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11-year-old boy with falls

By Joshua Sonnen, MD

Nov 30, 2023

Inclusion body myopathy , IBM,

Clinical History

  • 11-year-old boy
  • Progressive weakness, Gower sign, falls 3 to 4 times a week, and leg pain
  • PMH: ADHD, flat feet, Achilles tendinitis, and chronic constipation. Family history: lupus, no other neuromuscular conditions
  • MRI: fatty infiltration paraspinal and psoas
  • Lab results: CK 1075 H, ANA borderline, B12 and folate normal, RF negative.
  • Genetic neuropathy panel: heterozygous for VUS in SCN11A


What is the best diagnosis?

A. Autophagic vacuoles with sarcolemmal features

B. Reducing bodies

C. Myositis with rimmed vacuoles

D. Inclusion body myopathy



Correct answer: Inclusion body myopathy

Inclusion body myopathy vs. myositis

  • Rimmed vacuoles = inclusion bodies (IB)
  • IBs are a finding, not a diagnosis
  • Young person with many IBs – inclusion body myopathy most likely
    • Possibly familial or genetic
    • In this case no relevant gene/family history identified
  • >50 years + lymphocytic inflammation – inclusion body myositis most likely


Quick note: This post is to be used for informational purposes only and does not constitute medical or health advice. Each person should consult their own doctor with respect to matters referenced. Arkana Laboratories assumes no liability for actions taken in reliance upon the information contained herein.