DUCHENNE MUSCULAR DYSTROPHY (DMD) ; Physiotherapy/ Physical Therapy for DMD,

DUCHENNE MUSCULAR DYSTROPHY (DMD)

Duchenne dystrophy is not only the most common and also the most severe types of muscular dystrophy.

Incidence

1 out of 3,000 to 4,000 male babies born.

(As the disease is linked it is noticed only in males. The female carrier transmits the disease through genes to the male child. In the majority of the female carriers there are no apparent signs or symptoms.)

Clinical Presentation

The disease may not show any indication during the early infancy although in some of the children walking may not be attained even at eighteen months of age.

Onset

The disease is usually noticed at about three years of age. 

It has a subacute type of onset. 

The parents may notice a very slow clumpsy walking in their child with frequent falls. 

Climbing upstairs becomes a very laborious work and cannot be attained without any support.

Progression

Gradually the child develops a lordotic posture due to gross weakness of the abdominal muscles. 

Getting up from squatting is impossible without support and the child adopts the typical Gower’s sign which consists of a typical getting up manner by the child using support of various parts in the lower limb. It appears as though he is climbing up into standing using support of his lower limb. 

He develops waddling gait and is no longer able to jump or run around like any other kid of his age. 

Walking becomes progressively difficult. For some period the child may continue to be ambulant with the help of orthosis, but eventually by around 8 to 12 years he is confined to bed and mobility can be achieved only with the help of wheelchair.

Weakness

The muscular weakness will be typically of a lower motor neuron type. 

The muscles which commonly develop progressive weakness are plantar flexors, evertors, quadriceps, gluteus muscles, long extensors of the hand, biceps, triceps, deltoid, pectoralis, latissimus dorsi and some shoulder girdle muscles.

Hypertrophy

In contrast to other lower motor neuron type of disorder where there is wasting, DMD child will show hypertrophy of certain muscles like plantar flexors, quadriceps, deltoid, temporalis, hip extensors and even pectoralis. This hypertrophies is called as Pseudohypertrophy as it is caused due to abnormal deposition of fatty tissue and fibrous tissue in the muscle mass.

Reflexes

The superficial reflexes are lost and eventually even the deep tendon jerks are lost.

Contracture and Deformity

The muscular imbalance produced makes the limb and trunk prone for developing contractures and deformity.

Hip deformity due to TFL contractures, knee flexion deformity, ankle plantar flexion deformity, lordosis, scoliosis, etc. are noticed.

Functional Independency

The functional capacity of the child keeps deteriorating day by day and eventually the child will be totally dependent for dressing, bathing, toileting and even rolling in bed at night.

Respiratory Insufficiency

Although diaphragm is the only muscles which is never involved in DMD, respiratory complication are inevitable in this condition mainly because of the total inactivity. 

The child frequently gets respiratory infection due to lack of mobility and adequate chest expansion. 

Death is usually due to respiratory complication.

Intelligence

Usually the mean IQ of these children is around 75 to 80 percent. However it does not deteriorate with age.

GIT Abnormalities

Due to immobility the child may have constipation, vomiting due to pressure of superior mesenteric vessels on the third part of duodenum may be noted.

Obesity

Due to total inactivity and compensatory over eating the child may put on too much of weight if not guided properly.

Emotional Disturbances

The constant deterioration of the child comes as a shock to the family member who generally needs some time to understand the situation completely and cope up with it. Needless to say, both the child and the parents are depressed looking at the helpless situation.

Investigative Findings

The CPK level is very high

EMG shows typical myogenic pictures with small amplitude, small duration polyphasic potential. The interference pattern is early. Sometimes later on during the course of the disease there may be presence of fasciculation potentials.

The muscle biopsy will show extensive variation in the size of the fibers with increased infiltration of fatty tissues and fibrous tissues.

PT Management

The management of dystrophy is a team approach and none of the team member can ever claim superior influence then his counterpart because it requires interdisciplinary approach the stage of influence by various rehabilitation professional may be different.

The physiotherapist role in a child with muscular dystrophy consists of the following:

Parental Counseling

Unlike parents of children with neurological problems such as CP, polio, etc. the parents of a child with dystrophy tends to develop a psychological state which is different from a stage of shock. They have seen a child born normal, attaining a normal milestone, leading a absolutely normal life like any other kid and then gradually deteriorating.  Thus they need to be counselled in a polite and correct way regarding this probability.

Exercises

The patient should be encouraged to lead active life as long as possible. 

Activities of daily living by itself can strengthen and maintain flexibility of various muscles in the functional range. 

Mild strengthening techniques especially using PNF techniques like Repeated contraction can prove to be beneficial. 

The therapist should avoid giving vigorous strengthening exercises as they may aggravate damage to the muscles and thus may prove to be more harmful than beneficial. 

Of course the functional capacity of the child will decline consistently but one should aim at prolonging the independence capacity of the child. 

In addition to trying and maintaining the muscle strength and property as long as possible, the therapist should also give mobility exercises to the child. 

These mobility exercises taught should be simple and something that the child can do actively in the house without having to depend on someone else's assistance. 

Parents of the child may also be taught these exercises so that they can assist the child especially in the later stages. Suspension and modification in the therapeutic exercises should be determined by periodic rechecks at least once every three months.

Preventing Contractures

Contractures set in very early and are quite severe which could be due to direct involvement of the muscle itself. 

The two joint muscles of the body like the gastrocnemius, tensor fascia lata, rectus femoris and hamstring in the lower limb are very prone to develop tightness and contractures. 

