In this issue: Cardiac risks seen in both type 2 MMD and limb-girdle type 2I ** People with myasthenia gravis frequently exhibit higher levels of anxiety
The U.S. Centers for Disease Control and Prevention and the American Association of Medical Colleges are sponsoring a study of the impact of Duchenne muscular dystrophy (DMD) on families and on what services affected families are receiving. The investigators plan to survey 1,500 families in which at least one person has DMD.
Investigators say the survey questions will take two to three hours to answer.
For information, call project coordinator Marie Ritzo at (800) 343-5878, or write to the National Initiative for Families with Duchenne, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC 20010.
Researchers at the University of Wurzburg in Germany say they’ve found evidence that people with type 2 myotonic dystrophy (MMD2) can have subtle heart problems long before symptoms appear and even before changes can be detected on routine cardiac exams.
The investigators, who published their findings in the November issue of Muscle & Nerve, studied 11 people with MMD2 and compared them to a group of healthy subjects. They examined the participants’ hearts with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS).
In people of all ages with MMD2, MRS showed evidence of reduced energy production in cardiac muscle tissue compared to the healthy group. In older MMD2 patients, MRI examination revealed moderate enlargement and dilation of the left ventricle, which the researchers say indicates early, mild cardiomyopathy (cardiac muscle disease).
John Day, a neurologist who directs the MDA clinic at Fairview University Medical Center in Minneapolis and sees many patients with MMD2, says he and his colleagues have detected abnormalities in cardiac muscle function and in heartbeat rhythms in many people with this disorder.
“Involvement of the heart can be clinically important and potentially life-threatening, dictating that patients receive regular checkups and thorough investigation of any cardiac symptoms,” Day says.
“The new findings support the impression that type 2 myotonic dystrophy might cause a primary [initial] cardiomyopathy, in addition to altering heart function by development of arrhythmias and conduction defects [heartbeat irregularities].”
Milind Kothari at Pennsylvania State University College of Medicine in Hershey, and colleagues, have conducted a study showing that anxiety may be higher than average, even for people with chronic disease, in those with myasthenia gravis (MG).
The investigators, who published their results in the September issue of the Journal of Clinical Neuromuscular Disease, gave self-administered questionnaires to 69 people with MG.
The questionnaire, which included a standardized test called the Beck Anxiety Inventory, showed that 55 percent had scores suggesting they were experiencing anxiety. Some 40 percent were judged mildly anxious, 12 percent moderately anxious, and 3 percent severely anxious.
The authors cite another study showing that the prevalence of anxiety in the general population is about 7.7 percent.
The MG survey didn’t ask subjects what medications they were taking or formally assess variations in disease severity.
The investigators say that depression is known to be common in people with chronic medical conditions but that anxiety hasn’t been widely recognized.
Kate Bushby at the Institute of Human Genetics in Newcastle upon Tyne, England, and colleagues in Britain, Germany and Canada, recently found a high incidence of involvement of the heart or respiratory system in 38 people with type 2I limb-girdle muscular dystrophy (LGMD2I), a form of MD caused by mutations in the gene for fukutin-related protein.
The investigators, who published their findings in the November issue of Annals of Neurology, found that 21 of the 38 subjects (55 percent) had either possible or definite cardiac involvement. Of the 36 participants whose respiratory function was measured, 13 (36 percent) had moderate respiratory impairment, and three (8 percent) had severe respiratory impairment.
The authors write, “This multicenter study confirms that patients with LGMD2I are at risk of cardiac and respiratory failure that will progress with time....
“Our data also indicate that treatment with standard cardiac therapy [ACE inhibitor drugs and diuretics were prescribed for some patients] is effective in delaying progression.... Nonetheless, some patients are likely to show progression of their cardiac disease, necessitating cardiac transplantation.”
The authors also note, “There was no absolute correlation between skeletal muscle weakness and cardiomyopathy [cardiac muscle disease] or respiratory insufficiency.”