Dialysis-related Amyloidosis

CKD Bone Diseasemedium

A 66-year-old man with ESRD due to analgesic nephropathy has received HD via a left forearm AVF for 14 years. Over the last year, he has developed pain and stiffness in both shoulders. The pain is located anterolaterally and is aggravated by abduction of the shoulders. He also has neck pain and tingling in both hands, especially at night. Examination of shoulders reveal mild tenderness to palpation and protuberance of soft tissue above the shoulders, more prominent on the left. There is no tenderness or warmth. Radiography of the shoulders shows bone cysts with sclerotic margins that have grown in size compared with images obtained 6 months ago. Electromyography and nerve conduction studies show results consistent with bilateral carpal tunnel syndrome. Which of the following diagnostic tests is most likely to identify the cause of this patient’s shoulder pain?

  1. A.Synovial tissue biopsyCorrect
  2. B.Magnetic resonance imaging
  3. C.Sestamibi parathyroid scan
  4. D.Technetium bone scan

Explanation

The patient should undergo synovial biopsy to establish the diagnosis of B2 microglobulin amyloidosis. The diagnosis is likely based on the long duration of dialysis, the distribution of symptoms (involving the neck, both shoulders, and hands), soft tissue prominence over shoulder (pad sign), and bone cysts on radiography. Definitive diagnosis is made by staining biopsy tissue from affected joint or bone cyst with Congo red and demonstration of apple-green birefringence under polarized light.

Why each option

A.
Synovial biopsy can confirm amyloidosis by demonstrating amyloid deposits with Congo red staining.
B.
MRI can show structural changes but not confirm amyloidosis.
C.
Parathyroid scan is not relevant for diagnosing amyloidosis.
D.
Bone scan is used for metastatic disease, not amyloidosis.

Reference: Gejyo F et al. A new form of amyloid protein associated with chronic hemodialysis was identified as beta-2 microglobulin. Biochem Biophys Res Commun 1985;129:701-706; Scarpioni R et al. Dialysis-related amyloidosis: pathogenesis and clinical features. J Nephrol 2016;29:159-167.

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