Symptoms
The affected children usually stand out due to delayed motor development: they move little, learn to walk with a delay, fall frequently and show themselves “clumsy”. After learning to walk, the calves often increase considerably in size, the reason for this is the pseudohypertrophy of the calf muscles outlined above. In the course of the disease, the abdominal and back muscles are increasingly affected, which leads to an increasingly strong hollow back in the patients.
This is accompanied to varying degrees by shortening and hardening of the muscles, which lead to additional restrictions of movement, especially in the hip, foot and knee joints. Muscular atrophy in the shoulder region leads to protruding shoulder blades (med. : Scapulae alatae, “angel wings”), while atrophy of the neck muscles makes it difficult to straighten the head when lying down.
Most patients are dependent on a wheelchair from about the age of 8-12, and over time, a spinal curvature (scoliosis) and deformation of the chest often develops. Over time, this and the progressive deterioration of the respiratory musculature lead to an increasingly limited respiratory capacity and possibly to a serious endangerment of the patients. The restricted breathing in turn promotes infections of the lungs and airways (see pneumonia), which pose an additional threat to patients.
In the late stages of the disease, patients must be given artificial respiration. In the course of the disease, the heart muscle weakens, which leads to cardiac arrhythmia. In about 1/3 of the cases, there is also an additional intellectual impairment, which manifests itself as learning disability.
Exudative diseases (differential diagnoses)
The clinical picture and the course of Duchenne muscular dystrophy are very characteristic. The Becker or Becker-Kiener muscular dystrophy shows a basically similar disease mechanism which has to be distinguished from Duchenne dystrophy.In muscular dystrophy of the Becker type, the dystrophin protein is not missing but is present in a strongly altered form so that it can only perform a residual function. The affected muscle parts are similar to those in Duchenne dystrophy, but the course is much slower and the expression is less pronounced. In the early stage, there are other possible reasons for a delayed development, such as brain damage due to oxygen deficiency before or during birth.
