Rise in creatine kinase in a patient on statin

Abstract

Introduction: Statins are commonly used in family medicine practice. Myopathy is one of the known possible side effects. Should creatine kinase (CK) be routinely checked for patients on statin? This is a clinical case report. Methods: A 62-years old lady was followed-up in a general outpatient clinic for hypertension, hyperlipidaemia and obesity. Her 10-years cardiovascular risk was medium. A routine blood test of her in June 2017 showed low density lipoprotein cholesterol (LDL_C) 4.1mmol/L. She was put on simvastatin 20mg nocte. The attending doctor ordered a follow-up lipid profile, routine liver function and CK checking 3 months later. Patient had her blood test in Sept 2017. Here LDL_C dropped to 2.7mmol/L. Her liver function was normal but her CK was elevated to 198 U/L (Ref: 40-161U/L). Patient reported no myalgia. However, she recalled having an upper respiratory tract infection treated symptomatically during her blood test. The simvastatin was continued at the same dose. CK was rechecked 1 month later in Oct 2017 and dropped to 177U/L. Patient remained asymptomatic. Simvastatin was continued. Further repeating of CK another month later in Nov 2017 noticed the level almost normalized (169U/L). Results and Discussion: Upon a 3 months’ observation without intervention, the rise in CK didn’t seem to be related to the statin given. This case demonstrated a routine checking of CK in an asymptomatic patient on statin would be unnecessary. This echoes with most of the international guidelines.