Clinical Profile and Treatment Outcome of Patients with Trigeminal Neuralgia: A Retrospective study in a Tertiary Hospital of Eastern Nepal

Introduction: Neuropathic orofacial pain is common non-dontogenic pain. Diagnosis relies primarily on history taking with less of pathologic change visible. Trigeminal neuralgia (TGN) is a common neuropathic pain affecting the maxillofacial region of fifth cranial nerve (V). Objective: To assess clinical characteristics, effective therapeutic regimen, side effect, radiographic and laboratory investigation in Trigeminal neuralgia patients. Methods: Retrospective study included all patients visiting the department with records from 2014 to 2021. After ethical approval for study, eighty patients were diagnosed based on ICHD3 criteria. Patient with atypical feature with sensory deficit underwent CT OR MRI to rule of mass or lesion along the cerebello-pontine angle recess and other organic cause. The data were analysed using SPSS version 11.5 and Microsoft Excel 2017. Results: A total of 80 patients were retrieved. The common side affected were right 46 (57.5%) followed by left 28 (35%), bilateral four (5%) and anterior region two (2.5%). The most common branch involved was mandibular followed by maxillary branch and combination. Management was primarily done by carbamazepine (CBZ) or in combination. Common side effects were drowsiness, dizziness, nausea and diplopia. CT scan and MRI showed space occupying lesion in three cases. Refractory cases underwent neurolysis and symptomatic and few classical TGN cases were sent for surgical management. Conclusions: Diagnosis of Trigeminal neuralgia is primarily based on clinical characteristic due to high cost and unavailability of imaging and nerve testing. Treatment is by single or multiple drugs with adjunct therapy.


INTRODUCTION
Orofacial pain is one of the most common cause for a patient to visit a dental hospital.Neuropathic pain is one of the causes, whose diagnosis relies primarily on history taking as there is less of pathologic change seen clinically.Trigeminal neuralgia (TN) or Fothergill's disease has been described as among the most painful orofacial pain of neuropathic origin.2][3][4] The annual incidence of TN is 4 to 5/ 100,000. 3TN affects one or more sensory branches of the trigeminal nerve, mostly the second or third division. 4,6Three clinical types as per ICHD-3 are-classic, idiopathic and symptomatic.[9] The objective of the study was to describe the clinical characteristics, effective treatment regimen and side effects in Trigeminal neuralgia patients.On extensive literature review there were few case series and case report from Nepal and hence the study was planned. 9

METHODS
The study was conducted after ethical approval from the institutional review committee of B.P Koirala

RESULTS
The study included 80 patients who met the inclusion criteria.Sample age range was 23 to 84 years old with mean of 56.13± 13.35 years.Age categorisation: there were 38 (40%) patient below 50 years and 42 (60%) above 50 years.There were 35 (43.2%) male and 45 (56.2%) were female with female to male ratio of 1.28.The common side of face involvement was right 46 (57.5%) followed by left 28 (35%), bilateral four (5%) and anterior region two (2.5%).The duration of pain at the time of

