SCIENTIFIC
Narcolepsy in a 4-Year-Old
AUTHORS : Rutvi Shah , MD 1
Rahiya Rehman , MD 1 Youmna Mousattat , MD 2 John Bishara , MD 3
1
Department of Pediatrics , Charleston Area Medical Center / West Virginia University
2
Department of Inpatient Pediatric Services , Charleston Area Medical Center / West Virginia University
3
Department of Pediatric Pulmonology and Sleep Medicine , Charleston Area Medical Center / West Virginia University
CASE PRESENTATION
A 4-year-old girl presented with three months of hypersomnolence and new onset of slurred speech and difficulty forming full sentences . The child ’ s mother noted that she was sleeping for 14 to 16 hours per day . The child napped and appeared refreshed after each nap and displayed aggression when not allowed to nap . The child initially napped for one to two hours up to two times per day until she started sleeping 14 to 16 hours per day .
Over the course of one month , her symptoms progressively worsened . Her parents reported that at times she would have poor coordination and balance with weakening of her motor strength . Parents also reported that at times , the patient had poor head control and had difficulty keeping her eyes open . Furthermore , she began falling more than usual . Her total sleep time then increased to 16 to 18 hours per day , which prompted a visit to her primary care physician . A complete blood count , a basic metabolic panel , and Lyme titers were obtained , which were normal .
After two and a half months , the patient continued to become more irritable and developed abnormal movements of her head and eyebrows . A pediatric neurol-
ABSTRACT
INTRODUCTION
ogist recommended an inpatient evaluation . The parents denied any dietary changes , recent trauma , travel , or illnesses , and there was no relevant family history . The child was not on any medications and did not receive any recent vaccinations . Her physical examination was normal except for mild drowsiness . Laboratory evaluation investigated potential exposures , infections , and metabolic and neurologic etiologies . An in-depth workup for these etiologies was normal . A brain magnetic-resonance imaging revealed no intracranial abnormality . An electroencephalogram showed nonspecific diffuse cerebral dysfunction . The official reading did not include information about sleep onset rapid eye movement ( REM ). Cerebrospinal fluid ( CSF ) studies for a meningitis and encephalitis panel and cultures were negative . CSF for orexin / hypocretin-1 level was ordered . The hypocretin-1 level result was less than 50 picograms per milliliter ( pg / mL ). The patient met criteria for narcolepsy type 1 , as she had both cataplexy and a low hypocretin-1 level . With the administration of methylphenidate , her hypersomnolence improved . A second opinion agreed with the diagnosis of narcolepsy type 1 , and venlafaxine was added to treat the cataplexy .
DISCUSSION
Narcolepsy is a disabling neurodegenerative condition that is characterized by the hallmark of excessive daytime sleepiness . Diagnosis of narcolepsy can be difficult in all aged patients , but especially so in children less than 5 years old . We present a unique case of a 4-year-old girl who presented with slurred speech , behavioral changes , and hypersomnolence . After a thorough evaluation , she was diagnosed with narcolepsy type 1 . We provide a literature review about this diagnosis and discuss the signs , symptoms , and workup , with a focus on the challenges associated with determining the definitive diagnosis . The role of obtaining cerebrospinal fluid hypocretin-1 levels in the diagnostic evaluation of patient with suspected narcolepsy is emphasized .
Narcolepsy is a physiologic disorder of REM sleep . Typical signs and symptoms are excessive daytime somnolence with recurrent sleep paralysis , hypnagogic hallucinations , and fragmented sleep with or without cataplexy . 1 Incidence of narcolepsy is not well studied in the pediatric population . One European study estimated a pooled incidence rate of 0.83 per 100,000 children aged 5-19 years . 2 The usual onset of symptoms in children is 9-10 years of age , with a peak in the second decade of life . 1 , 3 Narcolepsy is rarely seen in children less than 5 years of age . In one case series the earliest diagnosed case occurred in a 2-year-old child . 4 , 5
Diagnosing narcolepsy is challenging in children as it presents differently than in adults . 6 Cataplexy may manifest itself as a movement disorder in children with either a negative ( hypotonic ) and / or positive motor phenomenon . 7 Hypotonic features include poor head control , tongue protrusion , facial hypotonia , and ptosis . 7 Generalized hypotonia ( i . e ., wide-based or unsteady gait ) may be present and involuntary falls may occur . 7 Positive motor phenomenon include dyskinesias ( i . e ., facial tics and grimaces ), repetitive finger movements , and / or dystonic trunk movements . 7 Pediatric cataplexy may present with slurred speech . 8 Children have a high prevalence of inattention , aggression , and oppositional behaviors , and affected patients may be labeled as aggressive or lazy . 9 , 10 Narcolepsy may be misdiagnosed as seizure disorders , myopathies , or non-
11 , 12 specific encephalopathies .
Careful history taking and a thorough examination are crucial . Laboratory and radiological workup are also required to pinpoint the diagnosis . Misdiagnosis is common due to its unique presentation as
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