1017 Laughing in the Face of Laughter: Narcolepsy with severe cataplexy refractory to medication: A case report

Abstract Introduction Cataplexy, a transient muscle atonia, typically occurs in response to positive emotions such as laughter or mirth. Cataplexy occurs in association with hypocretin deficiency/narcolepsy type 1 (NT1) and involves descending REM sleep-motor inhibition pathways. 1. Here we present a case with late – onset NT1, refractory to medication. Report of case(s) A 65-year-old man with a normal BMI presented to the autonomic clinic for presumed syncope, facial and leg weakness, occurring up to 50 times daily, triggered by laughter and a stressful life event from 4 years prior. Tilt testing and brain magnetic resonance imaging, were unremarkable, while sleep–deprived electroencephalogram was concerning for cataplectic versus functional attacks. He underwent diagnostic polysomnography (PSG) that showed severe obstructive sleep apnea (OSA) and was treated with bilevel positive airway pressure (BPAP). A repeat PSG after his OSA was controlled on BPAP, followed by a multiple sleep latency test the next day, showed a mean sleep latency of 2.7, and sleep onset rapid eye movement in 3 of 5 naps; cerebrospinal fluid hypocretin was undetectable and DQB1*06:02 was positive. He denied sleep paralysis and sleepiness, and jovial by nature, he joked as a hobby, leading to cataplexy. Trials of sodium oxybate was ineffective causing vivid dreams and hallucinations. Venlafaxine was subsequently added, initially controlling his cataplexy, but lost efficacy, warranting a trial of duloxetine, also ineffective. He was then started on solriamfetol, which improved sleepiness. We attempted to enroll him in a clinical trial of Reboxetine, thereby discontinuing duloxetine; severe OSA disqualified him from the trial. Subsequently, status cataplecticus ensued, leading to abolished reflexes and multiple falls. Clomipramine 100mg and Modafinil 200mg was started, reportedly reducing the frequency of cataplexy to 12 episodes daily. Conclusion Our case is notable because of the challenges working through the differential of drop attacks, and his late onset of severe NT1. One suggestion is an associated functional component to the disease could be involved, and though the diagnosis is solid, an additional functional overlay, or his joking personality, render symptom control unusually difficult. This case illustrates complexities of some cases with late-onset NT1. Support (if any)