How can Myotonic Dystrophy affect your health?

It is important to remember that Myotonic Dystrophy is a highly variable condition so it is difficult to predict how one individual will be affected. The range of symptoms and severity of symptoms both vary enormously. Age at onset when the condition first appears ranges from birth to old age. Although the disease is highly variable it can be broadly grouped into four categories.

 

1.Minimal. Individuals develop symptoms late in life. Cataracts are often the only symptom or there may also be mild muscle involvement.

 

2.Classical or adult onset. This begins in adult life and is characterised by muscle stiffness and slowly progressive muscle weakness. Other systems can be involved in varying degrees.

 

3.Childhood onset. This begins during childhood, but with no problems at birth. Like adult onset it can cause muscle weakness and stiffness, but sometimes it can also cause learning difficulties, glue ear and eye problems.

 

4.Congenital Myotonic Dystrophy. This is the most marked form of the condition and is present from birth. Babies with this can be quite ill, with breathing and swallowing difficulties around the time of birth. Children with it have fewer problems with muscle weakness than adults, but they can often have problems with learning difficulties, glue ear and eyes.

Important features involving other systems may be more troublesome than the muscle symptoms and can seriously affect health. Specialists in these other systems may be unfamiliar with Myotonic Dystrophy and may not diagnose it.

 

5.Muscle Weakness - Weakness is very variable and may range from mild to severe. It particularly involves the face and eyelids, jaw, neck, forearms and hands, lower legs and feet. It can affect speech and result in a lack of facial expression.

 

6.Myotonia - Myotonia is difficulty in relaxing a muscle after it has been contracted, for example it may be difficult to let go after gripping something.

 

7.Heart problems – An abnormal rhythm or slow conduction of the electrical impulse through the heart might require treatment. This can sometimes affect those without other symptoms. Regular ECGs (heart tracings) are advised to detect problems at an early stage.

 

8.Chest and Breathing problems - Chest infections may result from weakness of breathing muscles or form food entering the lungs as a result of poor swallowing. Inadequate breathing during the night may lead to disturbed sleep, difficulty waking, morning headaches, loss of appetite and daytime sleepiness. Regular breathing tests, and sometimes overnight oxygen saturation tests, are advised to detect problems early. Inadequate breathing during the night can sometimes be helped by non-invasive ventilation.

 

9.Tiredness and sleepiness- These are very common and can occur at any time of the day. Usually they are part of the condition and may be present at an early stage. If they become a lot worse but no obvious reason that is when they may be due to breathing problems (see above) and should then be investigated.

 

10.Digestive problems - These are common as the muscle throughout the digestive system may be affected. This may lead to: swallowing problems (which can also be a cause of food entering the lungs), pains in the bowels with constipation and diarrhea, soiling of underwear particularly when stressed or excited and occasionally enlargement of the large bowel. Gallstones which can cause painful spasms after eating fatty food can be a problem in Myotonic Dystrophy and great care needs to be taken with any surgical treatment.

 

11.Eye problems - Cataracts can cause blurring and dimming of vision. This may be the only problem caused by Myotonic Dystrophy especially in the first affected generation of a family. Droopy eyelids can cause a problem with reading and watching television. Affected individuals should have regular check ups at the optician and see a medical eye specialist if there is any concern.

 

12.Anaesthetics and surgery - Myotonic Dystrophy can cause problems with recovery after an operation when certain anaesthetic drugs are used. Make sure that the surgeon and anaesthetist are aware of the condition before an operation. They may wish to contact a specialist centre for advice. A medical alert card or document (supplied free of charge by the support group) should be carried at all times in your wallet or purse in case of an accident or emergency.

 

13.Problems with thinking and planning - The brain may be affected. In children with congenital myotonic dystrophy this can cause  learning difficulties and behavioural problems. In older children and adults it can cause problems with paying attention to things, planning and self motivation.

 

14.Speech and jaw problems – The muscles  that control speech are affected, leading to slurring of speech. This can mean that speech is indistinct and difficult for others to hear. It can be helped by talking more slowly. In children with congenital or childhood onset myotonic dystrophy the weakness of speech and facial muscles can cause problems with growth of jaw and facial bones leading to difficulty closing the jaw properly,  appearance and development of a correct bite (malocclusion).

 

15.Other problems include - Male infertility; diabetes (ask to have your blood or urine sugar checked regularly); the muscle in the womb may be involved and lead to a long difficult labour so that obstetric help may be required; a certain skin lesion called a calcifying epithelioma or pilomatrixoma may occur and in some people the bladder muscle may be affected.  

 

16.Inheritance and genetics - Normally when the condition is passed on to the next generation it becomes more severe and the age at onset decreases. This pattern is called anticipation and means that in one family the grandparent may have cataracts as the only symptom, the parent may have the adult onset form of the disease and the child could be severely affected with congenital Myotonic Dystrophy.

 

Accurate genetic tests are possible for healthy individuals who are at risk of developing Myotonic Dystrophy in the future because they have an affected parent or grandparent and early in pregnancy where one parent is affected. Genetic counselling is advised if genetic testing is being considered.

Not all people with myotonic dystrophy need to be followed by a specialist clinic but all should be given full information about the condition and its consequences, including genetic aspects, and should have a clear plan for when medical help is needed. Specialist advice should always be sought in relation to surgery and anaesthesia, pregnancy or serious illness. A wide range of disability aids exist. It is important that these are chosen with expert assistance.

At present there is no cure for Myotonic Dystrophy but this may change as a result of rapid progress in our understanding of how the disorder is caused - meanwhile all people with Myotonic Dystrophy can help themselves by knowing about their condition, recognising and avoiding hazards, and by informing doctors and other professionals

Information supplied by Prof. Peter Harper CBE FRCP DM, Emeritus Professor and Consultant in Medical Genetics, University of Wales College of Medicine, Cardiff; by Professor David Brook PhD, University of Nottingham and by Dr Margaret Phillips FRCP MD Associate Professor in Rehabilitation Medicine, University of Nottingham.