COMPLEX REGIONAL PAIN SYNDROME

GENERAL

Complex regional pain syndrome (C.R.P.S.) was previously referred to as REFLEX SYMPATHETIC DYSTROPHY (RSD). It is a condition characterised by 4 main features...

1. Severe Pain
2. Swelling
3. Stiffness
4. Skin discolouration or abnormal sweating

   

Normally pain is a warning signal that the body is at risk of injury or damage. The pain in a CRP is disproportionate to the injury or stimulus applied. This does not mean that it is not real. It may extend to affect the whole arm or leg. The pain may be of a "burning" quality.

CAUSE

The cause is poorly understood, although Psychological, Physical and Environmental factors play a role in its development. There may be genetic factors that predispose an individual to this condition.



It is believed that there is a chemical change at the spinal cord level, which "sensitises" the pain receptors. When the pain receptors are sensitised even light touch on the skin can become a painful stimulus.

In a normal situation the brain has the ability to dampen down ones perception of pain. This occurs by signals travelling down from the brain to provide an inhibiting effect (-ve influence) on the pain receptors in the spinal cord. In this way a footballer may keep playing with a broken arm because his mind is so focused on the game. Once the game is over he may then realise that the arm is broken and he begins to perceive the pain. The brain also has the ability to increase our perception of pain by causing a +ve effect at the spinal cord. In this way it is believed that people who are very anxious or depressed have a greater perception of pain.

In a CRPS, the +ve effect at the spinal cord level may be very prolonged or even permanent. This does not imply that you are dreaming up the pain. The pain is very real and there are definite chemical changes at the spinal cord level. A secondary effect of a CRP may result in abnormal firing of the sympathetic nerves. The sympathetic nerves are not normal nerves for feeling sensation or for causing muscles to contract. Rather, the sympathetic nervous system is used for controlling the heart rate, causing hairs to stand on end and causing sweating and colour changes in the skin. The sympathetic nerves are "automatic" nerves over which we have little direct control.

A CRPS may be triggered by a variety of causes such as minor trauma or even surgery. It not infrequently follows trauma to nerves. It appears to occur more frequently in patients who are anxious or depressed although this is certainly not always the case. There may be a genetic predisposition to this condition, which may run in families.

TREATMENT

Treatment is best in a multidisciplanary pain clinic run by anaesthetists (Pain Clinic Specialists).

1. Drugs: The aim is to break the pain cycle and control the inflammation. This is achieved not only with painkillers but also antidepressant medications, which appear to have a specific effect at the spinal cord level to dampen down (-ve influence) the pain receptors. e.g. Tryptanol. Prothiaden. Anti-inflammatory drugs e.g. Voltaren may also be used.

2. Sympathetic Blocks: It may also involve sympathetic blocks, which involve injections either around the nerves in the neck, or arm or injections into the veins. This is done as a day procedure in the pain clinic by an anaesthetist who is highly skilled in the treatment of this condition.

3. Local anaesthetic may be used around nerves to block the pain and also as a test.

4. Hand Therapy: The treatment also involves intensive hand therapy, which may involve a programme known as the "Stress Loading Programme". This involves scrubbing, such as scrubbing the floor and leaning heavily on the hand as this is performed. This should be done for 3 minutes 3-4 times a day. The second component is carrying an object such as a briefcase or handbag in the affecting hand, ranging between 0.5 - 2 kgs. The weight should be carried whenever the patient is standing or walking for at least 3 minutes and longer if possible. With this programme the pain may initially increase for a week or so but it gradually settles and it is worth persevering with it.

5. T.E.N.S. (TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION) : Other physiotherapy modalities include a TENS machine which involve a minor electrical stimulation of the hand or arm to reduce the amount of pain.

6. Positive Outlook: This is a very frustrating condition. There is no doubt that a positive approach will help the situation. In general pain is a warning. In this condition pain is a nuisance but does not equal damage - so you should endeavour to continue to do as much as you can, knowing that you are not causing damage to the effected arm or leg by using it.

PROGNOSIS

The condition may take months to years settle down. 75% of patients improve dramatically with time returning to normal or very near normal. Approximately 15% of patients have moderate permanent disability and about 10% of patients have severe permanent disability.