RASMUSSEN SYNDROME (RS)

	Mandatory	Alerts	Exclusionary
Seizures	Focal (hemispheric) seizures that often increase in frequency over weeks to months	Focal seizures arising independently in both hemispheres	Generalized onset seizures
EEG	Hemispheric slowing and epileptiform abnormality	Generalized spike-wave
Age at onset		Adolescence or adulthood
Development at onset		Prior abnormal development
Neurological exam			Hemiparesis present at seizure onset
Imaging	Progressive hemiatrophy (early atrophy affects the insult and head of caudate)	Lack of hyperintense signal and/or atrophy of the caudate head Lack of T2/FLAIR hyperintense signal in grey or white matter	Sturge-Weber syndrome
Other tests			Metabolic or antibody-mediated cause
Course of illness	Drug resistant epilepsy Progressive neurological deterioration
Are MRI or ictal EEG required for diagnosis? An MRI is required for diagnosis to exclude other causes An ictal EEG is not required
Syndrome in evolution: children with drug-resistant, focal (hemispheric) that progressively increase in frequency, with progressive neurological deficits, but whose MRI is normal and tests do not reveal an alternate metabolic or autoimmune cause, can be suspected of having this syndrome. However, mandatory imaging features are required for final diagnosis
Syndrome without laboratory confirmation: in resource-limited regions, this syndrome can be diagnosed without EEG in a patient with focal (hemispheric) seizures, who shows the typical clinical evolution, who meets all other mandatory and no exclusionary or alert criteria. However, imaging (CT or MRI) is required to exclude other causes

NOTE Alert criteria are absent in the vast majority of patients with the syndrome, but rarely can be seen. Their presence should result in caution in diagnosing the syndrome and consideration of other conditions