SEARCH

SEARCH BY CITATION

Keywords:

  • facial pain;
  • diagnostic criteria;
  • trigeminal neuralgia;
  • persistent idiopathic facial pain

Abstract

  1. Top of page
  2. Abstract
  3. PATIENTS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Background.—Recurrent or chronic facial pain may be a diagnostic challenge. Applying the diagnostic criteria of the second edition of the International Classification of Headache Disorders (ICHD-II) leaves a considerable number of patients unclassifiable.

Objective.—The aim of this study was to establish and evaluate revised criteria of trigeminal neuralgia and persistent idiopathic facial pain.

Methods.—Based on the diagnostic value of 12 clinical features of trigeminal neuralgia and 15 features of persistent idiopathic facial in 97 patients referred for facial pain to a neurological tertiary care centre we established revised criteria for persistent idiopathic facial pain and additional criteria for probable trigeminal neuralgia and probable idiopathic facial pain.

Results.—Applying the newly proposed criteria reduced the number of patients with facial pain not classifiable by more than 50%. The new criteria improved the sensitivity, particularly in idiopathic facial pain and did not cause a relevant decrease in specificity compared to ICHD-II.

Conclusion.—This study suggests that amendments to the ICHD-II criteria improve the diagnostic classification of facial pain.

Facial pain may be caused by an underlying disease of facial structures, it may originate from cranial nerves or it may occur without detectable structural lesions.1,2 Recurrent or chronic facial pain may be a diagnostic challenge due to overlapping symptoms, complex history, or equivocal findings in the diagnostic work-up.3–6 This is particularly true for a condition known in clinical practice as “atypical facial pain” and called “persistent idiopathic facial pain” in the second edition of the International Classification of Headache Disorders (ICHD-II).1

Only a few original papers are dealing with the differential diagnoses of recurrent or chronic facial pain on a broader basis,7–9 but these studies did not apply ICHD criteria. Considering this lack of information as well as the clinical observation that the definite diagnosis remains uncertain in a considerable number of patients with facial pain, we conducted a study focusing on the diagnostic spectrum of facial pain in a neurological tertiary care centre and comparing the first and second edition of ICHD. The results of this study have been published elsewhere.10 In summary, 39% of the patients had cranial neuralgias, 21% had persistent idiopathic facial pain, 11% had other disorders such as cluster headache or symptomatic facial pain, and 29% could not be diagnosed according to ICHD-II.

Amendments to the diagnostic criteria for certain types of facial pain might be helpful to reduce the large number of patients with unclassifiable facial pain. Accordingly, the objective of this study was to evaluate the diagnostic value of alternative diagnostic criteria of trigeminal neuralgia and persistent idiopathic facial pain.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. PATIENTS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

We investigated 97 consecutive patients with recurrent or persistent facial pain referred for neurological investigation by an anaesthesiological pain clinic. The methods have been described elsewhere in detail.10 In summary, all subjects underwent a clinical interview and a clinical neurological examination and if necessary, they were referred to other specialists such as an otorhinolaryngologist, a maxillofacial surgeon, or a dentist. Plain X-rays, computed tomography, magnetic resonance imaging, or scintigraphic examinations were performed as required. All diagnoses were based on the criteria of ICHD-II.1

In order to establish modified diagnostic criteria, we calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 12 features of trigeminal neuralgia and 15 features of persistent idiopathic facial pain considering a number of features not included in ICHD-II. Sensitivity, specificity, PPV, and NPV ≥0.7 were regarded as clinically relevant. For statistical analysis SPSS 11.0 software was used.

RESULTS

  1. Top of page
  2. Abstract
  3. PATIENTS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

The sensitivity, specificity, PPV and NPV of the clinical features of trigeminal neuralgia are shown in Figure 1. The sensitivity and NPV were good to excellent for all ICHD-II criteria. The specificity was ≥0.7 in four of six ICHD-II criteria and the PPV was sufficient in three criteria. Additional clinical features of trigeminal neuralgia not included in ICHD-II (ie, daily occurrence, unilateral localization, severe or unbearable intensity, absence of pain between attacks, absence of autonomic symptoms, and presence of remission periods) did not add to the diagnostic accuracy.

image

Figure 1.—. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 12 clinical features of trigeminal neuralgia. Features in bold indicate ICHD-II criteria. Black bars indicate values ≥0.7, gray bars indicate values <0.7.

