This 7-year-old boy presented with history of difficulty in standing up and had delayed motor mile stones.
1. What is the sign called which is shown in the picture above?
2. What is the most probable diagnosis?
3. What is the prognosis of this disease?
4. Which cardiac problem is likely in such children?
5. Why males are exclusively affected?
Answers And Discussion:
1. What is the sign called which is shown in the picture above?
Answer: This sign is called as Gower’s sign. (classical climbing over one’s own legs to stand up from sitting posture is known as Gower's sign)
2. What is the most probable diagnosis?
Answer: The most probable diagnosis is Duchenne muscular dystrophy (DMD).
Presence of prominent calf muscles in a boy with classical Gower’s sign and history of delayed motor mile stones is very much suggestive of Duchenne muscular dystrophy. Presence of raised CPK and absence of dystrophin in muscle biopsy would confirm the diagnosis.
It is initially characterized by delayed motor development in the child. Later on other characteristic features of this disease as calf muscle hypetrophy, Waddling gait (Trendelenburg gait) and classical climbing over one’s own legs (Gower’s sign) become apparent. Gower’s sign is seen by 3 years and
is fully manifested by 6 years. Along with the weakness of the muscles in lower limbs there is also weakness of the shoulder girdle muscles in these children. Pain is usually not associated with this weakness. Mental retardation is usually found to be associated with this disease. Hypertrophy is observed in tongue and the muscles of forearm in addition to the obvious hypertrophy of calf muscles. Though they appear hypertrophied but are actually weak in strength.Similarly, intellectual impairment occurs in all patients although only 20-30% have IQ less than 70.
CPK is raised classically and muscle biopsy reveals degeneration of muscle. If CPK levels are high in a child suspected to suffer from DMD then there is high probability of DMD. But if the CPK levels are normal then it definitely excludes the possibility of DMD in the child. Thus high level of CPK increases the possibility of DMD but the final confirmation of the diagnosis is possible only if the muscle biopsy reveals too low level of dystrophin in the muscle.
3. What is the prognosis of this disease?
Answer: This disease has a relentless progressive course. It ultimately results in bed ridden state of the child. Child in later stage is even unable to comb his hairs. Death usually occurs by about 18-20 years. The cause of death may be respiratory failure in sleep, intractable congestive cardiac failure, pneumonia, aspiration or airway obstruction.
Management
Maintenance of good nutrition and physiotherapy are the mainstays of its management. Steroids have no role in its management.
Myoblast transfer is the latest technique being tried for its management. Its success is yet not established. In it myoblasts from the normal muscles of close but unaffected relatives usually the father is cultured in vitro. It is then injected in the dystrophic muscle. Simultaneously, the patient is immunosuppressed to prevent the rejection of the graft.
4. Which cardiac problem is likely in such children?
Answer: Cardiac assessment is important in these patients as cardiomyopathy is usually associated with it. It is a constant feature of DMD.
5. Why males are exclusively affected?
Answer: This disorder is classically transmitted as an X-linked recessive trait. So, it
is mostly seen in boys.
