Abstracts

Clinical study of patients with persistent orofacial pain

Estudo clínico de pacientes com dor orofacial persistente

José Tadeu Tesseroli de Siqueira^I; Lin Hui Ching^II; Cibele Nasri^III; Silvia Regina Dowgan Tesseroli de Siqueira^IV; Manoel JacobsenTeixeira^V; Gary Heir^VI; Luís Biela S. Valle^VII

Dentistry Division of the Central Institute and Experimental Neurosurgery Division of the Psychiatric Institute, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo SP, Brazil (HC/FMUSP)

^IDDS, PhD, Head, Orofacial Pain Team, Dentistry Division, HC- FMUSP

^IIDDS, MsC, Orofacial Pain Team, Dentistry Division, HC/FMUSP

^IIIDDS, Orofacial Pain Team, Dentistry Division, HC/FMUSP

^IVDDS, Post-graduation Student, Orofacial Pain Team, Dentistry Division ,HC/FMUSP

^VMD, PhD, Head, Pain Multidisciplinary Center, Neurology Division, and Experimental Neurosurgery Division, Psychiatric Institute, HC/FMUSP

^VIDMD, Professor of University of Dentistry and Medicine of New Jersey/USA

^VIIDDS, MD, PhD, Pharmacology Professor, University of Santo Amaro (UNISA), São Paulo SP, Brazil

^{Correspondence} Correspondence to Dr. José Tadeu Tesseroli de Siqueira Rua Maria Cândida 135 02071010 São Paulo SP - Brasil E-mail: jtts@uol.com.br

ABSTRACT

OBJETIVE: To evaluate a sample of patients with persistent facial pain unresponsive to prior treatments.

METHODS: Hospital records of 26 patients with persistent facial pain were reviewed (20 female and 6 male).

RESULTS: Patients were classified into three groups according to their presenting symptoms: a)Group I, eight patients (30.7%) with severe, diffuse pain at the face, teeth or head; b)Group II, eight patients (30.7%) with chronic non-myofascial pain and; c)Group III, ten patients with chronic myofascial pain (38.4%). We find 11 different diagnoses among the 26 patients: pulpitis(7), leukemia(1), oropharyngeal tumor(1), atypical odontalgia(1), Eagle's syndrome(1), trigeminal neuralgia(4), continuous neuralgia(1), temporomandibular disorders (9), fibromyalgia (2), tension-type headache(1), conversion hysteria(2). After the treatment program all patients had a six-month follow-up period with pain relief, except the patient with tumor.

CONCLUSION: The wide variability of orofacial pain diagnosis (benign to life-threatening diseases) indicates the necessity to reevaluate patients presenting recurrent pain that is refractory to the usual treatments.

Key words: orofacial pain, trigeminal neuralgia, tumor, temporomandibular disorders, atypical facial pain

RESUMO

OBJETIVO: Avaliar uma amostra de doentes com dor facial persistente.

MÉTODO: Foram revisados 26 prontuários de doentes com dor facial persistente (20 mulheres e 6 homens).

RESULTADOS: Classificação dos doentes, após o diagnóstico: a)Grupo I, oito pacientes (30,7%) com dor facial difusa de fortíssima intensidade; b)Grupo II, oito pacientes (30,7%) com dor crônica de natureza não-miofascial e; c)Grupo III, dez pacientes com dor crônica miofascial (38,4%). Foram encontrados 11 diagnósticos diferentes entre os 26 pacientes: pulpites(7), leucemia(1), tumor de orofaringe(1), odontalgia atípica(1), síndrome de Eagle(1), neuralgia idiopática do trigêmeo(4), neuralgia atípica(1), disordens temporomandibular (9), fibromialgia(2) cefaléia tipo-tensão(1), histeria de conversão(2). O acompanhamento dos doentes, após receberem a respectiva terapia, foi de seis meses, com alívio da dor, exceto para o doente com tumor de orofaringe.

CONCLUSÃO: A variabilidade das fontes da dor facial inclui doenças benignas e doenças graves, sendo indispensável a reavaliaçâo de doentes que não respondem aos tratamentos convencionais para a dor.

Palavras-chave: dor orofacial, neuralgia trigeminal, tumor, articulação temporomandibular, dor facial atípica.