Download figure to PowerPoint

The sensitivity, specificity, PPV, and NPV of the clinical features of persistent idiopathic facial pain are shown in Figure 2. Among the ICHD-II criteria, deep and poorly localized pain had the best diagnostic value, followed by persistence of pain for all or most of the day. The other ICHD-II criteria (daily presence and unilateral localization of pain at onset) showed poor specificity and PPV. Among 11 additional features not included in ICHD-II, the absence of pain paroxysms and the absence of precipitation of pain from trigger areas or by daily activities had the best diagnostic value. In total, sensitivity and NPV were good to excellent in the vast majority of the additional clinical features of persistent idiopathic facial pain. Specificity was ≥0.7 in five features and PPV was <0.7 in all features.

image

Figure 2.—. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 15 clinical features of persistent idiopathic facial pain. Features in bold indicate ICHD-II criteria. Black bars indicate values ≥0.7, gray bars indicate values <0.7.

Download figure to PowerPoint

The diagnostic value of the features given in Figure 1 suggests that there is no need to change the criteria of trigeminal neuralgia. However, we propose an additional diagnostic category, ie, “probable trigeminal neuralgia” corresponding to probable migraine, probable tension-type headache, or probable cluster headache already established in ICHD-II (Table 1).

Table 1.—. New Proposal for Diagnostic Criteria of Probable Trigeminal Neuralgia
A. Paroxysmal attacks of pain affecting one or more divisions
 of the trigeminal nerve fulfilling all but one of criteria B–D
B. Duration lasting from a fraction of seconds to 2 minutes
C. Pain has at least one of the following pain characteristics:
 1. Intense, sharp, superficial, or stabbing
 2. Precipitated from trigger areas or by trigger factors
D. Attacks are stereotyped in the individual patient
E. Not attributed to another disorder

In contrast to trigeminal neuralgia, several features in persistent idiopathic facial pain not yet included in ICHD-II showed a good diagnostic value. Therefore, we propose an amendment to the ICHD-II criteria of persistent idiopathic facial pain (Table 2). Finally, we propose an additional diagnostic category, ie, probable idiopathic facial pain (Table 3).

Table 2.—. New Proposal for Diagnostic Criteria of Persistent Idiopathic Facial Pain
A. Pain in the face, present daily for at least 1 month and persisting for all or most of the day
B. At least four of the following five characteristics:
 1. Pain is confined at onset to a limited area on one side of the face
 2. Pain is deep and poorly localized
 3. Intensity is moderate or severe, but not unbearable
 4. Pain paroxysms do not occur
 5. Pain is not precipitated from trigger areas or by daily activities
C. Both of the following:
 1. No autonomic symptoms
 2. No sensory loss or other physical signs, but dysaesthesia may occur
D. Laboratory investigations including X-ray of face and jaws do not demonstrate relevant abnormality
Table 3.—. New Proposal for Diagnostic Criteria of Probable Idiopathic Facial Pain
A. Pain in the face fulfilling either criterion A or criterion B of persistent idiopathic facial pain (as described in Table 2)
B. Both of the following:
 1. No autonomic symptoms
 2. No sensory loss or other physical signs, but dysaesthesia may occur
C. Laboratory investigations including X-ray of face and jaws do not demonstrate relevant abnormality
D. Not attributed to another disorder

Applying this new set of criteria, 6 out of the 28 patients with facial pain not classifiable according to ICHD-II had probable trigeminal neuralgia, the number of patients with persistent idiopathic facial pain increased from 20 to 23 and 6 patients fulfilled the criteria of probable idiopathic facial pain. Accordingly, the number of patients with facial pain not classifiable was reduced from 28 (29%) to 13 (13%).

