Diagnosing acute pancreatitis

Presenting features A 50-year-old man with a past medical history notable for chronic alcohol abuse, injection drug abuse, and a seizure disorder ran out of his medications, including phenytoin. Several days later he had a generalized tonic-clonic seizure. He was brought to the hospital by the emergency medical service. After his confusion cleared in the emergency department, the patient reported 1 week of severe diffuse epigastric abdominal pain with radiation to the back. The pain was not relieved or exacerbated by food, and he denied nausea, vomiting, change in bowel habits, fevers, chills, or sweats. Of note, the patient continued to use intravenous heroin and drank approximately 1 pint of vodka daily until the day of admission. The patient’s physical examination on admission showed normal vital signs, mild agitation, and tremulousness. He had dry mucus membranes, with normal cardiac and pulmonary findings. His abdomen had normal bowel sounds and mild epigastric tenderness without hepatosplenomegaly, rebound tenderness, or guarding. Examination of his skin was notable for periumbilical ecchymosis (Figure 1) and signs of intravenous drug use. He was fully oriented, and his neurologic examination was symmetric and nonfocal by the time he was admitted to the hospital. Laboratory examination showed a white blood cell count of 3100 cells/uL, hematocrit of 31.6%, and a normal basic metabolic panel with the exception of a potassium level of 3.0 mEq/L. Liver studies included an aspartate aminotransferase level of 119 U/L, alanine aminotransferase level of 42 IU/L, total bilirubin level of 0.6 mg/dL and alkaline phosphatase level of 298 IU/L. What is the diagnosis?