The complex innervation and function of facial structures makes the diagnosis of facial pain and its treatment very difficult and frustrating^1,2. Patients with chronic facial pain, even after receiving multiple treatments, should be carefully reassessed and clinically re-examined. Myofascial pain syndromes, temporo mandibular disorders (TMD), neuralgias, ENT diseases, dental pain, tumors, neurovascular pain or psychiatric diseases frequently present with overlapping signs and symptoms^3,4. Referred, severe, acute pain frequently makes the diagnosis difficult.

It is known that dental pain can radiate to the face and simulate other sources of pain due to sensitization of neurons in the central nervous system^5,6. This can cause other phenomena including secondary adjacent muscle hyperactivity. Patients can present with muscular hyperactivity resulting from persistent acute or chronic pain, and elicit secondary muscle pain^7-9. Therefore, the elimination of the primary source of pain is essential but, in chronic pain, is not always enough for control of pain. An incorrect and ineffective treatment may perpetuate or generate chronic pain. The understanding of secondary pain mechanisms of craniofacial pain is necessary for the formulation of an accurate diagnosis¹⁰.

The goal of this study is to demonstrate the variability of possible diagnoses in a sample of patients with persistent facial pain and how the orofacial pain specialty team was able to assist in their diagnosis and management.

METHOD

This is a retrospective study of a sample of patients with persistent facial pain unresponsive to previous treatments who were referred to an orofacial pain team of a large teaching hospital. The study was approved by the Ethics Commission of the hospital.

The records of 26 consecutive patients, 20 female and 6 male, were analyzed. Patients were selected according to the description of their chronic pain symptoms and classified in accordance with the criteria of the International Association for the Study of Pain¹¹ and references of the American Academy of Orofacial Pain¹². This sample represents 4% of all new patients with orofacial pain complaints admitted to the Orofacial Pain Clinic during the period of this study (August 1992 - December 1996). In order to ensure consistency in interview methods, the diagnoses were confirmed by clinical examination performed by members of a trained and calibrated interdisciplinary pain team.

The standardized diagnostic protocol was applied to all patients equally. It consists of a standardized interview and systematic evaluation of cervical, cranial, facial, oral and dental structures. The general characteristics for differential diagnosis of the diseases are presented in Table 1. Diagnoses were:

Pulpitis – History of daily, throbbing, diffuse pain, trigger by hot or cold and waking the patient during the night. The dental source of pain was identified by a clinical evaluation and diagnostic anesthetic block¹².

Acute leukemia – Diagnosis is made with laboratory examination of the peripheral blood (WBC) and bone marrow. WBC is usually elevated, but some case present with normal or decreased counts. Anemia (pallor, shortness of breath and fatigue) and thrombocytopenia are other frequent clinical findings¹³. Oral signs and symptoms frequently lead to a diagnosis of the leukemia; i.e., looseness and mobility of the teeth and paresthesia of the lips is reported during the leukemic cellular infiltration in the periodontal membrane and peripheral trigeminal nerve, respectively¹³.

Trigeminal neuralgia – History and clinical evaluation and the presence of paroxysmal and electric shock-like pain with a trigger zone¹¹.

Tumor (Oropharyngeal) - Based on computed tomography (CT) and magnetic resonance image (MRI) of the cranial and facial region. The clinical characteristics of the pain are variable and atypical¹⁴.

Temporomandibular disorders – The diagnosis is by history and clinical exam. Inclusionary criteria include the presence of limited opening, tenderness of the masticatory muscles and joint sounds during mandibular function. CT is used in degenerative process of the temporomandibular joint (TMJ)^12,14.

Eagle' syndrome – Characterized by pain in the oropharyngeal region during mandibular activities, meanly swallowing. Image exams usually show a styloid process elongated and the inflammation is the cause of the pain. Palpation of the posterior and medial region of the mandible angle is painful. The precise diagnosis is made with clinical examination¹⁴.

Fibromyalgia – Characterized by widespread pain, decreased pain threshold, sleep disturbance, fatigue, psychological distress and chronic headache. Patients thought to have fibromyalgia were diagnosed based on the demonstration of multiple tender points. These tender points were bilaterally, symmetrical but did not refer pain when provoked. Diagnosis in this condition is clinical¹⁵.

Diagnosis of mental health disorders was made by a psychiatric examination according to the diagnostic criteria for hysterical conversion, or pain associated with depression^11,16.

