Conditions That Affect the Muscles
MUSCULAR SYSTEM
Problems with the muscular system can range from mild and temporary discomfort to the extreme of muscle loss (atrophy) and death. Most will experience the first at some point, while the extreme conditions are much less common. However, it is likely that you will encounter someone who has been affected by muscular disease in your lifetime. Infections, autoimmune diseases, and cancer can affect the muscles.
Injury and Overuse
If you’ve ever strained your back moving furniture, then you know that injuries to muscles are a common problem. Some injuries that appear to be muscle-related actually affect the connective tissue that attaches a muscle to a bone (a tendon) or a bone to a bone (a ligament). Here are two common injuries and their causes:
· Sprains: A sprain affects the ligament—it is stretched or torn, causing swelling, tenderness in the affected area, and pain. This commonly occurs when you fall or accidentally twist a joint.
· Strains: A strain affects a tendon or muscle—as with a sprain, the tendon or muscle is stretched or torn, causing swelling, tenderness, and pain. With a strain you might also get muscle spasms and difficulty moving the muscle. Sports injuries are quite commonly strains. Strains can happen because of overuse over a period of time or can occur suddenly.
Rest, ice, and compression are the usual treatments for both sprains and strains.
Muscle Spasms
Resulting largely from dehydration, muscle spasms are involuntary and repetitive or constant contraction of a muscle without being able to relax. Often uncomfortable or painful, these spasmodic contractions occur because the muscle has received an inappropriate electrical signal to contract and remain contracted until the electrical signal stops. Recall that muscles are signaled to contract by a nerve stimulating a change in voltage on the muscle membrane. If the concentration of these charged ions changes because of dehydration and become more concentrated around the muscle cell, this can yield the same change in voltage as a nervous stimulus and lead to a contraction. Since this is not regulated as a normal contraction, the signal doesn’t stop until the ions become balanced once again.
Often, therapists or trainers massage and stretch the affected muscle to increase the circulation in and around the muscle in order to balance the ions as quickly as possible. Additionally, immediate rehydration will aid in preventing the recurrence of the cramps.
What is the difference between a muscle cramp and a spasm?
Muscle spasms are involuntary contractions of the muscle, and a cramp is what we call the result of the spasm, so they are basically the same thing. A muscle spasm can create other symptoms associated with a cramp (such as pain). Occasionally medications can cause muscle spasms.
Muscular Dystrophy
The most common form of muscular dystrophy is Duchenne muscular dystrophy (DMD), which occurs most commonly in childhood. This debilitating disease not only reduces muscle mass and mobility; it also considerably shortens life expectancy.
The cause of DMD is a mutation of the gene for dystrophin, a protein that interconnects the muscle cytoskeleton (the intercellular proteins) to the extracellular environment through the muscle membrane. Loss of dystrophin function results in highly disorganized muscle, smaller muscle mass, and an increase in connective and inflammatory tissue.
Becker muscular dystrophy is a variant of DMD where dystrophin is shortened but remains functional, and is therefore a less severe form of DMD.
Are there other causes of muscle problems?
Some diseases that affect the muscles are actually neurological diseases. Parkinson’s disease is one example. It causes muscle tremors, slowness in movement, and decline in agility, but the cause is related to the death or breakdown of neurons, not muscle problems. This is why it is classified as a neurological disorder. Other neuromuscular diseases include multiple sclerosis, amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), and myasthenia gravis.