Myopathy, acquired and genetic
Proximal weakness with normal sensation and reflexes, a stepwise workup built on CK, TSH, antibodies, EMG, MRI and biopsy, the acquired causes a physician must catch (statins and anti-HMGCR, steroids, thyroid, colchicine, inclusion body myositis) and the genetic myopathies seen in adults (FSHD, OPMD, Pompe, McArdle, mitochondrial).
Tier 2Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Myopathy causes symmetrical proximal weakness (stairs, rising from a chair, lifting arms) with normal sensation and reflexes preserved until late.
- Some patterns point elsewhere: distal weakness (myotonic dystrophy, IBM), facial and scapular (FSHD), ptosis and dysphagia (OPMD, MG), early respiratory failure (Pompe, myotonic dystrophy, IBM rarely).
- CK separates necrotising and inflammatory disease (high) from steroid, endocrine and many congenital myopathies (normal or mildly raised).
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Sources
- About the Life Saving Drugs Program (LSDP medicines table, including Pompe disease)AU/NZAustralian Government Department of Health, Disability and Ageing, 2026
- 272nd ENMC international workshop: revision of the ENMC 2013 diagnostic criteria for inclusion body myositis and clinical trial readiness (Lilleker JB et al. Neuromuscul Disord 2024;37:36-51)European Neuromuscular Centre, 2024
- International guideline for idiopathic inflammatory myopathy-associated cancer screening: an IMACS initiative (Oldroyd AGS et al. Nat Rev Rheumatol 2023;19:805-817)International Myositis Assessment and Clinical Studies Group, 2023
- 224th ENMC international workshop: clinico-sero-pathological classification of immune-mediated necrotizing myopathies (Allenbach Y et al. Neuromuscul Disord 2018;28:87-99)European Neuromuscular Centre, 2018
- N-of-1 trial of a statin, placebo, or no treatment to assess side effects (SAMSON; Wood FA et al. N Engl J Med 2020;383:2182-2184)New England Journal of Medicine, 2020
- Statin-associated muscle symptoms: identification and recommendations for management (Maki KC et al. Curr Atheroscler Rep 2025;27(1):5; epub November 2024)Current Atherosclerosis Reports, 2024
- Therapeutic Guidelines: NeurologyAU/NZTherapeutic Guidelines Limited
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback