Acute Hepatitis B versus Autoimmune Hepatitis: A Clinical Conundrum

Abstract

A 42-year-old Hispanic male presented with10 days of right upper quadrant pain, fatigue and jaundice. Past medical history was significant for gallstone pancreatitis s/p cholecystectomy and papillary thyroid cancer s/p thyroidectomy. He denied smoking, drinking alcohol or use of illicit substances. He had no family history of liver disease. He was from Mexico and most recently visited there one year prior. His only medication was levothyroxine and denied use of acetaminophen, NSAIDs or herbal medications. Physical exam revealed normal vital signs, jaundice and mild RUQ tenderness. Labs were remarkable for ALT of 4136 U/L, AST 3609 U/L, alkaline phosphatase 223 U/L, total bilirubin 17.3 mg/dl, direct bilirubin of 15 mg/dl, and INR of 2.2. All other laboratory tests were unremarkable. Ultrasound was unremarkable except for post-cholecystectomy state. MRCP showed mild peri-portal edema and enlarged peri-portal lymph nodes consistent with acute hepatitis. HBV IgM core Ab and HBV surface Ag were positive while HbSAb was negative. The remainder of the hepatitis viral panel was negative. Hepatitis B PCR showed viral load of 44844 IU/ml. Anti-Smooth muscle antibody (ASMA) also came back positive (1:320). ANA, Immunoglobulin, anti-mitochondrial Ab, anti-LK microsomal Ab were negative. Iron panel and ceruloplasmin were unremarkable. Liver biopsy showed minimal portal inflammation along with diffuse hepatocyte balloon degeneration non-specific for either autoimmune hepatitis or acute hepatitis B infection. He was started on tenofovir as well as prednisone, and liver function tests (LFTs) were monitored. With this dual therapy approach, LFTs improved and INR trended down. He was discharged from hospital and down trending LFTs and INR were confirmed during subsequent clinic visits. There are sporadic reports of antigen mimicry between HBV DNA polymerase and smooth muscle protein. In a study of 31 patients with acute Hepatitis B infection, 22 also had positive ASMA. Only 2 had a titer greater than 1:200 and only 1 had titer greater than 1:400. This leads to clinical uncertainty about the diagnosis of acute hepatitis B infection vs. autoimmune hepatitis in a patient with high ASMA titer. This patient had evidence of acute HBV, however given ASMA titer as high as 1:320 and non-diagnostic biopsy, no clear guideline exists for management in this scenario. We opted for management of both conditions with short term clinic follow up which confirmed favorable response.Figure: Diffuse hepatocyte ballooning and degeneration.Figure: Portal and periportal fibrosis.