LASH: A Review of the Current Literature.

PURPOSE OF REVIEW: The purpose of this review is to evaluate and explain our current understanding of a very rare disorder, long-lasting autonomic symptoms with associated hemicranias (LASH).

RECENT FINDINGS: At present, there are four known cases in the literature of LASH. Its characteristics and reported response to indomethacin link it most closely to the trigeminal autonomic cephalalgias (TACs). Its pathophysiology and epidemiology remain unclear. Variance in the pain and autonomic symptom relationship in the existing TAC literature along with the reports of TAC sine headache suggests that LASH may represent a far end of the spectrum of TACs, with most similarities to paroxysmal hemicrania (PH) and hemicrania continua (HC).