According to The Myositis Association: Necrotizing myopathy can also be referred to as necrotizing autoimmune myopathy (NAM) or immune-mediated necrotizing myopathy (IMNM). The condition is characterized by signs of necrosis, or cell death, in the muscles, which causes weakness and fatigue. As with other types of myositis, there is no known cause or cure for necrotizing myopathy. Like other forms of myositis, patients with necrotizing myopathy may experience the following symptoms: weakness in the muscles closest to the center of the body, such as the forearms, thighs, hips, shoulders, neck, and back; difficulty climbing stairs and standing up from a chair; difficulty lifting arms over the head; falling and difficulty getting up from a fall; and a general feeling of tiredness(https://www.myositis.org/about-myositis/types-of-myositis/necrotizing-myopathy/)