Lecture presented by Chris W. Höweler M.D. of the University of Maastricht at the yearly meeting organised in October 1997 by the “Werkgroep Myotone Dystrofie (Myotonieën)” for patients and other people involved in myotonic dystrophy.

Myotonic Dystrophy (MD) is a muscle-dystrophy, which also causes disorders in other organ systems. So symptoms as cataract, irregular heart-beat, pneumonia or bowel troubles appear. The VSN-handbook for muscle diseases gives at page 32 a summary of the organ disorders. These disorders vary among patients and luckily not all of them appear simultaneously in one patient. Sometimes organ disorders end up in dangerous complications, particularly this is the case with irregular heart-beat and pneumonia. If timely detected medical treatment is often effective.

Although the heart is a kind of a muscle, weakness of the heart muscle and narrowing of the coronary arteries seldom occur with MD. Heart problems with MD are almost always initiated by irregular heart-beat, as the disease influences mainly the nervous system which transmits electric impulses in the heart. This is a special nerve-bundle from the auricles through the partition of the ventricles to both ventricles. This nervous system provides for contraction of the auricles and ventricles in a regular pattern. If this system does not properly function this may result in irregular heart-beat. Disorders in this nervous system are visible on the heartfilm produced by the electrocardiograph (ECG). With many MD-patients slight disorders are visible on the heartfilm. This may not result in complaints, but with a part of the patients this may result in palpitation, faintness and in worst cases in heart block. In recent years it became clear that a beginning disorder in the heartrythm, which is only detectable on the ECG, in the cause of 5 till 10 years can gradually grow worse. To prevent a sudden heart block the family doctor or nerve-specialist may perform an ECG-examination once a year or every few years. If beginning deflections are found, it is wise to consult a heart-specialist. He then performs a more extensive examination, for instance a ECG during  exertion on a bicycle or on a conveyor belt. Thus he is able to decide whether the disorder in the heartrythm needs treatment with medicine or makes insertion of a pacemaker necessary. Disorders in the heartrythm mainly occur during the advanced stage of the disease, but sometimes with people almost not yet troubled with their MD.

Lung problems mostly occur during the advanced stage of the disease. Here too the weakness of the breathing muscles is not the main problem, because with MD in the worst case the breathing muscles are slightly affected. Chronic mechanical respiration, which is sometimes necessary with other muscular diseases, is seldom necessary with MD-patients.

The main problem with MD is the acute pneumonia. It is often caused by choking, though the patient is not always aware of it. Obviously he is choking on saliva when asleep, because swallowing is more difficult when lying down than being upright. Pneumonia mostly starts in the lower lobe of the lungs, but it can extend within a few days and become a serious and dangerous infection of a complete lung. This should be treated quickly with antibiotics and cough-medicine. Often admittance to hospital is necessary and sometimes patients require temporarily a mechanical ventilator at an Intensive Care. Sometimes the trachea must be sucked out with a bronchoscope, a flexible thin pipe, slid through the trachea by a lung-physician. Often this way of fighting pneumonia is successful. With some patients who frequently choke, within a few years several times pneumonia occurs. This can be prevented by sleeping at night in upright position, thus preventing choking.. In this case it is wise not to eat in the evening because from a filled stomach sometimes  food is belched up, which can reach the lungs.

P.T.O.

During operations under general narcosis irregular heart-beat and pneumonia occur easier. Pneumonia can occur easily because MD-patients react more strongly on anaesthetics than average. They are longer dull, breathing is suppressed and they swallow difficulty in lying position. The irregular heart-beat can worsen too by anaesthetics. The combination of these problems makes operations under general narcosis more dangerous than with healthy patients. The risk of complications can rise up till 40% if no special precautions are taken during and after narcosis. The anaesthetist should be instructed before the operation that the patient has DM. Especially in case of acute problems, such as a broken leg or appendicitis, dangerous situations may arise because the surgeon does not recognise the muscular disease and has to operate quickly. The patient and his relatives themselves must take care that the surgeon and the anaesthetist are aware of the disease.

Another way to prevent these complications is to ask for an operation with local anaesthesia such as spinal block anaesthesia. Local anaesthesia is possible with many operations, among others with cataract operations or during  insertion of a pacemaker. It is wise to have operations performed only if it is absolutely necessary, for instance in case of a life-threatening disease.

