Beyond Septic Encephalopathy: A Case Report of Severe RCVS and PRES in a Patient With HLH due to Appendicitis

<b>Background and Objectives</b>: We report a rare case of severe posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) in an adult patient with hemophagocytic lymphohistiocytosis (HLH), and speculate that these three diagnoses are related by similar mechanisms of vascular endothelial dysfunction. <b>Methods</b>: Informed consent for this case report was obtained from the patient's legally authorized surrogate decision maker. <b>Discussion and Practical Implications</b>: Our patient initially presented with HLH secondary to intra-abdominal sepsis, and was later found to have severe PRES and RCVS resulting in extensive border-zone cortex infarction. Improvement of the severe systemic inflammatory syndrome characteristic of HLH and arrest of PRES and RCVS progression occurred only after HLH-specific treatment was initiated. In addition to illustrating the potential of HLH to manifest as PRES and RCVS, this case emphasizes the importance of prompt recognition and treatment of HLH and the role the neurologist can play in this process. This case also sheds light on the pathophysiological links between PRES, RCVS, and HLH. These three diagnoses may be related by similar mechanisms of vascular endothelial dysfunction caused by uncontrolled and severe systemic inflammation.