Differential Diagnoses for Bilateral and Symmetric Sensorimotor Peripheral Neuropathy

Single Most Likely Diagnosis

• Diabetic Neuropathy: This is the most common cause of bilateral and symmetric sensorimotor peripheral neuropathy, especially in patients with a history of diabetes mellitus. The high prevalence of diabetes and its well-documented association with peripheral neuropathy make it a leading consideration.

Other Likely Diagnoses

• Alcoholic Neuropathy: Chronic alcohol abuse is a common cause of peripheral neuropathy, presenting with symmetric sensorimotor deficits. The mechanism involves both direct toxicity of alcohol and nutritional deficiencies.
• Vitamin B12 Deficiency: A deficiency in vitamin B12 can lead to a neuropathy that is often symmetric and affects both sensory and motor functions. This condition is more common in individuals with dietary restrictions, malabsorption, or increased demand.
• Idiopathic Neuropathy: A significant proportion of peripheral neuropathies are idiopathic, meaning their cause is unknown. These cases often present with a symmetric pattern and can affect both sensory and motor nerves.

Do Not Miss Diagnoses

• Amyloidosis: Although rare, amyloidosis can cause a systemic illness that includes peripheral neuropathy. It's crucial to consider this diagnosis due to its potential for serious systemic involvement and the availability of specific treatments.
• Heavy Metal Poisoning (e.g., Lead, Arsenic): Exposure to certain heavy metals can result in a peripheral neuropathy that may be symmetric. Identifying and removing the source of exposure is critical for treatment and prevention of further damage.
• Vasculitic Neuropathy: Conditions like polyarteritis nodosa or rheumatoid vasculitis can cause a neuropathy that may present with symmetric features, although asymmetric patterns are more common. Early diagnosis is vital due to the potential for systemic complications.

Rare Diagnoses

• Charcot-Marie-Tooth Disease: A group of hereditary disorders that affect the peripheral nerves, leading to symmetric sensorimotor neuropathy. While it's a significant consideration in the differential diagnosis of young patients with a family history, it's less common than acquired causes.
• Tangier Disease: A rare genetic disorder characterized by severe reduction in HDL cholesterol, leading to peripheral neuropathy among other symptoms. Its rarity and specific diagnostic criteria make it a less likely but interesting consideration.
• Fabry Disease: An X-linked lysosomal storage disorder that can cause a variety of systemic symptoms, including peripheral neuropathy. Its rarity and the availability of specific enzyme replacement therapy make it an important diagnosis not to overlook in the right clinical context.

Each of these diagnoses has a distinct set of clinical features, diagnostic tests, and management strategies. A thorough history, physical examination, and appropriate laboratory tests are essential for narrowing down the differential diagnosis and guiding treatment.