G70-G73: Diseases of myoneural junction and muscle

G71: Primary disorders of muscles

Primary disorders of muscles, represented by the ICD-10 code group range G71, encompass a variety of conditions that significantly affect muscle function. Generally, these conditions originate from a malfunction or damage to the muscles themselves, rather than being secondary to issues with the nerves or other systems. They can be inherited, resulting from specific genetic mutations, or they may develop due to external factors like toxins or infections. Commonly-observed symptoms across these disorders include progressive muscle weakness or wasting, fatigue, cramping, stiffness, and in some cases, difficulties with movement or coordination. As these disorders progress, they often lead to increasing physical disability due to the deteriorating function of the muscles. It's important to note that the specific characteristics, causes, and disease progression can vary considerably across the conditions within this group.