Complications obviously occur more frequently with patients elder than 45 years of age. It is a problem that rather little is known about the later stage of MD. The disease often begins at an early grown-up age and increases very slowly. Most research is done among patients in a relatively early stage of the disease. The disease may however last 40 years or longer and the research-worker seldom can follow a patient from the beginning till the end.. That is why for instance we do not know how serious the disablement is in a later stage of the disease, neither how often and at which moment organ-complications occur. We too do not know which age most people get and what causes their death. For that reason during the last years research was made in South-Limburg among patients who were examined since 1950 by the late nerve-specialist De Jong. He graduated in 1955 on research made on MD. Data from these patients could mostly be overtaken, among others in the archives of hospitals in Maastricht, Heerlen and Sittard. Nerve-specialists from these hospitals collected these data and they were elaborated by Mrs. De Die-Smulders, clinical genetic-specialist in Maastricht.

She collected data from 330 MD-patients in South-Limburg.  83 patient with the adult type of the disease died since 1950. Many patients died between the ages of 50 and 65 years. A smaller group of patients grew elder and we know a patient who is now 75 years of age. A conclusion from this research is that the average life of patients with MD is shorter than the life of  healthy people. It is however not possible to make a prediction for an individual patient. The cause of death of these patients was also investigated. The cause of death could be established with 70 patients with the  adult type of MD. It came out that about 1/3 of the patients died of pneumonia and another 1/3 died  of irregular heart-beat. These complications often occur without reason, but too as complication of an operation or a broken leg. All in all it came out that a bit more than 70% of the patients died of one of the known complications of MD. Herewith it should be observed that many of these patients died decades ago in a time that hospitals were not equipped with an intensive care and pacemakers generally were not used. The prospects may be in favour of  patients who live now.

About 1/3 of the patients died of other causes, among others accidents, tuberculosis and cancer. An unexpected outcome of this research was that only 10% of the patients died of cancer, whereas in this age 37% of the people without MD die of cancer. So it is obvious that patients with myotonic dystrophy have less chance to get cancer than other people. To be able to say this for certain this research should be repeated among a bigger group of patients. So now we know that pneumonia and irregular heart-beat are the most dangerous complications of MD. Therefore it is important to try to prevent them and to attend early if they occur. These complications frequently occur after operations under narcosis, especially after the age of 45. They too can occur after breaking a bone with patients who tend to fall easier because of their muscle-dystrophy. This can be prevented by timely use of mechanical aids in case of falling frequently. These mechanical aids may consist of a  foothold to prevent stumbling over ruggedness, a shopping-cart for patients with week knees and in the worst case a wheelchair if walking outdoors is a problem.

Childhood type (3)

Age at onset: 1 – 12 years

Early symptoms:

Problems with learning

Problematic behaviour (less concentration, keeping oneself to oneself, fussy)

Problems with speaking

Bowel troubles

In the childhood type learning problems can be the only symptoms of DM, without any other complaints. Muscle weakness is often mild, or appears at adult age. The diagnosis DM is often not considered, especially if the disease is not (yet) known in one of the parents. Behavioural problems are frequent. These children may also have problems with their speech.

The types in families: the younger the more severe

In families the symptoms occur earlier in the successive generations = anticipation

Example:

Cataract in grandfather at the age of 50

Daughter: adult type from the age of 20

Grandson: congenital type

Anticipation is due to the growth in length of the expansion of the CTG building blocks in the DM-gene of each next generation.

Myotonic dystrophy is an autosomal dominant disorder. This means that both affected women as men can pass on the DM-gene to their sons and daughters. Any child of an affected person has a 50 % risk of inheriting the disorder. It is striking  that the disorder occurs in each next generation at younger age and the symptoms are more severe. As a rule the eldest generation in a family only has cataract (mild type), in the next generation are patients with the adult type, whilst in the youngest generation the congenital type occurs. This phenomenon is called anticipation. Recently a genetic explanation was found: It was found that the hereditary quality when passed on to the next generation gets longer, resulting in symptoms at a younger age and a more severe type of DM.

