Your muscle weakness may not just be a sign of aging

Nearly 70-80% of the people who complain of back pain actually find that the fault is in their posture. Photo: iStockphoto
Nearly 70-80% of the people who complain of back pain actually find that the fault is in their posture. Photo: iStockphoto

Summary

Muscle weakness and pain can be the result of disease, infection or medication—some of which is easily addressed

After a certain age, when muscle weakness and pain start to accompany exercise and simple daily tasks like getting up from a chair, we often dismiss it as part of the package of getting older.

But researchers are learning that some of these ailments that people dismiss as the result of aging may in fact be caused by medication, or an undiagnosed disease or infection. Some studies also have suggested that Covid-19 infection and its treatments can lead to muscle damage, including decreased muscle strength and endurance.

Often the causes of muscle weakness or pain are easy to identify and to treat. For example, electrolytes, the minerals necessary to help nerves and muscles function, can be imbalanced. Other causes can be more serious. Unexplained pain in the limbs, difficulty climbing stairs, or more frequent trips and falls could be signs of myositis, a term for illnesses that include chronic inflammation of the muscles.

While loss of muscle mass is normal in aging and can be managed with exercise and better nutrition, different forms of myositis are muscle-wasting diseases that can start in middle age and get progressively worse.

“People assume they are supposed to get weak as they get older, but having difficulty with walking and falls and getting up off the floor is not normal," says Conrad C. Weihl, a neurologist at Washington University in St. Louis and chairman of a medical advisory board for the Myositis Association, a nonprofit that sponsors research and provides information and support for patients.

Autoimmune role

Though its causes aren’t clear, most types of myositis are classified as autoimmune diseases, in which the immune system begins to attack normal, healthy tissue. Muscles, joints, heart, lungs, skin and the digestive tract can be affected.

Some patients might have a predisposition to autoimmune disease, which can be triggered by an infection, virus, toxin or even sunlight. Some forms appear with other connective-tissue diseases such as rheumatoid arthritis and lupus. Myositis is also sometimes linked to cancer.

While there are no cures for any of the forms of myositis, a number of medications can ease the symptoms, as can physical therapy and exercise. Researchers are investigating additional potential therapies.

Dr. Weihl says it’s important to create greater awareness of the different forms of myositis, which are also known as idiopathic inflammatory myopathies. Presented with symptoms, primary-care doctors may be hesitant to consider a serious muscle disease, and be unaware of what to look for. Many patients are diagnosed only after being referred to specialists such as rheumatologists and neurologists.

To arrive at a diagnosis, Julie J. Paik, a rheumatologist and director of clinical trials at Johns Hopkins Medicine’s Myositis Center in Baltimore, says she starts with a medical history and physical exam to identify which muscles are experiencing weakness, as different muscle groups are affected by different conditions. Blood tests can identify levels of certain muscle enzymes and Dr. Paik may order an MRI of the muscles to pinpoint inflammation spots, as well as a muscle biopsy, which can show abnormalities including inflammation.

Myositis usually starts gradually, such as with weakness climbing stairs and standing from a sitting position. One type, inclusion body myositis, can also cause weakness in hands and feet. While other forms are relatively treatable, there is no effective treatment at present. In 2019, musician Peter Frampton announced he had been diagnosed with the disease, whose symptoms include wasting of the quadriceps and forearm muscles. A fund named after him at Johns Hopkins offers support for patients and backs research seeking a cure.

Another form, dermatomyositis, is more common among women, and can cause both skin rashes and muscle weakness. Medications including immunosuppressants and steroids have been used in treatment, and last year, the Food and Drug Administration approved the first drug made from intravenous immune globulin, or IVIG, which uses antibodies derived from plasma. The approval was based on a study, published in the New England Journal of Medicine in October, that showed a significantly higher percentage of patients experienced improvement compared with those who received a placebo.

Elisa Glass, 61, began feeling ill and weak one day in 2016. Her skin felt as if it was burning, she says. Within days she was unable to move or get up from a sitting position. A battery of tests was inconclusive, until rheumatology experts noticed she had a rash suggestive of dermatomyositis and diagnosed the condition. Ms. Glass was hospitalized for four months, and has been treated with a combination of chemotherapy drugs, steroids and IVIG.

Ms. Glass says her symptoms came on suddenly. She often felt as if she was in a fog, and was too weak to do much of anything. She had to leave a teaching position and close a small store she owned, she says.

Patient advocate

To share with other patients her strategies for coping and other information, she has become a leader of support groups sponsored by the Myositis Association. Ms. Glass is a caregiver for her husband, a veteran, and says she is determined to manage the disease and its treatments.

“I still have flares and muscle weakness, with some days better than others," she says, “but I’m determined to stay healthy because I need to live and be an advocate."

There can be other causes of muscle weakness and pain, of course, including infections and medications. Patients who take diuretics for such conditions as high blood pressure can become deficient in potassium, a mineral in the electrolyte class that helps cells, muscles and nerves function correctly. Low potassium levels can lead to hypokalemia, which can cause muscle weakness, spasms, cramps, tingling, numbness and, in severe cases, paralysis. Doctors might prescribe potassium supplements to reverse this imbalance.

Statins, too, which many patients take for heart disease, are sometimes associated with muscle pain. But a review of 19 clinical trials published recently in the Lancet found that more than 90% of muscle symptoms reported by study participants were not due to the statin. The cardiovascular benefits of taking statins, the review concludes, outweigh the small risks of muscle symptoms. For patients with mild muscle symptoms, the study authors recommend that statins be continued until other potential causes of muscle pain have been explored.

Role of Covid

Scientists are continuing to investigate the role of Covid-19 in muscle pain and weakness. Patients with symptoms of long Covid, a condition in which fatigue can persist for months, hold particular interest. Researchers at the University of California San Francisco recently reported in the Journal of the American Medical Association that long-Covid patients may have a reduced rate of oxygen extraction in their muscles, affecting endurance, and may be unable to increase their heart rate adequately during exercise.

Lead author and Assistant Professor of Medicine Matthew S. Durstenfeld suggests that patients reporting fatigue and muscle pain consider cardiopulmonary exercise testing, which might give clues as to why they can’t exercise.

“The most important thing," he says, “is to listen to their bodies and if they are able to make slow and steady progress, great. If symptoms get worse with exercise, talk with your doctor."

 

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