Joshua's mysterious bouts of leg pain recurred, on and off, for several years. Sometimes he would just complain of a slight discomfort in his knees during the evening; at other times we would be roused from our beds by full-blown agony. All we could do was rub where he said it hurt, give him a dose of Calpol and try to settle him down to sleep, reassuring ourselves that all would be well in the morning. Eventually I accepted that there was not much point taking him to the doctor, because I'd just get the same response my mother did when she sought advice on my regular attacks of knee-ache: "just growing-pains".
Growing-pains have been the subject of extensive debate for 100 years or more. If your children have never been visited by these night-time heebie-jeebies it's tempting to assume that they don't really exist. But doctors now agree that they do, and have even given them a fancy title: nocturnal idiopathic (of unknown cause) muscular-skeletal pain syndrome.
"I see a lot of children referred with these pains, which often disturb them at night or prevent them getting to sleep in the first place," says Dr Joel David, consultant rheumatologist at the Royal Berkshire Hospital. "It can range from a dull ache to horrendous pain, where children wake up screaming. It's distressing for the child and the parents, but it's always gone by morning."
Growing-pains are usually confined to the legs, particularly around the calves and knee joints; they are not directly linkedto an injury or infection. They may last from just a few minutes to several hours, and tend to occur irregularly. Most children will get pains on both sides of their legs, but will still have a normal range of movement; the pain is often accompanied by a feeling of restlessness.
Just how common are growing-pains? Little research has been carried out into this condition, although a 1972 Danish study by a school doctor found that 15 per cent of the 2,178 children he investigated experienced them; an earlier, Swedish study put the figure at closer to 20 per cent. Children are most commonly affected between the ages of four and 12, with slightly more girl sufferers than boys. Growing-pains also tend to run in families.
According to rheumatologists, some children are more prone to growing- pains than others. Those with hypermobile joints, more commonly known as double joints, are much more likely to succumb, especially if they are particularly athletic or take a lot of exercise. "Children who get growing-pains are often very flexible in their joints," says Dr Helen Foster, an adult and paediatric rheumatologist at Freeman hospital in Newcastle. "If they are very active, perhaps running around at school all day, they seem to be particularly prone to getting aches in their calves, thighs and knees that evening."
She believes that the excessive range of some children's joints makes them more prone to minor strains and ligament damage, which may cause temporary pains. But currently, there is no consensus as to what causes growing-pains. Professor Patricia Woo, consultant rheumatologist at Great Ormond Street Hospital for Children, says they are associated with periods of particularly fast growth.
"During a growth spurt the bones grow first, causing the muscles to stretch and work harder. If the bone growth is fast and you're quite athletic, using your muscles a lot, it can result in pain in the muscle, tendon and joints. It's usually transient, because the muscles soon catch up with the bone."
It sounds plausible, but many of Professor Woo's peers disagree. The bottom line is that no one really knows what causes growing-pains, says Dr David. "There is no evidence to support the theory that they occur most commonly in children who are growing very rapidly. If that were the case then growing-pains would be most common during the first year of life and adolescence, but actually it's very rare for children to get them then. The truth is, we really don't know what's behind them."
There is some evidence that children experiencing emotional disturbance or stress may be more susceptible to growing-pains than others. Small children do not have the ability to express their anxieties in other ways, so may vent their stress or unhappiness through vague muscular aches. But Dr David warns against assuming that they are all in the mind. "I don't think true growing-pains are a psychosomatic disorder, although there's no doubt that children may sometimes use them as an attention- seeking behaviour, and they may get slightly worse in times of stress, or if there is some family trauma."
Parents should take comfort from the fact that leg aches, however distressing, are rarely a sign of serious disease. According to Dr Foster, many parents worry that their child's growing-pains are a sign of childhood arthritis or leukaemia. While these diseases can present themselves in exactly the same way, they are usually accompanied by other symptoms which suggest that the pains are more than just a part of growing up.
In the case of arthritis, there is pronounced swelling in the affected joints, which will often be stiff and painful in the morning. Children with leukaemia are usually generally unwell, prone to infections and fevers, with a tendency to bruise easily and to experience pain if you press on their bones. The hallmark of growing-pains, on the other hand, is that in the morning the child feels and looks completely well.
Nevertheless, parents who are really worried can always ask their GP to refer them to a specialist,who may conduct blood tests, X-rays or even a bone marrow examination to eliminate possible causes. Most of us, however, can rest assured that growing-pains are an entirely benign, if mysterious condition that invariably gets better quite spontaneously, usually by the teensn
The three Rs: rest, relief and reassurance
l Massaging the affected area will increase the blood flow and reduce muscle spasms.
l A hot compress or warm bath will often help relax the child's muscles and soothe the pain.
l Paracetamol (in paediatric dose) may provide sufficient relief to allow your child to get to sleep.
l If your child is going through a particularly bad bout of growing-pains, try getting him or her to rest more frequently, or to cut down on physical activity for a while.
Swimming, which puts minimum pressure on the joints, may be better than load-bearing exercise such as running or football.
l Good, supportive training-shoes will lessen the impact on joints when walking, running or playing sports, and may reduce the frequency and severity of growing pains.
l The most important thing is to reassure your child that there is nothing seriously wrong, and that the leg pains will soon subside.