Age: 8.0
Sex: F
Vaccine: FLUX(H1N1), FLUX(H1N1)
Symptoms: Cataplexy, Dysarthria, Dyskinesia, Electroencephalogram abnormal, Epstein-Barr virus test negative
Clinical narrative: Case number PHHY2012US054680 is an initial literature report received on 25 Jun 2012. The author discussed about clinical features, pathophysiology of narcolepsy with special considerations regarding diagnosis and treatment in the pediatric population. This case refers to an 8-year-old female patient. Her past medical history included intermittent migraine headaches. She was vaccinated with H1N1 (manufacture and batch number: unknown, conservatively considered as pandemic influenza vaccine INN) on an unspecified date. Two-months after vaccination, she developed sudden onset of excessive daytime sleepiness (EDS). The nocturnal sleep periods increased from 9 to 10 hours to 12 to 13 hours with a sleep latency of 5 minutes and she began napping for 2 to 3 hours per day. In the morning, her mother reported that, she was difficult to wake for school and would fall asleep suddenly many times throughout the day with loud snoring and leg jerking movements. During episodes of laughing, she was observed to have decreased muscle tone with facial drooping. The extremely vivid and frightening "dreams" at sleep onset were also reported. Increased appetite also was noted and she had a 4-kg weight gain over a 2-month time span. Following a competitive sporting event during which she experienced an episode of sudden weakness and bowel incontinence, she was admitted to the hospital for further evaluation. Physical examination including neurologic examination was unremarkable except for noticeable bilateral laxity of facial muscles with tongue protrusion. She was noted to fall asleep in mother's lap on several occasions with leg jerking movements and was groggy upon awakening. A complete metabolic profile included, blood count, thyroid function tests, Epstein-Barr virus titers and mitochondrial DNA were within normal limits. CSF examination showed no evidence of infection. Both a brain MRI and magnetic resonance angiography were normal; 24-hours video electroencephalograph recording captured five episodes of staring spells, slurred speech and facial twitching without evidence of epileptiform discharges. Nocturnal polysonogram revealed a normal apnea hypopnea index of 0.79/h without oxyhemoglobin desaturations, CO2 retention or significant sleep fragmentation. Periodic limb movement index was elevated at 12/h. Sleep and REM-onset latencies and total sleep time were within normal range for age. A multiple sleep latency test performed on the day after the sleep study revealed sleep on all five naps, a mean sleep-onset latency of 2.8 min and sleep-onset REM periods on all five naps, consistent with a diagnosis of narcolepsy with cataplexy. Treatment for EDS was initiated with short-acting and then extended-release methylphenidate, due to continued sleepiness, she was switched to modafinil. Fluoxetine was initiated for symptoms of cataplexy, however, there were tolerance issues (suicidal ideation) and she was switched to Venlafaxine. Because she continued to experience symptoms on maximum doses of modafinil and venlafaxine, a trial of sodium-oxybate was initiated. The final outcome and causality of the events was not reported. The authors concluded that, the narcolepsy with and without cataplexy in children remain a difficult disorder to both diagnose and treat. Symptoms may be more difficult to accurately assess in young children and the absence of normative data for MSLTs in prepubescent children requires caution be used to not miss false negatives. Ancillary testing, such as CSF hypocretin levels are not yet widely available. Additionally, the provider must extrapolate from adult studies in pharmacologically managing the symptoms of narcolepsy and cataplexy in children. In the future, it can be expected that the recent advances in understanding narcolepsy will lead to new and improved therapeutics, as well as strategies for altering the course of this disease.