Radiographic and laboratory evaluation - Panoramic radiography of the jaw was performed for all patients. CT scan of the craniofacial region with contrast, MRI and hematological examination (complete blood count) was performed in those cases with recurrent pain without clinical evidences of benign pain if a structural lesion was suspected. CT, MRI and hematological tests were made for patients with clinical diagnostic of trigeminal neuralgia for differential diagnostic between idiopathic and symptomatic trigeminal neuralgia.

Treatment – Patients received appropriate treatment after achieving an accurate diagnosis. Pulpitis was treated with conventional dental management. Trigeminal neuralgia was treated with carbamazepine. Patients with systemic disorders, oropharyngeal tumor and leukemia, were referred for specific treatment, according to the diagnosis. No further commentary regarding treatment of systemic diseases is included in this study as these patients were referred out of the study. A pain assessment was performed immediately after the treatment program and after a six-month follow-up period. A subjective scale was used for this evaluation included five items: SD (Pain free), O (Optimum), S (Satisfactory), PM (Poor improvement) and SM (Without improvement).

Statistical analysis – Patients were separated into groups and comparisons were conducted for general characteristics of the sample. The data was analyzed in the SPSS 10 for Windows program.

RESULTS

In 80.7% of the patients the previous diagnosis was incorrect and the average number of health professionals consulted was 4.7.

Patients were classified into three groups according their final diagnoses: Group I - Acute pain: Eight patients (30.7%) with severe, diffuse pain referred to the ipsilateral face, teeth or temporal region; Group II - Chronic non-myofascial pain: Eight patients (30.7%) with chronic non-myofascial pain and; Group III - Chronic myofascial pain: Ten patients with chronic myofascial pain (38.4%) associated with other painful comorbidities such as fibromyalgia, trigeminal neuralgia and continuous neuralgia

Acute and chronic pain conditions were classified according to the IASP¹¹ classification of chronic pain. Throbbing pain during the day or the night was more common in dental lesions; paroxysmal pain was the most common expression of trigeminal neuralgias; and constant, pressure and burning pain were the most common complaints in chronic musculoskeletal pain.

Group I - Acute pain – Eight patients (5 women and 3 men) in otherwise good oral health, aging 13 to 60 years old (median 39.50±13.74) described diffuse and severe pain during the day and at night with pain referring to the facial or cranial region. On average, pain was of one-month duration. Prior diagnoses were trigeminal neuralgia, TMD, myofascial pain, and atypical facial pain. A re-evaluation led to the correct diagnosis of leukemia in one patient and pulpitis in seven others. Pulpitis arose in the following teeth: an inferior canine (#43), two inferior pre-molars (#34, #35), two superior molars (#17, #18) and two inferior molars (#46, #47).Two patients reported referred pain to the adjacent teeth and to ipsilateral face; one patient had referred pain to all ipsilateral teeth, face and temporal area; one patient had referred pain of the opposing teeth, ipsilateral face and temporal area; and three patients had referred pain to the ipsilateral face. In six patients, the teeth were painful to vertical and/or horizontal percussion and in three, airflow stimulation of the teeth trigged the pain. Pulpitis was treated with conventional dental therapy. The patient with leukemia was referred to a hematologist and received chemotherapy and a bone marrow transplant.

In summary, in the Group I, seven patients presented with diffuse unilateral craniofacial pain from dental causes (pulpitis), and one patient had dental pain and general dental mobility because of a systemic disorder. Two patients in this group received either dental extractions or oral surgery for the treatment without any improvement prior to receiving a final diagnosis.

All the patients of this group were pain free after an accurate diagnosis and correct treatment and remained so at six months of follow-up evaluation.

Group II - Chronic non-myofascial pain – Eight patients (3 men and 5 women), ranging in age from 18 to 57 years old (median 36.50±13.59) reported unilateral (6) and bilateral (2) localized pain which was diurnal and moderate to severe in the facial or cranial region. The duration of pain was on average 31.2 months. The previous diagnosis was TMD for all patients. A final diagnosis and respective treatments were provided. For Eagle's syndrome (1) the patient received a styloidectomy. Oropharyngeal tumor (1) was treated with chemotherapy. The patient with tension-type headache (TTH) (1) was treated with tricyclic antidepressants (TCAs). Trigeminal neuralgia (2) was treated with carbamazepine (1) and trigeminal percutaneous radiofrequency rhizotomy (1). Psychiatric disorders (2) received psychotherapy. Atypical odontalgia (1) was treated with TCAs. All, except for the patient with tumor, reported relief.

