Clinical outcomes of cryptogenic new onset refractory status epilepticus (NORSE) in a tertiary hospital in Singapore: a case series.

Background: New Onset Refractory Status Epilepticus (NORSE) is a neurological emergency with high mortality. Cryptogenic NORSE (cNORSE) is defined by a lack of an identifiable structural, toxic or metabolic etiology despite extensive workup. Survivors often develop significant long-term neurological sequelae and drug-resistant epilepsy. However, studies have shown that despite prolonged hospitalization, a significant proportion of cNORSE patients can achieve favourable functional outcomes.

Methods: A retrospective review of adult cNORSE patients between July 2019 and July 2023 in a tertiary hospital in Singapore was performed.

Results: Thirteen patients with cNORSE were identified. Median age at presentation was 32.2 [IQR: 23.9-44.1] years and 6 (46.2%) of the patients were male. Eight (61.5%) patients fulfilled criteria for Febrile Infection-Related Epilepsy Syndrome (FIRES). Eight (61.5%) patients had abnormal index brain MRIs. The median duration of ICU stay was 37.0 [22.8-41.5] days. The total number of anti-seizure medications (ASMs) and anesthetics used was 6 [5-7] and 3 [2-4] respectively. All patients received immunotherapy and the time to immunotherapy initiation from SE onset was 2 [1-3] days. 4 (30.8%) patients demised during inpatient stay. Of 9 surviving patients, the median MRS on discharge was 4 [3-5]. MRS at 3 month and 1 year follow ups was 2 [1-5] and 1.0 [0.8-5.0] respectively.

Conclusions: This retrospective study characterizes a cryptogenic NORSE cohort in a tertiary hospital in Singapore. Cryptogenic NORSE is associated with significant morbidity and mortality; however, long term outcomes may still be favourable in patients with initially severe illness and protracted ICU stay.