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Abstract: SA-PO487

Unusual Case of Hypokalemia After Gastric Band

Session Information

Category: Fluid‚ Electrolyte‚ and Acid-Base Disorders

  • 1002 Fluid‚ Electrolyte‚ and Acid-Base Disorders: Clinical


  • Ewing, Elise, Houston Methodist Hospital, Houston, Texas, United States
  • Ibrahim, Hassan N., Houston Methodist Hospital, Houston, Texas, United States

55 year old woman with prior laparoscopic gastric band 10 years ago presented to primary care for new onset fatigue, concentration difficulty, and cold intolerance. She also has severe heartburn for the past few years and takes over-the-counter calcium carbonate multiple times per day. She has hypokalemia worsening over the past 3 years and several other metabolic disturbances, and was referred to nephrology clinic.

Case Description

Lab results included low potassium 3.0 mmol/L (3.5–5.3), elevated serum bicarbonate 30 mmol/L (20–32), BUN 12 mg/dL, creatinine 0.98 mg/dL, elevated serum calcium 10.4 mg/dL (8.3–10.2) and PTH 21 pg/dL (15–65). VBG revealed pH 7.36, pCO2 57mmHg (45–51), and bicarbonate 32 mmol/L (21–28). Hemoglobin was 10.2 g/dL (11.7–15.5) with microcytosis (MCV 82). Serum iron level was 11 mcg/dL (45-160), with 3% iron saturation (16-45). Urine studies indicated renal wasting with random UNa 60 mEq/L, UCl 41 mEq/L, UK 28 mEq/L and UCa 22 mEq/L. CT scan of the abdomen revealed a significantly dilated esophagus above the gastric band with excessive restriction. The electrolyte disturbances were likely sequelae of this with frequent calcium carbonate intake leading to hypercalcemia, suppressed PTH, and metabolic alkalosis. The metabolic alkalosis induces kaliuresis and intracellular shift of potassium resulting in hypokalemia.
She was advised to discontinue calcium carbonate and instead use Esomeprazole 40mg daily for GERD, and to discuss gastric band adjustment with bariatric surgeon.
At a 1 month follow-up visit, there was normalization of potassium 3.7 mmol/L, bicarbonate 25 mmol/L, and calcium 9.5 mg/dL. She also received two IV iron infusions and hemoglobin increased to 13.2 g/dL within 2 months. Energy level, concentration, and cold tolerance all improved.


Milk Alkali syndrome includes a triad of hypercalcemia, metabolic alkalosis, and acute kidney injury. Discontinuing the offending agent usually results in rapid resolution. Calcium carbonate can also impact iron absorption. Typically iron is conjugated within gastric acid and absorbed in the upper gastrointestinal tract. If this process is impaired and iron reaches the alkaline secretions in the proximal jejunum, it is converted to ferric hydroxide and cannot be absorbed. Excess calcium can impair iron absorption. Also since an acidic gastric environment is needed, medications such as PPIs or antacids can decrease iron absorption.