Hypoglossal nerve palsy: 245 cases

Imaging of hypoglossal palsy: a pictorial synopsis

Palsy of the hypoglossal nerve, the 12th cranial nerve, is rare and presents with specific clinical features depending on the anatomical location of the underlying pathology. As such, knowledge of clinical presentation and detailed anatomy of the nerve is vital to aid in localisation and identification of the pathology. This pictorial review details the anatomy of the nerve, including innervation, segments, and branches, with particular reference to magnetic resonance imaging (MRI). The role of clinical examination and multimodality imaging in differentiating between types of hypoglossal palsy is highlighted. Key pathologies affecting the different nerve segments are described and illustrated on multimodality imaging.

Hypoglossal Nerve Neuropathies-Analysis of Causes and Anatomical Background

The hypoglossal nerve is the last, and often neglected, cranial nerve. It is mainly responsible for motor innervation of the tongue and therefore the process of chewing and articulation. However, tumors, aneurysms, dissections, trauma, and various iatrogenic factors such as complications after surgeries, radiotherapy, or airway management can result in dysfunction. Correct differential diagnosis and suitable treatment require a thorough knowledge of the anatomical background of the region. This review presents the broad spectrum of hypoglossal neuropathies, paying particular attention to these with a compressive background. As many of these etiologies are not common and can be easily overlooked without prior preparation, it is important to have a comprehensive understanding of the special relations and characteristic traits of these medical conditions, as well as the most common concomitant disorders and morphological traits, influencing the clinical image. Due to the diverse etiology of hypoglossal neuropathies, specialists from many different medical branches might expect to encounter patients presenting such symptoms.

The ptotic tongue-imaging appearance and pathology localization along the course of the hypoglossal nerve

CT and MRI findings of tongue ptosis and atrophy should alert radiologists to potential pathology along the course of the hypoglossal nerve (cranial nerve XII), a purely motor cranial nerve which supplies the intrinsic and extrinsic muscles of the tongue. While relatively specific for hypoglossal nerve pathology, these findings do not accurately localize the site or cause of denervation. A detailed understanding of the anatomic extent of the nerve, which crosses multiple anatomic spaces, is essential to identify possible underlying pathology, which ranges from benign postoperative changes to life-threatening medical emergencies. This review will describe key imaging findings of tongue denervation, segmental anatomy of the hypoglossal nerve, imaging optimization, and comprehensive imaging examples of diverse pathology which may affect the hypoglossal nerve. Armed with this knowledge, radiologists will increase their sensitivity for detection of pathology and provide clinically relevant differential diagnoses when faced with findings of tongue ptosis and denervation.

Yin-Yang tongue sign: An imaging clue of lesions involving the skull base segment in the hypoglossal pathway

OBJECTIVE

To investigate the diagnostic value of the Yin-Yang tongue sign in patients with tongue deviation.

METHODS

According to the presence of the Yin-Yang tongue sign on CT/MR, 107 patients with tongue deviation were divided into a positive group and a negative group. The involvement categories of the hypoglossal canal (HC) in the positive group were evaluated and classified as HC dilation and HC erosion. The correlations between HC involvement categories and the presence of the sign were analysed.

RESULTS

There were 55 cases (55/107, 51.4%) in the positive group and 52 cases (52/107, 48.6%) in the negative group. Hypoglossal nerve (HN) involvement mainly occurred in the skull base (61.8%), skull base and carotid space (10.9%), and carotid space segment (12.7%). Neurogenic (50.9%), squamous cell carcinoma (14.5%), and metastases (12.7%) were the predominant aetiologies. The sensitivity, specificity, and accuracy of this sign for suggesting skull base lesions around HC were 72.4%, 80.8%, and 76.6%, respectively. In the positive group, HC dilation was seen in 21 patients (21/55, 38.2%) and 21 cases were all benign. HC erosion were noted in 19 patients (19/55, 34.5%), of whom 12 cases were malignant.

CONCLUSION

The Yin-Yang tongue sign is formed by unilateral tongue atrophy and fat infiltration caused by lesions in the HN pathway, especially compressive or invasive lesions involving the skull base segment.

