When to suspect DMD

The first suspicions are usually raised by one of the following signs (even when there is no history of DMD in the family):

Problems with muscle function

It is often a family member who notices something is wrong. Boys who have DMD walk later than other boys their own age. They have enlarged calf muscles and have trouble running, jumping or climbing stairs. They fall easily and may have a tendency to walk on their toes. They may also have a speech delay. One of the classic signs of DMD is what is known as the “Gowers’” manoeuvre or sign, where the boy has to use his hands and arms to “walk” up his body in order to push himself to an upright position. This is due to weakness in the hips and thigh muscles (see photos below).

High levels of the muscle protein creatine kinase (CK)

in a blood test. The finding of a high CK level should prompt an urgent referral to a neuromuscular specialist for confirmation of the diagnosis. High levels of CK are seen in people with other kinds of muscle conditions and a high CK alone is not enough to confirm DMD.

High levels of the “liver enzymes” AST and ALT

in a blood test. High levels of these enzymes in the blood are often associated with liver disease, but muscular dystrophies can also cause this elevation. Unexpectedly high levels of these enzymes without another cause should raise the suspicion that the CK will be high as well and so a diagnosis of muscular dystrophy might be suspected. A liver biopsy is not recommended.

Delayed speech development

Children with DMD often also have some delay in their speech development and sometimes that is the symptom that is first noticed (see Psychosocial management).

Information based on consensus statement (published in January 2010)