ‘palmar hollow’, formed by the Carpal bones and is roofed by the transverse carpal ligament, the Flexor Retinaculam. This tunnel contains all the flexor tendons and the Median Nerve as they pass from the forearm to the hand through the Carpal Tunnel.
What is Carpal Tunnel Syndrome?
Pain, paresthesia, numbness and/or tingling sensation in the area of sensory distribution of Median Nerve in the hand due to the compression of the Median Nerve as it enters the hand through the Carpal Tunnel. Any space occupying mass or swelling of the structures in the Carpal Tunnel causes pressure on the Median Nerve. The Carpal Tunnel Syndrome can be defined as a Median Nerve Entrapment Neuropathy that causes pain, paresthesia, numbness, tingling sensation and other symptoms in the area of sensory distribution of the Median Nerve in the hand due to its compression at the level of the wrist as it passes through the Carpal Tunnel. A variety of patient factors that can lead to Carpal Tunnel Syndrome include heredity, associated local systematic diseases, size of the Carpal Tunnel, certain habits, certain occupations, certain traumatic conditions etc. The symptoms due to traumatic causes get triggered suddenly by one single event whereas the symptoms due to non traumatic causes occur slowly and over a period of time. Many of the non traumatic causes are usually the manifestations of physiological aging.
- Idiopathic- Causes for most of Carpal Tunnel Syndromes are unknown.
- Intrinsic factors that exert pressure within the Carpal Tunnel and the extrinsic factors that exert pressure from outside the Carpal Tunnel- which includes benign tumors such as lipomas, ganglions, vascular malformations. Anyway compression due to tumors is very rare (less than 1%). The tumors may protrude into the Carpal Tunnel narrowing the tunnel and compressing the Median Nerve. Broken wrist bones, dislocated wrist bones, new bone growths from healing bones, non united fractures, mal- united fractures, bone spurs etc. may also protrude into the tunnel narrowing it and compressing the Median Nerve.
- Rheumatoid Arthritis, Inflammatory Arthritis and other similar disease conditions- Such disease conditions cause inflammation of the flexor tendons that pass through the Carpal Tunnel. These inflamed tendons occupy more space in the tunnel narrowing it and compressing the Median Nerve.
- Hypothyroidism- Generalised Myxoedema (the clinical symptom of Hypothyroidism) causes the deposition of ‘ mucopolysaccharides’ within the perineurium of the Median Nerve as well as on the flexor tendons passing through the tunnel narrowing the tunnel and compressing the Median Nerve.
- Pregnancy- Due to hormonal changes (high progesterone levels) and water retention which swells the synovium narrowing the Carpal Tunnel and compressing the Median Nerve. Women between the ages of 40 and 60 have the highest risk. The symptoms are also found in women who are taking birth control pills, those who are passing through menopause and those who are taking oestrogen.
- Acromegaly- There is excessive production of growth harmones. As a result the soft tissues and the bones that ‘boundary’ the Carpal Tunnel do have unwanted growth further narrowing the tunnel and compressing the Median Nerve.
- Obesity- Obese people may present with the symptoms of Carpal Tunnel Syndrome.
- Diabetes- Diabetic patients may present with the symptoms of Carpal Tunnel Syndrome.
- Charcot’s Joint- In Charcot’s Joints, there is complete disorganization of the joint. Such joints are seen in Syringomyelia and in advanced cases of Tabes Dorsalis.
- Double- Crush Syndrome- Compression or irritation of nerve branches that contribute to the Median Nerve in the neck or anywhere above the wrist increases the sensitivity of the nerve leading to the presentation of symptoms of Carpal Tunnel Syndrome.
- Smoking- Smoking may adversely affect the blood supply to the Median Nerve. Deficiency of blood flow to the nerve may result in the presentation of symptoms of Carpal Tunnel Syndrome.
- Normal wear and tear of the bones and the soft tissues in the wrist and hand due to aging- results in the narrowing of the Carpal Tunnel presenting the symptoms of Carpal Tunnel Syndrome.
- Sleeping Positions- Always sleeping on one side may result in the presentation of symptoms of Carpal Tunnel Syndrome. The symptoms often occur or enhance at night because the wrist is usually held in the flexed position most of the time at night.
