Accurate diagnosis of facial pain

Blackwell Publishing LtdOxford,

UKCHACephalalgia0333-1024Blackwell Science, 2006267902903Letter to the EditorLetters to the editorLetters to the editor

LETTERS TO THE EDITOR

Accurate diagnosis of facial pain

Dear Sir We read with interest the timely article published by Zebenholzer et al. (1). Their findings should alert us all to the need for further study regarding the diagnosis and classification of facial pain. Applying the most recent classification of the International Headache Society (IHS) (2) to the 97 patients studied they found that about 21% were diagnosed with persistent idiopathic facial pain and about 29% were unclassifiable. As a tertiary pain centre the patients such as those reported (1) are usually complex, whilst it is reasonable to assume that straightforward cases such as temporomandibular disorders (TMD) are commonly diagnosed and treated efficiently at primary care centres. However, the finding that 50% of cases are essentially labelled as idiopathic or undiagnosable (1) according to IHS criteria is disturbing. In the 20– 30 years that we have been involved in the care of chronic orofacial pain patients we have similar (3, 4) although largely unpublished observations. We have persistently applied the IHS classifications for both research and clinical activities but have found these insufficient in orofacial pain patients, particularly those with TMDs or with facial pain accompanied by atypical features. For example, clinical differences between tension-type headache (TTH) and regional masticatory muscle myofascial pain (MMP) justify separate classification. MMP is viewed by orofacial pain specialists as a primary facial pain (5), not secondary to temporomandibular joint disease (6, 7), and has been shown to be largely unrelated to muscle hyperactivity (8). Although MMP may share pathophysiological mechanisms with TTH, it seems to be a distinct entity justifying separate classification (7). In such cases we are forced to rely on alternative classifications that detail orofacial pain syndromes, most recently the classification published by the American Academy of Orofacial Pain (5), conveniently modelled on the IHS classification. Analysing the cases presented by Zebenholzer et al. (1), one could argue that in cases with pain beginning after surgery accompanied by sensory deficit, a diagnosis of post-traumatic neuropathic pain may reasonably be applied (5, 9). Similarly, a patient with long-lasting paroxysmal pain accompanied by autonomic signs could be suffering from vascular orofa902

cial pain (3) or a trigeminal autonomic cephalgia (TAC) variant, i.e. probable TAC (2). However, the aim of this letter is not to criticize the diagnoses presented in this excellent publication, rather to utilize its findings as a platform to encourage the IHS to cooperate more extensively with orofacial pain specialties so as to expand its classification of orofacial pain syndromes. This will no doubt expand our abilities to diagnose such pain entities accurately and limit inconclusive diagnoses such as idiopathic persistent facial pain and atypical facial pain.

References 1 Zebenholzer K, Wober C, Vigl M, Wessely P, Wober-Bingol C. Facial pain in a neurological tertiary care centre— evaluation of the International Classification of Headache Disorders. Cephalalgia 2005; 25:689–99. 2 Headache Classification Subcommittee of the International Headache Society. The International Classification of Headache Disorders, 2nd edition. Cephalalgia 2004; 24 (Suppl. 1):24–150. 3 Benoliel R, Elishoov H, Sharav Y. Orofacial pain with vascular-type features. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 84:506–12. 4 Benoliel R, Sharav Y. Trigeminal neuralgia with lacrimation or SUNCT syndrome? Cephalalgia 1998; 18:85–90. 5 Okeson JP. Orofacial pain: guidelines for assessment, classification, and management. Mount Royal, NJ: The American Academy of Orofacial Pain, Quintessence Publishing Co., Inc. 1996. 6 Eliav E, Teich S, Nitzan D, Elaziq DA, Nahliel O, Tal M et al. Facial arthralgia and myalgia: can they be differentiated by trigeminal sensory assessment? Pain 2003; 104:481–90. 7 Eliav E, Benoliel R. Myofascial pain syndromes of the head and face. In: Wallace DJ, Clauw DJ, editors. Fibromyalgia and other central pain syndromes. Baltimore, MD: Lippincott Williams & Wilkins 2005:145–63. 8 Lund JP, Donga R, Widmer CG, Stohler CS. The painadaptation model: a discussion of the relationship between chronic musculoskeletal pain and motor activity. Can J Physiol Pharmacol 1991; 69:683–94. 9 Benoliel R, Eliav E, Elishoov H, Sharav Y. Diagnosis and treatment of persistent pain after trauma to the head and neck. J Oral Maxillofac Surg 1994; 52:1138–47; discussion 1147–8. R Benoliel and Y Sharav, The Department of Oral Medicine, Hadassah-The Hebrew University, POB 12000, Jerusalem, Israel 91120. E-mail [email protected]

