Differential Diagnosis for Muscle Atrophy Leg with Fasciculations

Single Most Likely Diagnosis

• Amyotrophic Lateral Sclerosis (ALS): This is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord, leading to loss of muscle control. ALS is characterized by muscle atrophy, fasciculations, and progressive weakness, making it the most likely diagnosis given the symptoms.

Other Likely Diagnoses

• Spinal Muscular Atrophy (SMA): A genetic disorder that affects the nerve cells responsible for controlling voluntary muscle movement, leading to muscle weakness and atrophy. Fasciculations can be seen in SMA, especially in the later stages.
• Peripheral Neuropathy: Conditions that damage the peripheral nerves, such as diabetic neuropathy or neuropathy due to vitamin deficiencies, can lead to muscle atrophy and fasciculations, particularly if the nerves supplying the muscles are affected.
• Muscular Dystrophy: A group of inherited disorders characterized by progressive muscle weakness and atrophy. While fasciculations are not a hallmark, some forms like Becker muscular dystrophy can present with muscle atrophy and occasional fasciculations.

Do Not Miss Diagnoses

• Heavy Metal Poisoning (e.g., Lead, Mercury): Exposure to heavy metals can cause a range of neurological symptoms, including muscle weakness, atrophy, and fasciculations. It's crucial to consider environmental or occupational exposure.
• Vitamin Deficiencies (e.g., Vitamin B12 Deficiency): Certain vitamin deficiencies can lead to neurological symptoms, including muscle weakness and atrophy. Early diagnosis and treatment can prevent long-term damage.
• Infections (e.g., Poliomyelitis, West Nile Virus): Although less common, infections can cause acute flaccid paralysis and muscle atrophy. These conditions require immediate medical attention.

Rare Diagnoses

• Kennedy's Disease (Spinal and Bulbar Muscular Atrophy): A rare, inherited disorder that affects the nerve cells responsible for controlling voluntary muscle movement, leading to muscle atrophy, fasciculations, and other symptoms.
• Inclusion Body Myositis: A rare inflammatory muscle disease characterized by progressive muscle weakness and atrophy, which can sometimes present with fasciculations.
• Multifocal Motor Neuropathy: A rare condition that affects the nerves supplying the muscles, leading to muscle weakness, atrophy, and fasciculations, typically in a multifocal pattern.