Secondary hypnic headache: A literature review in the last 34 years

Introduction: Hypnic headache is a rare primary disorder that occurs during sleep. Its pathophysiology uncertain, but hypothalamic dysfunction hypothesized. It usually headache, it can have secondary causes.
 Objectives: We aimed was to review articles published in the last 34 years on hypnic and analyze cases.
 Methods: Based literature search major medical databases using descriptor “hypnic headache” we included between 1988 2020. Of 359 patients found, only 18 met inclusion criteria were analyzed.
 Results: found (6 men 12 women) with headache. The mean age of 58.7±15.0 years, ranging from 20 84 years. causes attributed cranial vascular (five), non-vascular intracranial (six), substance or its withdrawal (three) homoeostasis (four).
 Conclusions: Although most cases are primary, some symptomatic described literature.