Differential Diagnosis for Leg Weakness
- Single most likely diagnosis:
- Peripheral neuropathy: This is a common cause of leg weakness, often due to diabetes, vitamin deficiencies, or alcohol abuse. It typically presents with gradual onset of weakness, numbness, and tingling in the legs.
- Other Likely diagnoses:
- Muscular dystrophy: A group of inherited disorders characterized by progressive muscle weakness and degeneration, often starting in the legs.
- Chronic inflammatory demyelinating polyneuropathy (CIDP): An autoimmune disorder that causes progressive weakness and loss of sensation in the legs.
- Lumbar disc herniation or spinal stenosis: Compression of the spinal cord or nerve roots can cause leg weakness, pain, and numbness.
- Stroke or transient ischemic attack (TIA): Although more commonly associated with arm weakness, stroke or TIA can also cause leg weakness, especially if the lesion is in the brainstem or spinal cord.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
- Guillain-Barré syndrome: A rare autoimmune disorder that can cause rapid onset of leg weakness, which can progress to respiratory failure if not promptly treated.
- Spinal cord compression: Compression of the spinal cord due to trauma, tumor, or infection can cause rapid onset of leg weakness, loss of sensation, and bowel/bladder dysfunction.
- Vasculitis (e.g., giant cell arteritis, polyarteritis nodosa): Inflammation of the blood vessels can cause leg weakness, pain, and numbness, and can be life-threatening if not treated promptly.
- Rare diagnoses:
- Amyotrophic lateral sclerosis (ALS): A progressive neurodegenerative disorder that affects motor neurons, causing leg weakness, atrophy, and fasciculations.
- Tick-borne illnesses (e.g., Lyme disease, tick paralysis): Certain tick-borne illnesses can cause leg weakness, numbness, and tingling, often with a distinctive rash or other systemic symptoms.
- Heavy metal poisoning (e.g., lead, mercury): Exposure to heavy metals can cause leg weakness, numbness, and tingling, often with other systemic symptoms such as abdominal pain or cognitive impairment.