Differential Diagnosis for Progressive Muscle Weakness
Single Most Likely Diagnosis
- Myasthenia Gravis: An autoimmune disease characterized by fluctuating muscle weakness, often affecting the muscles of the face, eyes, and swallowing, but can progress to involve other muscle groups. It is a common cause of progressive muscle weakness and has a relatively high prevalence among neuromuscular disorders.
Other Likely Diagnoses
- Muscular Dystrophy: A group of inherited disorders characterized by progressive muscle weakness and degeneration. The age of onset and the rate of progression can vary widely among the different types.
- Polymyositis/Dermatomyositis: Inflammatory muscle diseases that cause progressive muscle weakness, typically affecting the proximal muscles. Dermatomyositis also involves skin manifestations.
- Amyotrophic Lateral Sclerosis (ALS): A progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord, leading to loss of muscle control. ALS is known for its rapid progression of muscle weakness.
Do Not Miss Diagnoses
- Guillain-Barré Syndrome: An autoimmune disorder where the body's immune system mistakenly attacks part of its peripheral nervous system, leading to muscle weakness and sometimes paralysis. It can progress rapidly and requires immediate medical attention.
- Botulism: A rare but potentially life-threatening illness caused by a toxin produced by the bacteria Clostridium botulinum. It leads to muscle weakness, paralysis, and respiratory issues if not treated promptly.
- Lambert-Eaton Myasthenic Syndrome (LEMS): A rare autoimmune disorder that affects the nerve-muscle connection, causing muscle weakness, fatigue, and sometimes paralysis. It is often associated with small cell lung cancer.
Rare Diagnoses
- Mitochondrial Myopathies: A group of disorders caused by mitochondrial dysfunction, leading to muscle weakness and other systemic symptoms. These are rare and often present with a mix of neurological and non-neurological features.
- Inclusion Body Myositis: The most common acquired myopathy in adults older than 50 years, characterized by progressive muscle weakness and wasting, especially of the distal muscles. It is rare and often misdiagnosed.
- Pompe Disease: A genetic disorder caused by the deficiency of acid alpha-glucosidase, leading to glycogen accumulation in muscles and resulting in progressive muscle weakness. It is extremely rare and can present at any age.