[Steinert disease: abnormal onset or "casual" diagnosis?].

The most frequent myopathy is "Steinert's disease" (also called myotonic dystrophy). We present a case of particular interest due to the way diagnosis was made. A 20-year-old male was transferred to our Department from another Hospital with a diagnosis of "acute liver disease". He presented with fever (39 degrees C), tetrahyposthenia, dehydration and spatial-temporal disorientation. The most apparent laboratory data was a significant increase in serum levels of creatine phosphokinase (196,260 IU/L; normal values < 50 IU/L). After therapy based on parenteral nutrition and steroids, our patient improved progressively, with normalization of laboratory values. Muscle biopsy and electromyography yielded a diagnosis of Steinert's disease, and the patient's mother was found to be the carrier of a myotonine-kinase gene mutation. In this case, the onset of what appeared to be an influenza-A virus infection (the only positive data observed in the serological analysis) permitted the diagnosis of a hereditary myopathy that had remained asymptomatic up to that time.