Glossopharyngeal neuralgia (GN) is a rare cause of facial pain, with an incidence of only 0.2–0.7 per 100,000 people per year. ^{Reference Laha and Jannetta1} It results in lancinating electrical pain to the tongue, pharynx or ear. It was first treated by sectioning of the glossopharyngeal nerve, prior to the popularization of microvascular decompression (MVD). ^{Reference Laha and Jannetta1}

Hemi-laryngopharyngeal spasm (HeLPS) syndrome is a recently described syndrome resulting from neurovascular conflict with the vagus nerve causing episodic throat contractions and cough. ^{Reference Hu, Morrison and Honey2} The advent of neurogenic cough alone from compression of the vagus nerve has been more recently described as a separate entity. ^{Reference Honey, Krüger, Morrison, Dhaliwal and Hu3} To our knowledge, there are only eight previously reported cases of HeLPS syndrome, seven of which come from a single center. Only three of these cases occurred in conjunction with another neurovascular compression syndrome. ^{Reference Katayama, Noro and Asayama4–Reference Honey, Krüger, Rheaume, Avecillas-Chasin, Morrison and Honey6}

We describe a patient with concurrent GN and HeLPS syndrome, which was successfully treated with MVD.

A 75-year-old man presented with a 35-year history of GN, managed medically with carbamazepine and gabapentin. Relevant medical history included gastroesophageal reflux disease (GERD) and hypertension. He also described episodic coughing fits, which started at the same time as his diagnosis of GN. He was diagnosed with GERD and started on esomeprazole, resulting in a slight improvement in his coughing spells.

He presented with gradual worsening of his symptoms despite no change in his medical regimen. He described the pain as electrical and lancinating, starting at the back of his throat and radiating to his left ear and jaw. Attacks were accompanied by coughing fits and throat contractions on the affected side, with episodes occurring multiple times per day. He endorsed three different levels of pain: minor, moderate and severe. Throat contractions accompanied severe episodes. Following these episodes, he often experienced vocal hoarseness. He described no precipitating events besides drinking cold water.

His neurological examination was unremarkable, including a normal cranial nerve examination. Vocal fold function was not assessed.

MRI demonstrated a prominent loop of the left posterior inferior cerebellar artery (PICA) in contact with the lower cranial nerves on constructive interference in steady state sequences (Figure 1). Given the patient’s symptomatology and concordant imaging, we elected to proceed with MVD.

Figure 1. T2 SPACE MRI demonstrating neurovascular conflict between the lower cranial nerves and a loop of PICA. JF = jugular foramen, *PICA, solid arrow demarcates lower cranial nerves, dashed arrow demarcates neurovascular conflict. PICA = posterior inferior cerebellar artery.

Consent was obtained and the patient was put under a general anesthetic and positioned for a left-sided retrosigmoid craniotomy. Intraoperative monitoring was used to monitor vagus nerve function using endotracheal probes. Following durotomy, the arachnoid overlying the lateral cerebellomedullary cistern was incised to facilitate cerebrospinal fluid egress. We then retracted the cerebellum superolaterally and sharply opened the arachnoid over the lower cranial nerves.

We identified the lower cranial nerves and the compressive loop of PICA, which was in direct contact with the ventral aspect of the rootlets of the vagus nerve (Figure 2, upper image). Interestingly, the glossopharyngeal nerve was free from neurovascular conflict. We transposed the PICA loop away from the vagus rootlets, then placed Teflon pledgets between the vagus nerve and the transposed vessel (Figure 2, lower image). Intraoperative electrophysiology confirmed the identity of all visualized nerves. Motor responses were recorded in all rootlets of the vagus nerve.

Figure 2. (Upper) Intraoperative photograph depicting a broad-based loop of PICA in contact with the ventral aspect of the vagus nerve. (Lower) Intraoperative photograph depicting the loop of PICA having been transposed and separated from the vagus nerve by a Teflon pledget. VA = vertebral artery, IX = glossopharyngeal nerve, X = vagus nerve, XI = accessory nerve, XII = hypoglossal nerve, PICA = posterior inferior cerebellar artery, *: neurovascular conflict, T = teflon.

The patient did well post-operatively, with immediate resolution of his pain as well as his throat contractions and coughing. He was neurologically intact and discharged home on post-operative day 2.

At 1-year follow-up, the patient had sustained resolution of his symptoms. He suffered no neurological deficit or complicating features. The patient provided feedback on his outcome, stating that he “had his life back.”

This case report provides support to the existence of the newly described HeLPS syndrome. A unique feature of the presented case is that the pathology all seemingly occurred secondary to compromise of the vagus nerve, with no evident neurovascular compromise of adjacent cranial nerves at the time of surgery. The offending vessel in this case was a prominent loop of PICA in contact with all rootlets of the vagus nerve.

Despite having no compromise of the glossopharyngeal nerve, the patient’s GN symptoms could be fully explained by crossover of the glossopharyngeal pain fibers into the vagus nerve. After the technique of neurectomy was first described in GN, it was noted that transection of the glossopharyngeal nerve alone was not successful in all cases. ^{Reference Stowell and Gardner7} It was determined subsequently that the pain fibers of the glossopharyngeal nerve can cross over to the upper rootlets of the vagus nerve. ^{Reference Krüger, Dong and Honey8} In our case, the patient had classical GN pain despite no neurovascular compromise of the glossopharyngeal nerve, which is likely explained by this phenomenon. The GN symptoms fully resolved following MVD of the vagus nerve.

This patient had both coughing episodes and episodic throat contractions, often overlying the episodes of GN pain. While cough is not uncommon, being present in up to 20% of patients with GN, ^{Reference Krüger, Dong and Honey8} the episodic throat contractions as well as the temporal relationship with GN pain suggest a common etiology related to the vagus nerve itself. The vagus nerve is usually organized with sensory rootlets most rostral, followed by motor rootlets, and parasympathetic rootlets most caudal. ^{Reference Krüger, Dong and Honey8} In some patients, the more rostral rootlets carry both motor and sensory fibers, dubbed “type B” vagus nerve. ^{Reference Krüger, Dong and Honey8} On intra-operative neurophysiological testing, our patient had motor signal from the rostral rootlets, implying a “type B” configuration, which may explain the overlap between the coughing and throat contractions. Given that the glossopharyngeal nerve was free of vessel compromise, the symptoms experienced by our patient likely all had common origin in the more rostral rootlets of the vagus nerve.

This is a rare case of co-incident GN and HeLPS syndrome, both occurring secondary to neurovascular conflict of the vagus nerve that resolved following MVD. This case provides evidence of the recently proposed HeLPS syndrome. It illustrates the complexity of vagus nerve pathology and that it may be multifaceted and patient dependent.