HyperCKemia-MB due to macroCK type 1: Case report

HyperCKemia is a rare condition characterized by a persistent increase in serum creatine kinase (CK) levels or some isoenzymes. Usually, there are no clinical, electromyography or histological manifestations, which involves a challenge at the time of diagnosis. The patient in question showed no characteristic signs or symptoms, apart from fatigue and post-exercise myalgia. Assessment was performed by rheumatology and endocrinology, determination of total CK and MB fraction in blood, and electromyography and protein electrophoresis were requested as part of the approach. This case report is considered as novel, interesting, and useful for clinical practice as few similar ones were found in the scientific literature. The difficult etiological diagnosis of this entity, and the algorithm used to arrive at it, are all presented. It is concluded that in those patients with hyperCKemia of unknown etiology, this diagnosis should be kept in mind, and be confirmed by performing a CK electrophoresis.

La hiperCKemia es una condición poco frecuente caracterizada por un aumento persistente de los niveles de creatina quinasa (CK) sérica o de algunas isoenzimas, sin que suelan presentarse manifestaciones clínicas, electromiográficas o histológicas, lo cual implica un desafío a la hora del diagnóstico. El paciente cuyo caso se presenta aquí no mostró signos o síntomas característicos, únicamente fatiga y mialgias posteriores al ejercicio. Se llevó a cabo valoración por reumatología y endocrinología, determinación de CK total y fracción MB en sangre; además, se solicitó electromiografía y electroforesis de proteínas como parte del abordaje. Consideramos que este reporte de caso es novedoso, interesante y de utilidad para la práctica clínica pues se encuentran pocos similares en la literatura científica; adicionalmente, se pone en evidencia el difícil diagnóstico etiológico de esta entidad, así como el algoritmo utilizado para llegar a ella. Se concluye que este diagnóstico debe tenerse en mente en aquellos pacientes con hiperCKemia de etiología desconocida, y para confirmarlo es necesario hacer una electroforesis de CK.

A Patient's Post-Cardiovascular Surgery Needs for the Differential Diagnosis of Postoperative Myocardial Ischemia Because of Macro Creatine Kinase / 日本心臓血管外科学会雑誌

A 61 year old woman who had been receiving treatment for ulcerative colitis for 14 years complained of respiratory discomfort on exertion and was diagnosed with severe mitral regurgitation due to mitral valve prolapse. Minimally invasive mitral valvuloplasty with right mini-thoracotomy was performed in our facility. Laboratory findings showed elevated levels of serum creatine kinase (CK) and CK-MB immediately after surgery. In addition to elevated levels of myocardial enzymes, ST depression was seen in an electrocardiogram on postoperative day 2 ; therefore, we suspected myocardial ischemia during the surgery. Despite the persistently elevated levels of myocardial enzymes, coronary angiography showed no significant abnormalities. Because of the possibility of false CK elevation, we performed CK electrophoresis, which revealed the presence of macro-CK type 1. CK-MB activity is often falsely elevated when determined by immune-inhibition in macro-CK patients, and that leads to the suspicion of myocardial ischemia. We considered that it may be highly difficult to identify macro-CK in a patient after cardiovascular surgery owing to elevated levels of myocardial enzymes in most such patients.