In summary, this group presented with different diagnosis for their chronic pain. Six patients previously received some form of oral surgery (dental extractions or periapical surgery), without improvement.

The final evaluation of this group was: pain free in six, satisfactory improvement in one (TTH) and without improvement in one (oropharyngeal tumor).

Group III - Chronic myofascial pain – Ten patients (women) aging 42 to 70 years old (median 59±9) received a prior diagnosis of TMD. The average duration of pain was 6.8 years. Despite the diagnosis of TMD, pain control was unsatisfactory due to inadequate treatment and the presence of other causes. The final diagnoses were, respectively, TMD (5), TMD associated with fibromyalgia (2); TMD associated with traumatic trigeminal neuralgia (2); or TMD associate with trigeminal neuralgia (tic doulourex) (1). Treatment was performed accordingly: a) neuropathic pain⁷; b) fibromyalgia¹⁵ or c) chronic myofascial pain¹⁷.

Summarizing, in this group, the musculoskeletal facial pain was associated with trigeminal neuralgia, fibromyalgia or non-paroxysmal pain of the oral cavity. Four patients reported the beginning of the pain after facial surgery. Three patients reported oral surgery and one patient changed the dental prosthesis previously as the treatment of pain, without any improvement. The final evaluation of this group was: pain free in six and satisfactory improvement in four.

The Table 2 shows the general characteristics of the sample. The diagnosis of patients with organic pathology was achieved in accordance with the International Association for the Study of Pain¹¹ (Table 3).

DISCUSSION

The original diagnosis was incorrect or incomplete in 80.7% of the cases. We find 11 different diagnoses among the 26 patients of this sample: pulpitis (7), leukemia (1), oropharyngeal tumor (1), atypical odontalgia (1), Eagle's syndrome (1), trigeminal neuralgia (4), continuous neuralgia (1), TMD (9), fibromyalgia (2), conversion hysteria (2) and tension-type headache (1). All of the 26 patients were referred to our service with a prior suspect diagnosis of TMD. These patients failed to improve due to misdiagnosis.

The patients in this study were seen by an average of 4.6 dentists or physicians before to arriving at our clinic. Only after appropriate treatment, adequate pain control was achieved in the majority of the patients remained pain free six-month follow up evaluation. The average of 4.88 health care, 70% of the patients saw a general dentist and 30% saw a physician, was found in another study about referral patterns for all types for facial pain¹⁸.

Dental pain, trigeminal neuralgia and oncologic conditions may present with similar clinical symptoms^7,13,19. Tumors can provoke throbbing pain when compressing tissues, such as the patient with an oropharyngeal tumor who reported pain during the mouth opening movement. They cause neurological abnormalities too, as the left lips paresthesia in the patient with leukemia. Trigeminal neuralgia is a sudden, usually unilateral, severe, brief, stabbing and recurrent pain in the distribution of one or more branches of the V cranial nerve¹¹; and seldom awakens the patient from sleep²⁰. On the other hand, pulpalgias can be triggered by cold or hot liquids, and can awaken the patient from sleep causing dental tenderness^6,20. Therefore, the use of specific diagnostic criteria is important to help in the differential diagnostic process. A simple example is seen in six of the seven patients that presented with pulpitis who described nocturnal episodes of pain. Three of these patients realized an increase in pain with an application of a external stimulus in their teeth (cold air). These pains were interrupted by the local anesthesia block.

This sample included two interesting cases of dental pain of nonodontogenic origin (acute leukemia and atypical odontalgia), and seven patients with craniofacial pain from odontogenic origin. This demonstrated that the location of pain is not always the same as its source¹⁰. The atypical odontalgia, that is a neuropathic pain, is localized in the tooth or gingival, but the pain of pulpitis can vary greatly in its clinical presentation and intensity^6,20,21.

