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Abstract: SA-PO389

No Stone Unturned: A Case of Sjogren Syndrome Diagnosed by Recurrent Nephrolithiasis

Session Information

Category: Trainee Case Report

  • 902 Fluid and Electrolytes: Clinical

Authors

  • Tharian, Antonia, NYU Winthrop, Manhasset, New York, United States
  • Carson, John M., NYU Winthrop Hospital, Mineola, New York, United States
Introduction

The cause of nephrolithiasis is idiopathic in the majority of cases. Patients who are young, form stones recurrently, or have high stone burdens warrant more thorough investigation into an underlying cause.


Case Description

59 year old female with past medical history of hypertension, Raynaud’s, gastric reflux, and recently diagnosed nephrolithiasis who presented with malaise, dysuria, fever, and chills after a seven day course of antibiotics for a urinary tract infection. She was evaluated in emergency department one month prior for right sided flank pain and was found to have a 4 mm obstructing stone in the proximal right ureter. This stone passed with medical expulsive therapy after which she continued to pass sandy urine sediment. On the current admission, imaging demonstrated a new 6 mm obstructing stone in the distal right ureter and a non-obstructing stone in the left renal pelvis not present a month earlier. Routine laboratory evaluation revealed a creatinine of 1.8mg/dL, non-anion gap metabolic acidosis, hypokalemia with elevated urinary potassium, and a urine pH of 6. The urine anion gap was positive and a distal renal tubular acidosis (RTA) was suspected. Further serologic testing was notable for a positive ANA (1:80), negative double stranded DNA, strongly positive anti SS-A and anti SS-B antibodies, low C3 and very low C4. Anti-Scl-70 was normal. A diagnosis of Sjogrens with possible systemic lupus erythematosus overlap was made. She was treated with antibiotics and urology removed the stone cystoscopically. Her creatinine improved from 1.8 to 1.1mg/dL on discharge. As expected, the composition of her stone was 98% calcium phosphate, 2% calcium oxalate. She was started on potassium citrate which improved her hypokalemia and acidosis significantly.

Discussion

Distal RTA increases stone risk due to alkaline urine, hypocitraturia, and hypercalciuria related to bone buffering in chronic acidosis. General causes of distal RTA from defects in the tubular transporters in the alpha intercalated cell of the renal collecting duct include genetic mutations, autoimmune diseases, and medications. Systematic evaluation of this patient’s nephrolithiasis led to a diagnosis of distal renal tubular acidosis and ultimately an underlying systemic disease, Sjogren’s syndrome.