POLYMYOSITIS

SUMMARY

1. PM manifests as symmetric proximal muscle weakness & mild myalgia.

2. Weakness begins in the proximal muscles initially - present(s) with difficulty rising. This differentiates it from PMR.

3. CK is high in myositis, while in PMR the ESR and CRP is high but CK is normal.

4. As PM progresses, dysphagia (from tongue, pharynx, and upper oesophageal dysfunction), dysphonia, dyspnoea (from diaphragm weakness), and cardiac changes (from myocarditis or CAD) can occur.

Reference(s)

Wilkinson, I. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].