Differential Diagnosis for Numbness and Tingling of Feet Only When Sitting and Lying Down

• Single Most Likely Diagnosis
  • Peripheral neuropathy: This condition often presents with symptoms that worsen at night or when in certain positions due to increased pressure on the nerves. The fact that symptoms occur when sitting and lying down suggests a possible exacerbation of neuropathic symptoms due to positional factors.
• Other Likely Diagnoses
  • Lumbar spinal stenosis: Although more commonly associated with walking, certain positions can exacerbate spinal stenosis symptoms, leading to numbness and tingling in the feet.
  • Peripheral nerve entrapment (e.g., peroneal or tibial nerve entrapment): Specific nerves can become compressed in certain positions, leading to localized numbness and tingling.
  • Vitamin deficiencies (e.g., B12 deficiency): Deficiencies can cause neuropathic symptoms that might be exacerbated by certain positions due to increased pressure on affected nerves.
• Do Not Miss Diagnoses
  • Cauda equina syndrome: A serious condition that requires immediate medical attention, characterized by numbness in the legs, which can be exacerbated by certain positions. Although less likely, missing this diagnosis could have severe consequences.
  • Spinal cord compression: Similar to cauda equina syndrome, this is a medical emergency that could present with worsening neurological symptoms in certain positions.
• Rare Diagnoses
  • Tarlov cysts: These are rare, fluid-filled sacs that can compress nerves, potentially causing numbness and tingling that could be position-dependent.
  • Chronic inflammatory demyelinating polyneuropathy (CIDP): A rare autoimmune disorder that could present with variable neuropathic symptoms, potentially worsening in certain positions.
  • Fabry disease: A genetic disorder that can cause neuropathic pain and numbness, which might be influenced by positional factors, although this would be a less common presentation.