Trigeminal neuralgia: diagnostic criteria, clinical aspects and treatment outcomes. A retrospective study

Pathways to a diagnosis of trigeminal neuralgia: a qualitative study of patients' experiences

BACKGROUND

Trigeminal Neuralgia (TN) is a rare disorder which causes episodes of intense facial pain and has been described as the 'suicide disease'. Hence, prompt diagnosis and timely initiation of treatment is vital. However, delays to diagnosis and high rates of misdiagnosis are common, particularly within primary care. To date, most research has focused upon treatment options rather than improving diagnostic experiences. This study sought to explore patients' experiences of the events leading up to their TN diagnosis and their views about the care and support they received when they were diagnosed to provide recommendations for improving the TN diagnostic pathway.

METHODS

This was a qualitative, exploratory study using in-depth interviews. Interviews were conducted with (n = 25) UK-based people with TN recruited via online forums. Data were analysed thematically.

RESULTS

Following the onset of their TN pain, most participants described an arduous and uncertain journey to diagnosis, with many encountering significant delays, misdiagnoses and receiving inappropriate referrals and treatment. As a consequence, participants reported experiencing profound distress, anxiety, depression and, in extreme cases, suicidal ideation; some also described drug and alcohol misuse during this time. Most participants conveyed relief upon finally receiving a diagnosis. However, this was often by eclipsed by what they saw as poor and insensitive communication and inadequate information provisioning.

CONCLUSIONS

The present study highlights the importance of developing bespoke training for primary care and other professionals to facilitate timely recognition of TN symptomatology and ensure that they deliver a TN diagnosis in clear, sensitive and empathetic ways.

Pathogenesis, Diagnosis, and Management of Trigeminal Neuralgia: A Narrative Review

Trigeminal neuralgia (TN) is an excruciating neurological disorder characterized by intense, stimulus-induced, and transient facial stabbing pain. The classification of TN has changed as a result of new discoveries in the last decade regarding its symptomatology, pathogenesis, and management. Because different types of facial pain have different clinical therapy and neuroimaging interpretations, a precise diagnosis is essential. Diagnosis should include magnetic resonance imaging with specific sequences to rule out secondary causes and to identify possible neurovascular contact. The purpose of demonstrating a neurovascular contact is to aid in surgical decision making, not to validate a diagnosis. Microvascular decompression is the first-line procedure for individuals who do not respond to medical management, whereas carbamazepine and oxcarbazepine are the preferred medications for long-term care. New developments in animal models and neuroimaging methods will shed more light on the biology and etiology of TN. This paper reviews the pathogenesis, the clinical features, the diagnosis, and the management of TN. Furthermore, the potential role of low-intensity pulsed ultrasound in neurological disorders is discussed.

Evaluation of transcutaneous electrical nerve stimulation as an adjunct therapy in trigeminal neuralgia - a randomized double-blind placebo-controlled clinical study

BACKGROUND

Trigeminal neuralgia (TN) is a severe form of pain that affects the daily activities of a patient. Transcutaneous electrical nerve stimulation (TENS) therapy is an emerging option for the treatment of acute and chronic pain. The aim of this study was to evaluate the effect of TENS therapy as an adjunct to drug therapy for the treatment of TN.

METHODS

A total of 52 patients diagnosed with TN according to the International Classification of Headache Disorders (version 3) were included. Each patient was randomized to either the TENS or placebo TENS groups. Intervention was given in continuous mode and 100-Hz frequency for 20 mins biweekly for 6 weeks. Parameters were measured at baseline, TENS completion and 3 months, 6 months, and 1 year of follow up. The parameters observed were mean carbamazepine dose, mean visual analog scale (VAS) score, mean present pain intensity (PPI) score, and functional outcome. Non-parametric analyses, one-way ANOVA and the Kruskal-Wallis test were applied for intragroup comparisons, while the Mann-Whitney U test and independent t-test were used for intergroup comparisons of variables. The chi-square test was applied to analyze categorical data.

RESULTS

Compared to the placebo TENS group, the mean dose of carbamazepine in the TENS group was significantly reduced at TENS completion, as well as at 6 months and 1 year follow up. Changes in mean VAS score, mean PPI score, and functional outcome did not show significant differences between the groups (P>0.05).

