Differential Diagnosis for Numbness in the Medial Portion of Both Feet
Single Most Likely Diagnosis
- Diabetic Neuropathy: Given the patient's pre-diabetic status, early signs of diabetic neuropathy could be presenting, even with normal vitamin B12 levels. Diabetic neuropathy often affects the distal extremities and can cause numbness, tingling, and pain in a symmetrical pattern.
Other Likely Diagnoses
- Tarsal Tunnel Syndrome: This condition involves compression of the posterior tibial nerve as it travels through the tarsal tunnel on the inner side of the ankle, leading to numbness in the medial portion of the foot.
- Peripheral Artery Disease (PAD): Reduced blood flow to the feet can cause numbness, especially in older adults or those with risk factors like pre-diabetes. PAD might not be the first consideration for numbness but is a plausible cause given the patient's age and pre-diabetic status.
- Morton's Neuroma: Although more commonly associated with pain between the toes, Morton's neuroma can cause numbness in the foot, particularly if it affects the nerves supplying the medial portion.
Do Not Miss Diagnoses
- Spinal Stenosis or Lumbar Radiculopathy: While less common, spinal stenosis or lumbar radiculopathy (nerve root compression) can cause numbness in the feet. Missing these diagnoses could lead to significant morbidity if not addressed promptly.
- Vasculitis: Certain types of vasculitis, like Buerger's disease, can cause peripheral neuropathy and numbness due to inflammation of blood vessels. Although rare, vasculitis is a critical diagnosis not to miss due to its potential for serious complications.
Rare Diagnoses
- Charcot-Marie-Tooth Disease: A group of inherited disorders that affect the peripheral nerves, leading to numbness, muscle weakness, and atrophy, primarily in the feet and legs.
- Amyloidosis: A condition characterized by the deposition of amyloid proteins in various tissues, including nerves, which can cause peripheral neuropathy and numbness.
- Sjögren's Syndrome: An autoimmune disorder that can cause peripheral neuropathy among its myriad of symptoms, including numbness in the feet.