A Myopathy is essentially a disease or pathological condition of the muscles and Myopathies refer to a group of myopathic conditions. A myopathy can rise due to several reasons and most myopathies are grouped under muscle diseases. Some of the most common types of muscle disease myopathies have been detailed below:

Neuromuscular Myopathy
This refers to neuromuscular disorders where the functioning of the nervous system is impaired, i.e. the conduction of the electrical pulses from neurons or nerves to the skeletal muscles isn’t properly executed. This causes lack of movement and reduced contractions in the muscles, causing them to become more inactive and uncoordinated. Muscle mass loss and muscle weakness are the main symptoms of this muscle disease myopathy. Other typical symptoms include stiffness of joins, pain and cramping in the muscles and bouts of muscular spasms. Many of the neuromuscular myopathies are inherited, i.e. they are genetically communicated from the parents to the child. Examples of Neuromuscular Myopathy includes:

Muscular Dystrophies—this condition has no known cure and it causes progressive muscle wasting, including the muscles of the face and hips. The patient might also show signs of mental retardation and an abnormal curvature in the spine.

Endocrinal Myopathies
These are muscle diseases caused by problems in the endocrine system, i.e. the system responsible for synthesizing and regulating hormones in the body. Examples of endocrinal myopathies include:

Hyperthyroid Myopathy—muscle diseases wherein there is an excessive secretion of the thyroxine hormone. This hormone is produced by the thyroid gland. The excess of thyroxine is a deterrent to the overall health of the muscles. This is interpreted as an autoimmune disease where the thyroid gland is perceived as a threat by the body’s immune system. The onset of this muscle disease is rather late, i.e. mid-adulthood period, around the age of 40 years. The wasting of muscles is more pronounced around the shoulders and hips. There is a possibility of weakness in the facial muscles which can cause impaired functioning of the throat, i.e. the respiratory muscles are also weakened. Sometimes, muscles of the eyes/eyelids are also affected. This condition can be cured to some extent with medication or surgery to reduce the amount of thyroxine being produced. Hyperthyroid myopathy does have a genetic predisposition like most other autoimmune diseases.

Metabolic Myopathy
A metabolic muscle disease or metabolic myopathy is established when the compromised functioning or weakening of muscles is caused by problems in metabolic functions such as the inability to process the energy resources of the body.. Example of metabolic myopathy includes:

Mitochondrial Myopathies—in this condition, the mitochondria of the cells are affected. Mitochondria are the energy-generating part of the human cells. This condition is known by different names such as Kearns-Sayre Syndrome and Leigh’s Syndrome. However, the term Mitochondrial DNA Depletion Syndrome or MDS is regarded as the most, medically-accurate nomenclature. There are no defined patterns in terms of onset of this muscle disease. Along with weakening of the skeletal muscles, some patients might hint at nervous system impairment. There are problems in the functioning of eyes apart from risk of developing cardiac abnormalities and even problems in the gastrointestinal tract.

Inflammatory Myopathies
This is among the more detectable of muscle disease since the widespread inflammation is very palpable. The inflammation spreads to the tissues surrounding the muscles, even the joints and the outer skin. Example of Inflammatory Myopathy includes:

Polymyositis (PM)—this condition develops due to a connective tissue autoimmune problem where the blood vessels supplying the muscles are attacked by the body’s immune system. This causes decreased supply of blood to the muscle fibers that start to shrink due to the decreased amount of oxygenated blood supply. The onset of Polymyositis is usually after the age of 20 years and it is more common among women. Typical symptoms include weakness of muscles of the upper back, neck, hips and shoulders, making the movement of the neck labored. There is a small risk of the patient developing cardiac irregularities or respiratory problems.