We know that early diagnosis, highly specialized care and access to promising clinical trials help ensure the best possible outcomes for individuals and families facing muscular dystrophy, ALS and related muscle-debilitating diseases. Our MDA Care Centers offer families best-in-class, comprehensive care from a wide variety of health care specialists at one location on the same day. MDA has more than 150 Care Centers across the United States and in Puerto Rico located at top hospitals and health care facilities.
MDA clinics utilize a multidisciplinary team approach, meaning individuals can see knowledgeable health care specialists from a variety of disciplines, all at one location.
Specialists can include:
The MDA Family Care Specialist (FCS) is a central figure at MDA Care Center visits. He or she is usually present to answer questions, distribute MDA educational materials, coordinate MDA services and assist with community resource referrals.
The first step in ensuring that appropriate medical management strategies are implemented is confirming a diagnosis. Neuromuscular diseases can present in a variety of ways and at different ages. Prior to receiving a confirmed diagnosis, your MDA Care Center physician will perform diagnostic examinations and recommend specific laboratory tests to ensure that as much information as possible is obtained and other diseases are ruled out.
Following a clinical examination and analysis of laboratory tests, many neuromuscular diseases can be quickly and accurately identified. Some neuromuscular diseases, however, can be more difficult to diagnose. In these cases, the physician will make what is called a “differential diagnosis,” listing two or more diseases that have similar symptoms. A definitive diagnosis may require waiting until the diseases has progressed to a stage that’s unique to that disorder.
With the majority of neuromuscular diseases, the first noticeable symptom is usually a persistent weakness in one or more muscles. Muscles can become weak for many reasons. The first question the MDA Care Center physician will seek to answer in trying to establish a diagnosis is whether muscle function is abnormal because there is a disease of muscle itself, or whether muscle function is abnormal because of a disorder that has developed in other tissue (e.g., nerve).
The most common diagnostic and laboratory procedures used to determine why muscle function is abnormal, and ultimately to arrive at a definitive diagnosis, are as follows:
The clinical examination of someone suspected of having a neuromuscular disease focuses on muscle strength. Muscles are examined with special attention given to those of the arms, legs, shoulders and hips. A few neuromuscular diseases affect facial muscles, and these too are examined.
Determining which muscles are not weak is as important as determining which muscles are weak. Each neuromuscular disease typically shows a specific pattern of muscle involvement. A final diagnosis is based in large part on the pattern of muscle involvement detected during the clinical examination.
Many neuromuscular diseases — including all of the muscular dystrophies — are genetic diseases. Knowledge of other individuals in the family who have similar symptoms or have been diagnosed with a neuromuscular disease can help to establish and/or confirm a diagnosis.
These two tests are often performed at the same evaluation. The nerve conduction velocity test (NCV) measures the ability of nerves to conduct impulses to muscle; this is an important test when evaluating for disorders such as Charcot-Marie-Tooth disease (CMT). It’s done by placing electrodes on the skin at various points on a limb. One electrode delivers a mild electrical impulse to the nerve, stimulating it to generate a response; the other electrodes record the response as it’s conducted through the nerve.
An electromyogram (EMG) measures electrical activity of muscle, making it useful for diagnosing diseases that primarily affect muscle function — including the muscular dystrophies. Weak muscle has an electrical activity characteristically different from that of normal muscle. During an EMG, the doctor inserts a needle-like electrode into a muscle. The electrode records responses when the muscle is at rest and during specific voluntary contractions.
NCVs and EMGs can be valuable tools for physicians, but they can be distressing for the patient. Some find the electrical impulses of the NCV or the needle of the EMG to be uncomfortable or even painful, especially children. Topical anesthetic or other medications can be used to ease discomfort, so talk to your MDA Care Center physician beforehand to discuss options.
Serum enzyme tests measure the amount of muscle proteins present in the blood. Where muscle tissue is healthy, these proteins remain in muscle and the amount present in blood is relatively low.
Many, but not all, neuromuscular diseases that cause muscle deterioration lead to a significant increase in the muscle protein levels found in the blood. Thus, serum enzyme tests can be important aids in the diagnosis of neuromuscular diseases.
The value of these tests typically is greatest at early stages of the disease. At the earliest disease stage, muscle mass is relatively great, and changes in serum protein levels may occur even before symptoms such as weakness become apparent.
At later stages of some diseases, however, muscle mass may be so reduced that serum protein levels may even appear normal.
Creatine kinase (CK): This protein is confined almost exclusively to muscle. A higher-than-normal CK level in blood indicates a leakage from muscle tissue. Determination of the serum CK level is an important laboratory test in the diagnosis of Duchenne muscular dystrophy and related muscle-debilitating diseases.
Other enzymes: Increased levels in blood of aldolase, lactic dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), pyruvate kinase (PK) and several other enzymes also may indicate the presence of a neuromuscular disease.
A small amount of blood can be used to extract DNA from blood cells. This is extremely valuable for diagnosing genetic defects that can cause specific neuromuscular diseases. One of the strengths of these tests is that they reveal the same abnormality regardless of the stage of the disease. Information about genetic-based diagnostic testing is available through your MDA Care Center team.
In this test, muscle tissue is surgically removed (usually as an outpatient procedure) for microscopic and/or biochemical analysis. For some neuromuscular diseases, a final diagnosis depends on the analysis of a muscle biopsy. The amount of muscle removed is roughly equivalent in size to the tip of a little finger. In some conditions, such as the inflammatory myopathies (polymyositis, dermatomyositis, inclusion-body myositis) and central core disease, the muscle tissue has a characteristic appearance under the microscope.
The muscle tissue can be analyzed for abnormalities in a number of proteins within muscle cells. For example, dystrophin is absent or greatly diminished in muscle cells of those with Duchenne muscular dystrophy. It’s present in an abnormally low amount or altered form in the muscle cells of those with Becker muscular dystrophy. Similarly, other muscle proteins may be missing in different types of muscular dystrophy.