A 62-year-old woman comes to the office due to tingling and numbness in her feet over the last several months. The patient has also noticed a small ulcer on her right foot that "doesn't seem to be healing." Medical history is significant for long-term diabetes, hypertension, and gout. Physical examination shows decreased pain sensation over both feet and bilateral absence of ankle reflexes. This patient's neurological symptoms are most likely associated with which of the following features?

Question

A 62-year-old woman comes to the office due to tingling and numbness in her feet over the last several months.  The patient has also noticed a small ulcer on her right foot that "doesn't seem to be healing."  Medical history is significant for long-term diabetes, hypertension, and gout.  Physical examination shows decreased pain sensation over both feet and bilateral absence of ankle reflexes.  This patient's neurological symptoms are most likely associated with which of the following features?

Quizplus · Accepted Answer

11ec160b_39d8_e5df_9249_9b5b20f3fc89_MD0001_00 This patient with long-standing diabetes has numbness and tingling in her feet and reduced ankle reflexes bilaterally. This presentation suggests diabetic neuropathy, a common complication of diabetes mellitus that is associated with poor glycemic control and/or long disease duration. It often manifests as a length-dependent peripheral polyneuropathy that primarily affects sensory axons; patients typically develop a stocking-and-glove pattern of pain or paresthesia. Diminished pain sensation coupled with poor wound healing predisposes diabetic patients to develop nonhealing wounds. Neuronal injury in diabetes mellitus is multifactorial but largely occurs through the following mechanisms: (Choice B) Endoneurial inflammatory infiltration of the peripheral nerves is characteristic of Guillain-Barré syndrome, which typically causes a rapidly progressive ascending paralysis rather than a slowly progressive paresthesia. Segmental demyelination is another typical pathologic finding. (Choice C) Myelin protein gene mutations are involved in the pathogenesis of Charcot-Marie-Tooth disease, which presents with weakness of foot dorsiflexion due to involvement of the common peroneal nerve; sensory symptoms are typically less prominent. (Choice D) Entrapment of a nerve within an anatomic compartment leads to compression neuropathy. The most common example is carpal tunnel syndrome, which occurs due to compression of the median nerve at the wrist. (Choice E) Abnormal signal transmission at the neuromuscular junction is characteristic of myasthenia gravis (MG), which occurs due to antibodies against acetylcholine receptors, and Lambert-Eaton syndrome (LES), which occurs due to antibodies against presynaptic calcium channels. MG causes fatigable weakness that is most prominent in the proximal and facial muscles, while LES results in weakness that improves with repetition. Educational objective: Diabetic peripheral neuropathy is characterized by numbness and paresthesia in a stocking-and-glove distribution. It results from nonenzymatic glycosylation of proteins, leading to hyalinization of endoneurial arteries and ischemic nerve damage. In addition, accumulation toxic substances within neurons results in deranged metabolism and increased oxidative stress.

A 62-Year-Old Woman Comes to the Office Due to Tingling