Trigeminal autonomic cephalalgias: spectrum or continuum? Insights from a family

Excerpt

The ICHD3 classification [1] identifies trigeminal autonomic cephalalgias (TACs) as a spectrum of discrete nosographic entities, whose boundaries are primarily demarcated by the different duration and frequency of single headache attacks; other clinical features (e.g., demographic characteristics of patients, the time-course, and the response to treatments) are considered to be supportive. Nonetheless, neuroimaging studies showing common neuroanatomic substrates (i.e., PET evidence of activation of the posterior hypothalamus during headache attacks), and the description of cases with overlapping clinical features or with attacks transforming from one to another phenotype, suggest that TACs may represent a continuum of clinical entities and may be determined by common pathophysiological mechanisms. …