Muscular system disorders

Diseases and disorders of the muscular system often involve other body systems, including the skeletal and nervous systems. Common signs and symptoms of muscular disorders include the following:

• Swelling in the joints and muscles
• Malaise (generalized weakness or discomfort)
• Myalgia (muscle pain), myositis (inflammation of a muscle), and muscle tenderness
• Temporary loss of function or loss of normal mobility

The following sections address common muscular system disorders.

Compartment syndrome

Compartment syndrome is a serious condition that can occur after a traumatic injury. Increased pressure is applied to muscle compartments, leading to muscle and nerve damage.

Fascia separates groups of muscles. Inside each fascial layer is a compartment space that contains muscle tissue, nerves, and blood vessels. Swelling in the compartment space will lead to increased pressure in the area because the fascia does not expand. Increased pressure can cause an interruption in the blood flow to the area, leading to muscle death.

Acute compartment syndrome can be caused by a fracture, bruised muscle, severe sprain, or a crushing injury. This condition can also occur if a cast or bandage is too tight. Chronic compartment syndrome is caused by repetitive activities, such as running. Compartment syndrome can cause pale skin, swelling, severe pain, and inability to move the extremity. The person may experience a decrease in sensation, numbness, tingling, or weakness in the extremity.

After an exam, the provider may need to measure the compartment’s pressure. A needle attached to a pressure meter is inserted into the compartment. Treatment includes immediate surgery (fasciotomy) to prevent permanent damage. An incision is made in the fascia and muscle to relieve the pressure. With prompt treatment, the prognosis is good. If treatment is delayed, permanent muscle loss and nerve injury can occur.

Fibromyalgia

Fibromyalgia causes muscle pain, fatigue, and “tender points” on the legs, hips, back, arms, shoulders, and neck. It is estimated that 10 million people in the United States have fibromyalgia. Women develop fibromyalgia more often than men. Usually, the diagnosis occurs before age 50.

The etiology is unknown. Research indicates that trauma, infection, or injury may change how the central nervous system (CNS) responds to pain, leading to chronic pain. The signs and symptoms of fibromyalgia include widespread muscle pain, burning, aching, stiffness, or soreness. Additional symptoms include fatigue, sleep disturbances, mood and concentration problems, anxiety, headache, abdominal pain, bloating, constipation, diarrhea, bladder spasms, dizziness, numbness or tingling in the hands and feet, and tender points around the body.

The provider will perform an examination and rule out other conditions. With no diagnostic tests for fibromyalgia, the provider may use these results:

• Widespread Pain Index (WPI) score, which evaluates 19 areas of the body for pain
• Symptom Severity (SS) score, on which the patient scores specific fibromyalgia symptoms, including cognitive issues, fatigue, headache, and dizziness

The treatment is focused on minimizing the pain and fatigue experienced through the use of medications (e.g., pregabalin, duloxetine, and milnacipran), exercise, biofeedback, and acupuncture.

Muscular dystrophy

Muscular dystrophy (MD) is a collection of more than 30 inherited diseases that cause muscle weakness and muscle loss. Some of these diseases affect children, whereas others appear in middle-aged adults.

About half of the people with MD have Duchenne muscular dystrophy (DMD), which is the most common form of MD. DMD is usually diagnosed in boys between the ages of 3 and 5. This fast-progressing condition usually causes weakness in the arms and legs, leading to trouble walking. It is usually diagnosed by the age of 3. Boys are affected much more frequently than girls.

Muscular dystrophy may be congenital or caused by a genetic mutation that disrupts the body’s ability to make muscle-protecting proteins. The signs, symptoms, onset, and affected muscle groups depend on the specific disease, though the main sign of MD is progressive muscle weakness. The signs and symptoms of Duchenne muscular dystrophy include frequent falls, trouble running and moving from lying to sitting position, muscle pain and stiffness, and learning disabilities.

After the examination, the provider may order a creatine kinase (CK) blood test. Without trauma, high levels of CK suggest muscle disease, such as MD. Additional diagnostic tests include electromyography, genetic testing, and a muscle biopsy. Treatments can help improve quality of life, help people remain mobile for as long as possible, and reduce or prevent bone and spinal complications. Treatments include corticosteroids, heart medication, range of motion and stretching exercises, braces, and assistive devices (e.g., walkers, wheelchairs). There is no cure for muscular dystrophy.

Myalgic encephalomyelitis

Myalgic encephalomyelitis (ME), also called chronic fatigue syndrome (CFS), is a disabling, complex illness. People who have ME are not able to do their normal activities.

ME is most common in people between the ages of 40 and 60, though it can affect anyone. Women are affected by it more often than men. The cause of ME is unknown, but it has been associated with viral infections. Myalgic encephalomyelitis can cause the following conditions:

• Greatly diminished ability to do activities that the person could do prior to the illness.
• Severe fatigue not relieved by sleep or rest.
• Sleep problems, either falling asleep or staying asleep.
• Problems with memory or thinking. Brain fog is common.
• Irregular heartbeat, shortness of breath, and orthostatic intolerance. The person may become dizzy, weak, faint, or lightheaded upon standing or sitting upright.
• Digestive issues and allergies and sensitivities to foods and other products.
• Chills, night sweats, joint pain, and muscle weakness.

The provider may do a complete physical and mental status examination. Blood, urine, and other tests may be ordered to rule out other conditions. Treatment includes the management of symptoms. There is no cure for myalgic encephalomyelitis.

Myasthenia gravis

Myasthenia gravis affects the voluntary muscles, causing weakness and fatigue with activity, which improves with rest. Myasthenia gravis is most common in men older than 60 and women younger than 40 years of age.

The etiology is an autoimmune neuromuscular disease. The body produces antibodies that block the muscle cells from responding to neurotransmitters from nerve cells. Myasthenia gravis causes muscle weakness, leading to issues with breathing, chewing, swallowing, talking, climbing stairs, lifting objects, and maintaining a steady gaze. Additional symptoms include drooping eyelids, facial paralysis, fatigue, hoarseness, and double vision.

After a detailed neurologic examination, the provider will order imaging tests (CT or MRI), pulmonary function tests, and electromyography (EMG). With myasthenia gravis, the person will have a positive result on an acetylcholine receptor antibody blood test. The treatment is focused on increasing periods of remission. Lifestyle changes are encouraged, including resting, using eye patches, and avoiding stress and heat exposure, which can make symptoms worse. Medications such as neostigmine and pyridostigmine can help with the neuromuscular communication process. Immunosuppressants (e.g., prednisone, azathioprine, cyclosporine, and mycophenolate) may also be used. There is no cure for myasthenia gravis.