Muscle Weakness: Possible Causes and When It Needs Prompt Attention

What it involves

MedlinePlus describes muscle function loss as a muscle that does not work or move normally, with complete loss called paralysis. It says the cause can sit in the muscle itself, in the place where nerve and muscle meet, or in the nervous system, including nerve damage, spinal cord injury or a stroke.

Who this is for

• Adults who notice difficulty rising from a chair, climbing stairs or lifting an arm overhead
• Patients whose grip, wrist or foot seems weaker than it used to be
• Patients who started a new medicine and then noticed weakness or muscle aching
• Adults who feel weak and tired together and want to know where to start

What to expect

• Questions about which muscles are affected, whether one or both sides, and how fast it developed
• A physical exam and a review of the medicines you take, including cholesterol and steroid medicines
• Blood work when your provider thinks it will help, drawn at the visit or ordered for a lab
• A referral to a specialist or for nerve, muscle or imaging studies if the pattern calls for one

Weak, tired or both

People use the word weak for several different problems, and sorting out which one you have is the first job of the visit. True muscle weakness means a muscle cannot produce its usual force, so a jar will not open or a stair will not climb. Tiredness is a lack of energy without a specific muscle that fails. Both can occur together, and the fatigue and tiredness guide covers the second problem. Your provider will ask you to describe a task you can no longer do, because that detail separates the two better than any label.

Where the problem can start

The MedlinePlus encyclopedia entry on muscle function loss lists three places. The first is the muscle itself, which it calls a myopathy, with examples such as alcohol-associated myopathy, congenital myopathies, dermatomyositis and polymyositis, drug-induced myopathy and muscular dystrophy. The second is the area where nerve and muscle meet, called the neuromuscular junction. The third is the nervous system, including neuropathy, spinal cord injury and brain damage from stroke or another brain injury. The page notes that in some cases strength may not fully return, even with treatment.

Medicines that can affect muscles

The same encyclopedia entry names statins and steroids as medicines that can cause a drug-induced myopathy. That does not mean either should be stopped on your own, and MedlinePlus advises against changing a medicine without talking to your provider. It does mean the medicine list matters at this visit, so bring every bottle or a photo of each label. Cholesterol treatment is explained on the high cholesterol management page, and the vitamin D and B12 blood test guide describes two common lab checks that are sometimes part of a weakness work-up.

Signs that should not wait

MedlinePlus is direct about timing. It says sudden loss of muscle function is a medical emergency, that muscle paralysis always requires immediate medical attention, and that paralysis of the muscles used for breathing is quickly life threatening. Call 911 for weakness that comes on suddenly, especially on one side of the body, or with trouble speaking, vision changes or trouble breathing. For gradual weakening or a muscle that is not working as it should, the encyclopedia says to get medical attention as soon as possible, which is the kind of problem a scheduled visit is for.

What your provider will ask

The encyclopedia lists the questions a provider is likely to ask. Which parts of the body are affected, and is it one side or both? Is it hard to get out of a chair, climb stairs, lift an arm overhead, extend the wrist or grip? Is there pain, numbness, tingling, trouble controlling the bladder or bowels, or shortness of breath? Is it getting worse, and does it worsen as the day goes on or after a medicine such as potassium supplements? The numbness and tingling guide and the hand tremor guide explain two related symptoms you may be asked about.

Tests that may follow

According to MedlinePlus, tests that may be performed include blood tests such as a blood count, blood chemistry and muscle enzyme levels, CT or MRI of the head or spine, a spinal tap, muscle or nerve biopsy, muscle ultrasound, and nerve conduction studies with electromyography. Serenity By A Dr. Sareen lists blood work among its services, and the thyroid blood test guide describes one panel often checked. Imaging, nerve studies and biopsies would be a referral to a specialist or facility, not something this practice performs, and your provider explains which test is worth doing and why.

Sources

• MedlinePlus — Muscle function loss (medical encyclopedia)