Several experts presented their views of "best practices" for care of people with neuromuscular disorders at MDA's 2012 Clinical Conference, held in Las Vegas March 4-7.
Many questions remain about optimal care in these disorders, but it's clear that attention to heart and respiratory function are of paramount importance.
This article looks at:
Cardiac care in muscular dystrophies
Elizabeth McNally, a cardiologist at the University of Chicago and expert on the genetics of heart disease, discussed diagnosing and treating the cardiac aspects of several forms of muscular dystrophy.
Regarding cardiac care in DMD and BMD, McNally said:
- A precise genetic diagnosis, including exact location of the mutation in a particular gene, can sometimes help predict the risk of cardiac disease in people with these conditions. For example, in DMD and BMD, mutations in the part of the dystrophin gene that codes for the "actin binding domain" of the dystrophin protein are associated with a higher risk of heart disease.
- Drugs known as angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and beta blockers can improve heart function.
- In some circumstances, other drugs can be considered to help manage DMD- and BMD-associated cardiomyopathy (cardiac muscle damage). These include aldosterone antagonists, diuretics and digoxin.
- Some patients may require drugs known as antiarrhythmics (heart rhythm stabilizers) or anticoagulants (anti-clotting drugs). Respiratory care, starting by age 15, can help cardiac function.
- Some people with DMD or BMD can benefit from an implanted defibrillator if a cardiac measurement known as the ejection fraction is less than 35 percent.
- Respiratory care, starting at age 15, can help cardiac function.
- There is generally more scarring in DMD- and BMD-affected hearts with cardiomyopathy than in hearts with cardiomyopathy from other causes.
- Regular surveillance for cardiac dysfunction via echocardiograms, electrocardiograms (EKGs),Holter monitoring and/or cardiac magnetic resonance imaging (MRI) are important in DMD and BMD.
Regarding cardiac care in EDMD, McNally said:
- EDMD can be caused by mutations in either the emerin gene or the lamin A/C gene. In lamin A/C-caused EDMD, the cardiac involvement may be more pronounced than the skeletal muscle involvement.
- EDMD related to a lamin A/C gene mutation may lead to sudden cardiac death, sometimes preventable with a pacemaker or implantable cardioverter defibrillator (ICD).
Regarding cardiac care in MMD (also known as DM), McNally said:
- Both type 1 MMD (MMD1 or DM1) and type 2 MMD (MMD2 or DM2) are associated with cardiac involvement, particularly atrioventricular heart block (blockage of the signal that normally moves from the upper to the lower part of the heart); arrhythmias (heart rhythm abnormalities); and a risk of sudden death.
- Older patients also may develop coronary artery disease.
- Some patients need anticoagulant medications, and some may need electronic devices, such as a pacemaker or ICD.
- Respiratory muscle weakness can lead to cardiac involvement.
- People with MMD should undergo regular cardiac testing.
Respiratory care in neuromuscular disease
Lisa Wolfe, a pulmonologist and specialist in sleep medicine at Northwestern University in Chicago, discussed respiratory care in neuromuscular disease.
With respect to suveillance of respiratory function for people with neuromuscular disease, Wolfe said:
- Many people with neuromuscular disorders don't report difficulty breathing unless they are lying flat on their backs. Doctors should screen for respiratory impairment by asking patients to lie flat and then asking about their breathing.
- Doctors should ask patients with neuromuscular disease whether they can cough and whether they can clear mucus from their nose. These maneuvers reflect the strength of important respiratory muscles that can weaken in neuromuscular disease.
- Testing for respiratory dysfunction may involve overnight oximetry (oxygen measurement), carbon dioxide screening or a polysomnogram (full sleep study).
- Sleep studies, though widely used to diagnose various conditions, are only needed in neuromuscular disease under certain circumstances. A sleep study should only be undertaken in a sleep lab that understands neuromuscular disease and has a neuromuscular disease protocol.
- If the criteria for an assistive ventilation device are met by the person with a neuromuscular disease, it may not be necessary to do other respiratory testing.
