A case report of renal tubular acidosis type 1 with severe hypokalemia

Abstract

Background: Distal renal tubular acidosis is an uncommon condition with complex pathophysiology that can present with life-threatening electrolyte abnormalities. Case presentation: We describe the case of a 53-year-old woman with previous episodes of severe hypokalemia, severe muscle weakness and fatigue. In addition she is suffering from symptoms of dry eye and dry mouth. Initial evaluation revealed hyperchloremic metabolic acidosis, severe hypokalemia, persistent alkaline urine and a positive urinary anion gap, suggestive of distal renal tubular acidosis type 1. Additional laboratory work up and renal biopsy led to the diagnosis of primary Sjogren’s syndrome with associated chronic tubulo-interstitial nephritis. She had taken mycophenolate mofetil and prednisone for the Sjogren’s syndrome and systemic scleroderma since 2016. We started to treat with potassium and bicarbonate supplementation. Nonetheless, her renal function failed to improve and remained steady with an estimated glomerular filtration rate of 47 ml/min/1.73 m2. She is clinically quiet stable including blood potassium level and metabolic acidosis. Conclusions: Hypokalemia should be carefully evaluated to prevent adverse complications, uncover a potentially treatable condition, and prevent the progression to chronic kidney disease. Repeated episodes of unexplained hypokalemia could be an important clue for diagnosis. For that reason, to figure out of the cause of the unspecified hypokalaemia is crucial.