A 56-year-old man comes to the office due to burning pain in his feet. The patient initially began experiencing pins and needles in his toes several months ago, which gradually worsened to involve the entire foot. Lately, he has had burning and cramping pain daily in both feet, which is more pronounced at night. The patient has had occasional back pain but has no chronic medical conditions and takes no medications. He is a construction worker and is frequently exposed to vibrating machinery. He does not smoke but drinks 4-6 beers daily and more on the weekends. Vital signs are within normal limits. Physical examination shows loss of bilateral ankle reflex and impaired light touch and vibration sensation in both feet. The remainder of the examination reveals no abnormalities. Hemoglobin A1c and methylmalonic acid levels are within normal limits. Which of the following is the most likely cause of this patient's symptoms?

Question

A 56-year-old man comes to the office due to burning pain in his feet.  The patient initially began experiencing pins and needles in his toes several months ago, which gradually worsened to involve the entire foot.  Lately, he has had burning and cramping pain daily in both feet, which is more pronounced at night.  The patient has had occasional back pain but has no chronic medical conditions and takes no medications.  He is a construction worker and is frequently exposed to vibrating machinery.  He does not smoke but drinks 4-6 beers daily and more on the weekends.  Vital signs are within normal limits.  Physical examination shows loss of bilateral ankle reflex and impaired light touch and vibration sensation in both feet.  The remainder of the examination reveals no abnormalities.  Hemoglobin A1c and methylmalonic acid levels are within normal limits.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d5be_f037_bc81_2f7871ced2c2_MD0003_00 This patient has a symmetric distal polyneuropathy. Peripheral neuropathy is often idiopathic but can be caused by a wide variety of toxic and metabolic disorders that impair axonal function. Common causes include diabetes mellitus, hypothyroidism, vitamin B₁₂ deficiency, and medications (eg, cisplatin). However, this patient's heavy alcohol use makes alcoholic neuropathy most likely. Chronic, excessive alcohol ingestion is neurotoxic and results in an axonal neuropathy characterized by a reduction in the number of small myelinated and unmyelinated fibers. It may occur alone or in association with thiamine deficiency (resulting in concurrent demyelination). Alcoholic neuropathy typically results in a symmetric distal polyneuropathy (ie, stocking and glove pattern); symptoms include paresthesia, burning pain, and numbness. Loss of deep tendon reflexes is common and almost invariably begins with loss of the ankle reflex. Physical examination typically demonstrates loss of light touch and vibratory sense; gait ataxia is common. Cessation of alcohol is associated with improvement in symptoms, and thiamine supplementation is recommended to prevent secondary neuropathies. Gabapentin and tricyclic antidepressants are often used to treat refractory pain. (Choice A) Guillain-Barré syndrome is the most common autoimmune neuropathy and presents as a rapidly progressive, ascending polyneuropathy that typically follows a gastrointestinal or upper respiratory illness. This patient's pain-predominant symptoms and slow progression make this unlikely. (Choice B) Compression neuropathies can affect a nerve root (eg, spondylolisthesis) or solitary nerve (eg, common peroneal nerve). However, compression of a nerve root typically results in back pain with weakness of the innervated muscles and radicular (dermatomal) paresthesia. Common peroneal nerve compression results in foot drop and dorsal foot paresthesia. This patient's stocking-like distribution does not follow a single nerve (or nerve root) pattern. (Choice C) Charcot-Marie-Tooth disease is the most common hereditary polyneuropathy; however, it typically occurs as a slowly progressive neuropathy that results in foot drop, muscle weakness, and lower leg atrophy. There is usually a strong family history of the disorder. (Choice E) Vasculitic neuropathies typically occur when vasculitis affects the vasa nervorum, leading to nerve ischemia. It generally occurs in the setting of systemic vasculitis (eg, polyarteritis nodosa) and results in a patchy, asymmetric neuropathy that affects several nerves (ie, mononeuritis multiplex); severe pain is a prominent feature. In addition, systemic symptoms (eg, fever, fatigue) are common. Educational objective: Alcoholic neuropathy is a toxic neuropathy that typically results in a symmetric distal polyneuropathy (ie, stocking and glove pattern) characterized by paresthesia, burning pain, and ataxia. Loss of distal deep tendon reflexes (eg, ankle) and light touch and vibratory sense are common.

A 56-Year-Old Man Comes to the Office Due to Burning