Exceptionally elevated creatine kinase levels in a laryngectomized patient: hypothyroid myopathy

Abstract

We present a laryngectomized patient with unspecific complaints of fatigue whose laboratory findings were out of proportion with the clinical presentation. The enormously high blood levels of creatine kinase (CPK) (8000 IU/l, normal range 30–190 IU/l) and thyroid-stimulating hormone (100 mU/l, normal range 0.5–4.5 mU/l) led to diagnosis and treatment of and recovery from hypothyroid myopathy. Hypothyroidism reduces the ability of the muscle to maintain its adequate energetic economy, via several suggested mechanisms. This may lead to injury (myopathy) that allows enzymes such as CPK to leak out of cells and causes elevation of their serum levels. To our knowledge, this is the first reported case of a patient previously treated for head and neck cancer who developed hypothyroid myopathy, presenting with exceptionally elevated CPK levels. This is noteworthy, since hypothyroidism may be easily avoided by a comprehensive follow-up of patients treated for head and neck cancer.