Neuromuscular disease

Causes

Neuromuscular disease has several origins. It can stem from autoimmune conditions, genetic or hereditary factors, and certain cases of the collagen disorder Ehlers–Danlos syndrome. Exposure to environmental toxins or poisons, including heavy metals, is another cause. When the body fails to absorb vitamin B-12, the myelin sheath that insulates nerves can break down.

Motor end plate disorders include myasthenia gravis, where antibodies attack acetylcholine receptors, causing muscle weakness, and its related condition Lambert–Eaton myasthenic syndrome. Bacterial infections like tetanus and botulism alter muscle tone through toxins, increasing or decreasing it respectively. Muscular dystrophies, such as Duchenne's and Becker's, are often hereditary or caused by genetic mutations; they disrupt muscle structure, leading to progressive weakness and a shorter lifespan.

Inflammatory muscle conditions also contribute. Polymyalgia rheumatica, mainly affecting older adults and linked to giant-cell arteritis, often responds to prednisolone.

Polymyositis is an autoimmune disease that impacts muscle tissue. Rhabdomyolysis involves the breakdown of muscle from any cause. Benign tumors can also occur: leiomyoma in smooth muscle and rhabdomyoma in striated muscle.

Did You Know?

• Symptoms of neuromuscular disease may include a pseudoathletic appearance, exercise intolerance, myalgia, fasciculations, myotonia, and hypotonia.
• Fixed muscle weakness is a static symptom, while premature muscle fatigue is a dynamic symptom.