Something Got Your Tongue? A Unique Cause of Hypoglossal Nerve Palsy

Introduction

The authors report a rare cause of isolated hypoglossal nerve palsy caused by a high cervical osteophyte. This case increases clinical knowledge of an underreported condition and teaches the clinician radiologic pearls in making the diagnosis. To their knowledge, this is the first case report showing surgical remediation of this condition. Symptoms and Clinical Findings. A 73-year-old female presented with several months of occipital headache, progressive dysarthria, dysphagia, and tongue deviation to the right. Her neurologic exam was significant for atrophy of the right hemitongue with tongue fasciculations. On protrusion, her tongue deviated rightward. Diagnosis and Therapeutic Intervention. Careful review of her initial head computed tomography (CT) imaging revealed that a high cervical osteophyte caused unilateral, isolated hypoglossal nerve palsy. Neurosurgery performed a right, far lateral approach for decompression of this osteophyte and over the ensuing months her symptoms improved.

Conclusion

High cervical osteophyte is an underrecognized cause of isolated hypoglossal nerve palsy. The imaging investigation should be systematic and focus on the skull base with magnetic resonance imaging (MRI) or CT. This is a rare occasion when high resolution CT of the skull base can actually be the more helpful imaging modality. As shown in this case, an osteoarthritic cause can be surgically ameliorated.

Isolated Unilateral Hypoglossal Nerve Palsy Caused by Internal Carotid Artery Loop

Isolated unilateral hypoglossal nerve (HN) palsy caused by vascular compression is a rare condition. We report a case of a 42-year-old male, presenting with tongue paresis and unilateral atrophy of the tongue due to an internal carotid artery (ICA) loop. The compression of HN by ICA loop and concomitant wall irregularities of the loop segment were observed in magnetic resonance imaging and digital subtraction angiography (DSA). The patient was managed with antithrombotic without the need of any further intervention. To our best knowledge, this is the first reported case of isolated compressive neuropathy of the HN caused by loop of the ICA. Here, the clinical presentation, etiology, and management of isolated HN palsy caused by vascular lesions are discussed along with the relevant literature.

Hypoglossal nerve palsy after gasless trans-axillary endoscopic thyroidectomy: a case report

Background

Gasless trans-axillary endoscopic thyroidectomy (GTAET) has satisfactory cosmetic effects for the patients who have benign goiter and small thyroid carcinoma, however the complications of this surgical procedure have not been fully documented. Ipsilateral hypoglossal nerve palsy (IHNP) associated with GTAET has never been reported before.

Case presentation

A 33-year old male patient presented with a 4 × 5 mm solid thyroid nodule in the right lobe. Papillary thyroid carcinoma was confirmed by the fine needle aspiration. He had strong cosmetic demand, therefore GTAET for right lobectomy and central cervical lymphadenectomy was performed in a supine position with cervical extension. Six hours after the operation, he developed tongue deviation to the right side, speech and swallowing difficulties, indicating IHNP. Head and cervical MRI showed no abnormality. The intravenous steroid was used for three days, and oral vitamin B1 and mecobalamin was prescribed for 1 month. Nine days after surgery, he was discharged. Three months after the operation, all the symptoms were completely resolved.

Conclusions

To the best of the authors’ knowledge, this is the first case of IHNP after GTAET, which will be valuable to add our knowledge to diagnose and treat rare complications of GTAET.

Parálisis idiopática del nervio hipogloso. Descripción de un caso

Introducción: La parálisis del nervio hipogloso es una mononeuropatía poco fre-cuente. Las etiologías más habituales son la tumoral, la traumática, la isquémica cere-bral y la iatrogénica, Descripción: Presentamos el caso de un paciente con neuropa-tía idiopática del nervio hipogloso, en el que por edad, la presencia de factores de riesgo vascular, la microangiopaía cerebral y la evolución nos lleva a discutir acerca de la posibilidad de que se trate de una mononeuropatía isquémica o diabética como etiología del déficit. Discusión: En estudios publicados de parálisis idiopáticas del nervio hipogloso la edad de presentación se sitúa entre los 20 y 45 años y tienen una evolución y recuperación favorable, atribuyéndole un mecanismo fisiopatológico similar al de la paralisis de Bell. En nuestro caso la exploración física y las pruebas complementarias realizadas no mostraron etiología del déficit, encontrándonos ante un nuevo caso de parálisis idiopática del nervio hipogloso. Sin embargo por la edad del paciente, la presencia de múltiples factores de riesgo vascular, la microangiopía cerebral y la persistencia de la sintomatología nos hace plantear la existencia de un mecanismo local, isquémico o diabético, como causa de la mononeuropatía presen-tada y pensar que nos podemos encontrar ante un mecanismo fisiopatológico similar al producido en otras mononeuropatías, como la del III o VI par craneal. Conclusión: Presentamos una parálisis del nervio hipogloso idiopática, que por las característi-cas de nuestro paciente nos hace pensar y discuti una posible etiología isquémica o diabética del déficit.

