Diagnosis and management of Duchenne muscular dystrophy

Authors


Earlier this year a two-part article was published giving recommendations on best practice in the management of people with Duchenne muscular dystrophy (DMD).1,2 A largely North American group of 84 experts in different aspects of care were commissioned by the US Centers for Disease Control and Prevention to form panels to reviewe available evidence and where this was lacking they used the ‘RAM’ method to reach conclusions. The latter was preferred because it is not consensus driven and, therefore, reveals areas of disagreement as well as agreement. The result is a very impressive overview. It comes at an exciting time for people with DMD because survival has begun to improve sharply over the last decade using currently available treatments, and there is the heady prospect of benefits from new gene modulating therapies currently undergoing phase 1 and 2 studies.

The document covers all aspects such as diagnosis (where neurophysiological investigations are no longer recommended), neuromuscular and orthopaedic management, rehabilitation, respiratory, cardiac, gastrointestinal, speech, swallowing, and nutritional aspects, and in particular gives a very welcome emphasis to psychosocial aspects. It emphasizes the importance of the availability and involvement of multidisciplinary care teams for patients, although it sensibly does not go into the details of how and where the facilities should be based since this will naturally vary between centres and countries. The panel also highlights the vital role of care coordinators who need to be highly trained professionals in their own right. Although mainly reflecting best North American practice, it can be easily adopted by countries with similar facilities, as its authors hope that it will be.

The RAM methodology means that there is overt discussion of the limitations of evidence. Currently controversial areas are handled sensitively. In diagnosis this includes whether or not muscle biopsy is needed or justified. By far the biggest section concerns steroid therapy which, understandably, the panels advocate strongly, recommending daily rather than intermittent regimens, although current practice worldwide may not reflect this. There seems little doubt that daily steroids do have more benefit but nobody is yet sure how high the price might be in terms of increased side effects. Other uncertain areas include whether steroids should be given to non-ambulant patients, including steroid naïve ones, which expert opinion is increasingly supporting; cardiac care, where the panel comments that current monitoring may not adequately predict who is going to develop cardiac complications; and bone care where again there is little data and a wide variety of opinion.

There is very little that could be added, but as always, some queries still need answers. In younger people steroid dosage is usually decided by weight, with a maximum of 30 to 40mg per day. If a younger child gains weight with steroids, should the dose be increased according to their actual weight or to their expected weight if they had followed their previous centile? In terms of weight more generally, should we expect males with DMD to follow the same centiles as those without, since the muscle wasting that is part of the disease will normally lead to reduced weight? How should height be best measured? In addressing adverse effects such as growth retardation or delayed puberty, the panel suggests that endocrine evaluation should be considered, but if an endocrinologist confirms that these are the result of steroid therapy, what should be done at that point? In those where side effects are unacceptable, how should the steroids be weaned? In adulthood, all too frequently leaving school or college means an isolated existence at home without any social facilities available. While this is not so much a health service issue as a more general social issue, and it can apply to all people with significant disabilities, what specifically can be done to help? What about sexual needs too? In the section on emergency care, the guideline states, ‘Use of opiates and other sedating medication is essential as is the use of oxygen without ventilation owing to the risk of hypercapnia’, which is difficult to understand. Can any useful suggestions be made for patients in countries with less resources? Hopefully with more experience and more data, future versions will be able to give more advice on these aspects of care as well.

Overall, this is a very welcome practical guide that will help set expectations for families. As such, it has already been promoted by some patient support groups. For those services with funding difficulties it should provide useful support in arguing for more resources. For all of us it will help set standards.

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