In the upper extremity, the forearm pronators, wrist flexors, finger flexors are often tight. 

Simple stretching techniques for these muscles may be taught to the parents so that these exercises can be done at home. 

Advises like lying prone for sometime everyday will prevent hip flexion deformity. This can be done while watching TV, while playing some games, etc. 

Stretching should be done gently but up to the maximum range possible so that walking can be retained as long as possible. 

After some time splinting may become necessary especially to maintain knee extension, ankle dorsiflexion. But the splint should be made of light polypropylene type of material so that it can be used as a functional splint also. 

Deformities of the lower limb can cause multiple secondary problems like for instance asymmetric muscle tightness of an iliotibial band causes scoliosis at the spine, pelvic tilt, subluxation of the hip, etc. The collapsing spine needs proper support. 

Braces to maintain extension of the spine become necessary to prevent undue strain on the vertebral column which can otherwise cause mechanical pain that will only add on to the discomfort to the patient.

Home Adaptation

Modification in the house for easy accessibility and functional independence of the patient can be best brought about by contributions from therapists, social workers and local housing authority. The pathways, width of the doorway, provision of ramps or lift, support bars in the toilet, accessibility of the patient into various rooms, should be considered in the modification agenda.The height of the bed, chair and toilet are critical for independence. Moreover at one stage the parents or attainder may have to transfer the child by lifting hence the height of various furniture is very essential. The mattresses should be firm and resilient so that bed activities and transfer of the patient becomes easier. In later stages providing an alarm bell near to the cot of the child will make night care much more easier.

Schooling

In the initial stages when the child is ambulant local schools can manage but as the child’s weakness becomes quite increased such that it interferes with his walking then at that stage special schools may be necessary. Sending the child with gross muscular weakness to ordinary schools will definitely set a complexity in him which may interfere with his mind set preventing him from concentrating on his education. Moreover normal schools are not accessible for wheelchair bound people thereby locomotion of the child becomes difficult.

Recreational Activities

As the child is absolutely normal mentally he is well aware of his deteriorating situation but cannot resist the temptation of getting involved in various sports despite experiencing some sense of difficulty. Hence the parents should wisely advise the child against getting involved in various contact sports that may cause further injuries. But some kind of recreational activity should be given which won’t be physically demanding like playing carom, chess, watching television, bird watching, fishing, etc. The situation is quite pitiful because unlike a mentally retarded child, a child with muscular dystrophy has all the desire to enjoy games of a physically normal child but is forced to abstain from these.

6. Encouraging Functional Independency

The usual age at which walking becomes impossible varies between 8 to 12. The therapist should encourage walking as long as possible because it is one of the ways of exercising the muscles of the lower extremities. Also walking keeps the spine in extension as well as prevents any contractures and deformity. But too much exertion should be discouraged at each stage of this condition. In the initial stages the child walks without any calliperization but eventually he will need some light weighted orthosis to continue walking. As the condition is progressive the functional independence of the child keeps deteriorating. It is not in our capacity to prevent this deterioration but one should make all possible attempts to slow down this process of deterioration and try to keep the child active as long as possible.

Lifting Techniques and Transfer

By the time a child becomes totally non-ambulant, he is already quite grown up and may even become heavy due to lack of mobility hence the parents, teacher and other attainers of the child are taught correct lifting techniques like use of belt, so that they don’t strain themselves. The child may be taught how to roll over in the bed, use of sliding boards etc. for transfer. However the child should be encouraged to carry out all his activities on his own as long as possible.

Wheelchair Management

Once the child no longer is able to walk even with orthosis then it is wiser to advise him to use the wheelchair. The wheel chair should be used only as a mode of transfer because the more time the child spends on the wheelchair the more are the chances for him to develop contractures and deformity. Initially the child may be able to manage maneuvering the wheelchair with his hand but as the weakness progresses further involving the upper limb musculature then a motorized wheelchair becomes necessary. However in Indian conditions managing with a wheelchair becomes difficult due to horrible road conditions, inadequate space in the house, etc. The wheelchair should be of appropriate size for the child so that the sitting posture of the child is good with 90 degree angulation at the knee, foot support should be good, the back support should be such that the child doesn’t stoop or side bend to any one side. When the muscle  power becomes poor and the child is unable to maintain his position in the wheelchair, lateral support or strapping may be added.

Secondary Complication that Needs to be Prevented

Due to progressive muscular weakness and immobility, the child should be prevented from developing the following secondary complication, which will only increase the discomfort of the patient.

Spinal Deformity

Muscular imbalance to the trunk coupled with abnormal sitting posture can cause spinal deformities like scoliosis and kyphosis. Hence the spine of the child should be regularly inspected for spinal deformity. Various stretching procedures may be carried out to prevent opposite group of muscles from going into contractures. Spinal braces with proper padding may be given to prevent the spinal deformities from aggravating.

Obesity

Lack of normal mobility makes the child gain weight. The diet of the child should be strictly the ones rich in protein and carbohydrate without any fat. Eating habits should be properly supervised to prevent the child from becoming a mechanical eater who is being left out with less other options.

Fractures

As the ambulation of the child becomes more and more difficult the chances of the child falling and developing a fracture is more. Moreover due to decreased weight bearing, there is demineralization of the bone which increases the chances of stress fracture. The chances increase especially when the child is walking around with his callipers. This can be prevented if the child is kept under careful observation and not allowing him to walk alone in places where there are a lot of obstacles.