Myositis – Grade 1

Management escalation pathway

  • In case of doubt withhold ICPI
  • Initiate paracetamol/NSAID
  • If symptom severity increases despite NSAID consider treatment cfr grade 2
  • Control CK after one week, if increasing: discuss with local myositis specialist

Assessment and Investigations

  • Complete history of all organ systems
  • Perform examination of joints and skin
  • Exclude cardiac origin (CKMB/troponin/pro-BNP and ECG) and in case of doubt perform cardiac MRI
  • ! Troponin I is more specific of cardiac involvement than troponin T
  • Exclude other causes of elevated CK: IM injection, physical activity, …


ACPA: Anti Citrullinated Antibody
ANF: Anti Nuclear Factor
C3/C4: Complement Factor 3 or 4
CK: Creatine Kinase
CK MB: Creatine Kinase Muscle
ECG: ElectroCardioGram
EMG: ElectroMyoGram
ICPi: Immune Checkpoint Blockade Inhibition
MRI: Magnetic Resonance Imaging
PD: Per Day
PO: Per Os
Pro-BNP: Pro-Brain Natriuretic Peptide
RF: Rheuma Factor
ULN: Upper Limit of Normal