Rock icon Peter Frampton recently announced that he has begun his final tour. Frampton, 68, revealed that he is taking this Farewell Tour because he is suffering from a degenerative muscle disorder called inclusion body myositis (IBM). According to an article in Rolling Stone, the "Show Me the Way" singer . Over time, his legs began to feel weak as well.
Three and a half years ago, Frampton fell over trying to kick back a beach ball a fan had tossed onto the stage: "My legs just gave out," he says. "We all joked, 'He's fallen, and he can't get up.' But I was embarrassed." He also noticed difficulty lifting heavy objects, such as his carry-on luggage over his head.
He finally arranged an appointment with a neurologist who made the diagnosis. In an interview with CBS This Morning, Saturday, Frampton explained that he is ending his public performances because IBM will begin to impair his ability to perform:
"What will happen unfortunately is that it affects the finger flexors," he said. "So for a guitar player, it's not very good. I'm able to play great right now, but in a year's time, maybe not so good. I'm a perfectionist, and I do not want to go out there and feel like, 'This isn't good.' That would be a nightmare for me."
Frampton has also been busy in Nashville, recording as many new songs while he is able, and has already completed two albums. Fortunately, his voice has not been affected by the disease although about 50% of patients with IBM can have difficulty with swallowing.
Frampton was referred to Johns Hopkins Hospital in Baltimore and to the director of the Johns Hopkins Myositis Clinic, Lisa Christopher-Stine, MD, MPH. Along with regular exercise to maintain his muscle strength, he is participating in a new drug trial at Hopkins, a . Although pioglitazone is primarily used as an antiglycemic agent in patients with type 2 diabetes, it has also been noted to have an effect on muscle tissue inflammatory markers (Joya-Galeana, et al., 2011; Iida, et al., 2015).
What is Inclusion Body Myositis?
IBM is one of a group of muscle diseases known as the inflammatory myopathies. These disorders are characterized by chronic, progressive muscle inflammation accompanied by muscle weakness. The onset of muscle weakness in IBM is generally gradual (over months or years) and affects both proximal and distal muscles. IBM develops in adulthood, usually after age 50, although the disease can occur earlier. IBM occurs more frequently in men than in women. According to the , its prevalence is estimated to be from 10-71 people per 1,000,000 in the general population. The prevalence is estimated to be 51-139 per 1 million individuals in the general population over 50. This makes IBM the most common acquired myopathy in that age group.
Most people with IBM progress to disability over a period of years. In general, the older a person is when IBM begins, the more rapid the progression of the condition. Most people need assistance with basic daily activities within 15 years, and some people will need to use a wheelchair. Lifespan is thought to be normal, but severe complications (e.g., aspiration pneumonia) can lead to loss of life.
The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Although originally thought to be a primary inflammatory myopathy, pathologic evidence now suggests that neurodegeneration may play a significant, if not the primary, role in the pathogenesis of the disorder.
Symptoms of IBM
The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists, with a majority of patients having coexisting proximal leg and distal arm weakness. Up to 82% of patients have marked asymmetry in quadriceps weakness leading to falls as a common presenting symptom. Another frequent symptom is weakness of the finger flexors- which presents as deterioration in fine motor skills, such as difficulty with pinching, buttoning, and gripping objects.
Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon but have been reported in some people.
Diagnosis of IBM
There is no definitive laboratory test for IBM. The diagnosis is made based on a combination of signs, symptoms, and laboratory testing suggestive for the disease.
Serum creatine kinase levels may be normal or elevated up to 10 times the upper limit of normal. Acute phase reactants, such as erythrocyte sedimentation rate and C-reactive protein are usually normal.
Electromyography typically shows an "irritative myopathy" pattern. In up to 30% of patients with IBM, nerve conduction studies show a mild sensory axonal peripheral polyneuropathy.
A muscle biopsy is often performed to aid in the diagnosis of IBM. Histologically, there is a mononuclear cell infiltrate- prominently CD8+ T lymphocytes and macrophages. In addition, there are small groups of atrophic fibers, eosinophilic deposits within fibers, and myofibers with one or more rimmed vacuoles. These vacuoles, one of the most suggestive features of IBM, are filled with amyloid or protein aggregates which immunostain positive for p62 and TDP-43. It should be noted that the vacuoles may not be seen on an initial biopsy, but may be found on later muscle biopsies performed on treatment-refractory patients.
Treatment of IBM
There is currently no cure for IBM. The primary goal of management is to optimize muscle strength and function. Management may include exercise, fall prevention, physical therapy, occupational therapy, and speech therapy (for dysphagia). Although there are few clinical studies, results from clinical practice find that patients with IBM do not respond to immunosuppressive and immunomodulatory therapies. At best there may be a temporary stabilization, followed by disease progression. There is, however, limited evidence that a small proportion of patients (particularly those who also have an underlying autoimmune disorders) may benefit from drugs that suppress these immunosuppressive agents. A by Needham and Mastaglia points out some new avenues of treatment in clinical trials. A number of groups are looking at bimagrumab, a monoclonal antibody that blocks receptors which bind myostatin and other ligands. This allows uninhibited muscle growth and promotes muscle hypertrophy. Another , although the .
Other clinical trials can be found at .
Michele R. Berman, MD, and Mark S. Boguski, MD, PhD, are a wife and husband team of physicians who have trained and taught at some of the top medical schools in the country including Harvard, Johns Hopkins, and Washington University in St. Louis. Their mission is both a journalistic and educational one: to report on common diseases affecting uncommon people and summarize the evidence-based medicine behind the headlines.