The mean age of our study participants, the proportion of Classical TN to Symptomatic TN, predominant right side involvement were consistent with regional and global figures (Omoregie & Okoh, 2015, Bendtsen et al., 2019, Jainkittivong et al., 2012). Trigeminal neuralgia most often affects females compared to male (Bendtsen et al. 2019); but our study showed slight male predominance (50.8%), this is consistent with the regional report (Omoregie and Okoh 2015, O et al. 2018) This difference could be explained with the fact that males tend to seek more medical attention for their illnesses as compared to females in Sub-Saharan countries (O et al. 2018, Wharton-Smith et al. 2019, Omoregie and Okoh 2015). Symptomatic TN was commonly seen among younger patients, this is consistent with previous reports (Bahgat et al., 2011, Omoregie & Okoh, 2015). A higher proportion of our patients had a history of dental extraction, a sign of initial visit to the dental physician before the diagnosis of Trigeminal neuralgia was made. This finding is similar to report from Thailand (Jainkittivong et al. 2012) where 40.5% reported a history of tooth extraction. The mandibular nerve was the commonest branch to be affected, followed by a mixed mandibular + maxillary branch, while the ophthalmic branch was not involved in any of our study participants, which is in line with previous reports (Maarbjerg et al., 2014, Majeed et al., 2018).
The diagnosis of TN is established based on its characteristic clinical symptoms and investigations are only recommended in atypical presentations. While some of our participants primarily characterized their pain as "lancinating", "feeling of being injected with a red hot needle", "burning" and "electric shock-like" in descending order, most (26.2%) described it in mixed terms. A similar study from Thailand reported, mixed pain quality in 22.3% of TN patients, although the majority of their patients described it as sharp pain and stabbing/lancinating pain (Jainkittivong et al. 2012) The discrepancies in pain characterization could be explained by patients experience and response to an open or closed question which may lead the patient to one specific answer. All of our participants had some form of pain triggering stimuli and multiple factors were attributed by the majority while no specific factor identified in 13.1%. Clear pain triggering zone was identified in only one-third of the patients. These areas include angles of the mouth, nasolabial fold, lower mandibular edge, and lower gum on the painful side. A study from Thailand also showed among the 188 TN patient's majority reacted to multiple types of stimulus and the most common trigger was chewing (Jainkittivong et al. 2012). These findings were consistent with reports from Italy, which showed trigger zones were predominantly found around the perioral and nasal region; the authors also recommended utilizing triggers as an essential diagnostic feature of trigeminal neuralgia (Di Stefano et al. 2018).
Carbamazepine was the most commonly prescribed drug as initial treatment, while a quarter of the patients required the addition of another drug. Two patients were shifted to another drug because of carbamazepine induced adverse reaction (Garg et al. 2013) Gabapentin, clonazepam, and amitriptyline were also prescribed to those not tolerating carbamazepine (Gulur et al. 2011, Santos et al. 2013). Patients on carbamazepine reported prominent treatment satisfaction (Jainkittivong et al. 2012). The mean carbamazepine dose of the study participants was 691.8 mg, which is consistent with similar reports (Obermann 2019, Omoregie & Okoh, 2015, Bendtsen et al., 2019). We found that those patients who had history tooth extraction required a higher dose of carbamazepine compared to those without a history of tooth extraction. These findings are indicative of the potential diagnoses delay and suboptimal treatment of patients with TN experience in Ethiopia. This is parallel to previous reports showing a significant proportion of patients with TN initially visit non-neurologist health professionals (Bendtsen et al., 2019, O et al., 2018).
Symptomatic TN was commonly observed among younger patients. Similarly, two-thirds of patients with Classical TN are the age below 60 years. These findings were consistent with regional reports (Omoregie & Okoh, 2015, Bahgat et al., 2011). One (1.6%) of our study participants reported a family history of Trigeminal neuralgia. This finding was supported by a cluster of familial classic trigeminal neuralgia reported from Spain (Fernández Rodríguez et al. 2019). Individuals with the involvement of a single branch of trigeminal nerve were associated with prominent treatment satisfaction compared to patients with multiple branch involvement. However, no significant agreement was observed between treatment satisfaction and gender and history of tooth extraction, which could be attributable to the small sample size. A small proportion of our patients reported associated autonomic symptoms during episodic pain, which in line with a recently published prospective study on 158 patients with TN (Maarbjerg et al. 2014). A limitation of our study includes small sample size few patients investigated with MRI and absence of high-resolution brain MRI which can detect contact between vessel and nerve root, no electrophysiology study was performed, and failed to utilize validated treatment satisfaction scale.