Extreme sleep pattern in Lewy body dementia: a hypothalamic matter?

A Case Report of Probable Dementia With Lewy Bodies Diagnosed Through Repeated Episodes of Depressed Consciousness

This case report details the diagnostic challenges of an 84-year-old male with unrecognized dementia with Lewy bodies (DLB) who presented to the emergency department (ED) with episodes of unresponsiveness and depressed consciousness. Despite normal initial laboratory and imaging tests, recurrent symptoms prompted further evaluation, which, along with a detailed history and physical examination, led to the DLB diagnosis. This case underscores the importance of considering DLB in patients with unexplained recurrent depressed consciousness and highlights the importance of clarifying the etiologies of dementia.

Sleep disorders and the hypothalamus

As early as the 1920s, pathological studies of encephalitis lethargica allowed Von Economo to correctly identify hypothalamic damage as crucial for the profound associated sleep-related symptoms that helped define the condition. Only over the last 3 decades, however, has the key role of the hypothalamus in sleep-wake regulation become increasingly recognized. As a consequence, a close relation between abnormal sleep symptomatology and hypothalamic pathology is now widely accepted for a variety of medical disorders. Narcolepsy is discussed in some detail as the cardinal primary sleep disorder that is caused directly and specifically by hypothalamic pathology, most notably destruction of hypocretin (orexin)-containing neurons. Thereafter, various conditions are described that most likely result from hypothalamic damage, in part at least, producing a clinical picture resembling (symptomatic) narcolepsy. Kleine-Levin syndrome is a rare primary sleep disorder with intermittent symptoms, highly suggestive of hypothalamic involvement but probably reflecting a wider pathophysiology. ROHHAD (rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation) and Prader-Willi syndrome are also covered as hypothalamic syndromes with prominent sleep-related symptoms. Finally, sleep issues in several endocrine disorders are briefly discussed.