Abstract: FR-PO0906
Why Did K Get Away? A Case Study of Occult Distal Renal Tubular Acidosis Masked by Milk-Alkali Syndrome
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Case Reports - 1
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Author
- Dhanani, Sophia, Texas Health Resources, Arlington, Texas, United States
Introduction
Distal Renal Tubular Acidosis (RTA) classically presents with non-anion-gap metabolic acidosis, potassium wasting, and elevated urinary pH and is associated with nephrocalcinosis and autoimmune disease. Concurrent conditions may obscure the diagnosis and alter the expected acid-base presentation.
Case Description
A 73-year-old female with rheumatoid arthritis and nephrolithiasis presented with progressive weakness, confusion, gait instability, and urinary incontinence. Laboratory evaluation demonstrated hypokalemia of 2.4,AKI, hypercalcemia of 12.8, and bicarbonate of 28. MRI brain showed diffuse parenchymal atrophy and ventriculomegaly without acute stroke. Neurologic evaluation determined her symptoms were inconsistent with Normal Pressure Hydrocephalus.Further workup revealed significant calcium carbonate intake for GERD symptoms, raising concern for milk-alkali syndrome. SPEP, PTHrP, ACE levels, and malignancy workup were negative. PTH was appropriately suppressed at 11.8. Despite IV fluids and potassium replacement, the patient developed persistent hypokalemia and hyperchloremic metabolic acidosis. TTKG was 9, consistent with renal potassium wasting. Bartter syndrome was initially considered given metabolic alkalosis, hypercalciuria, and potassium wasting.The patient was discharged on potassium supplementation but returned within 48 hours with recurrent dehydration and bicarbonate of 16. Further evaluation demonstrated persistently elevated urinary pH above 5.5, positive urine anion gap, hypercalciuria, and continued potassium wasting despite systemic acidosis. Given non-anion-gap metabolic acidosis with bicarbonate of 17 and urinary pH of 7, the patient was ultimately diagnosed with distal RTA and discharged on potassium citrate.
Discussion
This case demonstrates how distal RTA may initially be masked by concurrent milk-alkali syndrome and contraction alkalosis, obscuring the expected presentation of non-anion-gap metabolic acidosis.