Imaging and surgical utilization for pediatric cystinuria patients: A single-institution cohort study

Objective: Although cystinuria is rare, its clinical manifestations are life-long. Little is known about healthcare utilization in this population.

Study design: Through billing records and chart review, we identified pediatric patients with cystinuria treated at our institution. Variables included demographics, gender, race, comorbidities, location of presentation, presenting symptoms, initial laboratory data, and stone characteristics. Outcomes included the number and type of imaging tests and procedures performed. Descriptive statistics were performed. Median annual frequencies of procedures and imaging were calculated.

Results: Twenty-three patients who presented between 1995 and 2011 were identified. The median age at presentation was 12 years, 48% of our patients were male, and 91% were Caucasian. Median follow-up was 4.6 years. Over half were diagnosed in clinic (13/23), while 30% (7/23) presented to the ED. Pain was the most common presenting symptom (13/23), followed by nausea/vomiting (6/23), gross hematuria (5/23), and fevers (5/23). Only one patient presented with acute renal failure. Five patients were discovered by sibling screening. The median number of stones at presentation was two and median size of the largest stone was 9 mm, with three staghorn calculi. During follow-up, a total of 110 stone procedures were performed in 15 patients. Five patients underwent 13 PCNLs, 11 patients underwent 44 ureteroscopy procedures, and nine underwent open or robotic surgery, including one nephrectomy. Among patients identified by sibling screening, most (4/5) were managed with medical therapy alone. A total of 390 imaging procedures were performed. Radiation-associated imaging comprised half of all imaging tests.

Discussion: The high rates of imaging and surgical utilization among pediatric cystinuria patients reflect the morbidity of this condition and the need for preventative management. By practicing the ALARA principle during urologic procedures, urologists can reduce radiation exposure. Multiple procedures are often required to render patients stone-free. URS/LL and PCNL are likely to be more effective than ESWL. In complex cases, robotic-assist lithotomy provides the advantage of a minimally invasive approach. Both sibling screening and transitional care represent long-term strategies with the potential to reduce life-long morbidity. The limitations of this study include its small sample size, retrospective nature, and single-center experience.

Conclusions: Our study demonstrates that the clinical impact of disease among pediatric patients presenting with cystinuria at our institution is considerable, with most requiring surgery. Our population also generates heavy utilization of diagnostic imaging. Given the lifelong nature of this disease, research on improved preventive therapies is urgently needed.