Classification of Head, Neck, and Face Pains First Edition (WHS-MCH1): Position paper of the WHS Classification Committee

Abstract

The WHS classification of Head, Neck and Face pain, Edition 1 Version 1 (WHS-MCH1) is the official document of the World Headache Society. It was conceptualized and developed by the Society's Classification Committee. The work began with a clean slate to create a comprehensive, updated and holistic classification of headache disorders; where 'headache' was defined as any pain above the shoulders, thus including head, neck and face pain. This new classification reflects a scientifically robust understanding of disease and also places patient experience in the qualia of pain. It is a training manual to be used at the bedside and office as an aid to the diagnosis and management of headache disorders. The dynamic nature of this first ever live classification of headaches also means that ultra-rapid updates, or versions, will be available electronically. It is not a disease criteria but a classification criteria (1) and is useful to pick extended spectra and 'mimickers' of diseases. Although increased sensitivity usually comes at the expense of reduced specificity, an expanded spectrum of diseases in this case also means increased specificity. WHS-MCH1 is a syndromic classification. A syndrome is a recognizable complex of symptoms and physical findings which may have more than one aetiology. Although disease is nominalist and culture-relativistic (2) , a syndrome based approach reflects the discipline of first widening the view of possibilities before analysing each to formulate a diagnostic hypothesis. Such an approach provides a useful framework for organizing the complexity of clinical experience in order to derive inferences about outcome and guide decisions about treatment. WHS-MCH1 has a vertical grouping designed for use by clinicians of all levels of experience; this is linked to the horizontal groupings which are syndrome-based. The syndrome groups are also interlinked to one another. This design enables clinicians to efficiently create the 'big picture' so as not to miss any diagnosis. Axis 1 and 2 are the vertical and horizontal grouping categories, respectively. Axis 3 is the patient narrative of bothersome symptoms and level of impairment. Axis 4 are biomarkers that may be derived from investigations and this is the best example of the continuum of better understanding of disease defining markers. Axis 5 is an objective impairment scale that clinicians may choose based on availability. The World Headache Society hopes that the use of such a robust and inclusive framework will lead to better patient outcomes and improved patient and clinician satisfaction with the investigative and diagnostic process.