Neurol India Home 

Year : 2014  |  Volume : 62  |  Issue : 5  |  Page : 567--568

Hypoglossal nerve palsy: A rare consequence of dengue fever

Shantini Jaganathan, Rajagopalan Raman 
 Department of Otorhinolaryngology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia

Correspondence Address:
Shantini Jaganathan
Department of Otorhinolaryngology, Faculty of Medicine, University Malaya, Kuala Lumpur

How to cite this article:
Jaganathan S, Raman R. Hypoglossal nerve palsy: A rare consequence of dengue fever.Neurol India 2014;62:567-568

How to cite this URL:
Jaganathan S, Raman R. Hypoglossal nerve palsy: A rare consequence of dengue fever. Neurol India [serial online] 2014 [cited 2022 Jan 28 ];62:567-568
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Dengue is the most common arboviral disease caused by four antigenetically distinct dengue virus serotypes (DEN-1 to DEN-4). In recent years, neurological sequelae are being increasingly reported though exact incidence of various neurological complications is uncertain. [1] Hypoglossal nerve palsy usually appears as a sign rather than a symptom and the causes range from intracranial or extracranial space-occupying lesion, head and neck trauma, vascular abnormality, infection and autoimmune diseases. [2] Herein, we report hypoglossal nerve palsy in a case of serologically confirmed dengue fever.

A 53-year-old lady presented with sudden onset of mild dysarthria and difficulty in swallowing on day five of serologically confirmed dengue fever. Examination revealed deviation of tongue towards the left side at rest [Figure 1]a and deviation of tongue towards the right upon protrusion [Figure 1]b with normal pharyngeal sensation and bilateral gag reflex. Hematological studies showed total white blood cell count of 1800/mm 3 , hemoglobin of 12 g/dl, packed cell volume (PCV) 36% and thrombocytopenia with a platelet count 93,000/mm 3 which further dropped to a low of 35,000/mm 3 before convalescence. She was managed with intravenous fluids according to national guidelines. Once she was afebrile for more than 48 hours and platelet count was more than 50,000/mm 3 , anti-platelet was started by the medical team. However, her symptoms of dysarthria and tongue deviation persisted. Therefore, the patient was referred to our otorhinolaryngology department for opinion. We proceeded further as no mass was seen or palpable on endoscopic examination of the nasopharynx, laryngopharnx, neck and oral cavity. Computed tomography (CT) scan and magnetic resonance imaging (MRI) of head and neck [Figure 2] excluded intracranial bleed or infarct but reported base of tongue mass. Magnetic resonance angiography (MRA) revealed no vascular pathology. She was managed expectantly for isolated right hypoglossal nerve palsy, reassured and was on our monthly follow-up. The patient showed gradual improvement of swallowing and speech function over the next five months. Currently, her speech and swallowing is normal with tongue deviation to the right near normal [Figure 3].{Figure 1}{Figure 2}{Figure 3}

This report highlights two interesting issues. Firstly, it reports a rare occurrence of isolated hypoglossal nerve palsy following dengue infection. Secondly, the imaging studies of the patient were misinterpreted as tongue base mass and literature search also report similar mistakes.

The pathogenesis of neurological manifestations of dengue include: Direct neurotropic effect of dengue virus, related to systemic or metabolic complication of dengue or immune mediated. [1] Literature search shows demyelinating type of conduction defects with axonal components on nerve conduction studies also has been associated with monoenuropathies following dengue. [3] Thirteen cases of cranial palsy have been documented which included Bell's palsy and long thoracic nerve palsies till 1996. [4] Since then, few more Bell's palsy, diaphragmatic hernia secondary to phrenic nerve palsy. [3] lateral rectus palsy, occulomotor nerve. [5] palsy have been documented. Isolated unilateral hypoglossal nerve palsy is rare and the infective causes of hypoglossal nerve palsy reported to date are infectious mononucleosis streptococcal and even common cold. [2] In this patient, dengue serology was positive and all other causes for hypoglossal nerve palsy have been excluded. [2] Moreover, she gradually obtained near full recovery of her symptoms by five months just as most reported mononeuropathies associated with dengue have shown. [3],[5] To date, there is no established treatment for mononeuropathies following dengue though expectant management has shown to have a favorable outcome. [3],[5] This clear temporal relationship with dengue infection establishes the relationship between hypoglossal nerve palsy and dengue fever in our patient.

Retrospective review of MRI belonging to seven patients of clinically and/or radiologically suspected tongue base mass were studied and all patients actually showed MRI findings typical of tongue denervation: T2-weighted hyper intensity of involved hemitongue, protrusion of tongue onto oropharynx, variable fatty infiltration. [6] Therefore, the radiologist should be aware of various appearances of tongue denervation and not confuse it with base of tongue mass to avoid unnecessary biopsy in search of a tumor.


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