7289 An interesting case of Diabetes Mellitus Type 1 induced Renal Tubal Acidosis Type 1
Authors: Ripa Rashelle , Itani Assma , Patel Shivangi K 
Published: October 2024

Disclosure: R. Ripa: None. A. Itani: None. S.K. Patel: None.

Introduction: Renal Tubular Acidosis (RTA) are a group of disorders that involve dysfunctional transporters and channels in the renal system. These disorders can be acquired (idiopathic, medication side effects, and medical disorders) or inherited. The most common type worldwide is type 4 RTA, the main cause is diabetic nephropathy leading to hypoaldosteronism. The association of type 1 RTA with diabetes has rarely been reported in studies. Here, we report the presentation, diagnosis and management of a rare case of type 1 RTA in a patient with a history of diabetes mellitus type 1. Case: A male in his 50s with a 30-year history of uncontrolled type 1 diabetes mellitus on insulin pump and coronary artery disease presented to his cardiologist with worsening chest pain, fatigue, polyuria, weight loss of 15 lbs, and recent insulin pump change. Blood tests revealed serum bicarbonate of 10 mmol/L and he was sent to the hospital. On examination, he was hypotensive and bradycardic with dry mouth and decreased skin turgor. His blood tests were consistent with type 1 RTA, he was treated with intravenous fluids containing bicarbonate plus potassium and transitioned to oral potassium citrate on discharge. He underwent renal biopsy as work up was unrevealing for a cause of type 1 RTA. Biopsy revealed normal glomeruli with negative immunofluorescence and Congo red stain. The biopsy, however, did show mild patchy chronic interstitial fibrosis with lymphocytes and mild tubular atrophy. At one year follow up, he remained on oral potassium citrate with resulting serum bicarbonate of 26 mmol/L and a normal renal function. Discussion: Diabetes mellitus can lead to a variety of renal pathologies, specifically metabolic acidosis that can be either seen as diabetic ketoacidosis or hyporeninemic hypoaldosteronism (Type 4 RTA). In our patient, despite being a diabetic, he did not present with either elevated anion gap, ketonuria or hyperkalemic hyperchloremic acidosis typical of type 4 RTA. He was noted to have hypokalemic hyperchloremic acidosis, with a positive urine anion gap, and an alkaline urine, all characteristic of type 1 RTA. Acquired distal RTA occurs more commonly due to certain medications or autoimmune diseases as in Sjögren’s syndrome. The relationship between distal RTA and Sjögren’s syndrome has already been established, unlike the relationship with type 1 diabetes. There have been few case reports of distal RTA in association with type 1 diabetes mellitus, implying a possible autoimmune pathology. Prior case reports also not only had patients who were insulin dependent, but diabetes was present for more than a decade at least suggesting chronicity of disease is needed. Traditional management consists of alkaline therapy and treatment of the underlying disease, or removal of offending medication. In this case, we hope to highlight distal RTA in a diabetic who doesn’t meet criteria for DKA or type 4 RTA.

Presentation: 6/1/2024