Miller-Fisher Syndrome Unveiled in the Presence of Cholangiocarcinoma.

Miller-Fisher syndrome (MFS) is a rare variant of Guillain-Barré syndrome, characterized by ataxia, areflexia, ophthalmoplegia, and possible facial, swallowing and limb weakness alongside respiratory failure. Variations within MFS may include respiratory and limb weakness and Bickerstaff brainstem encephalitis (BBE), marked by altered consciousness, ataxia, ophthalmoparesis, and paradoxical hyperreflexia. MFS can emerge in both children and adults, often following bacterial or viral illness. While autoimmune-driven nerve damage occurs, most MFS patients recover within six months without specific treatment, with a low risk of lasting neurological deficits or relapses. Rarely fatal, MFS's co-occurrence with cholangiocarcinoma (CCA) presents unique management challenges. CCA, primarily affecting bile ducts, has a bleak prognosis; surgical resection offers limited cure potential due to late-stage detection and high recurrence rates. Advances in CCA's molecular understanding have led to novel diagnostic and therapeutic approaches, requiring a comprehensive interdisciplinary care approach for optimal MFS and CCA management outcomes. Herein, we present a 50-year-old male with a complex medical history who was admitted to the hospital due to abdominal discomfort, nausea, vomiting, and ascites. Imaging revealed pneumonia and secondary bacterial peritonitis. Later, he developed neurological symptoms, including weakness, gait abnormalities, and brainstem symptoms, leading to the diagnosis of MFS. Despite treatment efforts, his condition deteriorated, leading to acute liver failure and unexplained anasarca. N-acetyl cysteine was initiated for liver issues. Neurologically, he showed quadriparesis and areflexia. Intravenous immunoglobulin (IVIG) treatment improved his neurological symptoms but worsened gastrointestinal issues, including ileus and elevated CA19-9 levels, suggesting a potential carcinoma. A liver biopsy was performed. After IVIG treatment, he experienced widespread discomfort, emotional unresponsiveness, swallowing difficulties, and aspiration risk, ultimately leading to his demise.