Peripheral Neuropathy: This is the most common cause of numbness in the lower limbs among the elderly, often due to diabetes, vitamin deficiencies, or age-related wear and tear on the nerves.

Lumbar Spinal Stenosis: A condition where the spinal canal narrows, putting pressure on the spinal cord and nerves, leading to numbness, weakness, and pain in the lower limbs.
Peripheral Artery Disease (PAD): Reduced blood flow to the limbs can cause numbness, pain, and weakness, especially during walking.
Hypothyroidism: Can cause peripheral neuropathy leading to numbness in the lower limbs among other symptoms.
Vitamin B12 Deficiency: A common cause of peripheral neuropathy in the elderly, leading to numbness in the hands and feet.

Spinal Cord Compression: Conditions like spinal tumors or abscesses can compress the spinal cord, leading to rapid progression of numbness, weakness, and potentially paralysis if not promptly treated.
Guillain-Barré Syndrome: An autoimmune disorder where the body's immune system mistakenly attacks part of its peripheral nervous system, which can lead to life-threatening paralysis if not recognized and treated early.
Multiple Sclerosis: Although less common in new diagnoses among the elderly, it can present with numbness and should be considered, especially if there are other neurological symptoms.

Amyloidosis: A condition caused by an abnormal protein (amyloid) that can accumulate in various organs, including nerves, leading to peripheral neuropathy.
Sjögren's Syndrome: An autoimmune disorder that can cause peripheral neuropathy among its wide range of symptoms.
Heavy Metal Poisoning: Exposure to heavy metals like lead or mercury can cause peripheral neuropathy, though this is less common in the elderly population without specific exposure risks.
Vasculitis: Inflammation of the blood vessels can lead to nerve damage and numbness, though it is a rare cause in the elderly without other systemic symptoms.