A testing time for low-tone kids

When we were told our nine-month old baby definitely had hypotonia (low muscle tone), the initial reaction was one of relief. Suddenly, everything was clearer - the delay in learning to sit up, the slowness in feeding, the way he would nearly slide out of our arms when we picked him up. He was making no attempt to crawl - though he was getting pretty good at rolling across the room to where he wanted to go. As first time parents, we weren't really sure there was a problem, but we were beginning to be aware he was behind other kids.

When a child has low muscle tone, every movement is a fight against gravity. It takes much longer than normal to build up the strength to raise the head off the floor, or to maintain a sitting position. Low muscle tone in the face and mouth affect sucking, chewing and speech. The child is floppy and joints are often hyperflexible, so he may adopt a "frog-like" position when lying on the floor, hips splayed.

But while knowing your child is a "floppy infant" provides an explanation for his or her delays, it does not give all the answers. Hypotonia is not a diagnosis but a symptom - which can indicate any number of neuromuscular, metabolic or genetic disorders.

One mother of a hypotonic child, writing in response to a query on an Internet Bulletin Board, says: "One piece of advice I do have is not to drive yourself crazy trying to research this area. There's practically nothing out there except anecdotal information and hypotonia can be a symptom of one of 1,000 syndromes or nothing at all! You'll see your child in a lot of rare syndromes which your child most likely doesn't have. It's upsetting and pointless and doesn't benefit your child at all."

Hypotonia can indicate specific syndromes - for example, hypotonia is symptomatic of children with an extra 21st chromosome, or Down syndrome. Babies with low muscle tone may turn out to have cerebral palsy, while if it is accompanied by progressive muscle weakness it may indicate a neurodegenerative disorder or a muscular dystrophy. But often there is no immediately obvious cause. Your child is officially a "grey area" child, or as one doctor told us, a "puzzle".

Children with hypotonia may be of normal intelligence. They may or may not turn out to have learning difficulties in later years. But in the first years, the child's basic skills are affected: the low muscle tone leads to delays in reaching the early developmental milestones - such as sitting, crawling, walking, independent feeding and talking. Sometimes it is only when the child is behind in reaching these milestones that the hypotonia becomes apparent.

Geneticists at Great Ormond Street Hospital for Sick Children in London told us they saw two or three families a week with children with hypotonia. "Most", they said, eventually got a diagnosis - a named disorder, syndrome or condition. Often, this is only after months or years of tests.

When it is clear your child does have hypotonia, the course of action will depend on your doctor. Some paediatricians take a wait and see approach with hypotonic children - so long as the child continues to progress, the risk of having a degenerative condition recedes. Others aggressively pursue testing, to rule out the more nasty disorders or diseases. Parents only become aware after talking to other parents, that they have a choice as to whether to go through those tests or not.

One mother spoke of going through months of testing in hospitals in England for her daughter, now five. "Each month it was a different blood test, each month they found nothing. In the end we just said no to more tests," she said. Now she just accepts her daughter has hypotonia of unknown cause.

Apart from blood tests for genetic and metabolic conditions, children with hypotonia may undergo EMGs, brain MRI scans, CT scans, spinal taps and muscle biopsies. All may prove negative or inconclusive. Some are invasive tests, requiring sedation or anaesthesia. The trauma of waiting for a result to confirm whether or not your child has a degenerative or even fatal condition can be immense. Having an inconclusive result can be just as terrifying as one which confirms a specific condition.

In the meantime, children usually begin physiotherapy and occupational therapy to overcome the motor delays caused by the low-tone. Speech therapists will work on delayed or poorly-articulated speech - as well as getting the child to achieve such seemingly simple tasks as blowing bubbles or sucking through a straw. When the hypotonia is global, every muscle is affected.

Even if a test does bring up a named disease or disorder, the treatment will be the same for the hypotonic child - any underlying disorder is likely to be incurable.

Some hypotonic children are given the diagnosis of "benign hypotonia" or "benign congenital hypotonia". This is essentially a diagnosis of exclusion, meaning all tests have proved negative and all known causes have been eliminated from the enquiry. The child has a non-progressive hypotonia, and was born with it. Others simply live with the diagnosis of "hypotonia - cause unknown". Some may find a reason for the hypotonia, such as a cerebellar anomaly or an abnormality in the muscle fibre.

As a parent of a hypotonic child, it is easy to feel isolated. You do not fit into the established network of support groups for children with specified conditions. It is hard to come to terms with the fact your child has a problem - when it is not entirely clear what the cause of the problem is. It may not be clear for some time what the prognosis for your child is. At every review appointment to monitor progress, you may need to again consider which tests should or could be done and whether h aving a more concrete diagnosis will help your child.

In the meantime, it is sometimes all too easy to forget what a wonderful child you have - as life becomes a hectic round of assessments, therapy sessions and appointments with neurologists and other medical specialists.

But help is at hand. The Internet is now providing access to virtual support for those with hypotonia - diagnosed or not. Marty White, who lives in New York State, was given a diagnosis of benign congenital hypotonia as a baby and when he set up his home page he included an account of living with hypotonia. He invited people with hypotonia to e-mail him and the result is a e-mail support group more than 50-strong, with members from a number of countries, including USA, Canada, United Kingdom, Austr alia, Denmark.

The Benign Congenital Hypotonia website is at: http://www.lightlink.com/vulcan/benign/.

Another hypotonia support group has been set up on the Parents Place web site, at http://rainforest.parentsplace.com/dialog/get/childhypotonia.html, while Massachussetts Hospital's Neurology forum, at http://neuro-www.mgh.harvard.edu/forum/ChildNeurologyMenu.html receives many posts from parents of hypotonic children.

If you wish to talk to the author, Natasha Brown, write C/O Marty.
The Benign Congenital Hypotonia Site
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