2439 Cystic Fibrosis Liver Disease: A Curious Case of Atypical Cystic Fibrosis Diagnosed in Adulthood

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INTRODUCTION: Cystic fibrosis (CF) poses considerable morbidity and mortality. Largely identified in children with “typical” pulmonary problems, some present past adolescence and instead display “atypical” complaints. CF liver disease (CFLD) has a significant disease burden as a leading cause of death in CF. Symptom variation makes diagnosing CF in adults difficult. Our case report describes a diagnosis of atypical CF and CFLD in adulthood after nearly two decades of inconclusive findings. The case highlights hepatic sequelae of CF, disease diversity, and the impact of delayed diagnosis. CASE DESCRIPTION/METHODS: We present a 32-year-old African American female first noted to have elevated liver function tests (LFTs) on routine labs at age 16, yet was asymptomatic. Despite numerous clinical encounters over 17 years - including chemistry panels, imaging, and biopsies - the etiology remained unclear. In adulthood, she began experiencing chronic abdominal pain, and was later found to have critically low magnesium levels resulting in a seizure. The differential was expanded, and sweat chloride testing was positive, though genetic testing was negative. Given clinical history of high LFTs with abdominal pain and hypomagnesemia, appearance of symptoms past age 18, and unfixed results, she qualified for the diagnosis of atypical CF with CFLD. Her delayed diagnosis was further masked by unconventional misnomers not typically seen in CF. The patient was enlisted by our CF team for treatment and surveillance, and her LFTs improved. DISCUSSION: Our patient's clinical course made the diagnosis of CF less obvious, including: age, race, lack of family history, absence of pulmonary complications, presence of fertility, and vagueness of complaints. While sweat chloride testing was positive, genetic testing was negative. Retrospectively, each result lends itself to the diagnosis of atypical CF, which may show negative genetics despite sweat testing. The presence of a positive sweat test and clinical history is consistent with non-classic CF, and the chronically elevated LFTs and abdominal complaints were indicative of CFLD. Formal declaration of CFLD is important, as it leads to biliary cirrhosis and portal HTN, imposing high mortality. No gold standard modality exists for CFLD, further making diagnosis difficult in lieu of typical CF features. Our case emphasizes the importance of identifying both atypical CF and CFDL, how limited findings confound diagnosis, and the role of a multi-disciplinary team approach for CF patients.