A committee convened by the American Academy of Neurology has published new recommendations for doctors who see children with congenital muscular dystrophy
This spring, the American Academy of Neurology (AAN) released a guideline for the diagnosis and care of children with congenital muscular dystrophy (CMD), a group of early-onset, genetic disorders that can involve skeletal (including respiratory) muscle weakness, heart problems, brain and eye abnormalities, and contractures (frozen joints).
An early-onset disease with many genetic causes
Traditionally, CMD was defined as a form of muscular dystrophy in which symptoms develop within the first year of life, but the AAN suggests that the term be broadened to include muscular dystrophies with symptoms that begin within the first two years of life.
Most CMDs fall into one of three categories: those related to abnormalities in a protein known as collagen 6; those related to a deficiency of the merosin (laminin 211) protein; and those related to abnormalities in the alpha-dystroglycan protein. All three of these proteins normally help muscle fibers attach to the tissues that surround them, and they may play a similar role with respect to brain tissue. More than a dozen different genes can, when flawed, cause CMD.
The new guideline for CMD diagnosis and care is based on a review of the medical literature by a panel of specialists that included several MDA-associated clinicians. It was published online March 30, 2015, in Neurology.
Recommendations for diagnostic procedures or care were rated by the AAN panel according to the strength of the recommendation. The AAN uses the following rating scale:
To read a family-friendly summary of the guideline on the AAN website, see Congenital Muscular Dystrophy: Summary of Evidence-Based Guideline for Patients and Their Families.
Monitoring of heart, breathing, nutritional status, mobility, educational needs emphasized
Here are some highlights of the recommendations made by the AAN-convened committee.
Consultations: Physicians caring for a child with suspected CMD should consult a pediatric neuromuscular disease specialist (level B), who should coordinate the multidisciplinary care when possible (level B). Genetic counselors can be consulted to help families understand genetic test results and make family planning decisions (level B).
Diagnosis: In attempting to pinpoint a CMD subtype, physicians should take into account the patient's ethnicity and geographic origin; the patterns of weakness and contractures; the involvement of the central nervous system and other organ systems; and the level of serum creatine kinase enzyme, which correlates with active muscle damage (level B). In addition, depending on the circumstances, physicians should consider a muscle biopsy to look for specific protein abnormalities, an MRI scan of the brain and/or imaging studies of skeletal muscles (levels B and C). They might also considering ordering targeted (specific) genetic testing or, in some situations, whole-exome or whole-genome (nonspecific) genetic testing (level C).
Respiratory care: Physicians should monitor pulmonary function in awake and asleep states in CMD patients, with ongoing monitoring frequency based on the child's status (level B), and they should inform families that respiratory insufficiency may not be obvious (level B). They should refer children with respiratory insufficiency to specialists who are experienced in managing the interacting respiratory and digestive abnormalities that can occur in CMD (level B).
Cardiac care: Doctors should refer all children with CMD for a baseline cardiac evaluation, with intervals of further evaluations dependent upon the baseline results and the subtype diagnosis (level B).
Nutrition and swallowing: Specialists should coordinate with primary care providers to follow the nutritional and growth status of patients with CMD (level B) and should order evaluations with swallowing therapists, gastroenterologists and/or radiologists if there is evidence of failure to thrive or respiratory symptoms or both (level B). A multidisciplinary team should consider feeding tube placement, with or without additional surgery to prevent reflux of stomach contents into the esophagus, in appropriate circumstances (level B).
Anesthesia and sedation precautions: Doctors should discuss the increased risks associated with anesthesia or sedation with CMD patients' families (level B) and should monitor children with CMD for longer than usual after procedures involving these (level B).
Mobility, comfort and communication: Doctors should refer CMD patients to physical, occupational or speech therapists, seating and mobility specialists, rehabilitation specialists, or orthopedic surgeons as needed to maximize function (level B). They may recommend range-of-motion exercises, bracing, procedures to lengthen heel cords (Achilles tendons) or a combination of interventions, depending on circumstances (level B). They may want to avoid using neuromuscular blocking agents, such as botulinum toxin, to treat contractures, unless the contractures are causing significantly greater impairment than would potential weakening of the muscle targeted with the blocking agent (level C).
Education: Physicians should refer children with CMD to developmental specialists, education specialists or special education advocates, when appropriate (level B).
For more information
To learn more about CMD, see Taking Aim at Congenital Muscular Dystrophies.