Etiología de la parálisis del nervio hipogloso. Revisión sistemática

Introducción y objetivo: La parálisis del nervio hipogloso es una entidad poco frecuente, caracterizada por alteración del habla y problemas para tragar. En este estudio realizamos una revisión de las etiologías de dicho déficit.Método: Realizamos una búsqueda en pubmed, seleccionando aquellos artículos en los cuales se mencione la etiología de la parálisis del nervio hipogloso. Resultados: Dos son los estudios con gran número de pacientes. En primero de ellos, publicado en 1996 con 100 pacientes, la etiología más frecuente es la tumoral, seguida de los traumatismos y las lesiones isquémicas. En el segundo de ellos, del 2016, con 245 pacientes incluidos, la etiología principal es la iatrogénica postoperatoria, seguida de la tumoral y la idiopática.Discusión: Son pocos los estudios que recogen un número importante de pacientes con parálisis del nervio hipogloso. Los primeros datan de la década de los 90, en los cuales la principal etiología era la tumoral. En el último estudio, publicado en 2016, la primera causa es la iatrogénica postquirúrgica, seguida de la neoplásica y la idiopática. Con 20 años de diferencia entre los dos principales estudios existe un cambio en la etiología. El aumento de los casos postquirúrgicos puede ser debido a un aumento en el número de intervenciones, siendo a su vez más largas y agresivas, resultando llamativo, y de difícil explicación, el creciente número de casos etiquetados como idiopáticos.Conclusiones: La etiología de la parálisis del nervio hipogloso ha cambiado a lo largo de las décadas. En el siglo XX la principal etiología era la tumoral. En el siglo XXI la etiología principal es la iatrogénica postquirúrgica, encontrándose en segundo lugar la tumoral y en tercero la idiopática. Con la inclusión de 345 pacientes de los dos grandes artículos en la revisión sistemática podemos concluir que la primera causa de parálisis es la tumoral, seguida de la iatrogénica y la idiopática.

XROMM and diceCT reveal a hydraulic mechanism of tongue base retraction in swallowing

During primate swallowing, tongue base retraction (TBR) drives the food bolus across the oropharynx towards the esophagus and flips the epiglottis over the laryngeal inlet, protecting against penetration and aspiration of food into the airway. Despite the importance of TBR for swallowing performance, the mechanics of TBR are poorly understood. Using biplanar videoradiography (XROMM) of four macaque monkeys, we tested the extrinsic muscle shortening hypothesis, which posits that shortening of the hyoglossus and styloglossus muscles pulls the tongue base posteriorly, and the muscular hydrostat or intrinsic tongue muscle hypothesis, which suggests that, because the tongue is composed of incompressible fluid, intrinsic muscle shortening increases tongue length and displaces the tongue base posteriorly. Our data falsify these hypotheses. Instead we suggest a novel hydraulic mechanism of TBR: shortening and rotation of suprahyoid muscles compresses the tongue between the hard palate, hyoid and mouth floor, squeezing the midline tongue base and food bolus back into the oropharynx. Our hydraulic mechanism is consistent with available data on human tongue swallowing kinematics. Rehabilitation for poor tongue base retraction might benefit from including suprahyoid muscle exercises during treatment.

Hypoglossal Nerve Palsy as a Cause of Severe Dysphagia along with the Oropharyngeal Stenosis due to Occipitocervical Kyphosis

Hypoglossal nerve palsy (HNP) is a potential cause of dysphagia. A 66-year-old man presented to our hospital with dysphagia and neck pain. One year prior to his first visit, he had been diagnosed with upper cervical tuberculosis and had undergone posterior C1-2 fixation. The physical examination led to the diagnosis of dysphagia with HNP, and he had severe weight loss. Radiographic examination revealed that the O-C kyphosis had been exacerbated and that the deformity was likely the primary cause of HNP. To restore the swallowing function, O-C fusion surgery was performed. Postoperatively, the patient showed immediate improvement of dysphagia with gradual recovery of hypoglossal nerve function. In the last follow-up evaluation, swallowing function was confirmed with no signs of HNP. Our results indicate that HNP could be more prevalent in cases with severe cervical kyphosis, being underdiagnosed due to the more apparent signs of the oropharyngeal narrowing.

