P0116 - Sharing (Mutations) Is Not Always Caring: Cystic Fibrosis and PSC

Isaac E. Perry, DO¹, John Erikson Yap, MD^2
1Medical College of Georgia, Augusta, GA; ²Medical College of Georgia at Augusta University, Augusta, GA

Introduction: Rare manifestations of cystic fibrosis (CF) include intrahepatic biliary disease and sclerosing cholangitis (PSC). In some patients, PSC may be a single organ presentation of CF. As the most common lethal autosomal recessive disease in Caucasians, knowledge of this entity is critical. A high clinical suspicion is obligatory as abdominal pain may be non-specific and many patients lack jaundice, as highlighted in this case.



Case Description/Methods: A 22-year-old Caucasian male with a history of CF (delF508/Q493X) and pancreatic insufficiency presented with subjective fevers, generalized abdominal pain and constipation. He was non-adherent with his modulator therapy (elexacaftor/tezacaftor/ivacaftor) for 2 months due to insurance issues and restarted one month prior. His vital signs were normal, and the physical exam revealed mild tenderness in his lower abdomen. Alkaline phosphatase was minimally elevated at 133 U/L (normal GGT) and the remaining labs were normal. An abdominal x-ray was unremarkable. His laxative and pancreatic enzymes were optimized. A CT scan of his abdomen and pelvis revealed mild intrahepatic biliary ductal dilation within the left hemiliver. MRCP demonstrated diffuse intra and extrahepatic irregular biliary ductal dilatation with a beaded and string appearance favoring sclerosing cholangitis (Figure A). EGD and ileocolonoscopy were completed revealing a 6 mm Forrest IIc duodenal bulb ulcer (pathology negative for H. pylori) and normal ileocolonic mucosa (pathology negative for IBD). He was placed on pantoprazole and discharged.



Discussion: There is substantial genotypic and phenotypic overlay between CF and PSC. Mutation of the CF transmembrane conductance regulator gene results in cholangiocytes generating nitric oxide which inhibits secretion leading to cholestasis. Inspissated mucus obstructs the hepatobiliary tract, manifesting as sclerosis cholangitis. Abdominal pain is the most common symptom. The diagnosis is made by having elevated alkaline phosphatase and GGT supported by biliary imaging either by MRCP or ERCP showing multifocal strictures and dilation in the bile ducts. If PSC is diagnosed, colonoscopy with random biopsies is recommended to evaluate for IBD given the association of PSC with IBD. Historical literature reveals a higher prevalence of IBD in CF patients. Patients with PSC are at a heightened risk for malignancies requiring imaging surveillance. Treatment consists of therapeutic ERCP for dominant strictures, UDCA, antibiotics and liver resection.





Disclosures:


Isaac E. Perry, DO¹, John Erikson Yap, MD². P0116 - Sharing (Mutations) Is Not Always Caring: Cystic Fibrosis and PSC, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.