Localized Pontine Uptake in Fluorine-18-Fuorodeoxyglucose Positron Emission Tomography/Computed Tomography in a Case of Hyponatremia: A Case Report and Review of Literature

A rare acquired demyelinating lesion of the pons central pontine myelinolysis (CPM) typically occurs after rapid correction of hyponatremia. There is disruption of blood–brain barrier due to osmotic stress allowing access for inflammatory mediators in extravascular brain tissue, which most likely attracts glial cells of the brain, attracts macrophages, and activates astrocytes. We present a case of female with a known history of inflammatory bowel disease who presented with altered sensorium and hyponatremia. Fluorine-18-fuorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) was performed which showed localized FDG uptake in the pons, consistent with the CPM findings observed on magnetic resonance imaging. Pontine uptake in F-18-FDG PET CT in hyponatremic patients who were clinically deteriotating even after correction of hyponatremic status aids for the diagnosis of CPM.