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., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
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].