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|TOPIC OF THE ISSUE: CASE REPORT
|Year : 2012 | Volume
| Issue : 1 | Page : 79-81
Narcolepsy: A case from India with polysomnographic findings
Ravi Gupta1, Deepak Goel2, Robert Farney3, Jim Walker3
1 Department of Psychiatry, Sleep Clinic, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India
2 Department of Neurology, Sleep Clinic, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India
3 Division of Sleep Medicine, LDS Hospital, Salt Lake City, Utah, India
|Date of Submission||20-Sep-2011|
|Date of Decision||20-Sep-2011|
|Date of Acceptance||20-Sep-2011|
|Date of Web Publication||7-Mar-2012|
Department of Psychiatry and Sleep Clinic, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Doiwala, Dehradun - 248140
Source of Support: None, Conflict of Interest: None
Narcolepsy is a common sleep disorder with a prevalence of about 0.02%. However, it may remain largely unrecognized in the Indian population owing to the perceived low prevalence. To the best of our knowledge there is only one case of narcolepsy reported from India so far. We present a case of narcolepsy with cataplexy with classical clinical and polysomnographic findings of narcolepsy.
Keywords: Multiple sleep latency test, narcolepsy with cataplexy, polysomnography
|How to cite this article:|
Gupta R, Goel D, Farney R, Walker J. Narcolepsy: A case from India with polysomnographic findings. Neurol India 2012;60:79-81
| » Introduction|| |
Patients with excessive daytime sleepiness and "tiredness" are frequently encountered in clinical practice. Besides lifestyle factors, a number of sleep disorders may cause this condition.  Obstructive sleep apnea syndrome, with a prevalence of 2% and 4% in adult females and males respectively, is relatively familiar to many clinicians.  On the other hand, narcolepsy may be unrecognized because of the perceived low prevalence as compared to obstructive sleep apnea. In the Western world, the reported prevalence is close to 50/100,000.  Assuming that the prevalence in India falls within this range, the estimated number of patients with undiagnosed narcolepsy in India would be a huge number. Yet, to the best of our knowledge only one systematically studied case of narcolepsy from India has been reported so far.  Here we describe a young male who presented with excessive daytime sleepiness and who was ultimately diagnosed as a case of narcolepsy, confirmed by appropriate studies in the sleep laboratory.
| » Case Report|| |
A 37-year-old male presented with complaints of non-refreshing sleep, morning inertia, and falling asleep inappropriately during the daytime despite averaging 7.5 h of sleep per night with a consistent sleep schedule from 22:30 to 06:00. He had a vague childhood history of disrupted sleep, somniloquy, and vivid and frightening dreams occurring two to three days per week. In the past two years, he noted increasing lethargy, post-prandial drowsiness and an irresistible urge to fall asleep seven to eight times a day. Sleep attacks occurred to such an extent that he started falling asleep as soon as 30 min after waking up in the morning. He was aware of dozing even during conversations or while at work. He was running a business and was not abusing any substance. He periodically had hypnagogic frightening hallucinations while falling asleep at night and with daytime naps. He had also frequently experienced frightening episodes characterized by body paralysis in which he awakened unable to move even his eyelids for a few seconds. He had also experienced a sense of muscle weakness associated with drooping of eyelids, brought on by extreme emotions (e.g. during laughing or shouting). His medical history was unremarkable except for occasional episodes of migraine without aura, occurring once every two to three months. There was no history to suggest chronic sleep deprivation, restless leg syndrome, sleep apnea, closed head injury or medication abuse. He was non-obese (68 kg, 163 cm and BMI 26 kg/m 2 ). The pharyngeal lumen was non-obstructive (Mallampati II) and neck circumference measured 37 cm. There were no craniofacial risk factors such as retrognathia. General physical and neurological examinations were unremarkable.
Based upon the clinical presentation, a presumptive diagnosis of narcolepsy with cataplexy was made. Secondary diagnoses included migraine without aura. All-night diagnostic attended polysomnography (PSG) and a multiple sleep latency test (MSLT) were performed.