Details of the diagnostic value of the new criteria are summarized in Table 4. Adding the diagnostic category of “probable trigeminal neuralgia” increased the sensitivity and NPV and this increase outweighed the mild decrease in specificity and PPV. Amending criteria B and C of persistent idiopathic facial pain and adding the diagnostic category of probable idiopathic facial pain increased the sensitivity of criterion B markedly from 0.75 to 0.93 without decreasing the specificity.

Table 4.—. Sensitivity, Specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of the Newly Proposed Criteria of Trigeminal Neuralgia and Persistent Idiopathic Facial Pain (Tables 13) Compared to the ICHD-II Criteria
 SensitivitySpecificityPPVNPV
Definite and probable trigeminal neuralgia (n = 41)
 ICHD-II criterion A0.930.980.970.94
 Proposed criterion A (Table 1)0.980.930.910.98
 ICHD-II criteria B and C0.900.770.740.91
 Proposed criteria B, C, and D1.000.770.761.00
Definite and probable idiopathic facial pain (n = 29)
 ICHD-II criterion A = Proposed criterion A (Table 2)0.890.970.930.96
 ICHD-II criterion B0.750.990.950.91
 Proposed criterion B0.930.990.960.97
 ICHD-II criterion C1.000.180.331.00
 Proposed criterion C1.000.320.381.00

DISCUSSION

  1. Top of page
  2. Abstract
  3. PATIENTS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

In this study, we examined 97 consecutive patients referred for facial pain to a neurological tertiary care centre in order to evaluate the diagnostic value of alternative diagnostic criteria for trigeminal neuralgia and persistent idiopathic facial pain.

Applying the newly proposed criteria for probable trigeminal neuralgia, persistent idiopathic facial pain, and probable idiopathic facial pain reduced the number of patients with facial pain not classifiable according to ICHD-II by more than 50%.

The newly proposed criteria for probable trigeminal neuralgia and probable idiopathic facial pain follow the style used in ICHD-II for primary headache disorders such as probable migraine, requiring that all but one of the criteria of the definite disorder are fulfilled.

The ICHD-II criteria of persistent idiopathic facial pain were widely revised adding new features with good to excellent diagnostic value (intensity moderate or severe but not unbearable, no paroxysms, no precipitation from trigger areas or by daily activities, no autonomic symptoms). Even though it is obvious that persistent idiopathic facial pain is not associated with autonomic symptoms, the inclusion of this criterion shall improve the differentiation from trigeminal autonomic headaches (TAHs)11 considering the fact, that some patients with TAHs in our study were initially misdiagnosed as having persistent idiopathic facial pain.11 Apart from that we added a minimum period of 1 month since onset of the symptoms and included dysaesthesia as a potential symptom.12

The study is an attempt to improve the classification in an area that is still poorly defined. One may criticize the creation of probable diagnoses, but in daily clinical practice we do see patients not fulfilling the ICHD-II criteria and ICHD-II already includes probable diagnoses for migraine, tension-type headache, cluster headache, and trigemino-autonomic cephalalgias.

A new classification must be useful in research and more importantly it must be helpful for the patient and the clinician. Applying the newly proposed criteria showed a marked reduction in the number of patients with unclassifiable facial pain. This promising finding reqires further evaluation, eg, regarding the results of the diagnostic work-up as well as the response to standard treatments in order to clarify whether patients with a definite diagnosis of trigeminal neuralgia and idiopathic facial pain differ from those with a probable diagnosis. Defining clinical features of certain types of facial pain and using these definitions for further examinations is one strategy to improve our knowledge of facial pain.

Finally, the term idiopathic may give rise to criticism. This term, however, was chosen by the Headache Classification Subcommittee of the IHS1 and it reflects the current state of knoweledge. Persistent idopathic facial pain is neither a definite primary disorder nor is it definitely secondary. Future studies in idiopathic facial pain should explore the initiation of the pain secondary to trauma, the presence of allodynia or hyperalgesia, and the effect or presence of a sympathetic component.

We realize that the validity of the newly proposed criteria is limited by the fact that the improvement of the diagnostic value was shown in referral patients only, but the time until the publication of ICHD-III offers a good chance for further evaluating our proposal including prospective longitudinal studies.

REFERENCES

  1. Top of page
  2. Abstract
  3. PATIENTS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES