A 65-year-old man comes to the emergency department because of severe right thigh pain for the last 4 weeks. Over the past two weeks, he has also noticed leg weakness that interferes with his walking. He has never had similar symptoms before. He had an unintentional weight loss of 15 lbs (6.8 kg) over the past 3 months. His other medical problems include type 2 diabetes mellitus, hypertension, and hyperlipidemia. He has no evidence of diabetic retinopathy or nephropathy. He had a right lung lobectomy for early stage, non-small cell lung cancer 7 years ago.
He was evaluated in the emergency department on two occasions over the last 2 months for severe lightheadedness that occurred in the morning while getting out of bed. His medications include glyburide, metformin, simvastatin, lisinopril, and low-dose aspirin.
His temperature is 37.0 C (98.6 F) , blood pressure is 145/90 mm Hg (sitting) and 120/80 mm Hg (standing) , and pulse is 90/min (sitting) and 105/min (standing) . His BMI is 29 kg/m². Neurological examination reveals normal mental status and cranial nerves. Manual motor testing reveals 3/5 strength in the right iliopsoas, hip adductors, and quadriceps with associated atrophy. Touch, pain, and temperature sensations are mildly decreased in this area. However, the hamstrings and distal muscles have 5/5 strength.
There are no fasciculations or contractures noted. His anal sphincter tone is normal. Deep tendon reflexes are 2+ in the arms and 0 in the lower extremities. Testing for Babinski sign shows down-going toes bilaterally. The remainder of the neurological examination is within normal limits.
Laboratory results are as follows:

Which of the following is the most likely cause for this patient's current complaints?

Question

A 65-year-old man comes to the emergency department because of severe right thigh pain for the last 4 weeks. Over the past two weeks, he has also noticed leg weakness that interferes with his walking. He has never had similar symptoms before. He had an unintentional weight loss of 15 lbs (6.8 kg) over the past 3 months. His other medical problems include type 2 diabetes mellitus, hypertension, and hyperlipidemia. He has no evidence of diabetic retinopathy or nephropathy. He had a right lung lobectomy for early stage, non-small cell lung cancer 7 years ago.
He was evaluated in the emergency department on two occasions over the last 2 months for severe lightheadedness that occurred in the morning while getting out of bed. His medications include glyburide, metformin, simvastatin, lisinopril, and low-dose aspirin.
His temperature is 37.0 C (98.6 F) , blood pressure is 145/90 mm Hg (sitting) and 120/80 mm Hg (standing) , and pulse is 90/min (sitting) and 105/min (standing) . His BMI is 29 kg/m². Neurological examination reveals normal mental status and cranial nerves. Manual motor testing reveals 3/5 strength in the right iliopsoas, hip adductors, and quadriceps with associated atrophy. Touch, pain, and temperature sensations are mildly decreased in this area. However, the hamstrings and distal muscles have 5/5 strength.
There are no fasciculations or contractures noted. His anal sphincter tone is normal. Deep tendon reflexes are 2+ in the arms and 0 in the lower extremities. Testing for Babinski sign shows down-going toes bilaterally. The remainder of the neurological examination is within normal limits.
Laboratory results are as follows:

Which of the following is the most likely cause for this patient's current complaints?

Quizplus · Accepted Answer

11ec193a_9660_3e5a_853d_ed6f3d3ac4c3_MD0002_00 This patient's presentation is consistent with diabetic amyotrophy (also known as proximal diabetic neuropathy or diabetic polyradiculopathy), which is a lumbosacral plexopathy that also affects the lumbosacral nerve roots and peripheral nerves. The pathophysiology is unclear but may be attributed to a nonsystemic microvasculitis leading to ischemic injury. Diabetic amyotrophy usually occurs in individuals over age 50 and in recently diagnosed or reasonably well-controlled diabetics (e.g., HbA1C ~ 7.5%). Patients classically present with acute and asymmetric focal proximal lower extremity pain associated with weakness, autonomic dysfunction (e.g., orthostatic hypotension), and unintentional weight loss (usually > 10 lbs). Diagnosis is made clinically and is usually a diagnosis of exclusion after other possible etiologies (e.g., cauda equina syndrome, Guillain-Barré syndrome, myositis/myopathy, structural plexus lesion, infections, and autoimmune or inflammatory conditions) are ruled out. An EMG/NCS can confirm the diagnosis. Over 60% of patients will notice improvement of their strength and pain symptoms within 12-24 months, but many may have residual weakness and pain. Since there is no definitive therapy, treatment usually involves symptomatic management including physical and occupational therapy, medication for pain control, and strict glycemic control. (Choice A) Amyotrophic lateral sclerosis (ALS) usually presents with a combination of upper motor neuron (e.g., hyperreflexia, spasticity) and lower motor neuron (e.g., atrophy, fasciculations) symptoms. Although asymmetric limb weakness is the main presentation, patients usually complain of distal muscle weakness (e.g., foot drop, dropping things) first. In addition, severe pain is not seen with ALS. (Choice C) Extramedullary tumor with compressive myelopathy usually presents with progressive weakness below the level of lesion with sensory loss, hyperreflexia, spasticity, and incontinence. This patient's focal involvement in the proximal right leg with normal anal sphincter tone and absent lower extremity reflexes makes this diagnosis unlikely. (Choice D) Polymyositis typically presents with symmetrical proximal muscle weakness with or without pain. ESR, CRP, CPK, and aldolase levels are usually elevated. This patient's asymmetrical weakness without marked CPK elevation makes this condition less likely. (Choice E) The anterior and lateral femoral cutaneous nerves are pure sensory nerves and their compression does not cause muscle weakness or absent reflexes. Educational objective: Diabetic amyotrophy usually presents with acute and asymmetric focal lower extremity pain associated with weakness, muscle atrophy, areflexia, autonomic dysfunction, and unintentional weight loss. Patients frequently have coexisting diabetic symmetrical polyneuropathy. Treatment is mainly symptomatic and includes physical and occupational therapy, medication for pain control, and strict glycemic control. Many patients make partial functional recovery. __________ References: Diabetic amyotrophy: current concepts. (http://www.ncbi.nlm.nih.gov/pubmed/8987131) Immunotherapy for diabetic amyotrophy. (http://www.ncbi.nlm.nih.gov/pubmed/19588395)

A 65-Year-Old Man Comes to the Emergency Department Because of Severe