Differential Diagnosis for Severe Peripheral Neuropathy with Bilateral Foot Drop
- Single Most Likely Diagnosis
- Diabetes Mellitus: This is the most common cause of peripheral neuropathy, and bilateral foot drop can be a complication of long-standing, poorly controlled diabetes due to nerve damage.
- Other Likely Diagnoses
- Chronic Alcohol Abuse: Long-term alcohol abuse can lead to nutritional deficiencies (notably thiamine) and direct toxic effects on nerves, causing peripheral neuropathy.
- Vitamin B12 Deficiency: A deficiency in vitamin B12 can cause demyelination and axonal degeneration, leading to peripheral neuropathy and potentially foot drop.
- Guillain-Barré Syndrome: An autoimmune disorder that can cause rapid onset of muscle weakness and peripheral neuropathy, sometimes leading to foot drop.
- Do Not Miss Diagnoses
- Lyme Disease: Although less common, Lyme disease can cause peripheral neuropathy, including foot drop, and is critical to diagnose due to its treatability with antibiotics.
- Sarcoidosis: A systemic disease that can affect nerves, causing neuropathy, and if missed, can lead to significant morbidity.
- Heavy Metal Poisoning (e.g., Lead, Arsenic): Exposure to heavy metals can cause severe peripheral neuropathy, and diagnosis is crucial for removal from the source of exposure and potential treatment.
- Rare Diagnoses
- Charcot-Marie-Tooth Disease: A group of inherited disorders that affect the peripheral nerves, leading to neuropathy and potentially foot drop, though symptoms typically start earlier in life.
- Amyloidosis: A condition characterized by the deposition of amyloid proteins in various tissues, including nerves, leading to peripheral neuropathy.
- Porphyria: A group of rare genetic disorders that can cause acute intermittent porphyria, leading to neuropathy and potentially foot drop.
- Tangier Disease: A rare genetic disorder affecting lipid metabolism, which can lead to peripheral neuropathy among other symptoms.