Introduction of the TIPIC syndrome in the next ICHD classification

Abstract

To the Editor: We read with much interest the third edition of the International Classification of Headache Disorders (ICHD), by the Headache Classification Committee of the International Headache Society (1). This new edition, driven by scientific evidence and research, provides a substantial amount of new information and updates. It forms the basis of all diagnosis and management of headache disorders in clinical practice as well as in research. However, we humbly believe that a new recently described entity called Thickened wall and Infiltration of the Perivascular fat Involving the Carotid bifurcation (TIPIC) syndrome is missing in this new classification and should be included in the next edition of the ICHD (2). The TIPIC syndrome is an unclassified entity in patients presenting with an uncommon acute carotid artery disease revealed by an acute cervical pain and striking vascular and perivascular abnormalities not fitting any classification, but classically reported as ‘‘carotidynia’’, ‘‘carotidodynia’’, ‘‘carotiditis’’ or ‘‘carotidobulbia’’ in the literature. Carotidynia was a clinical entity described in 1927, characterized by tenderness and pain at the level of the carotid bifurcation. Initially classified as an idiopathic neck pain syndrome in the first International Classification of Headache Disorders (ICHD) in 1988, it was subsequently removed as a distinct entity in 2004 (3). Indeed, the two clinical signs of carotidynia were neither specific nor constant, and other causes of neck pain might have the same clinical presentation (4). However, since 2000, a few case reports have described imaging abnormalities in patients presenting tenderness and pain at the level of the carotid bifurcation (5–10). In 2017, a large multicentric study provided a precise clinico-radiological description of this unclassified entity among 47 patients from 10 centers presenting with acute neck pain and abnormal carotid and pericarotidian tissues on imaging. The authors provided diagnostic criteria in order to help clinicians to make the diagnosis and suggested a name for this yet unclassified entity: TIPIC syndrome (2). This acronym was chosen in consensus by neurologists, neuroradiologists and pathologists to avoid the use of the term ‘‘carotidynia’’, which was confusing and should not be used any more. Recognition of this entity should change clinical practice: It would favor further large prospective studies to assess its prevalence, to understand physiopathological mechanisms, risk factors and etiological processes, and to evaluate therapeutics. That is why we believe that it should be included in the next ICHD classification.