Level I nocturnal polysomnography with synchronized video recording was conducted with Cadwell Easy III sleep acquisition system. Sleep measures and respiratory measures were collected and scored according to the American Academy of Sleep Medicine (AASM) criteria.  A sleep specialist, trained in polysomnography scoring analyzed the polysomnogram (RG) whereas relevant epochs were reviewed by experts in the field of sleep medicine (RF & JW). During the 323-min recording period his sleep efficiency was 96%. Sleep stages were unremarkable with the exception of slightly increased percent N1 (19%). His sleep architecture was unusual in that sleep onset was slightly less than normal (6 min) followed by an immediate Rapid Eye Movement (REM) sleep onset (1.5 min) [Figure 1]. Morning report suggested a dream-like hypnogogic imagery upon falling asleep in night. Respiratory disturbance index (RDI) score was 2 and mean arterial oxygen saturation of 94%. Other aspects of his polysomnogram indicated occasional snoring, tachycardia throughout the night, and frequent periodic limb movements (42/h). A multiple sleep latency test,  consisting of five naps conducted 2 h apart and starting 3 h after his morning wakeup time showed sleep on all naps with an average sleep latency of 0.7 min (normal ~10 min). Four of the five naps were positive for sleep-onset REM [Table 1].
| » Discussion|| |
In narcolepsy the onset of symptoms is usually during adolescence, however, some patients may develop symptoms close to the age of 40 years.  Another reported case from India also had clear-cut symptoms during the third decade.  Narcoleptic subjects develop an irresistible urge to fall asleep at odd times, especially when they are idle or engaged in monotonous activities.  Excessive daytime sleepiness is usually the first symptom to appear in narcoleptics, as seen in the present patient.  Hypnogogic hallucinations and sleep paralysis are seen only in a proportion of narcoleptics and are not specific to narcolepsy as they can be seen in other conditions like chronic sleep deprivation, stress, etc.  However, both these features were reported by our patient, further substantiating the diagnosis of narcolepsy.
Cataplexy is sudden onset muscular weakness that may be generalized or localized and usually triggered by emotions, especially anger and laughter.  The weakness is transient lasting for a few seconds to minutes and can vary in severity or distribution with complete recovery.  Although the patient may be unable to respond, there is no loss of consciousness. Of note, cataplexy is the most specific symptom for narcolepsy and differentiates it from other causes of hypersomnolence. ,
Diagnosis of narcolepsy is made by clinical picture, patient examination, ruling out the other causes of excessive daytime sleepiness and objective testing of a patient's sleep. ,, Obstructive sleep apnea was ruled out by the normal Respiratory Disturbance Index (<5/ hr) and normal oxygen saturation. Two or more naps with sleep-onset REM and reduced sleep latency (i.e. generally less than five minutes) favors the diagnosis of narcolepsy or chronic sleep deprivation but rules out restless-leg syndrome (along with clinical information).  Frightening dreams or REMBD have also been reported in narcolepsy patients.  However, we did not find any evidence of parasomnia in this patient in the study night. Interestingly, nocturnal sleep disturbance, as witnessed in this patient, is limited to the patients of narcolepsy with cataplexy and not seen in subjects without cataplexy. 
MSLT in the present patient showed sleep-onset REM periods with shortened sleep latency (<8 min). Besides narcolepsy, other conditions may also present with a positive MSLT.  These causes were excluded by the history and a normal whole-night polysomnogram. Besides clinical history and polysomnographic findings, two other tests have been recommended in narcolepsy subjects. However, both these tests are invasive and at present have limited usefulness. One of these tests is Human Leukocyte Antigen (HLA) typing (DQB1*0602 and HLA DQA1*0102) and the other is measurement of Cerebro-Spinal Fluid (CSF) hypocretin level.  However, these tests have their limitations and should be used in specific circumstances only.  In conclusion, this is one of the rare cases reported from Indian population with polysomnographic data. In certain circumstances, this may be a life threatening situation that also worsens the quality of life. Hence, there is a need to screen for narcolepsy in Indian population in future.
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