Although trigeminal neuralgia (TN) has a well defined diagnosis, it is often confused with other sources of facial pain with similar symptoms²². This is due to the great variety of facial pain sources, the relative rarity of TN and the absence of the specific tests for its diagnosis²³. In this sample, we examined 5 patients with a diagnosis of TN and three of them were associated with TMD. Two patients presented with neoplasias (leukemia and nasopharyngeal tumor). This shows a necessity and importance of a differential diagnosis in orofacial pain¹⁰, and demonstrated that pain may be an initial manifestation of a tumor^14,19. These cases also demonstrate the importance of the adjunctive testing such as CT and laboratory testing for diagnosis of pain. This also reinforces the fact that pain is a symptom that must be evaluated, especially when persistent, and despite treatment there is no significant improvement (5% of neuralgias can be symptomatic and secondary to tumor or neuronal diseases such as multiple sclerosis)⁷. In this study idiopathic trigeminal neuralgia was the prevalent diagnosis.

This sample includes a patient with Eagle's syndrome and another with tension-type headache. These patients also present with symptoms similar to TMD and we need know the diagnostic criteria for these disorders^14,23,24. Another difficulty is in the differential diagnosis of orofacial pain that involves psychiatric disorders and simulates organic facial pain. This was the case of two patients with psychiatric disturbances who were eventually diagnosed with hysterical conversion disorder. Diagnosis of mental health disorders is a challenge that demands careful examination by specialists¹⁶. The diagnosis of these cases was possible due the fact of they were seen in a large teaching hospital with great experience in chronic pain.

In Group III, chronic muscle pain was associated with neuropathic pain or fibromyalgia. This justifies the need for multiple therapies in some cases, and the treatment should be adjusted to the etiology. Five patients from Group III presented with musculoskeletal pain associate with other sources of pain (TN, fibromyalgia) and due to this factor, they did not improve with prior treatment. Another important point is the history of the patient's pain. In this sample, two patients with TMD also presented fibromyalgia, a condition frequently found in patients with TMD^25,26, which requires specific treatment. However, the patients presenting with muscle pain in Group III received therapeutic procedures directed at the removal of contributing factors that acted directly or indirectly to perpetuate the complaint. This included the correction of inadequate dentures, excessive loss of teeth without repositioning and parafunctional habits. The original complaints may worsen in patients with neuropathic pain due to accompanying myogenic disturbances²⁷. Invasive procedures should not be repeated when a relief of pain is not achieved (four patients in Group III had oral surgeries). The re-evaluation of the signs and symptoms is an essential step in these cases. Therefore, it is very important to have the ability to identify the various aspects of pain complaints and identify their primary causes when more than one type of pain is present as in the cases presented here.

The knowledge of the diagnostic criteria for facial pain is extremely important in the process of differential diagnosis. An accurate diagnosis leads to an effective therapeutic treatment strategy. Severe and diffuse pain, such as referred dental pain, can confuse the patient and the clinician and make the diagnostic process difficult. This often leads an incorrect diagnosis and treatment. The clinician must be prepared, and not allow the patient to influence the diagnosis, (the patient's report of the intensity of the complaint can confuse the clinician). In this way we can decrease the incidence of iatrogenic disorders and realize a more correct diagnosis, more effective treatment, and decrease the risk for chronic pain²⁸.

In conclusion, this study demonstrates a wide variability of different diagnosis for facial pain, including referred dental pain. It is important to remember that some pain conditions are uncommon (for example, tumor) and can be confused with other, more common pain conditions that are present with a typical signs and symptoms (for example, pulpitis), leading to a misdiagnosis, iatrogenesis and chronicity of the pain. In this entire sample, the cause for persistent pain was perpetuated by an incorrect diagnosis and misdirected treatment. This demonstrates that a systematic evaluation, based on specific diagnostic criteria can help to clarify the diagnoses and formulate the treatment strategies for an appropriate therapeutic regimen. Finally, an interdisciplinary team is often necessary for the diagnosis and treatment of many facial painful conditions²⁹. The data presented in this study are consistent with data reported in other studies, indicating that while most orofacial pain is benign, there are cases where it may represent serious and even life threatening disease. This study also highlights the responsibility of the general practitioner, dentist or physician, to refer difficult patients for a more detailed and specialized evaluation.

Received 15 January 2004, received in final form 23 June 2004, Accepted 9 August 2004.

^*The preliminary results of this study were presented at 8th World Congress on Pain, in Vancouver/Canada, August 1996.

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