The patient was an adolescent girl with normal vital signs (supine, standing, sitting), normocephalic, with nonspecific facial dysmorphic features and increased neck size. On general exam, SK was 62 inches tall and weighed 154 pounds. SK lived with her biological parents and received special education services at school.
Family history was negative for sleep disorders, although her maternal grandmother experienced infrequent syncopal events during stressful events (eg, funerals) in her older years. She denied drug, food, or environmental allergies, or use of tobacco, alcohol, caffeine, or illicit drugs. Current medications were montelukast, inhaled fluticasone/salmeterol, and ethinyl estradiol/levonorgestrel. SK’s medical history included mild asthma, developmental delay, mild mental retardation, and scoliosis. She denied EDS, vivid dreams, hypnagogic hallucinations, sleep paralysis, sleep attacks, snoring, witnessed apneic events, symptoms suggestive of restless legs or limb movements in sleep, parasomnias, and difficulty initiating/maintaining sleep. Associated injuries included multiple abrasions, ankle sprains, and left lower extremity fracture. Event frequency and severity worsened after use of oral contraceptives for menstrual cycle management. However, about half of these episodes were unprovoked. Triggers included stress, anxious thoughts, fear (eg, during thunderstorms), and excitement, and the episodes tended to occur more frequently during the initial days of the new school year. She denied aura or loss of awareness, duration was 1 to 3 seconds, and frequency varied from multiple daily to every 14 days. SK is a 17-year-old right-handed Caucasian woman with mild mental retardation, dysmorphic facial features, and four years of recurrent “drop attacks.” Episodes were described as sudden onset of bilateral lower extremity weakness ranging from “weak, trembling knees” to generalized weakness with falls if standing. Isolated cataplexy is a rare phenomenon, but has been reported as an inherited autosomal dominant condition, 1,2 in association with structural lesions of the brainstem, 3 hypercalcemia, 4 inborn errors of metabolism and genetic disorders (eg, Norrie disease, Coffin-Lowry syndrome, and Moebius syndrome5), and lipid-storage disorders (eg, Niemann-Pick disease type C). The absence of cataplexy does not rule out narcolepsy. In some cases, cataplexy may precede the onset of EDS. However, in the setting of EDS, the presence of definite cataplexy alone can substantiate the diagnosis of narcolepsy. Sleep paralysis, vivid dreams, and hypnagogic hallucinations can occur in normal individuals. Triggers include fatigue, emotional stress, and medications (eg, alpha-1 adrenergic blockers).Ĭataplexy, excessive daytime sleepiness (EDS), sleep paralysis, vivid dreams, and hypnagogic hallucinations are cardinal symptoms of narcolepsy.
Episodes can vary in duration, frequency, severity, and body area affected. BACKGROUNDĬataplexy is an abrupt, transient loss of bilateral postural muscle tone without altered awareness during wakefulness, precipitated by emotions such as anger or laughter. This patient case, which does not have a definitive etiology, highlights the importance of reviewing the diagnosis and pursuing additional diagnostic tests to broaden the differential and treatment options. An adolescent with mild mental retardation presented to our clinic with a rare case of isolated cataplexy that included provoked and unprovoked events.