Embedded Files
beneficial therapeutic intervention exists in infants with type I SMA. Therapies would need to be administered within the newborn period for maximum benefit which could potentially be accomplished through a newborn screening program for SMA. Management A first consensus for standards of care of SMA has been achieved in recent years [43]. Because of the complexity of medical problems associated with the diagnosis of SMA the primary care plays a central role in coordinating the follow-up and care. The role of follow-up coordination has to be managed by an expert in neuromuscular disorders and in SMA who is able to plan a multidisciplinary intervention that includes pulmonary, gastroenterology/nutrition, and orthopedic care. Pulmonary disease is the major cause of morbidity and mortality in SMA types I and II and may occur in a small proportion of patients with type III. Respiratory failure is caused by a greater involvement of expiratory and intercostal muscles whereas the diaphragm is relatively spared. Swallowing dysfunction and reflux are important contributors to pulmonary morbidity. Patient initially has recurrent chest infections, followed by nocturnal oxygen desaturation, nocturnal hypoventilation, and then daytime hypercarbia [52-54]. Recommendations for respiratory assessment include evaluation of cough effectiveness, observation of breathing, and monitoring gas exchange. Respiratory muscle function tests are indirect measures of cough effectiveness and include peak cough flow, maximal inspiratory pressure, and maximal expiratory pressure. In case of a diagnosis of weak cough effectiveness cough-assist device and oral suction pump is advised. Overnight pulse oximetry with chart recording can be used to screen for nocturnal hypoxemia. Polysomnography with transcutaneous CO2 measurement are useful tools to assess sleep-related hypoventilation. When nocturnal hypoventilation is detected nocturnal noninvasive ventilation (NIV) must be started with bilevel positive pressure support. NIV can be used as a routine therapy (also in daytime when it is needed) or as a palliative tool. A key goal is to prevent pediatric intensive care unit stays and avoid tracheotomy if possible. NIV should be the first choice to avoid tracheostomy. Additional therapies are medical or surgical gastroesophageal reflux disease management and nutritional support orally or via a gastrostomy. In SMA patients muscle weakness resulting in contracture formation, spinal deformity, limited mobility and activities of daily living, and increased risk of pain, osteopenia, and fractures. Infants should have appropriate evaluation for their presenting musculoskeletal and functional deficits. Goals of therapy and surgery depend on functional level and the family’s wishes. Whenever possible, walking should be encouraged with appropriate assistive devices and orthotics. Hip subluxation is rarely painful, and there is a high risk of recurrence despite surgical correction. Spinal orthoses may provide postural support but do not prevent curve progression and may impair respiratory effort. Scoliosis surgery appears to benefit patients who survive beyond 2 years of age when curves are severe and progressive and should be performed while pulmonary function is adequate. Over the past few years newer surgical treatments have been developed for the management of severe scoliosis in skeletally immature patients prior to definitive spinal fusion. Growing-rods [55] or Vertical Expandable Prosthetic Titanium Rib (VEPTR) [56] may be used to prevent the progression of the curve in very young children when bracing isn’t successful. D’Amico et al. Orphanet Journal of Rare Diseases 2011, 6:71 http://www.ojrd.com/content/6/1/71 Page 6 of 10 Therapeutic strategies Actually no cure is available for SMA, and the pathogenesis of the disorder is not completely understood. In the last few years however many progresses in understanding the molecular basis of the disease has been made and different therapeutic approaches are developing [57]. Pharmacological therapies Several mechanisms have been targeted in SMA drug trials such as neuroprotective drugs to rescue motorneurons (as
Report abuse