Diagnostic and treatment pitfalls in glossopharyngeal neuralgia: evidence from a case series

Abstract

Background: Glossopharyngeal neuralgia (GN) is a rare pain syndrome often underdiagnosed. This study aimed to assess the challenges in diagnosing GN and identify patients at risk of misdiagnosis.

Methods: Between 2010 and 2019, nine patients underwent microvascular decompression (MVD) of the glossopharyngeal nerve at two tertiary care hospitals. A retrospective analysis examined symptom characteristics, time to correct diagnosis, operative technique, and clinical outcomes. Barrow Neurological Institute (BNI) pain scores were assessed before surgery and on follow-up.

Results: Six women and three men, aged 55 ± 14.3 years, with unilateral GN were included. Pain was predominantly in the ear (otalgic type) in four patients (44.4%), the pharynx or base of the tongue (pharyngeal type) in four (44.4%), and mixed in one (11.1%). Five patients reported pain radiating to the mandible, all initially misdiagnosed with trigeminal neuralgia (TN) and treated for 2.4(± 3.1) years before presenting to our institution. One case resulted in MVD of the trigeminal nerve and subsequent thermocoagulation of the Gasserian ganglion due to persistent pain. The correct diagnosis of GN was established later in patients with otalgic or mixed pain (3.8 ± 3.4 years) compared to those with pharyngeal pain (0.5 ± 1.0 years), showing a trend (U = 17.0, p = 0.07). There was a significant association between pain radiation to the mandible and misdiagnosis (x² = 9.00, p = 0.003). Endoscopically assisted MVD via the median suboccipital subtonsillary approach was performed, resolving neurovascular conflicts with the PICA (9/9) and vertebral artery (3/9). Follow-up after 15.7(± 18.2) months showed significant pain reduction according to the BNI (preoperative BNI = 5.0 ± 0.0, postoperative BNI = 1.7 ± 1.0,t (8) = 10,CI [1.6-5.1], p < 0.001). No permanent surgery-related deficits occurred.

Conclusion: Patients with GN, especially those with predominant otalgic pain and pain radiating to the mandible, are at higher risk of misdiagnosis due to similarities with TN. Despite the rarity of GN, increased awareness of its various pain manifestations may lead to earlier correct diagnoses, which is crucial for surgical treatment.

Keywords: Facial pain; Glossopharyngeal neuralgia; Microvascular decompression; Trigeminal neuralgia; Vago-glossopharyngeal neuralgia.