title: Cyclic nocturnal awakening: a warning sign of a cluster bout.
abstract: BACKGROUND
  Cluster headache is an excruciating unilateral headache with autonomic symptoms whose periodic nocturnal activity, which interrupts sleep, has been attributed to a hypothalamic generator.
  
  
  METHODS
  We describe a patient with a longstanding episodic cluster headache who experienced, on two occasions, a period of nocturnal awakenings without pain or autonomic symptoms, lasting one week before the onset of a cluster bout. Awakenings occurred twice/night at the same hours of impending cluster attacks and had no apparent trigger, being unusual for this patient who had no previous sleep disturbances. Neurological examination and brain imaging were normal.
  
  
  CONCLUSIONS
  This case documents two new aspects of cluster headache. It suggests that repeated nocturnal awakenings can be a warning sign of an impending cluster period, a finding that may have therapeutic implications, and also that hypothalamic activation may begin several days before trigemino-autonomic symptoms, thus behaving as a true bout generator.
authors: Department of Clinical Neurosciences, Instituto de Medicina Molecular (IMM), Faculty of Medicine (IMM) University of Lisbon, Portugal Isabel_Martins@fm.ul.pt.
authors: Isabel Pavão
authors: IP
authors: Martins
mesh_terms: D003027:Cluster Headache / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D062706:Prodromal Symptoms; D012893:Sleep Wake Disorders / Q000209:etiology*
keywords: Cluster headache; cluster warning; hypothalamic generator; sleep and cluster