CONCLUSION

TENS therapy does not lead to any changes in pain levels but it may reduce the mean dose of carbamazepine when used as an adjunct treatment in patients with TN.

No Association of Polymorphisms in Nav1.7 or Nerve Growth Factor Receptor Genes with Trigeminal Neuralgia

OBJECTIVE

Trigeminal neuralgia is defined as a sudden severe shock-like pain within the distribution of the trigeminal nerve. Pain is a subjective experience that is influenced by gender, culture, environment, psychological traits, and genes. Sodium channels and nerve growth factor play important roles in the transmission of nociceptive signals and pain. The aim of this study was to investigate the occurrence of Nav1.7 sodium channel and nerve growth factor receptor TrkA gene polymorphisms (SCN9A/rs6746030 and NTRK1/rs633, respectively) in trigeminal neuralgia patients.

METHODS

Ninety-six subjects from pain specialty centers in the southeastern region of Brazil were divided into 2 groups: 48 with classical trigeminal neuralgia diagnosis and 48 controls. Pain was evaluated using the visual analog scale and multidimensional McGill Pain Questionnaire. Genomic DNA was obtained from oral swabs in all individuals and was analyzed by real-time polymerase chain reaction.

RESULTS

No association was observed between evaluated polymorphisms and trigeminal neuralgia. For allele analyses, patients and controls had similar frequencies for both genes. Genotype distribution or allele frequencies of polymorphisms analyzed here did not correlate to pain scores.

CONCLUSIONS

Although no association of evaluated polymorphisms and trigeminal neuralgia diagnosis or pain severity was observed, our data do not exclude the possibility that other genotypes affecting the expression of Nav1.7 or TrkA are associated with the disease. Further studies should investigate distinct genetic polymorphisms and epigenetic factors that may be important in expression of these molecules.

Characterizing Treatment Utilization Patterns for Trigeminal Neuralgia in the United States

BACKGROUND AND AIM

Trigeminal neuralgia (TN) is a rare orofacial disorder characterized by severe unilateral paroxysmal pain in the region of the fifth cranial nerve. Clinical guidelines recommend carbamazepine (only US Food and Drug Administration-approved drug for TN) and oxcarbazepine as first-line therapies. We utilized the US Truven Health MarketScan database to examine treatment patterns among patients with TN.

METHODS

Included patients were aged 18 years and above, newly diagnosed with TN (≥2 TN diagnoses ≥14 days apart; no diagnosis in the previous year), continuously enrolled 1 year before index, with ≥3 years' follow-up postindex. We assessed utilization of selected pharmacotherapies (carbamazepine, oxcarbazepine, pregabalin, gabapentin, baclofen, duloxetine, topiramate), surgery (posterior fossa, radiosurgery), and injections (peripheral anesthetic injections, Gasserian ganglion procedures) for TN.

RESULTS

In total, 3685 patients were included (2425 commercial, 1260 Medicare; 71.8% female; age, mean [SD], 59 [15] y). Overall, 72.5% of patients received at least 1 studied medication, most commonly carbamazepine (51.7%) or gabapentin (48.6%). In total, 65% of pharmacologically treated patients had ≥2 treatment episodes; 41.6% had ≥3 (defined by a change in pharmacotherapy [monotherapy/combination] regimen). Overall, 12.3% had surgery and 7.3% injections; 42.9% received opioids for TN.

CONCLUSIONS

In the 3 years after diagnosis, patients with TN in the United States receive a variety of pharmacological treatments, including opioids, despite carbamazepine being the only approved medication. A notable proportion utilize surgeries/injections. A high proportion of pharmacologically treated patients receive multiple treatment episodes, suggesting frequent therapy switching, perhaps because of suboptimal efficacy/tolerability. Our data suggest a high burden of illness associated with TN.

