CASE PRESENTATION: A 32 year-old female with history of Crohns disease presented to the hospital with worsening nausea, vomiting and lethargy. On admission, she was tachycardic at 110/minute, tachypenic at 25/minute and hypoxic to 87% on room air. Initial lab work revealed markedly elevated transaminases ALT 2350, AST 9616, and new coagulopathy with an INR 1.8. She was admitted for acute liver failure and emergent Hepatology evaluation for transplantation. Initial work-up included a negative toxicology screen for acetaminophen, salicylates and alcohol along with negative autoimmune and viral hepatitis panel. Infectious work-up was negative. She denied use of any new medications or herbal supplements. Given her worsening encephalopathy and liver failure, N-acetyl cysteine protocol was initiated, while awaiting evaluation by multidisciplinary teams for liver transplant. Review of her echocardiographic imaging revealed severe right ventricular (RV) enlargement with systolic dysfunction, along with inter-ventricular septal flattening and elevated pulmonary artery pressure of 53mmHg. Given these findings, there was a shift in the working diagnosis with strong consideration for PE. Diagnosis was confirmed with a high probability V/Q scan and subsequent CT PE which showed multiple large bilateral pulmonary emboli within the main pulmonary arteries with significant clot burden and reflux of contrast into hepatic veins. Treatment with IV heparin was initiated with eventual rapid improvement in liver enzymes. A diagnosis of acute PE resulting in RV decompensation was made which explained the patient’s clinical presentation and liver failure.