Organs which may be affected in myotonic dystrophy

Heart
irregular heart-beat

Lungs
pneumonia

Stomach
difficult swallowing

Bowels
diarrhoea, constipation

Glands
diabetes

Hormones
infertility in males

Womb
weak woes and raised loss of blood during delivery, irregular menstruation
 

Organ complications

Myotonic dystrophy is usually classified as a muscular disease, but in fact it is a disorder affecting many organs. A pneumonia caused by choking occurs often and has to be treated with antibiotics. Irregular heart-beat may cause  short-lasting fainting. If timely detected this can be treated by a heart-specialist with medicine or a pacemaker. There may be mental symptoms: The patients get slower, listless, and are lacking initiative; they need more sleep. Patients have increased risk during narcosis. There is a raised sensitivity for anaesthetics which combined with heart- and lung-problems may lead to complications during and after the operation. These problems especially occur when the anaesthetist and surgeon are not aware of the risks for patients with myotonic dystrophy.

BEHAVIOURAL AND EMOTIONAL FUNCTIONING OF CHILDREN AND ADOLESCENTS WITH THE JUVENILE TYPE OF MYOTONIC DYSTROPHY

Summary of the lecture delivered at the yearly meeting organised in October 1998 by the “Werkgroep Myotone Dystrofie” for patients and other people involved in myotonic dystrophy. This lecture was prepared by J Steyaert of Stichting Klinische Genetica Zuid-Oost Nederland, Maastricht.

The lecture was based on research among 29 children and adolescents between 8 and 18 years of age with the juvenile type of myotonic dystrophy.

To get information on the behavioural and emotional characteristics a standardised checklist, Achenbach’s CBCL (Child Behaviour CheckList), was used. Parents  were interviewed with ADIKA, a structured child psychiatric interview.

CBCL gave as result that 1 on 3 children and adolescents (10 of 29) scored in the clinical range for “internalising” problems. “Internalising” encompasses among others social problems and withdrawal. For “attention problems” also 1 on 3 scored in the clinical range. For “externalising” behaviour (aggression, criminality…) the score was comparable with the average score of  healthy people of the same age.

On the structured child psychiatric interview 9 on 29 fulfilled the criteria for the clinical syndrome ADHD (Attention Deficit and Hyperactivity Disorder). Main problems were impulsivity and attention deficit; hyperactivity was less conspicuous.

7 of 29 children and adolescents were suffering from clinical or unusual fears. 3 of 29 ever had problems of a depressive mood.

A number of the children and adolescents had two of the mentioned problems; 12 from the group of 29 had no behavioural or emotional problems.

Discussion

1. More than 50% of the assessed children and adolescents have behavioural and emotional problems which may hamper their education.

2.  Attention and concentration problems with impulsivity and lack of organising capabilities are the main problems. Fear problems come at the second stage. Problems with social integration frequently occur.

3.  Most children in the assessed group have more problems in the regions learning, behaviour and emotions than having motorial problems.

4   It is justified to examine children with major problems with learning or behaviour, if they have a hereditary taint for myotonic dystrophy, whether they indeed have this disorder. This may influence the education of these children.

LEARNING PROBLEMS OF CHILDREN AND ADOLESCENTS WITH THE JUVENILE TYPE OF MYOTONIC DYSTROPHY

Summary of the lecture delivered at the yearly meeting organised in October 1998 by the “Werkgroep Myotone Dystrofie” for patients and other people involved in myotonic dystrophy. This lecture was prepared by D.Willekens, Centrum Menselijke Erfelijkheid, University of Leuven, Belgium.

The lecture was based on research among 36 children and adolescents between 7 and 19 years of age with the juvenile type of myotonic dystrophy.

To get information on the intelligence, this was tested with the Wechsler scales: WISC-R (Wechsler Intelligence Scale for Children Revised)  for children from 6 till 16 years of age and WAIS (Wechsler Adult Intelligence Scale) for adolescents of 16 years of age and older.

