endocrine and metabolic disorders
Hypokalemia
Diagnosis of Hypokalemia
Serum potassium measurement ECG When the mechanism is not evident clinically, measurement of 24-hour urinary potassium excretion and serum magnesium concentration Hypokalemia (serum potassium<3.5 mEq/L [< 3.5 mmol/L]) may be found during routine serum electrolyte measurement. It should be suspected in patients with typical changes on an ECG or in those who have muscular symptoms and risk factors. Hypokalemia is confirmed by blood testing. ). Hypokalemia may cause Ventricular Premature Beats (VPB) and Serum potassium is in mEq/L and mmol/L. The cause of hypokalemia is usually apparent by history (particularly the medication history); when it is not, further investigation is warranted. After acidosis and other causes of intracellular potassium shift (increased beta-adrenergic effect, hyperinsulinemia) have been eliminated, 24-hour urinary potassium and serum magnesium concentrations are measured. In hypokalemia, potassium secretion is normally<15 mEq/L (< 15 mmol/L). Extrarenal (GI) potassium loss or decreased potassium ingestion is suspected in chronic unexplained hypokalemia when renal potassium secretion is<15 mEq/L (< 15 mmol/L). Secretion of>15 mEq/L (>15 mmol/L). suggests a renal cause for potassium loss. Unexplained hypokalemia with increased renal potassium secretion and hypertension suggests an aldosterone-secreting tumor or Liddle syndrome. Unexplained hypokalemia with increased renal potassium loss and normal blood pressure suggests Bartter syndrome or Gitelman syndrome, but hypomagnesemia, surreptitious vomiting, and diuretic abuse are more common and should also be considered. 