[The most frequent electrolyte disorders in the emergency department : what must be done immediately?]

Hyponatremia is the most common form of electrolyte disorder in the emergency room. The symptoms are unspecific and include nausea, dizziness and often falls. Typical symptoms of severe hypernatremia are vomiting, cerebral seizures, somnolence and even coma. The specific initial laboratory diagnostics include measurement of serum electrolytes, serum glucose, serum and urine osmolarity and sodium in urine. The main aim of the clinical examination is to estimate the volume status. If a patient has hypovolemia an infusion of isotonic sodium chloride solution (0.9 %) is the method of choice. If the patient is euvolemic the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or (neurotropic) drugs might be the cause. In these cases the primary measure is restriction of fluid intake. As a rapid correction of sodium levels can lead to pontine myelinolysis, the increase in sodium concentration must not be less than 10 mmol/l within the first 24 h and 18 mmol/l within the first 48 h. Clinical symptoms of hyperkalemia include neurological (e.g. muscle weakness, paresis, hyperreflexia, cramps and dysesthesia), gastrointestinal (e.g. nausea, vomiting and diarrhea) and cardiac symptoms (e.g. dysrhythmia and conductance disorders). Calcium injection stabilizes cardiac rhythm disorders immediately. For a rapid drop in potassium by shifting the potassium to the intracellular space, administration of glucose with insulin and high-dose inhalative administration of betamimetics can be used. Potassium elimination is achieved by infusion of isotonic sodium choride (0.9 %) with i.v. administration of furosemide, ion exchange resins and hemodialysis.