© Blackwell Publishing Ltd Cephalalgia, 2006, 26, 902–903

Letters to the editor

Reply from the authors Dear Sir We want to thank Benoliel and Sharav for the constructive comment on our paper on facial pain in a neurological tertiary care centre (1). The comment points directly to the dilemma in diagnosing and treating patients suffering from facial pain. Straightforward cases are usually treated successfully in primary care, and complex cases, especially when the pain cannot be attributed to a specific disorder, are referred to specialized centres. Among the latter, the proportion of patients with unrecognized well-defined disorders is small, as shown in our study (1). In the majority of patients, the cause of the pain remains uncertain and many of them are clinically classified as atypical facial pain or persistent idiopathic facial pain. However, applying the current IHS criteria (2) in a strict sense shows that a considerable number of patients even do not fulfil these criteria. Benoliel and Sharav confirm our findings from the perspective of the orofacial pain specialist. We agree totally with them in stressing the importance of cooperation between orofacial and neurological pain specialists in elucidating the aetiology and pathogenesis of idiopathic facial pain in order to improve the management of these patients. A prerequisite is the use of uniform, standardized diagnostic criteria. Accordingly, the differences between the IHS criteria (2) and the Guidelines of the American Academy of Orofacial Pain (3) should be surmounted. Our study aimed at pointing out the dimensions of the problem. The patients with persistent idiopathic and unclassifiable facial pain, respectively, did not fulfil the IHS criteria for other diagnoses, nor did they meet the criteria for myofascial pain or temporomandibular disorders (1, 2). Similarly, the patients did not fulfil the diagnostic criteria for TAC or post-

© Blackwell Publishing Ltd Cephalalgia, 2006, 26, 902–903

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traumatic pain which were discussed as possible diagnoses by Benoliel and Sharav. As pointed out in our paper, the interval between a possible causative trauma or operation and the patient’s presentation to a pain centre often amounts to many years, making it impossible to establish a definite causal relation retrospectively. This problem can be overcome only by prospective studies. The letter by Benoliel and Sharav demonstrates that orofacial pain specialists such as neurologists are aware of the substantial number of patients with chronic facial pain which cannot be diagnosed accurately. The crucial point is that a broad basis of both specialties should be willing to cooperate in developing improved diagnostic tools. We will be quite content if our paper, the comment by Benoliel and Sharav and this reply contribute to a closer, constructive cooperation between orofacial specialists and neurologists.

References 1 Zebenholzer K, Wöber C, Vigl M, Wessely P, Wöber-Bingöl Ç. Facial pain in a neurological tertiary care centre— evaluation of the International Classification of Headache Disorders. Cephalalgia 2005; 25:689–99. 2 Headache Classification Subcommittee of the International Headache Society. The International Classification of Headache Disorders, 2nd edition. Cephalalgia 2004; 24 (Suppl. 1). 3 Okeson JP. Orofacial pain: guidelines for assessment, classification and management. Mount Royal, NJ: The Academy of Orofacial Pain, Quintessence Publishing Co., Inc. 1996. Karin Zebenholzer, Christian Wöber, Marion Vigl, Peter Wessely and Çiçek Wöber-Bingöl. Department of Neurology, Vienna Medical University, Währinger Güntel 18–20, A-1090 Vienna, Austria. E-mail [email protected]