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Indian Pediatr 2019;56: 147 |
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Narcolepsy - A Rare but under-recognized Problem in Children
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JT Srikanta *
and KM Chandan Kumar
Institute of Pulmonology, Apollo Hospitals, Bengaluru,
India.
Email: [email protected]
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Narcolepsy is a rare but potentially debilitating,
rapid eye movement (REM) sleep disorder that causes significant
developmental morbidity [1]. It is characterized by the classic tetrad
of disproportionate daytime sleepiness with irrepressible sleep attacks,
cataplexy, hypnagogic hallucination, and sleep paralysis [2].
Narcolepsy has an early onset but is associated
with significant delay in – symptom recognition and diagnosis [2,3].
Nocturnal polysomnography (PSG) followed by a daytime multiple sleep
latency test (MSLT) is the diagnostic standard.
A 4-year-8-month old school-going boy, presented with
complaints of excessive daytime sleepiness and intense urge to sleep for
last one year, and drop attacks for last six months. There was no
significant family history of seizures or neurological disorder. In view
of recurrent/persistent symptoms, he was extensively evaluated for
seizure disorder/epilepsy syndrome/Wilson’s disease. In view of
inconclusive results and persistent symptoms, he was started on
anti-epileptics but later referred to us due to persistence of symptoms.
On examination, he was neuro-developmentally normal
with both general physical and systemic examination with in normal
limits. During conversation with the parents, the child not only had
intense urge to sleep but also had a drop attack. Considering the
symptoms and chronicity of presentation in otherwise developmentally
normal child, a provisional diagnosis of narcolepsy with cataplexy was
considered. Child underwent a nocturnal polysomnography (PSG) followed
by daytime multiple sleep latency test (MSLT). Nocturnal PSG was within
normal limits and MSLT showed, a mean sleep latency of 4 minutes with
average REM latency of 1.4 minutes, thus diagnostic of Narcolepsy. A
genetic test (HLA B1*0602) to support the diagnosis was positive, thus
confirming the diagnosis. He was treated with Modafanil (50 mg/day) with
good clinical response with respect to both excessive daytime sleepiness
and cataplexy.
Patients with narcolepsy are usually initially
investigated for epilepsy, encephalopathy, and psychiatric disease
[3,4]. A lack of awareness of the condition, delay in symptom
recognition and absence of all the characteristic features are the
primary reason for missed diagnosis of narcolepsy in children [3,4].
Administering daytime MSLT after overnight PSG is the
primary modality of choice for diagnosis of narcolepsy [3,5]. Presence
of both: (a) a mean sleep latency (MSL) of <8 minutes and
(b) two or more sleep onset REM periods (SOREMPs) on MSLT
performed after at least six hours of sleep during the previous night
confirms the diagnosis [3,5]. Management of narcolepsy is multimodal and
involves Sleep hygiene, frequent daytime naps, Diet recommendations,
Medications, and Caregiver counseling. Though lifestyle modifications
are important in management, medical treatment is the cornerstone and
should be initiated as early as possible after confirming the diagnosis.
References
1. Thorpy MJ, Krieger AC. Delayed diagnosis of
narcolepsy: Characterization and impact. Sleep Med. 2014;15:502-7.
2. Daniels LE. Narcolepsy. Medicine. 1934;13:1-122.
3. Thorpy MJ. Diagnostic criteria and delay in
diagnosis of narcolepsy. In: Goswami M, Thorpy M, Pandi-Perumal S
(eds). Narcolepsy. Springer Cham. 2016.
4. Morrish E, King MA, Smith IE, Shneerson JM.
Factors associated with a delay in the diagnosis of narcolepsy. Sleep
Med. 2004;5:37-41.
5. American Academy of Sleep Medicine. The International
Classification of Sleep Disorders, Diagnostic and Coding Manual. 2nd ed.
Westchester, IL: American Academy of Sleep Medicine. 2005.
p.298-9.
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