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Kidney Week

Abstract: SA-PO623

Rapid Development of Severe Nephrolithiasis in Febrile Infection-Related Epilepsy Syndrome

Session Information

  • Pediatric Nephrology - II
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1800 Pediatric Nephrology

Authors

  • Wang, Linda, Children's National Hospital, Washington, District of Columbia, United States
  • Ahn, Sun-Young, Children's National Hospital, Washington, District of Columbia, United States
Introduction

Febrile infection-related epilepsy syndrome (FIRES) is a rare disorder characterized by new onset of refractory status epilepticus, with development of seizures within 24 hours to 2 weeks of febrile illness. Nephrolithiasis has not been previously reported with FIRES.

Case Description

A 5-year-old previously healthy boy presented with fever followed by refractory seizures requiring multiple antiepileptics; he was subsequently diagnosed with FIRES. Serum electrolytes, calcium (Ca), phosphorus (P), uric acid, and creatinine were normal, but urinalysis showed blood and protein. Initial renal ultrasound(US) was normal; however, an abdominal US 11 days later showed extensive multiple bilateral kidney stones, largest measuring 10 mm, resulting in pelvicalyceal dilation bilaterally, with bilateral ureteral dilation from calculi and bladder wall calcification. Stone formation was initially attributed to furosemide (given 7 days), topiramate (11 days), and ketogenic diet (1 month). However, the patient continued to form numerous bilateral stones for several months after discontinuation of all 3 factors, requiring repeated lithotripsy, stone extraction, and bilateral ureteral stenting to relieve obstruction. Initial stone analyses revealed carbonate apatite (dahlite,100%) stones and a stone analysis 3 months later showed Ca hydrogen phosphate (brushite,100%) stones. A 24-hour urine analysis showed hypercalciuria (4.8 mg/kg Ca, nl<4) and phosphaturia (22.5 mg/kg P, nl<17). He received intravenous immunoglobulin, steroids, rituximab, anakinra and tocilizumab as treatment for FIRES with improvement in his seizures; hematuria and proteinuria resolved. Oral hydrochlorothiazide was initiated resulting in decreased stone burden on abdominal CT scan.

Discussion

Kidney stone formation has been associated with increased expression of molecules involved in inflammatory pathways, such as osteopontin which is detected in stone organic matrix. In addition, serum osteocalcin, elevated in our patient (98.4 ng/ml, nl 7.3-38.5), has been linked to development of renal calcium phosphate deposits. In our patient with possible underlying hypercalciuria, the pro-inflammatory state from FIRES may have triggered the rapid and massive kidney stone formation and bladder calcification. Further investigation is needed to delineate the association between nephrolithiasis and inflammatory conditions such as FIRES.