Phosphate in Acute Pancreatitis

The goal of this study is to learn if phosphate administration works to treat acute pancreatitis in adults presenting to the emergency department at Duke University Hospital. The main questions it aims to answer are: * Does having low phosphate levels increase the risk of acute pancreatitis and can giving phosphate through an IV make the illness less severe? * Is phosphate therapy practical to use, and what is the appropriate dose? * Is this study achievable, and how can the results help design a future randomized controlled trial to assess safety and effectiveness? Participants will: * Receive standard of care or intravenous (IV) phosphate during their hospital stay * Have blood samples collected during admission to monitor phosphorus levels * Complete follow-up assessments after hospital admission to evaluate how severe the illness is and the effects of phosphate supplementation

Inclusion Criteria: * Age 18 years or older * Presenting to the emergency department (ED) with acute pancreatitis meeting 2 or more characteristics of: (1) typical, persistent, severe upper abdominal pain, (2) lipase or amylase levels at least three times greater than the upper limit of normal, and/or (3) characteristic findings on abdominal imaging) * Trial treatment can be initiated within 24 hours of hospital admission * Consent can be obtained from the patient or their legal representative Exclusion Criteria: Contraindications to injectable phosphate including: * Hyperkalemia * Hypercalcemia or significant hypocalcemia * Severe renal impairment (eGFR \