Hemophagocytic Lymphohistiocytosis Masquerading as Autoimmune Hepatitis.

Hemophagocytic lymphohistiocytosis (HLH) is a complex disease disorder that involves dysregulated activation of the immune system resulting in cytokine storm which can lead to widespread tissue injury. HLH is associated with a mortality rate of 41%. The diagnosis of HLH requires a median of 14 days to reach likely due to a varied range of symptoms and signs the disease can present with. Liver disease and HLH can have a significant overlap. Liver injury itself is frequently noticed in patients with HLH, with more than 50% of patients having elevated aspartate transaminase, alanine transaminase, and bilirubin levels. This case report describes a young individual who had developed intermittent fever, vomiting, fatigue, and weight loss with labs remarkable for elevated transaminases and bilirubin. His initial workup revealed an acute Epstein-Barr virus infection. The patient later presented again with similar signs and symptoms. He underwent a liver biopsy with histopathological features initially concerning for autoimmune hepatitis. However, by engaging a multidisciplinary team, a correct diagnosis was achieved. This case report serves to highlight the increased level of suspicion required to correctly diagnose HLH, especially in the presence of clinical features concerning for autoimmune hepatitis.