- Repetitive Activities of the wrist and hand- The Median Nerve usually moves up to 9-6 mm to allow the wrist to flex and to a lesser extent during extension. Long time compression of the Median Nerve or its frequent movement in the Carpal Tunnel during repetitive activities can adversely affect the normal gliding movement of the nerve through the Carpal Tunnel. As a result the nerve may get injured and hence a scar may be formed. When the scar is formed, the nerve may get adhered to the surrounding tissues. As a result the nerve may get locked in certain fixed positions. Hence the nerve gets stretched and irritated during flexion and extension movements of the wrist resulting in the irritation of the Median Nerve presenting the symptoms of Carpal Tunnel Syndrome. It is also to be noted that the pressure within the Carpal Tunnel is increased 8 fold during flexion and 10 fold during extension. Repetitive flexion and extension of the wrist increases the fluid pressure within the tunnel due to the thickening of the synovium that lines the flexor tendons and the nerve within the tunnel. Thickened synovium narrows the Carpal Tunnel causing compression of the Median Nerve in the tunnel presenting the symptoms of Carpal Tunnel Syndrome. Activities which demand repetitive wrist movements or hand-arm vibrations or working for long periods with the wrist and hand in awkward positions may also lead to Carpal Tunnel Syndrome.
Signs and Symptoms-
- Numbness and tingling sensation- in the thumb, index and middle fingers ie. In the sensory areas of Median Nerve distribution. Sometimes ‘pins and needles’ sensation or pain in the sensory areas of Median Nerve distribution.
- Numbness and/or pain – Occasionally in the forearm, wrist and hand. Hence the sleep will be disturbed. The symptoms often occur at night because the wrist is usually held flexed during night. The symptoms may be relieved on shaking the hand or on moving the fingers.
- Numbness and/or pain- may get worse on using the wrist and hand repetitively. May get still worse if one holds an object with the hand and then flexing the wrist.
- Morning stiffness of fingers.
- Wasting, weakness – of thenar muscles and sensory impairment in that area- cannot pinch thumb and index finger together or the pinch is weak- cannot do simple and fine movements of fingers- drops objects accidently from the hand.
- Inco-ordination- Long term Carpal Tunnel Syndrome results in inco- ordination of the fingers and hand.
- Absence from work- Carpal Tunnel Syndrome is one of the most common causes of absence from work.
- Stiffness of shoulder joint- Long term Carpal Tunnel Syndrome may result in stiffness of shoulder joint.
- Carpal Tunnel Syndrome can affect anyone.
- Carpal Tunnel Syndrome accounts for nearly 90% of all nerve compressions.
- Women suffer more from Carpal Tunnel Syndrome than men with a ratio 3:1.
- Carpal Tunnel Syndrome more often finds in people between 45 and60 —less common in young people below 30 years of age- increasing age is a risk factor.
- Carpal Tunnel Syndrome is common during pregnancy.
- Electromyography and Nerve Conduction Tests- to compare the speed of conduction in the Median Nerve of the involved side with the conduction in Median Nerve of the normal side and also with the other nerves of the involved side. When the Median Nerve of the involved side is compressed its speed of conduction will be slower than that of the Median Nerve of the normal side. Its speed of conduction will also be slower than other nerves of the involved side.
- X rays- can reveal any bone problems, caused by past or recent injuries- past or recent fractures or dislocations of Carpal Bones - past or recent Colle’s fracture- tumors- Arthritis. Anyway one cannot solely depend on X rays for the diagnosis of Carpal Tunnel Syndrome. But they are helpful in reaching to a diagnosis.
- Ultra Sound Scan- to know the condition of the Median Nerve of the involved side- to see whether the nerve is inflamed. This investigation is not much expensive. It is comfortable and can be done without any delay. Anyway one cannot solely depend on Ultra Sound Scan for a diagnosis of Carpal Tunnel Syndrome.
- MRI Scan- to see whether there is inflammation or swelling of the Median Nerve, whether there is narrowing of the Carpal Tunnel or whether there is any deficiency of blood flow through the Carpal Tunnel. Anyway on cannot solely depend on MRI Scan for a diagnosis of Carpal Tunnel Syndrome.
- Blood Tests- to rule out other medical conditions such as Hypothyroidism, Diabetes, Acromegaly, Rheumatoid Arthritis, Inflammatory Arthritis etc.
- Clinical Test – 1- Phalen’s Test- flex the wrist gently as far as possible and hold in that maximum flexed position and wait for the symptoms to appear. If the test is positive, numbness occurs in the Median Nerve distribution areas when the wrist is held flexed for 60 seconds. If the symptoms appear even before 60 seconds, the condition may be judged as advanced. Phalen’s Sign is defined as pain and/or parasthesia in the Median Nerve distribution areas with one minute of wrist flexion.
- Clinical Test -2 – Tinel’s Test- This test is less sensitive. This test is performed by lightly tapping the skin over the Flexor Retinaculam to elicit a sensation of ‘tingling’ or a feeling of ‘pins and needles’ in the areas of sensory distribution of Median Nerve.
- Clinical Test-Durken Test – (Carpal Compression Test) - Apply firm pressure to the palm over the Median Nerve for up to 30 seconds to elicit the symptoms.