May 6, 2009 — Duchenne muscular dystrophy (DMD), an X-linked disorder, is the most common muscular dystrophy in children, presenting in early childhood and characterized by proximal muscle weakness and calf hypertrophy in affected boys. Patients usually become wheelchair-bound by the age of 12 years, and die of cardiorespiratory complications in their late teens to early twenties. Advances in the management of DMD, including treatment with corticosteroids and the use of intermittent positive pressure ventilation have provided improvements in function, ambulation, quality of life and life expectancy, although novel therapies still aim to provide a cure for this devastating disorder. The clinical features, investigations, and management of DMD …show more content…
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The most frequent presenting symptoms are motor delay or an abnormal gait. Affected boys may present with difficulty in running or getting up from the ground, frequent falls, or toe-walking. Most present between three to five years. Less frequent presentations include language or global developmental delay, or incidentally raised serum creatine kinase or transaminase levels when these investigations are performed for other reasons.

Weakness

Proximal weakness affects the lower before the upper extremities, with progression to the point of wheelchair dependence. Eventually distal lower and then upper limb weakness occurs. Weakness of neck flexors is often present at presentation, and most patients with DMD have never been able to jump. Patients have a waddling gait, calf enlargement, and lumbar lordosis which disappears on sitting. Most become wheelchair-bound by age 11-12 years [2]. …show more content…
[10] Four stages of hypercapnic chronic respiratory failure are typically described: Stage 1, sleep disordered breathing without hypercapnia; Stage 2, sleep disordered breathing with hypercapnia during rapid eye movement (REM) sleep; Stage 3, with hypercapnia during REM and Non-REM sleep; and Stage 4, diurnal hypercapnia. [10,11,12,13,14] At Stage 4, mean survival is less than 12 months without respiratory support. [15]

Intellectual disability

Intellectual disability is seen in 30% of boys with DMD, with the average intelligence quotient (IQ) being 85, normally distributed one standard deviation below the population norms. [16,17,18] Verbal IQ is more impaired than performance IQ. [16,19] Intellectual disability is not correlated with the severity of weakness. [16,20,21] Boys with DMD also have a higher incidence of attention deficit hyperactivity disorder [22,23]

Orthopedic