- Starting ventilation (mechanical breathing assistance), if that appears warranted, should not be delayed while waiting for the results of a sleep study.
Regarding respiratory interventions for the upper airway (nose and throat), Wolfe said:
- Breathe Right nasal strips (a product of GlaxoSmithKline), which hold the nostrils open, can be helpful.
- Antihistamine medications, normally thought of as allergy treatments, can help dry up secretions and relieve congestion.
For respiratory interventions targeting the lower airway (trachea and lungs), Wolfe said:
- A technique called breath stacking— taking in a series of breaths without exhaling — can be beneficial and can be accomplished by using a manual resuscitation bag that has a one-way valve.
- Manually assisted coughing or a mechanical insufflator-exsufflator (such as the CoughAssist by Philips Respironics) can improve the effectiveness of coughing.
- High-frequency chest wall oscillation devices can help loosen secretions.
- People with ALS generally need help with both inhalation and exhalation.
- Doctors should offer patients multiple techniques and allow choice. Assisted ventilation devices need to be appropriate for the particular situation in which they're being used.
Exercise in neuromuscular disease
Gita Ramdharry, a physical therapist and rehabilitation specialist at Kingston University London and St. George's University of London in the United Kingdom, discussed what is known and not known about the role of exercise in neuromuscular disease.
|Reliable data about exercise in neuromuscular disease are lacking.
- In neuromuscular disease, the challenge is to balance the danger of increasing weakness by overworking muscles against the danger of causing muscle atrophy (shrinkage) by underworking muscles.
- There are very few studies of exercise in neuromuscular disease that are good enough in quality to yield reliable data.
- It may not be possible to strengthen muscles that have less than 10 percent of normal strength.
- Strength increase does not always carry over to functional improvement.
- A 2004 study of handgrip training for 12 weeks in people with CMT found the training resulted in a significant increase in grip strength.
- Training the hip flexors in people with CMT brought about increased strength but did not improve walking ability. Hip flexors are the muscles that pull the knee upward.
- A 2004 study of dorsiflexor strength training in FSHD showed there was no change in strength in these muscles as a result of the training. Dorsiflexors are the muscles that pull the front of the foot up at the ankle joint.
- In ALS, some prevention of weakness can be achieved with exercise.
- Bicycle training studies in some types of muscular dystrophy have shown that an increase in knee extensor strength can occur. Knee extensors are the muscles that straighten the knee.
- Barriers to exercise in people with neuromuscular diseases include lack of energy, self-consciousness, lack of motivation, pain, getting to an exercise facility, the cost of an exercise facility and being told not to exercise by a professional.
Palliative care for children more than 'end-of-life' care
Ross Hays, a pediatrician with expertise in rehabilitation and palliative care at Seattle Children's Hospital, gave a thoughtful presentation on the medical professional's role in caring for children with life-limiting disorders.
Although often associated with end-of-life care, "palliative" care refers to care that is intended to provide comfort and alleviate physical and psychological pain, rather than care that is intended to cure a disease.
Palliative care is more than just "end-of-life" care; it's an attitude toward care that takes comfort and alleviation of suffering into account from the start.
- managing pain and other symptoms;
- addressing quality-of-life issues, such as mobility, environment and rehabilitation;
- addressing the emotional and spiritual needs of families;
- educating adolescents about their disease, prognosis and treatment; and
- adding palliative care professionals to a child’s health care team.
|Palliative care emphasizes quality of life.
- Palliative care for a potentially fatal disease should begin at diagnosis, but the mix of curative and palliative care should change over time. As the end of life approaches, there should be more palliative and less curative care.
- Some parents, particularly fathers, cope with anxiety over a child's illness by seeking technical solutions to small problems. This can be a comfort and should not necessarily be discouraged.
- Some parents cover their fear with anger, and this must be understood by the health care team.
- Life-altering events within a family — such as a serious diagnosis in a child — can cause "post-traumatic stress" but also can lead to "post-traumatic growth."
To learn more about the presentations given at the 2012 MDA Clinical Conference, see the related articles on genetics and immunology and targeted therapies.