A 70-year-old man comes to the physician with muscle pains and weakness over the last several weeks. He now has difficulty getting up from a chair and climbing stairs. He has no fever, weight loss, vision changes, or shortness of breath.
The patient's other medical problems include hyperlipidemia, gout, hypertension, chronic kidney disease, and degenerative joint disease of the hips and knees. His medications include lisinopril, allopurinol, colchicine, atorvastatin, and acetaminophen.
Vital signs are within normal limits. Examination shows some tenderness to palpation of his thighs and weakness of both thighs to extension and flexion. Deep-tendon reflexes are symmetrically diminished at the patellar tendons and absent at the Achilles tendons. Peripheral pulses are normal.
Laboratory results are as follows:

Electromyogram shows slowed sensory and motor nerve conduction velocities and small-amplitude, short-duration polyphasic waves.
A quadriceps muscle biopsy demonstrates widespread cytoplasmic vacuolization but no inflammation.
What is the most likely explanation for this patient's symptoms?

Question

A 70-year-old man comes to the physician with muscle pains and weakness over the last several weeks.  He now has difficulty getting up from a chair and climbing stairs.  He has no fever, weight loss, vision changes, or shortness of breath.
The patient's other medical problems include hyperlipidemia, gout, hypertension, chronic kidney disease, and degenerative joint disease of the hips and knees.  His medications include lisinopril, allopurinol, colchicine, atorvastatin, and acetaminophen.
Vital signs are within normal limits.  Examination shows some tenderness to palpation of his thighs and weakness of both thighs to extension and flexion.  Deep-tendon reflexes are symmetrically diminished at the patellar tendons and absent at the Achilles tendons.  Peripheral pulses are normal.
Laboratory results are as follows:

Electromyogram shows slowed sensory and motor nerve conduction velocities and small-amplitude, short-duration polyphasic waves.
A quadriceps muscle biopsy demonstrates widespread cytoplasmic vacuolization but no inflammation.
What is the most likely explanation for this patient's symptoms?

Quizplus · Accepted Answer

This patient's proximal muscle weakness, myalgia, and neuropathy are likely due to colchicine neuromyopathy. This condition is seen in chronic kidney disease patients who receive colchicine as a preventative therapy for gout. Creatine kinase (CK) is usually elevated 10-20 fold. The cytoplasmic vacuolization seen on muscle biopsy is characteristic. The condition rapidly resolves on discontinuation of colchicine. In patients with chronic kidney disease, periodic review of medications, careful dosage modification of drugs eliminated by the kidneys, and conservative use of medications are required to avoid an increased frequency of adverse drug-related events. (Choice A) Although statins can potentiate rhabdomyolysis in combination with colchicine, statins alone do not usually result in neuropathy. In statin-induced myopathy, the type of histologic change seen is myonecrosis without vasculitis/inflammation, and mononuclear cell infiltration in the later stages. (Choice C) Diabetic amyotrophy (lumbosacral plexopathy) classically presents with acute and asymmetric focal proximal lower-extremity pain associated with weakness, autonomic dysfunction (eg, orthostatic hypotension), and unintentional weight loss (usually > 4.5 kg [10 lb]). Muscle biopsy shows no abnormalities. (Choice D) Hypothyroidism is associated with a variety of muscular and neuropathic complaints and, in some patients, elevated CK. The presence of cytoplasmic vacuolization suggests colchicine neuromyopathy more likely than hypothyroidism. (Choice E) Polymyositis also presents with proximal muscle weakness, myalgias, and elevated CK. However, the neuropathic component of this patient's illness, presence of cytoplasmic vacuoles, and the lack of inflammation on muscle biopsy are not typical of polymyositis. Educational objective: Chronic accumulation of colchicine, often seen in patients with chronic kidney disease, can result in significant neuromyopathy. The cytoplasmic vacuolization seen on muscle biopsy is characteristic. This condition resolves on discontinuation of colchicine. __________ References: Colchicine neuromyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/19078054) Colchicine myoneuropathy in chronic renal failure patients with gout. (http://www.ncbi.nlm.nih.gov/pubmed/16669978)

A 70-Year-Old Man Comes to the Physician with Muscle Pains