The Gastrointestinal Implications of a Rare Lysosomal Storage Disorder, Cystinosis

Introduction: Cystinosis is a lysosomal storage disorder that results in amino acid - cystine, accumulating inside lysosomes. Cystine accumulation results in the formation of crystals that lead to cell damage and death of organs and tissues throughout the body. Cystinosis is a rare, inherited metabolic disorder that affects roughly 500-600 children in the United States. We present a rare case presentation of gastrointestinal bleed in a patient with cystinosis. Case Description/Methods: An 18-year-old White man with history of cystinosis, end stage renal disease secondary to cystinosis status post live donor renal transplant was admitted to the hospital for acute renal failure and concern for antibody-mediated rejection. Medications included tacrolimus, mycophenolate mofetil, prednisone and cysteamine bitartrate. While admitted he developed hematochezia with subsequent drop in hemoglobin/hematocrit from 7.1/24.2 g/dL to 4.8/16.4 g/dL. On examination vitals were stable, physical exam revealing no distention or guarding and positive abdominal tenderness and bowel sounds. CT Abdomen and Pelvis with/without contrast was completed and revealed acute hemorrhage of small branch of right colic artery into lumen of the cecum. Following multidisciplinary discussion patient underwent successful IR embolization. EGD/Colonoscopy was completed the next day to investigate source of bleed and rule out potential medication induced ulcerations from cysteamine bitartrate, for which he was prescribed for treatment of cystinosis. Colonoscopy revealed patchy severe mucosal changes characterized by friability and scarring in the sigmoid, descending, transverse, ascending and cecum, biopsied; and 5 polyps which were removed (Figure 1). Pathology revealed polypoid reactive colonic mucosa with crystals, chronic inactive colitis and CMV. The polyps were inflammatory. The overall histological features were suggestive of cystinosis related changes. Patient was treated for CMV and was ultimately discharge home with clinic follow up. Discussion: Although cystinosis is a multisystemic disease resulting from cystine accumulation, majority of the research to date has focused on the impact towards the kidney. We present a case demonstrating less commonly seen extrarenal complications of the effect on the gastrointestinal (GI) system. Our case highlights the effect this disease has on the GI tract and brings attention to clinicians on potential symptoms patient may develop as well as, endoscopy findings.Figure 1.: Colonoscopy image.