Abstract
Ipsilateral headache associated with hypoglossal nerve palsy is uncommon and is usually reported to be secondary to internal carotid artery dissection. Herein, we report three idiopathic cases of berign ipsilateral headache with hypoglossal nerve palsy.
Keywords
Introduction
Idiopathic hypoglossal nerve (HN) palsy is uncommon and may represent a phenomenon similar to Bell's palsy. Headache associated with unilateral HN palsy has been reported but is usually secondary to internal carotid artery dissection. We report three idiopathic cases of unilateral hypoglossal nerve palsy with ipsilateral headache.
Case reports
Case 1
A 55-year-old man had a 3-day history of severe, intermittent, non-throbbing, left, parietal headache following construction work, rated 10 out of 10 in severity. He noticed left-sided tongue weakness and complained of a non-painful leathery sensation in his tongue and throat. There were vague swallowing and chewing difficulties that persisted for 3 months with minimal improvement. He took aspirin, paracetamol, pantoprazole and an occasional ibuprofen. He reported visual aura, without headache, occurring rarely in the preceding year, but was otherwise well.
On examination, his left tongue was noted to be atrophic with some fasciculations. He had symmetrically decreased reflexes in the upper extremities and symmetrically increased reflexes in the lower extremities with no sensory level. There was moderate weakness with tongue protrusion and leftward deviation. There was no temporal artery tenderness and no visible or palpable lesions.
Electromyography of the tongue showed localized active denervation. Brain magnetic resonance imaging (MRI) with thin sections through the skull base, with and without gadolinium, as well as computed tomography (CT) imaging of the head and intracranial magnetic resonance angiography (MRA) were normal. Extracranial MRA showed right greater than left internal carotid artery tortuosity, but no evidence of dissection. Flexible scope examination of the pharynx and larynx and repeat otolaryngological exams were also normal. Erythrocyte sedimentation rate (ESR), antinuclear antibody (ANA), antiextractable nuclear antigen (ENA) antibodies
Nine months later, the tongue weakness and headaches resolved and, on examination, he had minimal residual tongue weakness. There was no recurrence at 20 months. The leathery sensation in his throat persisted.
Case 2
A 64-year-old man developed a severe, left frontal, continuous, dull, throbbing headache. He recalled a viral upper respiratory tract infection 1 month previously, which had resolved. He visited the local emergency department for his headache, approximately 1 month after onset, and noticed that he could not push his tongue into his left cheek or whistle and also had some tongue numbness. He had a remote past history of migraine with his last migraine occurring 6 years ago. He had moderate tongue weakness, with many fasciculations of the left side of the tongue, and moderate symmetric hyperreflexia of the biceps, quadriceps and gastrocsoleus. Normal investigations included an ESR, C-reactive protein (CRP), ANA, TSH, liver function tests, acetylcholine receptor binding antibody screen, urine heavy metal screen, head CT and CT angiogram, brain MRI with and without gadolinium, intracranial and extracranial MRA, cerebrospinal fluid (CSF) examination and swallowing evaluation.
He was given prednisone for a possible postviral syndrome and his headache resolved. After 2 weeks, the prednisone was stopped and his headache recurred. He was restarted on prednisone for an additional 3 weeks and the headache once again resolved. The prednisone was discontinued a second time. At this point, readministration of prednisone was no longer efficacious in relieving his headache, which then resolved with 300 mg thrice daily gabapentin. His tongue weakness did not progress but he was left with articulation deficits that were subjectively improving.
Case 3
A 68-year-old female presented with right occipitoparietal headaches that radiated anteriorly. This happened twice per year for 2 years until she finally sought medical attention for right-sided tongue weakness that accompanied the headache. She presented with speech changes and was thought to have had an ischaemic event, although no aetiology was found for her symptoms. Her symptoms failed to resolve with oxcarbazepine or clonazepam, but her headache improved with an occipital nerve block with oral prednisone and, later, with oral prednisone alone.
She had two more attacks of headache, 3 and 4 months later. Her tongue weakness did not improve. Although she denied frank dysphagia, she had lost 9.1 kg over the 5 months following her hypoglossal neuropathy. She also complained of dry eyes, requiring eye drops, and dry mouth with no recognizable cause.
Normal investigations included CT of the head and skull base, MRI of the head with and without gadolinium, MRI of the cervical spine, intracranial MRA, CRP, ANA, ACE, double-stranded DNA, ENA, ANCA, paraneoplastic panel, TSH and CSF examination. The sedimentation rate was mildly elevated once at 22, but repeat testing was normal. Right temporal artery biopsy was normal. Extracranial MRA show mild tortuosity of the mid cervical vertebral arteries bilaterally and a possible focal area of narrowing of the left vertebral artery 1 cm distal to its origin.
Discussion
Ipsilateral headache and hypoglossal nerve palsy rarely occur together, and when both occur simultaneously they are unlikely to be the patient's only symptoms. Just over 20 cases of ipsilateral headache and hypoglossal neuropathy, in the absence of other symptoms, have been reported to date. In the reported literature, spontaneous internal carotid artery (ICA) dissection is the most common aetiology of concurrent ipsilateral headache and hypoglossal nerve palsy, accounting for nearly half of the cases (1–4). In contrast, the most common aetiology of isolated hypoglossal neuropathy without headache is tumour (5, 6).
In the above patients, an isolated, reversible hypoglossal nerve palsy, similar to a Bell's palsy of the seventh cranial nerve, was diagnosed. Reversible hypoglossal nerve palsy, although recognized for more than a century (7), receives little attention in the neurological literature, probably because an isolated hypoglossal nerve palsy has historically heralded a grave diagnosis and is far less common than an isolated neuritis of the seventh or third nerves. However, it should be noted that 15% of hypoglossal nerve palsies are reversible (5) and these are probably due to a viral aetiology.
Patients often experience a good recovery. A case series (6) of nine patients with HN palsy found that four patients in whom a cause could not be identified experienced full recovery within 5 months. Three of the four idiopathic cases had continuous occipital pain as the initial symptom. An additional series (8) of three patients with HN palsy and no headache reported all patients to have an excellent outcome.
The aetiology of headache in idiopathic unilateral hypoglossal neuropathy with ipsilateral headache is unclear. The meningeal branch of the hypoglossal nerve carries sensory information from the posterior fossa and synapses in the upper cervical dorsal horn. Inflammation in that branch could cause occipital pain, and pain originating in structures innervated by the upper cervical roots can be referred to trigeminally innervated territories.
MRA did not suggest ICA dissection in our patients, but such imaging was not always promptly obtained and four-vessel conventional angiography was not performed. One autopsy series found that a very minor artery occasionally leaves the ICA close to the base of the skull and, potentially, interruption of the nutrient vessels to the hypoglossal nerve, causing segmental ischaemia to the nerve, could have occurred (9).
In the above cases, HN palsy and headache were ipsilateral, consistent with the previous literature. The lack of involvement of nearby cranial nerve nuclei and long tracts points to a highly localized phenomenon (10), and a non-progressive course marked all three patients with no further indication of underlying systemic disease. Although usually reported to be associated with underlying disease, hypoglossal neuropathy in association with headache can also be idiopathic and benign.
Competing interests
None declared.