Hyperemesis gravidarum followed by refeeding syndrome causes electrolyte abnormalities induced rhabdomyolysis and diabetes insipidus.

Although hyperemesis gravidarum (HG), an extreme form of morning sickness, is a common complication during pregnancy, HG associated simultaneous onset of rhabdomyolysis and diabetes insipidus due to electrolyte abnormalities are rare. A 34-year-old woman with severe HG at 17 weeks of gestation complicated with appetite loss, weight reduction by 17 kg, general fatigue, myalgia, weakness and polyuria was identified to have simultaneous hypophosphatemia (1.6 mg/dL) and hypokalemia (2.0 mEq/L). Appetite recovery and the improvement of the hypophosphatemia (3.2 mg/dL) were observed prior to the first visit to our department. At the admission, she presented polyuria around 7,000~8,000 mL/day with impaired concentrating activity (U-Osm 185 mOsm/L), and abnormal creatine kinase elevation (4,505 U/L). The electrolyte disturbances and physio-metabolic abnormalities in undernourished state due to HG let us diagnose this case as refeeding syndrome (RFS). In this case, abnormal loss by vomiting, insufficient intake and previous inappropriate fluid infusion as well as the development of RFS may accelerate the severity of hypokalemia due to HG. Thus, as her abnormalities were considered as results of rhabdomyolysis and diabetes insipidus due to severe HG associated hypokalemia based on RFS, oral supplementation of potassium chloride was initiated. After 6 days of potassium supplementation, her symptoms and biochemical abnormalities were completely resolved. Severe HG followed by RFS can be causes of electrolyte abnormalities and subsequent complications, including rhabdomyolysis and renal diabetes insipidus. Appropriate diagnosis and prompt interventions including adequate nutrition are necessary to prevent electrolyte imbalance induced cardiac, neuromuscular and/or renal complications.