The document discusses Expanded Dengue Syndrome (EDS), which was defined by the WHO in 2011 as unusual manifestations of dengue infection involving severe dysfunction of single or multiple organs like the liver, kidneys, brain or heart. EDS was not defined in 2009. The document notes that EDS involves conditions beyond dengue fever or hemorrhagic fever, and can be associated with underlying host conditions, co-infections, or profound shock. EDS includes dengue liver failure, acute respiratory distress syndrome, multiple organ dysfunction syndrome, hemophagocytic lymphohistiocytosis, encephalitis, and acute kidney injury. Treatment for EDS is organ-specific supportive care.