A 43-year-old woman with gastroesophageal reflux disease, ankylosing spondylitis on adalimumab, chronic sacroiliitis, and normocytic anemia presented for evaluation of persistent, severe hypokalemia with concurrent metabolic alkalosis and newly recognized hypertension. These abnormalities had first been noted 2 months earlier, whereas prior laboratory testing within the preceding year had shown normal potassium levels and no acid-base disturbances. A limited workup at an outside facility 2 months prior (Table 1) had not determined the etiology.