Results:

– Mean total intelligence quotient (FSIQ): 75,2

– Mean verbal intelligence quotient VIQ): 75,8 (information, similarities, arithmetic, vocabulary, comprehension and digit span)

– Mean performance intelligence quotient (PIQ): 78,5 (picture completion, picture arrangement, block design, object assembly, substitution and mazes

– IQ-scatter: 50 – 98

– IQ 85 – 100: 10 children / adolescents

– IQ 70 – 84: 13 children / adolescents

– IQ < 70: 13 children / adolescents

The intelligence of all tested children and adolescents scores below 100. There is no significant difference between the mean performance intelligence and mean verbal intelligence of this group.

The children and adolescents of the group with IQ 85 – 100 have learning problems; 6 are in normal schools and 4 of them  get a denominational education. Few research is done on the nature of these learning problems. Their slowness, attention problems and in some cases dyslection may initiate these schoolproblems.

All children and adolescents with lower intelligence get  some type of denominational education. By the combination of learning problems and muscle problems it is expected that their majority will need a permanent protected living and work-environment.

MYOTONIC DYSTROPHY: ASSISTANCE AT DIFFERENT  AGES

This article was published in “MYONET” no. 3 May 1996, a newsletter on neuromuscular diseases. Myonet is published by the Vereniging Spierziekten Nederland (VSN) and is distributed free of charge among professionel assistents who are involved in their daily practice in treatment of people with a muscular disease. VSN aims at exchange of knowledge on treatment of neuromuscular diseases through Myonet. Authors are Christine E.M. De Die- Smulders, clinical geneticist at the Department of Clinical Genetics and Chris W. Höweler M.D.Department of Neurology, Academic Hospital Maastricht.

Myotonic dystrophy (MD) is a relatively frequently occurring  (about 1 patient among 7000 people), hereditary muscular disorder. Other names are Dystrophia Myotonica or Steinert’s disease. Characteristic symptoms are myotonia (muscle stiffness due to muscles failing to relax properly)  and slowly  progressive muscle weakness, especially of the face-muscles, the throat- and neck-muscles and the muscles in the fore-arm and lower part of the legs. Other organs may also be affected. This manifests itself in symptoms as cataract, irregular heart-beat, slowness, loss of initiative and infertility in males. There may be a considerable variation in the severity among patients, from only cataract at elder age to life-threatening muscle weakness at birth. The age at onset of the disorder and the character of the symptoms are highly  depending upon the length of the hereditary predisposition. Assistants from many different professions may get in touch with myotonic dystrophy patients. No medicine is known which improves the natural course of the disease. Good assistance of the patient is of mayor importance.

THE DIFFERENT TYPES: ACCORDING TO THE AGE

Myotonic dystrophy can be classified in 4 different types, depending on age at onset and main symptoms (table 1):

-mild type: age at onset after 50. Most patients only have cataract.

-adult (classic) type: myotonia and muscle weakness develop from puberty till the age of 50. Later defects occur in several organs.

-childhood type: a delay in development is most prominent; muscle weakness is often mild. The diagnosis MD is often not considered, especially if the disease is not (yet) known in one of the parents.

-congenital type: severe muscle weakness is already present at birth, leading to breathing- and swallowing-problems. During pregnancy there is much amniotic fluid (because the baby does not  swallow) and the mother feels less stirring of the baby. Nearly one half of the babies dies because of respiration problems. If they survive they recover considerably from the muscle weakness during the first years of life, indeed these children often have the characteristic tent-shaped mouth. The patients show a retarded motor and mental development. Bowel complaints and constipation often occur, and also inflammation of the ears. Besides there are often articulation problems, among others due to weakness of the palate. At adult age muscle stiffness and muscle weakness occur.