Trigeminal Nerve Root Demyelination Not Seen in Six Horses Diagnosed with Trigeminal-Mediated Headshaking

Trigeminal-mediated headshaking is an idiopathic neuropathic facial pain syndrome in horses. There are clinical similarities to trigeminal neuralgia, a neuropathic facial pain syndrome in man, which is usually caused by demyelination of trigeminal sensory fibers within either the nerve root or, less commonly, the brainstem. Our hypothesis was that the neuropathological substrate of headshaking in horses is similar to that of trigeminal neuralgia in man. Trigeminal nerves, nerve roots, ganglia, infraorbital, and caudal nasal nerves from horse abattoir specimens and from horses euthanized due to trigeminal-mediated headshaking were removed, fixed, and processed for histological assessment by a veterinary pathologist and a neuropathologist with particular experience of trigeminal neuralgia histology. No histological differences were detected between samples from horses with headshaking and those from normal horses. These results suggest that trigeminal-mediated headshaking may have a different pathological substrate from trigeminal neuralgia in man.

Surgical variation of microvascular decompression for trigeminal neuralgia: A technical note and anatomical study

Background:

In this article, the authors described their experience in microvascular decompression for trigeminal neuralgia.

Methods:

The microvascular decompression technique used in the authors’ institution is described in a step by step manner with some illustrative cases as well as a cadaver dissection to highlight the differences with other previously described techniques.

Results:

Since 2013, 107 patients were operated in the Neurosurgery Division of the University of São Paulo using the described technique, with a shorter operative time and avoiding cerebellar retractor compared with classic techniques.

Conclusion:

Our modified microvascular decompression technique for trigeminal neuralgia can be used with safety and efficiency for treating trigeminal neuralgia.

Trigeminal neuralgia: a retrospective multicentre study of 320 Asian patients

OBJECTIVES

This study was performed to obtain the clinicodemographic data regarding patients with trigeminal neuralgia (TN) treated at oral-maxillofacial medicine clinics, as there is a paucity of such information in the Asian setting.

STUDY DESIGN

Retrospective multicenter study involving clinicodemographic information of 320 patients with TN diagnosed between 2001 and 2012 at eight regional oral-maxillofacial medicine clinics and followed up for at least 6 months. Statistical tests were performed to assess the associations among the clinicodemographic factors.

RESULTS

TN was mostly diagnosed during the seventh and sixth decades of life, with a median of 58.2 years (interquartile range = 13.0). Females were more commonly affected (61.6%). TN affected the right side more frequently, and the mandibular branch was most commonly involved (58.5%). Carbamazepine was the first-line drug of choice (87.5%).

CONCLUSIONS

Asian patients with TN exhibited features similar to those in Caucasian patients except for the increased affliction of the mandibular division.

Microvascular Decompression for Trigeminal Neuralgia: The Role of Mechanical Allodynia

OBJECTIVE

This study was conducted to determine whether mechanical allodynia (MA) acts as a predictor of outcome after microvascular decompression (MVD) for trigeminal neuralgia (TN) and to discuss the potential pathologic mechanisms involved.

METHODS

A series of 246 patients who underwent MVD for TN were involved in the study. The classifications were based on the characteristic of pain (shocklike or constant), and the presence of MA was defined from the chart review, retrospectively. Surgical outcomes are defined as excellent, good, or poor. Immediate and long-term outcomes were compared to provide the information on recurrence and delayed relief. The relationship among the groups was investigated, and the strength was determined.

RESULTS

The presence of MA and the type of TN pain are significant predictors of surgical outcome (P < 0.05). MA was proved to be an independent predictor of surgical outcome and a significant predictor of existence of neurovascular compression (P < 0.05) and lower rate of recurrence (P < 0.05). No statistically significant predictors of delayed relief were detected in this study.

CONCLUSIONS

The presence of MA is a reliable predictor of immediate and long-term outcome after MVD for TN. Compared with the patients without MA, the incidence rate of intraoperative neurovascular compression was higher in MA-positive patients, who were more likely to achieve a better outcome and lower rate of recurrence after MVD for TN. Application of the information in this study will be helpful in patient selection of MVD for TN.

Diagnosis, medication, and surgical management for patients with trigeminal neuralgia: a qualitative study

Background

Trigeminal neuralgia (TN) is a serious health problem, causing brief, recurrent episodes of stabbing or burning facial pain, which patients describe as feeling like an electric shock. The consequences of living with the condition are severe. There is currently no cure for TN and management of the condition can be complex, often delayed by misdiagnosis. Patients’ qualitative experiential accounts of TN have not been reported in the literature. Capturing subjective experiences can be used to inform the impact of the condition on quality of life and may contribute to a better understanding of current clinical practice with the aim of improving patient care.