Hypoglossal nerve palsy as an isolated syndrome of internal carotid artery dissection: A review of the literature and a case report

A review of literature on the dissection of internal carotid artery was presented with a presentation of a rare case of patient with transient left hypoglossal nerve palsy caused by mechanic compression from intramural hematoma in higher extracranial portion of dissected carotid artery confirmed in MRI and CT scans. The clinical presentation and management are discussed.

Unilateral Hypoglossal Nerve Palsy After Septoplasty Under General Anaesthesia

Hypoglossal nerve palsy (HNP) is a rare perioperative complication. Causes of this condition are mostly attributed to oropharyngeal manipulation during airway management, suggesting injuries involving the peripheral part of the nerve. Owing to the concomitant pathways of the nerves, the hypoglossal nerve might be injured together with the recurrent laryngeal (Tapia's syndrome) or lingual nerves. The present report described a case of isolated HNP as a rare perioperative complication.

Isolated hypoglossal nerve palsy as a presenting symptom of metastatic peripheral T-cell lymphoma - not otherwise specified (PTCL-NOS): a unique case & a review of the literature

Extensive and significant technological advancements have enhanced the sensitivity and accuracy of the pathologic classification, diagnosis, and therapeutics of lymphoma. These advances have prompted a more comprehensive understanding of neoplastic behavior and have led to improvements in both treatment and prognosis. This paper presents a comprehensive review of lymphoma and features a case report of a unique presentation of peripheral T-cell lymphoma - not otherwise specified that presented with isolated hypoglossal nerve dysfunction.

Skull Base Metastasis Revealed by Bone Scintigraphy in a Patient With Hypoglossal Nerve Palsy

Even though different imaging modalities are available in sole or in combination for the optimal detection of bone metastases, whole-body bone scintigraphy (BS) in a single session seems to be advantageous. We present an 80-year-old male with unilateral left hypoglossal nerve palsy (HNP) and no other focal deficits on neurological examination. Initial brain computed tomography (CT) scan revealed no pathological findings, while the subsequent cranial CT and magnetic resonance imaging (MRI) scans uncovered only mild nonspecific sclerotic lesions in left occipital condyle. All laboratory examinations were within normal limits, except for an elevated alkaline phosphatase (170 U/L) and a markedly increased prostate-specific antigen (609 ng/mL). The patient underwent whole-body BS with technetium-99m that revealed increased radiotracer deposition compatible with metastases in multiple foci, including the left occipital condyle. Prostate biopsy confirmed the diagnosis of prostate adenocarcinoma. Our case suggests that a complete and thorough workup for hidden malignancies should be performed in all patients with HNP, even in the absence of a finding in brain neuroimaging. Bone scintigraphy is an essential investigation that should be considered in uncertain cases of HNP, and especially in those with negative CT and MRI scans.

Microvascular decompression for hypoglossal nerve palsy secondary to vertebral artery compression: A case report and review of the literature

Background:

Neurovascular-compression syndrome (NCS) is described as a prominent pathological contact between cranial nerves and vessels. Trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia are typical clinical entities associated with NCS. On the other hand, the hyoglossal nerve is rarely affected by NCS.

Case Description:

We present a case of hypoglossal nerve palsy (HNP) secondary to vertebral artery (VA) compression. A 47-year-old man presented to our hospital with a 1-month history of dysarthria and dysphagia. Neurological examination revealed left HNP, with an intact swallowing reflex and no oropharyngeal or palatal weakness. Magnetic resonance imaging (constructive interference in steady state) revealed left hypoglossal nerve compression by the V4 segment of the left atherosclerotic VA. He underwent microvascular decompression (MVD) surgery. Intraoperatively, the VA was compressing the hypoglossal nerve. The left VA was moved and attached to the dura matter using a polytetrafluoroethylene (Teflon®) sheet and fibrin glue. Postoperatively, the patient exhibited gradual recovery of HNP in 3 months without dysfunction of lower cranial nerves.

Conclusion:

In patients with isolated HNP, vascular compression should be considered as a cause of these symptoms, and subsequent MVD can lead to resolution.