S5540 Spiraling Toward the Truth: A Rare Case of Syphilitic Hepatitis

Introduction: Syphilitic hepatitis is a rare manifestation of secondary syphilis that may present with nonspecific symptoms and abnormal liver function tests. Due to its variable presentation and low index of suspicion, it is often underdiagnosed. We present the case of a 26-year-old man with neurodevelopmental and psychiatric comorbidities who developed jaundice and cholestatic liver enzyme abnormalities. This case highlights the importance of including syphilitic hepatitis in the differential diagnosis of unexplained jaundice. Case Description/Methods: A 26-year-old man with a history of bipolar disorder, autism spectrum disorder, and attention-deficit hyperactivity disorder presented with scleral icterus and periumbilical abdominal pain for 2 days. He denied substance use, recent travel, or infectious contacts. On admission, labs showed total bilirubin of 11.5 mg/dL, alkaline phosphatase 961 U/L, aspartate aminotransferase 275 U/L, and alanine aminotransferase 298 U/L. Hepatitis panel was negative. CT abdomen/pelvis revealed no biliary obstruction. Right upper quadrant ultrasound showed no biliary ductal dilation, with a 3.2 mm common bile duct. Magnetic resonance cholangiopancreatography demonstrated enlarged porta hepatis and aortocaval lymph nodes with restricted diffusion. Cytomegalovirus and Epstein-Barr virus serologies were positive (IgG and IgM). Tumor markers CA 19-9 and CEA-125 were markedly elevated. Liver and lymph node biopsies showed acute inflammation with neutrophils and eosinophils, bile duct injury and proliferation, consistent with a biliary pattern of injury, without evidence of malignancy. Serum RPR returned reactive with positive treponemal confirmation. The diagnosis of syphilitic hepatitis was confirmed on reanalysis of liver tissue using spirochete immunostain, which showed rare Treponema pallidum organisms. The patient was treated with intramuscular penicillin G 2.4 million units weekly for 3 weeks, resulting in marked improvement in bilirubin and liver enzymes. Discussion: elevations when routine etiologies are excluded. Diagnosis can be challenging due to its nonspecific clinical features and resemblance to other hepatic or systemic diseases. In this case, liver biopsy with confirmatory immunostaining was crucial in establishing the diagnosis. Clinical and biochemical response to penicillin therapy supports the importance of early recognition and treatment. Providers should maintain a high index of suspicion for syphilitic hepatitis, even in patients without classic risk factors or symptoms.