HEREDITY: THE LONGER THE GENE THE WORSE THE DISORDER

Myotonic dystrophy is an autosomal dominant disorder. Both affected women and men can pass the disposition (the gene) to their children. The risk per child that the disposition is passed on is 50 %. Striking is that the disorder begins at younger age and the course is more severe in successive generations. It is often seen in a family that the eldest generation has only cataract (the mild type), the next generation has patients with the adult type, whereas in the youngest generation  the childhood type or congenital type are met. This phenomenon is called anticipation. Recently the genetic explanation was found. In 1992 the structure of the MD gene was cleared, it was already known that it was located on chromosome 19. The gene has a certain piece of DNA with different length per patient. This piece of DNA consists of a variable amount of CTG triplet repeats. C, T and G are DNA building blocks. Roughly the severity of the disorder increases with growing amount of CTG triplet repeats (table 1, last column). The amount of CTG triplet repeats as a rule increases at passing on to the next generation, with anticipation as a consequence. A second peculiarity at passing on is that the congenital type almost always is passed on by an affected mother and not by an affected father. The background is that men with the adult type are often sterile. If they do get children the gene is often not longer and sometimes is even shorter in their offspring. After the diagnosis has been made it is important to inform the patient and his relatives about the heredity of the disorder; if necessary they can be passed to a clinical genetic centre. DNA examination in relatives may point out if they are affected. Parents with one of them having the disorder can early during  the pregnancy (through a chorionic villus-biopsy about the 11th week), have examined if the future child is predispositioned. If the result of the test is negative the parents have to make the difficult choice about eventually terminating the pregnancy.

Table 1: The 4 types of myotonic dystrophy, age at onset, important early and later symptoms and number of  CTG triplet repeats

Type
Age at onset
Early symptoms
Later symptoms
Number of CTG triplet repeats

Mild
>50
cataract
myotonia

slight weakness
40 – 120

Adult
12 – 50
myotonia,

muscle weakness
increased weakness, cataract, slowness/apathy, organ complications
200 – >1000

Childhood
1 – 12
learning problems,

speaking problems,

bowel problems
myotonia,

muscle weakness,

as the adult type
500 -> 2000

Congenital
birth
hypotonia cf Hoppinen,

breathing and swallowing problems,

learning and speaking problems, clubfeet
as the childhood type
1000 – >5000
 

CLOSE LOOK AT THE MUSCLE COMPLAINTS

The diagnosis

The muscle weakness begins gradually and it can last for years before the patient consults a physician. It is striking that patients with MD complain little, often causing the late diagnosis in the course of the disease. Others have no specific complaints such as fatigue, weakness, loss of initiative, stomach-complaints or swallowing problems and in those cases the diagnosis MD will not be considered. The diagnosis myotonic dystrophy may be made by the neurologist based on the combination of myotonia (stiffness) and typically spread muscle weakness (figure). This pattern is not seen with other muscle diseases. The diagnosis can be confirmed by finding the characteristic “myotonic” discharging at EMG (electromyographia)-tests, or by DNA-tests.

Muscle weakness

Weakness of the facial muscles is found in an early stage: the eyelids start hanging down and if the patient is asleep part of the white of the eye stays visible. It is no longer possible to laugh broadly. The speech gets indistinct and it looks like the patient speaks “through his nose”. The temples shrink by atrophy of the jaw-muscles. The slightly expressionless feautures are denoted by the term myopathic face. In a later stage the mouth hangs open and swallowing is more difficult. The weakness and atrophy of the bending muscles of the neck (especially the M. sternocleidomastoideus) is often pronounced. Patients cannot raise their head when lying down. The loss of power in the muscles of the fore-arm and hands together with the myotonia make the hands clumsy. Regarding the muscles in the lower part of the legs especially the dorsal flexion (raising) of the feet is reduced: The patient starts shuffling, stumbles over minor roughness’ and falls more frequently. In a later stage of the disease the muscle weakness will increase and the muscles of the upper-arm and upper-leg will be affected.

Myotonia

Myotonia is a painless muscle stiffness, notably affecting the hands after a firm grip. The stiffness disappears spontaneously after a short time. Cold can evoke or stimulate myotonia. Complaints are: difficulties with letting loose a door-handle and after shaking hands or cramp when wringing out a cloth, especially in wintertime. Most patients are slightly troubled by myotonia and will not complain spontaneously about it. It is very well possible to suppress myotonia with medicine, but most patients have no need for it. Moreover this medicine can intensify the tendency for irregular heart-beat.

ORGAN COMPLICATIONS

MD is usually classified as muscle disease, but in fact it affects many organsystems. Table 2 gives a synopsis of the organ complications. A patient seldomly has all symptoms and complications. Some complications may be life-threatening. Swallowing problems can cause pneumonia by choking. Irregular heartbeat can cause unconsciousness during a short time but can also lead to sudden death. If timely diagnosed this can be treated by a heart-specialist with medicine or a pacemaker. The brains can be affected too: patients are slow, listless, and are lacking initiative; they need more sleep: many MD-patients regularly feel strongly inclined to doze of. If the disease starts at young age a developmental retardation is obvious.

