Narcolepsy: an interface among neurology, immunology, sleep, and genetics

Narcolepsy is a primary disorder of the central nervous system resulting from genetic, environmental, and immunological interactions defined as excessive daytime sleepiness plus cataplexy, hallucinations, sleep paralysis, and sleep fragmentation. The pathophysiology is not entirely known, but the interaction among genetic predisposition, environmental exposition, and immune component with consequent hypocretin-1 deficiency is the model to explain narcolepsy type I. The mechanism of narcolepsy type II is less understood. There is a delay of over ten years for the diagnosis of narcolepsy around the world. Patients with narcolepsy have many comorbidities with a negative impact on quality of life. The treatment of narcolepsy must contain an educational approach for the family, coworkers, and patients. Scheduled naps and sleep hygiene are essential to minimize the dose of medications. Much progress has been seen in the pharmacological treatment of narcolepsy with new stimulants, different presentations of oxybate, and recent studies with orexin agonists. Narcolepsy is a rare disease that needs to be more understood and highlighted to avoid delayed diagnosis and severe disabilities in patients.

[Characteristics of narcolepsy in childhood]

A narcolepsia napközbeni rövid alvásbetörésekkel, fokozott érzelmi szituációkban kialakuló átmeneti izomtónusvesztéssel (cataplexia), a rövid bealvások során is jelentkező álomtevékenységgel (hypnagog hallucináció), ébredéskor megfigyelt átmeneti mozgásképtelenséggel (alvási paralízis) járó, ritka betegség. Hazánkban mindössze 2–3000 embert érinthet. Jellegzetes tünetei ellenére a betegség felismerése nehézkes, sokszor évtizedes késés figyelhető meg a korrekt diagnózis és így a hatásos terápia kialakításáig. Különös figyelmet követelnek a gyermekkori kezdetű esetek, mivel a klasszikus fenti panaszokat számos egyéb tünet (például extrapyramidalis mozgászavarra hasonlító események stb.) is kíséri, a panaszok sokkal összetettebbek. Az egyes klasszikus tünetek – mint például a cataplexia – megjelenése is eltér a felnőttkorban észlelhetőtől. Ezek nagyban megnehezítik a felismerését. A szerteágazó panaszok és tünetek magyarázzák a diagnosztikus tévedéseket, késlekedéseket: a valós kórisme helyett sokszor különféle neurológiai és pszichiátriai betegség diagnózisával kezelik a pácienseket. A nem megfelelő kezelésnek negatív hatása lehet a gyermek iskolai teljesítményére, érintheti a szociális interakcióit, pályaválasztását, kihathat mindennapi életére, életminőségére. Az összefoglaló közleményben ismertetjük a narcolepsia klasszikus jellegzetességei mellett a gyermekkori esetek eltérő tüneteit, patofiziológiáját, a differenciáldiagnosztikai nehézségeket, a kezelés elmaradásának következményeit, a diagnosztikus kritériumokat és a terápiás lehetőségeket. Orv Hetil. 2024; 165(6): 211–220.

[Narcolepsy secondary to a rare fatal disease]

INTRODUCTION

ROHHAD (rapid-onset obesity with hypothalamic dysfunction, hypoventilation and autonomic dysregulation) is a rare disease, with only about two hundred cases reported to date, that starts in previously healthy children. The first sign is usually obesity, followed by hypothalamic dysfunction and sleep-disordered breathing, which rapidly progresses until the death of the patient. ROHHAD with narcolepsy is even rarer, with only two cases described so far.

CASE REPORT

We report the case of a boy who showed signs of obesity and sleepiness since he was 5 years old. At the age of 7, he suffered two tonic-clonic seizures and, over the next four years, displayed signs and symptoms of significant hypothalamic dysfunction; after multiple tests, he was then diagnosed with ROHHAD. Despite receiving a large number of treatments, the patient died at the age of 11.

CONCLUSION

The pathophysiology of this disease needs to be clarified in order to investigate effective treatments in the future.

[Sleep paralysis during naptime as initial symptom of narcolepsy]

INTRODUCTION

Narcolepsy is a disease of unknown etiology, with a very low prevalence (0.02-0.16% in adults, although it must be higher, given the underdiagnosis), characterized by the presence of excessive daytime sleepiness, hypnagogic and/or hypnopompic hallucinations, sleep paralysis and/or cataplexy (if present, we speak of type 1 narcolepsy and, if not, type 2 narcolepsy), whose average diagnostic delay is between 10 and 15 years.

CASE REPORT

A 16-year-old male who consulted after visiting different specialists for presenting sleep paralysis during naps, which cause him fear and occasional objects falling from his hands (diagnosed as possible myoclonus). In the anamnesis we were surprised by the presence of sleep paralysis immediately after the start of the naps and, in the directed anamnesis, these sudden movements caused by emotions were compatible with cataplexies, so we performed a nocturnal polysomnographic study and a multiple sleep latency test. With evolution came hypnopompic hallucinations and fragmented nocturnal sleep, as well as occasional daytime sleepiness (thus completing the typical symptomatic tetrad of type 1 narcolepsy with cataplexy).

CONCLUSION

Knowledge of this disease is important, considering it as a differential diagnosis in patients with episodes of intractable sleepiness, send these patients to expert doctors in sleep disorders and doing a good anamnesis, performing the necessary complementary tests for the diagnosis of this underdiagnosed disease for its correct management, which is decisive for improving the quality of life of these patients.

[Multidrug resistant narcolepsy]

INTRODUCTION

Narcolepsy type 1 is a focal degenerative disease of the hypothalamus that selectively affects orexin (hypocretin)-producing neurons. It presents multiple clinical manifestations, both in wakefulness and in sleep. The symptoms are often so disruptive that they cause enormous suffering and impair patients' quality of life. Although a non-pharmacological approach is sometimes sufficient, the vast majority of patients need medication for adequate clinical management.

CASE REPORT

A male who, at 43 years of age, began to present acutely with excessive daytime sleepiness and episodes of cataplexy. After a thorough examination, he was diagnosed with narcolepsy type 1. Throughout the course of the disease, he was prescribed antidepressants, neurostimulants and sodium oxybate, in monotherapy or in combination. The response to pharmacological treatment was insufficient and accompanied by numerous side effects. Following the introduction of pitolisant, there was a marked improvement in his symptoms and a reduction in the dose of the other drugs and their adverse effects was achieved.

CONCLUSION

A number of measures are now available to address the cardinal symptoms of the disease, although there are still cases that are resistant to anti-narcoleptic treatment. Drugs with mechanisms of action that act upon receptors in the histaminergic system can be very useful in these cases.