DISCUSSION
0][11]18 The findings in this study regarding TN are in agreement with most aspects of reports in other population groups.
Age of onset in this study was 56.13±13.35]18 Though, younger age patient in second decades were found to be affected and need a detailed neurological assessment to exclude associated secondary cause.
Right side of the face was affected more frequently than the left side can be attributed to narrow foramen rotundum and foramen ovale on right side.This observation is consistent with most reports. 2,8,10,18,22In present study, there was no sex difference regarding the side of the face involved.Bilateral involvement was a rare occurrence. 8,10,18Five percent of study sample had bilateral involvement which is lower than the incidence of 6.8% reported in Singaporean population by Loh et al. 10 Mandibular branch was the most frequently involved followed by maxillary and ophthalmic as reported by Loh et al. and Jainkittivong et al. 10,18 In contradiction other research reveal the most affected branch to be maxillary division; 8,13,14,18 Surprisingly, we found higher frequency of combinations of two or three branches and bilateral involvement in 13 (16.25%)Duration of treatment 2 months to 22 years which was higher than the previous studies .8,13,18Branch involved were confirmed by giving the respective nerve block, supratrochlear nerve block caused pain relief in 1 patient.Bilateral or multiple branches of cranial nerve involvement, sensory deficient and absence of corneal reflex is suspicious for secondary neuralgia study by Bagheri et al. 1,9,12,23.We observed that overtime; the single branch may involve two or more branches and sometimes the contralateral side.18 American Academy of Neurology and the European Federation of Neurological Societies recommend carbamazepine (CBZ) and oxcarbazepine (OXC) as the first drug of choice in (TN).10 Carbamazepine was more effective but overtime are found to need higher dose due to self-induction.Oxycarbazepine was used at a substitute or as alternate basis as night dose when side effect developed. Gabapntin was considered as drug of choice when allergic to carbamazepine.
Studies show that Oxcarbazepine has equivalent efficacy to carbamazepine and is well tolerated with lesser adverse effects and was used in cases with altered liver function to carbamazepine. 21In refractory cases, oxcarbazepine 600-1800 mg was useful alternative for the treatment of TN as in other studies by Zakrewska et al. 22,23 Cases with partial response or intolerable adverse effect were treated with combined medications such as carbamazepine with gabapentin300-1800mg or pregabalin75-300mg or baclofen20-60mg or lamotrizine 25-100mg or amitriptyline 10-25mg etc. [21][22][23] Younger patient unresponsive to gabapentin were given baclofen.
Pregabalin has lesser adverse effect and as effective as gabapentin when prescribed in this patient.Lamotrigine was used as second drug when pregabalin, gabapentin and baclofen were ineffective.The third drugs used in combination was amitriptyline and nortryptylline The common side effect was drowsiness and dizziness to Maharjan et al: Clinical Profile and Treatment Outcome of Patients with Trigeminal Neuralgia: A Retrospective study in a Tertiary Hospital of Eastern Nepal January 2014-October 2021.A proforma including detailed history on demographics, branch of nerve, severity using numeric rating scale (NRS), trigger zone, clinical types, radiographic and laboratory investigation, single or combination of medical therapy, physiotherapy, Transcutaneous Electric Nerve Stimulation (TENS), alcohol nerve block and referral for surgical treatment were recorded.Finding of clinical examination of trigeminal nerve including sensory, motor and corneal reflex with oral soft and hard tissue examination, pulp vitality testing and panoramic imaging done to rule out somatic cause were recorded.Patients with refractory or secondary feature with no corneal reflex and sensory deficient underwent CT or MRI to rule out mass or lesion along the cerebello-pontine angle recess and other organic cause. 1,2Patient were diagnosed with trigeminal neuralgia as per International Classification of Headache Disorders, 3rd edition, from the International Headache Society (ICHD-3/IHS) 4 as: paroxysmal attacks of pain affecting the trigeminal nerve, the pain can be described as sudden, superficial, or stabbing,-the attacks are similar among patients and no neurologic disorder is clinically evident.Deficient data having insufficient clinical recording and patient with unknown response to treatment were excluded.The complete blood count (CBC), liver function tests (LFT), and peripheral blood smear (PBS) and in elderly sodium/potassium were done as baseline investigation and on follow-up were recorded.The medical management done: drugs and its combination used, side effect of drugs, TENS therapy given, alcohol nerve block and neurosurgical management were recorded.The data were coded and entered in MS excel sheet and exported to SPSS software (version 11.5) for statistical test.The frequencies and percentage, Mean, median and standard deviation (SD) were used for descriptive analysis.
diagnosis was three days to 20 years.The most common trigeminal branch involved were mandibular branch 34 (42.5%) was followed by maxillary branch 33 (41.25%) and combination in 13 (16.25%) in which one involved ophthalmic branch.The mean pain severity in numeric rating scale (NRS) was 8.93±1.09,most having severe pain in 77 (96.2%) patients.Trigger zones were more frequently present extraoral in 62% of cases on the face and jaw and subsequently intraoral in 38% in the teeth and alveolus (Figure 1), 19 (23.75%) cases had multiple sites involved intraoral or extraoral or both.The clinical types of trigeminal neuralgia were classical 52 (65.0%), idiopathic 19 (23.8%), and symptomatic nine (11.3%) as in (Table 1

CONCLUSION
Trigeminal neuralgia is mostly seen neuropathic orofacial pain in elderly patients.Pain may originate in the extraoral and intra oral region.History and characteristic pain features is the mainstay of diagnosis due to high cost and unavailability of imaging and nerve testing.Medical management is first line of treatment unless secondary type.Carbamazepine is drug of choice for treatment and if ineffective use of combination two or more of drugs along with physiotherapy, neurolysis and neurosurgery is recommended.Regular monitoring for possible side effects from drugs is mandatory.Delayed and incorrect diagnosis leads to unnecessary dental intervention.Prospective study on clinical profiling, MRI findings and treatment outcome with larger sample size is recommended.Exploration on surgical outcome procedure in refractory cases including cryotherapy, laser therapy, peripheral neuroectomy, radiofrequency thermocoagulation and microvascular decompression can be assessed.Long term follow-up to find out the effect of single or combination treatment and adjunct on pain and the duration of effectiveness of medical management can be further researched.

Table 1 :
). Distribution of frequency of different socio-demographic characteristics.

Table 2 :
Different therapeutic regimen and associated drugs side effects.