Metabolic myopathies are myopathies that result from defects in biochemical metabolism that primarily affect muscle. They are generally genetic defects that interfere with muscles ability to create energy. At the cellular level, metabolic myopathies lack some kind of enzyme that prevent the chemical reactions necessary to create adenosine triphosphate (ATP). This prevents the muscle cells from being able to function properly and disrupts communication between joints and bones. Some people with a metabolic myopathy never develop symptoms due to the bodys ability to produce enough ATP through alternative pathways. In the event more ATP is needed from the affected pathway, the lack of it becomes an issue and symptoms develop. People with a metabolic myopathy often experience symptoms such as progressive muscle weakness, fatigue, pain and cramping after exercise, and considerable breakdown of muscle tissue. The degree of symptoms varies greatly from person to person and is dependent on the severity of enzymatic defect. In extreme cases it can lead to Rhabdomyolysis. Types
Metabolic myopathies are generally caused by an inherited genetic mutation. This mutation has an autosomal recessive inheritance pattern making it fairly rare to inherit, but it can also be caused by a random genetic mutation. Metabolic myopathies are named after the pathway in which the defective enzyme or a lack of enzymes is present. This causes the underproduction of adenosine triphosphate (ATP) and affects the muscles in different parts of the body.
Angiomatosis is a non-neoplastic condition characterised by nests of proliferating capillaries arranged in a lobular pattern, displacing adjacent muscle and fat. It consists of many angiomas.These tend to be cavernous hemangiomas, which are sharply defined, sponge-like tumors composed of large, dilated, cavernous vascular spaces. Presentation
Associated
They often appear in:

Von Hippel–Lindau disease: It can be associated with Von Hippel–Lindau disease and is a rare genetic multi-system disorder characterized by the abnormal growth of tumours in the body. Symptoms may include headaches, problems with balance and walking, dizziness, weakness of the limbs, vision problems and high blood pressure. Bacillary angiomatosis
Klippel–Trénaunay syndrome
Sturge–Weber syndrome

Histology
It is a vascular malformation wherein blood vessels proliferate along with accompanying mature fat and fibrous tissue, lymphatics and sometimes nerves. They may involve skin, subcutaneous tissue, skeletal muscle and occasionally bone. Prognosis
Prognosis depends on the size and location of the tumour, untreated angiomatosis may lead to blindness and/ or permanent brain damage. Death may occur, with complications in the kidney or brain. See also
Angioma
Hemangioma
List of skin conditions

References


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