Secondary BSS can have a multitude of causes, making it hard to pinpoint to a specific muscular disorder. Some examples of diseases that have secondary BSS as a symptom are myopathies caused by muscular dystrophies, neuromuscular disorders, and inflammatory muscle diseases; metabolic or endocrine disorders; and mitochondrial myopathies.[1] A muscle biopsy can clearly demonstrate whether primary BSS or secondary BSS is afflicting a patient, because primary BSS is much more identifiable.