Venlafaxine augmentation in an adolescent with narcolepsy and cataplexy: a case report

INTRODUCTION

Narcolepsy is a chronic neurological disorder characterized by excessive daytime sleepiness and may be accompanied by cataplexy, defined as a sudden loss of muscle tone triggered by emotions [1]. In pediatric populations, narcolepsy may present with attention difficulties and academic decline, often leading to initial misdiagnosis [2]. Pharmacological management primarily targets excessive daytime sleepiness; however, treatment of cataplexy remains equally important for functional improvement. Antidepressants, particularly serotonin-norepinephrine reuptake inhibitors, have been reported to be effective in reducing cataplexy symptoms [3]. In this report, we present an adolescent patient with narcolepsy and prominent cataplexy symptoms who showed significant improvement following venlafaxine treatment.

CASE PRESENTATION

A 15-year-old female patient presented to the child and adolescent psychiatry clinic with complaints of attention deficit, forgetfulness, excessive daytime sleepiness, and disrupted sleep patterns. She frequently fell asleep during classes and reported episodes of sudden sleep attacks. Academic difficulties were mainly related to inattention and daytime somnolence. One year prior to presentation, she had been initiated on methylphenidate for attention deficit symptoms, with the dose titrated up to 36 mg/day, which she was still using at the time of admission.

Her medical history was significant for asthma, and she was using inhaled salbutamol and budesonide. Family psychiatric history was unremarkable. Laboratory investigations revealed vitamin B12 and vitamin D deficiencies, and replacement therapy was initiated. The patient was referred to the neurology department for further evaluation. Cranial magnetic resonance imaging and electroencephalography findings were within normal limits, whereas polysomnography findings were consistent with narcolepsy.

Following a two-year course of methylphenidate (36 mg/day), modafinil treatment was initiated at 50 mg/day and titrated to 100 mg/day. At the six-month follow-up, excessive daytime sleepiness and sleep attacks and resolved completely. However, the patient continued to report non-restorative sleep, irritability, and episodes of sudden loss of muscle tone, including dropping objects, occasionally accompanied by tremor-like hand movements, which became more prominent with emotional triggers, consistent with cataplexy.

Mental status examination revealed a cooperative adolescent with age-appropriate appearance and adequate self-care. She was fully oriented, with normal speech and thought processes. Her mood was mildly depressed, with congruent affect. No perceptual disturbances or suicidal ideation were present.

Given the persistence of cataplexy symptoms and accompanying subdepressive features, venlafaxine 37.5 mg/day was added. At the four-month follow-up, a marked reduction in cataplexy episodes was observed, with previously every-other-day object-dropping episodes resolving completely and tremor-like hand movements decreasing to once weekly. Concurrently, mood symptoms improved, with the Clinical Global Impressions – Severity of Ilness (CGI-S) score decreasing from 5 to 2.

CONCLUSION

This case suggests that cataplexy symptoms in adolescents with narcolepsy may persist despite adequate control of excessive daytime sleepiness and may present with subtle motor manifestations such as tremor-like movements. Venlafaxine treatment was associated with a substantial reduction in cataplexy frequency and improvement in affective symptoms. These findings support the role of serotonin-norepinephrine reuptake inhibitors as an effective therapeutic option for cataplexy in pediatric narcolepsy [3]. Early recognition and targeted treatment of cataplexy are essential for optimizing clinical outcomes.

References

1. American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd ed. Darien, IL: AASM; 2014.
2. Thomas J. Dye. Clinical Evaluation and Management of Narcolepsy in Children and Adolescents. Seminars in Pediatric Neurology. 2023, https://doi.org/10.1016/j.spen.2023.101089.
3. Bassetti CL, Kallweit U, Vignatelli L, et al. European guideline and expert statements on the management of narcolepsy in adults and children. Eur J Neurol. 2021;28:2815-2830. https://doi.org/10.1111/ene.14888