Neuropathic and Psychogenic Components of Burning Mouth Syndrome: A Systematic Review

The pathophysiology of primary burning mouth syndrome (BMS) has been extensively debated but is poorly understood despite a large number of hypotheses attempting to explain its etiopathogenic mechanisms. The aim of the present work was to systematically review papers that could provide arguments in favour of the neuropathic and psychogenic components of primary BMS for a better understanding of the disease. This systematic review (SR) was registered in PROSPERO (CRD42021224160). The search was limited to articles in English or French from 1990 to 01 December 2020. A total of 113 articles were considered for data extraction. We divided them into four subgroups: pharmacological and nonpharmacological management studies (n = 23); neurophysiological studies (n = 35); biohistopathological studies (n = 25); and questionnaire-based studies (n = 30). Several of these studies have shown neuropathic involvement at various levels of the neuraxis in BMS with the contribution of quantitative sensory testing (QST), functional brain imaging, and biohistopathological or pharmacologic studies. On the other hand, the role of psychological factors in BMS has also been the focus of several studies and has shown a link with psychiatric disorders such as anxiety and/or depression symptoms. Depending on the patient, the neuropathic and psychogenic components may exist simultaneously, with a preponderance of one or the other, or exist individually. These two components cannot be dissociated to define BMS. Consequently, BMS may be considered nociplastic pain.

["A picture is worth a thousand words…" : Diagnosis of orofacial pain using Dolografie®]

BACKGROUND

Since 2017, the diagnosis of patients with orofacial pain at the University Center for Dental Medicine Basel has been supplemented by using standardized image graphics (Dolografie® [Affolter/Rüfenacht, Bern, Switzerland]). For this purpose, patients select from a set of 34 cards those that visually best match their pain and then explain the reason for their choice.

OBJECTIVES

(1) How many cards are selected on average? (2) Do sex and age influence the choice of cards? (3) Are there preferences in the choice of cards? (4) Are there correlations between pain diagnostic categories (e.g., musculoskeletal versus neuropathic orofacial pain) and the cards selected? (4) Are there correlations between pain diagnostic categories (e.g., musculoskeletal versus neuropathic orofacial pain) and the selected cards?

METHODS

The available complete pain anamnestic data of 143 patients were evaluated.

RESULTS

(1) Patients selected an average of 3.5 cards to describe their pain. Up to six cards were sufficient for a detailed description of pain in almost all patients. With the 16 most frequently chosen cards, the majority of patients were able to adequately describe their pain. (2) Sex and age had no influence on the number of selected cards. (3) There were clear preferences: Card 02 was chosen most often (45 times), followed by cards 05 and 13 (27 times each). (4) A differentiating choice was made most clearly in neuropathic pain by a strong preference for card 28 and a disregard of card 18.

CONCLUSION

The use of standardized image cards as a "visual communication tool" has proven to be a time-efficient procedure in the context of history taking, which helps to obtain clinically relevant information not previously expressed by the patient.