A 70-year-old woman comes to the office due to worsening bilateral shoulder pain for 3 months that is not responsive to analgesics. The patient also reports tingling in her right hand and forearm for the past 3 weeks. Medical history is significant for diabetic nephropathy and end-stage renal disease. The patient has been receiving hemodialysis 3 times a week for 20 years. Temperature is 37 C (98.6 F), blood pressure is 130/78 mm Hg, pulse is 80/min, and respirations are 16/min. Examination shows bilateral hypertrophy of the shoulders. Range of motion of the shoulder joints is restricted in all directions. Weakness and atrophy of the muscles of the thenar eminence, as well as decreased sensation in the thumb and index, middle, and ring fingers, are noted. Heart sounds are normal. There is no hepatosplenomegaly. X-ray reveals radiolucent bone cysts in both shoulders. Ultrasound reveals increased rotator cuff thickness and deposits with increased echogenicity between the muscles and tendons of the rotator cuff. Serum calcium is 8.1 mg/dL. Which of the following is the most likely diagnosis?

Question

A 70-year-old woman comes to the office due to worsening bilateral shoulder pain for 3 months that is not responsive to analgesics.  The patient also reports tingling in her right hand and forearm for the past 3 weeks.  Medical history is significant for diabetic nephropathy and end-stage renal disease.  The patient has been receiving hemodialysis 3 times a week for 20 years.  Temperature is 37 C (98.6 F), blood pressure is 130/78 mm Hg, pulse is 80/min, and respirations are 16/min.  Examination shows bilateral hypertrophy of the shoulders.  Range of motion of the shoulder joints is restricted in all directions.  Weakness and atrophy of the muscles of the thenar eminence, as well as decreased sensation in the thumb and index, middle, and ring fingers, are noted.  Heart sounds are normal.  There is no hepatosplenomegaly.  X-ray reveals radiolucent bone cysts in both shoulders.  Ultrasound reveals increased rotator cuff thickness and deposits with increased echogenicity between the muscles and tendons of the rotator cuff.  Serum calcium is 8.1 mg/dL.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: This patient on long-term dialysis has shoulder pain/hypertrophy and carpal tunnel syndrome due to dialysis-related amyloidosis (DRA). The unifying feature of amyloidoses is misfolded precursor proteins that deposit in extracellular tissues, causing organ dysfunction. When these precursor proteins undergo excessive production, inadequate clearance, or inherited mutation, amyloidosis results. amyloidosis In DRA, beta2-microglobulin (B2-m) is the precursor protein deposited as amyloid due to inadequate elimination despite dialysis. Along with sustained elevation of B2-m, several connective tissue components (eg, glycosaminoglycans, type I collagen) participate in amyloid fibril stabilization. This may explain DRA's affinity for osteoarticular structures, resulting in the following classic triad: Scapulohumeral periarthritis: shoulder pain/hypertrophy with increased rotator cuff thickness and hyperechogenic deposits on imaging Carpal tunnel syndrome: median neuropathy, with thenar eminence atrophy and weakness, tingling and decreased sensation in the first 3 fingers, as well as possible flexor tendosynovitis (finger contractures) Bone cysts: possible pathologic fracture DRA prevalence increases with age and dialysis duration. (Choice A) Acromegaly frequently causes carpal tunnel syndrome, and soft tissue hypertrophy is characteristic. However, enlargement is not isolated to the shoulders. Tissue overgrowth involves the jaw (macrognathia), brow ridge, tongue (macroglossia), and hands and feet. Headaches are a prominent symptom, and acromegaly is not associated with dialysis. Acromegaly (Choice C) Polymyalgia rheumatica prevalence increases with age, and shoulder pain is characteristic; however, the hip girdle is also involved, and there is no hypertrophy or bone cysts. (Choice D) Pseudogout (acute attacks of calcium pyrophosphate crystal deposition in synovial tissues) typically results in a monoarticular, self-limited inflammatory arthritis. Imaging can reveal chondrocalcinosis (calcification of articular cartilage appearing as linear radiodensities on x-ray) and hyperechoic bands within the tendons, not between the muscles and tendons, as in this patient. Bilateral shoulder involvement would be uncommon; it rarely causes bone cysts and is unrelated to dialysis. chondrocalcinosis (Choice E) Tertiary hyperparathyroidism results from inadequately controlled secondary hyperparathyroidism in end-stage kidney disease. Parathyroid hyperplasia results in the autonomous secretion of parathyroid hormone unresponsive to plasma calcium levels, typically resulting in hypercalcemia. Although tertiary hyperparathyroidism can cause bone cysts, this patient's low calcium make it highly unlikely, and soft tissue deposits are not typical. Educational objective: Dialysis-related amyloidosis results from inadequate clearance of beta2-microglobulin despite dialysis, and the prevalence increases with age and dialysis duration. It has a predilection for osteoarticular structures presenting as scapulohumeral periarthritis (shoulder pain/hypertrophy), carpal tunnel syndrome, and bone cysts.

A 70-Year-Old Woman Comes to the Office Due to Worsening