During narcosis patients have increased risk for complications. These problems especially occur when before the operation the anaesthetist and surgeon are not aware of the patient having MD, which often occurs with persons with mild symptoms. There is a raised sensitivity for anaesthetics and heart- and lung-problems may lead to complications during and after the operation.

NATURAL HISTORY AND DIAGNOSIS

It is obvious that the progression of the disorder is strongly dependent on the age at onset. In most cases the disorder is slowly progressive. Only after many years, about 20 till 30 years from the onset of the disorder, the muscle weakness spreads to the muscles of the upper arms and upper legs. Most patients stay mobile, although their radius of action is restricted till their homes. Seldom (in about 5% of the cases) patients get bound to a wheelchair. Lack of spirit, sleepiness and poor initiative have a strong influence upon the daily life of the persons concerned. Few research is done on the progress of the disorder nor the age of death. During follow-up research on a group of children with the congenital type the risk of dying before the age of 30 was found to be ± 50% (Reardon, 1992). In the group of MD patients under our control we found the mean age of dying for patients with the adult type is 55 – 60. Most frequent causes of death are pneumonia, sudden death by irregular heartbeat and complications after an operation under narcosis. It is still difficult to make a prognosis for an individual patient with MD.

ASSISTANCE OF THE PATIENT WITH MYOTONIC DYSTROPHY

Therapy is impossible (See below for updated information)

There is no medicine which improves the natural course of myotonic dystrophy or postpones the age of onset. Nevertheless it is very important to stay alert on factors which can be influenced, particularly many organ complications can be treated well. The possibilities for treatment are dealt with per age group.

BREAKING NEWS ON TREATMENTS: A recent study (Dec 2015) by Japanese and Polish researchers have found that Erythromycin an FDA approved drug might help with the treatment of Myotonic Dystrophy. This drug helped with the treatment of gastric symptoms in patients with myotonic dystrophy in a separate study in 2002. As the Congenital form of the disease is more severe and affects the brain more your doctor may want to consider this treatment. Read more about this potential treatment here. Other treatments are in development as well

New-born babies

If a woman having MD herself is pregnant, careful control is recommended. Anyhow the delivery should be in a hospital. If during pregnancy there are indications the baby having  the congenital type (much amniotic fluid, reduced foetal movements), adequate care for the new-born baby should be foreseen before birth. Insufficient breathing often occurs, it is caused by a combination of underdeveloped lungs and weakness of the breathing muscles, artificial respiration is often necessary. If a caesarean section is necessary attention should be paid to possible aneasthetic problems for the mother. Other problems at delivery are weak labour and excessive loss of blood. Moreover in many cases the diagnosis with the mother is made after giving birth to a baby with the congenital type!

Table 2: Organ systems which may be affected, main symptoms and their treatment

Organ system
Symptoms
Treatment

Heart
irregular heartbeat

sudden death
regular ECG-examination, in case of abnormalities consult of a heart-specialist. Treatment with medicines or a pacemaker.

.

Lungs
pneumonia resulting from choking

hypoventilation
antibiotics,

prevention: sleeping upright, adjustment of diet (embankment of food, more often small meals, no eating in the evening),

in case of repeated  pneumonia consider gastrotomia, eventually examine the function  of the gullet.

breathing exercises

Stomach and gut
swallowing problem

diarrhoea/constipation
mince food

medication (cisapride)

Skin
baldness

Endocrine organs
diabetes

male: infertility by atrophy of testis

woman: irregular menses
diet, insulin injections

Eyes
cataract
operative extraction of the lens, implanting an artificial lens

Brains
slowness, apathy, sleepiness, mental retardation
temporizing, excluding hypoventilation as cause

Operation/

anaesthesia
repiratory failure,

raised sensibility for  narcotics and sedatives,

disorders in the functioning of the heart
inform the anaesthetist timely, adapt medication, control of respiration and functioning of the heart after an operation, if possible local anaesthesia, especially operations of the belly are risky
 

From little child till adolescent

The muscle weakness seen with congenital affected children decreases without therapy during the first years of life through further ripening of the muscles. In case of continuing hypotonia an adapted chair or chart may be necessary. Scoliosis (extreme lateral curvature of the spine) and contractures (joints becoming deformed) seldomly occur with MD.

