Glycogen Storage Diseases
• Types II, III, V and VII cause muscle dysfunction. Painful cramps and contractures after exercise, myoglobinuria, accumulation of lactic acid in the blood and glycogen accumulation in muscle cells in ischemic conditions and exercise are the main symptoms, although not of all types.
Lipid Storage Myopathies
• It occurs as a result of carnitine and carnitine palmitoyl transferase deficiency. Diagnosis is made by finding abnormal lipids on muscle biopsy. Clinical signs are cramps, muscle weakness and hepatic failure.
Mitochondrial Myopathies
• In muscle biopsy, there are abnormal mitochondria accumulation called "ragged red fiber" appearance, degenerative changes in muscle fibers and respiratory chain defect in respiratory chain. The clinic is typically progressive, similar to congenital structural myopathy. It has central nervous system and neuromuscular manifestations (like MELAS).
- Kearns Sayre Syndrome
is the type with an onset of <20 years, with external ophthalmoplegia and retinal pigmental degeneration. Cardiac blocks and cerebellar problems are frequently shown in these patients. Visual evoked potentials (VEP) are impaired.
- MELAS Syndrome
Mitochondrial myopathy, encephalopathy, lactic acidosis, stroke (stroke)
Ragged-red-fiber (abnormal proliferation of mitochondria) in striated muscle biopsy
There are convulsions, focal deficits, and dementia.
- MERRF Syndrome
Convulsions, dementia, hearing loss, optic nerve atrophy, ataxia, profound sensory loss
There is an increase in CPK, lactic acidosis, and calcification in the basal ganglia.
Electrolyte Disorders
• Familial periodic paralysis: Episodes of muscle weakness are seen with hypocalcemia or hyperkalemia. Symptoms may begin in preschool age or may not manifest until the second decade of life. There is a lack of strength at certain times. It is characterized by loose type paralysis. The diagnosis is made by complete loss of DTR and absolute unresponsiveness to electrical stimuli. They rarely lead to death with respiratory failure. Acetozalamide can prevent or reduce attacks.
Endocrine Myopathies
• Hyperthyroidism, hypothyroidism
• Hyperparathyroidism
• Cushing's disease or exogenous steroid use