Methods

Participants with TN (n = 16; 11 female), including those who have and have not undergone surgical intervention(s), took part in one of four focus groups. We conducted a thematic analysis within an essentialist framework using transcripts.

Results

The impact of TN and treatment on the lives of participants emerged as four predominant themes: (1) diagnosis and support with TN, (2) living in fear of TN pain, (3) isolation and social withdrawal, and (4) medication burden and looking for a cure. Each theme is discussed and illustrated with extracts from the transcripts.

Conclusions

Key issues to address in the management of patients with TN include continued delays in diagnosis, persistent side effects from medication, and a lack of psychological support. Developing strategies to enhance the management of patients with TN, informed by a biopsychosocial approach and multidisciplinary team working, is essential to enhancing the provision of current care.

Immediate analgesic effect of 8% lidocaine applied to the oral mucosa in patients with trigeminal neuralgia

BACKGROUND

Trigeminal nerve block is widely used for trigeminal neuralgia (TN), though with much painful procedure and potential serious complications. The pain of TN occurs most frequently in the second and the third divisions of the trigeminal nerve, which are distributed in intraoral mucous membrane as well as face skin. Here, we examined the response to intraoral application of 8% lidocaine (LDC) in patients with oral TN pain in a double-blind, placebo (PBO)-controlled crossover study.

METHODS

Twenty-four outpatients with oral TN pain were randomized to receive intraoral application of either 8% LDC or saline PBO to the painful area. Following 7-days period, patients were crossed over to receive the alternative treatment. The pain was assessed with a numerical rating scale (NRS) before and 15 minutes after treatment. Patients used a descriptive scale to grade pain outcome and were asked to note any recurrence and the latency for recurrence after therapy.

RESULTS

Intraoral LDC, but not PBO, significantly decreased the NRS from 5 (4, 8) (median [25, 75 percentiles]) to 1 (0, 4) (P = 0.001). Of the 24 patients, 19 described marked or moderate relief of pain after LDC but only three described the same after PBO application. The effect of LDC and PBO persisted for 2.8 (0.3, 3.0) and 0 (0, 0) hours, respectively.

CONCLUSIONS

Intraoral application of 8% LDC produced prompt analgesia without serious side effects in patients with TN who presented with severe intraoral pain.

Sensory nerve conduction and somatosensory evoked potentials of the trigeminal nerve in horses with idiopathic headshaking

BACKGROUND

Idiopathic headshaking (HSK) in horses is a distressing disorder in which the etiology and pathophysiology are unknown.

HYPOTHESIS

Differences in sensory function of the trigeminal nerve exist between healthy and affected horses.

ANIMALS

Six healthy mature geldings and 6 mature geldings with idiopathic HSK.

METHODS

Prospective study. Sensory nerve action and somatosensory evoked potentials studies were performed. The stimulus site comprised the gingival mucosa dorsal to the maxillary canine. A pair of recording electrodes was placed along the sensory pathway of the trigeminal complex at the infraorbital nerve (R1), maxillary nerve (R2), spinal tract of trigeminal (R3), and somatosensory cortex (R4). Sensory nerve action potential latency (ms), amplitude (μV), duration (ms), area under the curve (μVms), and conduction velocity (m/s) were calculated.

RESULTS

Threshold for activation of the infraorbital branch of the trigeminal nerve was significantly different between 5 affected (≤ 5 mA) and 6 control horses (≥ 10 mA). After initiation of an action potential, there were no differences in all parameters measured and no differences between left and right sides. A horse with seasonal HSK tested during a time of no clinical manifestations showed a threshold for activation similar to control horses.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study confirms involvement of the trigeminal nerve hyperexcitability in the pathophysiology of disease. Further, results might support a functional rather than a structural alteration in the sensory pathway of the trigeminal complex that can be seasonal. The horse could serve as a natural animal model for humans with idiopathic trigeminal neuralgia.