Pediatric Neurology 50 (2014) 515e517

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Clinical Observations

Cataplectic Facies: Clinical Marker in the Diagnosis of Childhood NarcolepsydReport of Two Cases Manish Prasad MRCPCH a, *, Gururaj Setty MRCPCH b, Athi Ponnusamy FRCP c, Nahin Hussain MRCPCH d, Archana Desurkar MRCPCH e a

Department of Paediatrics, Pinderfield General Hospital, Wakefield, UK Department of Paediatrics, Horton General Hospital, Banbury, UK c Department of Clinical Neurophysiology, Sheffield Children’s Hospital, Sheffield, UK d Department of Paediatric Neurology, Leicester Royal Infirmary, Leicester, UK e Department of Paediatric Neurology, Sheffield Children’s Hospital, Sheffield, UK b

abstract BACKGROUND: Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood and/or adolescence. The full spectrum of clinical manifestations, namely excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis, is usually not present at disease onset, delaying diagnosis during childhood. Mean delay in diagnosis since symptom onset is known to be several years. Initial manifestations can sometimes be as subtle as only partial drooping of eyelids leading to confusion with a myasthenic condition. PATIENTS: We present two children who presented with “cataplectic facies,” an unusual facial feature only recently described in children with narcolepsy with cataplexy. RESULT: The diagnosis of narcolepsy was confirmed by multiple sleep latency test along with human leukocyte antigen typing and cerebrospinal fluid hypocretin assay. CONCLUSION: The diagnosis of narcolepsy with cataplexy at onset can be challenging in young children. With more awareness of subtle signs such as cataplectic facies, earlier diagnosis is possible. To date, only 11 children between 6 and 18 years of age presenting with typical cataplectic facies have been reported in the literature. We present two patients, one of whom is the youngest individual (4 years old) yet described with the typical cataplectic facies. Keywords: narcolepsy, cataplexy, Multiple sleep latency test (MSLT), hypocretin, childhood

Pediatr Neurol 2014; 50: 515-517 Ó 2014 Elsevier Inc. All rights reserved.

Introduction

Narcolepsy is a lifelong disease characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis.1 It affects both children and adults, with nearly 50% of the patients experiencing the onset of symptoms before 15 years of age.2 Delay in diagnosis is usually 10-15 years, although recent reports support an improving trend with increasing awareness.3 This delay is more

Article History: Received November 27, 2013; Accepted in final form January 1, 2014 * Communications should be addressed to: Dr. Manish Prasad; Department of Paediatrics; Pinderfield General Hospital; Aberford Road; Wakefield, UK; WF1 4DG. E-mail address: [email protected] 0887-8994/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pediatrneurol.2014.01.016

common in younger children in which common misdiagnosis include epilepsy, muscle disorders, attention deficit hyperactivity disorder, or other behavioral problems.4 Cataplexy is considered as a hallmark symptom for narcolepsy. In children with narcolepsy, cataplexy is only occasionally reported to be the first symptom of the disease (less than 10% of cases)5 and more often either presents together or after excessive daytime sleepiness.6 Eventually cataplexy is reported to be present in 60% to 100% of the children with this disease.5 In younger children, cataplexy is more often atypical leading to increased risk of misdiagnosis and delay in diagnosis. Narcolepsy is believed to result from loss of hypocretinproducing neurons. It is strongly associated with the human leukocyte antigen (HLA)-DQB1*0602 but evidently requires additional factors to trigger the onset of symptoms.7

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M. Prasad et al. / Pediatric Neurology 50 (2014) 515e517

FIGURE. Hypnogram during overnight polysomnography the night before the multiple sleep latency test in patient 1. Note short sleep latency of about 2 minutes and excessive REM sleep. 1-4, non-REM sleep stages 1-4; M, movement; R, REM sleep; REM, rapid eye movement; U, undefined; W, awake. (Color version of figure is available in the online edition.)

Along with clinical evaluation, the diagnosis can be established by sleep recordings, namely polysomnography (PSG) and the multiple sleep latency test (MSLT), showing a mean sleep latency of less than 8 minutes and more than two sleep-onset rapid eye movement periods (SOREMs).1 A cutoff value of longer than 8 minutes is suggested for pediatric MSLT. Lumbar puncture showing low hypocretin in the cerebral spinal fluid and/or genetic testing to look for HLA-DQB1*0602 may also be done. “Cataplectic facies” is an unusual facial feature only recently described in children with narcolepsy with cataplexy,8 usually at disease onset. The typical manifestations of cataplectic facies include repetitive mouth opening, tongue protrusion, and ptosis. Interestingly, the usual triggering emotions, such as laughter or joking, are not always present, hampering diagnosis.8 We present two children with characteristic cataplectic facies; we believe that earlier diagnosis is possible with more awareness of subtle signs such as cataplectic facies. Patient 1 A 4-year-old boy born at 36 weeks’ gestation, with background of subtle motor problems but otherwise well, presented with progressive tiredness, droopy eyelids, and fatigability over 2 weeks. He also became sleepier during the day with disrupted nighttime sleep. Motor abilities progressively worsened, with buckling at his knees. There was no cognitive deterioration and no bulbar dysfunction. There was no preceding history of infective illness. Initial observation of fluctuating bilateral ptosis and distal symmetrical muscle weakness with fluctuating speech volume led to suspicion of a myasthenic/myopathic process. Though his electromyelogram was deemed to be “myopathic,” repetitive nerve stimulation and single-fiber electromyelogram were normal. Subsequently, he developed falling episodes with laughing and tongue-thrusting episodes. Sleep disturbances continued.

With episodes suggestive of cataplexy and sleep disturbance, he underwent PSG and multiple sleep latency tests. During PSG, typical multiple episodes of cataplexy often triggered by laughing were recorded. Many episodes were associated with just subtle head drop and tongue-thrusting. His sleep-onset latency on the night of PSG (Fig) was only about 2 minutes (very short) and he remained mainly in lighter stages of sleep (stage I and II of NREM) and deeper stages of NREM sleep was noted for only 14% of his total sleep time of 10 hours. Despite a good sleep period the previous night, the next day during four naps of MSLT (Table 1), he had SOREMs in two naps (third and fourth naps). MSLT may be very challenging to complete in younger children.9 In our case, however, the presence of two definite SOREMs despite a good previous night sleep duration (>6 hours) supports the diagnosis of narcolepsy. His HLA analysis was positive for HLA-DQB1*0602.

Patient 2 A 9-year-old girl, previously fit and well, presented with excessive day time sleepiness for up to 15 hours a day, which has gradually increased to almost 20 hours plus. This was soon followed by droopy eyelids and abnormal tongue movements. She had onset of these symptoms following recurrent episodes of probable chest infections for which she received multiple antibiotic courses. She had a history of receiving a flu vaccination a year previous to onset of the symptoms. TABLE 1. Multiple Sleep Latency Test Results in Patient 1 (Four Naps)

Time

Sleep-Onset Latency

09:25:08 11:50:21 14:10:35 16:20:56

33 seconds I, REM Unable to cooperate for the study 3 min, 24 seconds REM 23 seconds I, REM

Abbreviation: REM ¼ Rapid eye movement

Sleep Stages Entered

Sleep-Onset REM Yes Yes Yes

M. Prasad et al. / Pediatric Neurology 50 (2014) 515e517 TABLE 2. Multiple Sleep Latency Test Results in Patient 2

Time

Sleep-Onset Latency

Sleep Stages Entered

Sleep-Onset REM

09:41:15 11:42:30 13:39:45 15:43:00

30 seconds 1 min, 30 seconds 30 seconds 1 min, 30 seconds

REM, I, II, III REM, I, II I, REM, II, III, IV I, II, III, IV

yes Yes Yes d

Abbreviation: REM ¼ Rapid eye movement

She also reported visual hallucinations starting around the time of the onset of excessive somnolence. These hypnagogic hallucinations consisted of monsters and spiders before the onset of sleep. She on many occasions gives a history of cataplexy in which most of the time she will be sitting and suddenly loses tone and falls asleep. On two occasions she experienced sleep paralysis in which she wanted to get up from bed and was not able to do so. Her cognition was normal. Characteristic facies with partial ptosis and forward thrusting and writhing movements of the tongue was noted. Her brain magnetic resonance imaging scan was normal. Her cataplectic facies, excessive sleepiness, hallucinations, and history of cataplexy prompted us to investigate further for narcolepsy. Her mean sleep onset latency on the MSLT (Table 2) of 1 minute confirmed severe pathological daytime sleepiness. She entered REM sleep in three of the MSLT naps. SOREMs also occurred in several of the spontaneous naps in between the polysomnography nights and were recorded on all three polysomnography nights. These findings were diagnostic of narcolepsy syndrome. Her hypocretin levels were low (

Cataplectic facies: clinical marker in the diagnosis of childhood narcolepsy-report of two cases.

Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood an...
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