idiopathic hemiconvulsion-hemiplegia syndrome (MONDO_0019485, a Monarch Disease Ontology entry) is a rare acute encephalopathy with inflammation-mediated status epilepticus characterized by infancy-onset of refractory unilateral, mainly clonic status epilepticus during or shortly after a febrile episode without evidence of central nervous system infection, followed by permanent or transient hemiplegia with a minimum duration of one week. The majority of children develop pharmaco-resistant epilepsy a few months later. Brain imaging shows edematous swelling of the affected hemisphere at the time of the initial status, followed by hemiatrophy that does not correlate with any vascular territory. Also known as: HHE syndrome, IHHS, hemiconvulsion-hemiplegia-epilepsy syndrome.