Clubfeet must be treated by plaster bandage or sometimes by surgical correction. A retarded motor development needs treatment by physical therapy. Almost all children sooner or later learn to walk. The mental retardation (intellectual disability) is an important characteristic of the congenital type and of the childhood type (IQ mostly 50-80). The children with the congenital type learn to speak and learn to take care of themselves, but mostly they do not learn to read and write. It is important to test the child in time and to choose the right type of school based on the test results. Most children need special education. Take care that the child is not underestimated. Factors which may influence underestimation are the facial muscle weakness (slightly expressionless features), the problems with speaking, poor hearing and slowness. In the childhood type problems with learning may be the only symptom, without any physical complaint. Probably behaviour problems and poor concentration occur frequently. Often children with MD get difficultly in touch with other children. Assistance by an educationist or psychologist is preferable. The problems with speaking result from a combination of weakness of the palate, other muscle problems and the generally retarded development. Speech therapy is then required. Medical problems such as abdominal complaints and inflammation of the ears and squinting have to be treated in the usual way. To co-ordinate the care for the child with MD it is wise to consult regularly a pediatrician or children’s neurologist.

Adult

The role of physical therapy in maintaining or improving the muscular strength is limited. According to recent research from E. Lindeman, rehabilitation doctor, muscle-strengthening exercises do not or scarcely influence the strength in the legs, but do not harm. If a patient stumbles frequently by weakness of the lower leg muscles consultation with the rehabilitation doctor is warranted, a boot or a foothold to prevent stumbling can be advised. With more extensive muscle weakness and problems with walking a walker or shopping-cart can do good service. Total dependence on a wheelchair occurs only in a very late stage of the disease; sometimes the wheelchair is only used outdoors. In case of weakness of the muscles of the neck make provisions for good  headrests in chairs especially in the car, also an adjusted collar may be necessary. At adult age the emphasis is on organ complications (table 2, last column).

SOCIAL FUNCTIONING, LIVING AND WORKING

Many patients for a long time can function independently in a family. Sometimes the house has to be adjusted and along the staircase a lift can be installed. The sleepiness and lack of initiative can cause problems. Especially the partner and inmates suffer from it. The patient himself often is not aware of it. Also at work these symptoms may cause problems. Employment for many patients is still possible for a long time if the tempo can be adjusted and the employer and the colleagues appreciate the problems of the patient. If this is not possible, working in a sheltered employment may give the solution. Many women are able to keep the house independently for a long time if inmates or others stand by. Sometimes adjustments in the kitchen are useful. Because of the complexity of the problems which arise in many cases ( co-ordination of the) assistance by a neurologist or rehabilitation doctor is recommendable. If necessary psychosocial assistance (for instance by a welfare worker) can be tendered. In case of mental disability independent functioning is not always possible. At adult age the patient will be admitted to a day-care centre or a home for mentally disabled people.

References

1. Handboek Spierziekten. Eindredactie YS. Poortman. De Fontein, Baarn, 1994.

2. Harper PS. Myotonic dystrophy, 2nd edn. WB Saunders, London and Philadelphia, 1989.

3. Höweler CJ. Nieuwe inzichten bij dystrophia myotonica. Ned Tijdschr Geneeskd 1988; 132:1076-1078.

4. Brunner HG, Höweler CJ, Smeets HJM, Wieringa B. Een instabiele mutatie als oorzaak van myotone dystrofie. Ned Tijdschr Geneeskd 1993; 137:2469-2472.

5. Lindeman E. Strength and effects of training in myotonic dystrphy and HMSN. Thesis 1996. Rijksuniversiteit Limburg, Maastricht.

6. Reardon W, Newcombe R, Fenton I, Sibert J. Harper PS. The natural history of congenital myotonic dystrophy: mortality and long term clinical aspects. Arch Dis Child 1993; 68:177-181.