Seizures with an atypical aetiology in an elderly patient: Eagle's syndrome—how does one treat it?

Abstract

Onset of epilepsy can occur at any age, but it is relatively rare in the elderly. Late onset epilepsy is usually secondary to stroke, tumour, trauma or neurodegenerative disorders. A 62-year-old Indian woman presented with frequent drop attacks sometimes leading to unconsciousness and, rarely, associated with seizure. Her epilepsy work up was unremarkable. As the disease progressed, she was diagnosed as having idiopathic epilepsy, syncope or pseudo-seizure, on different occasions, and was treated at length with no response. Finally, detailed history-taking revealed her as having glossopharyngeal neuralgia leading to syncope and seizures. She subsequently improved. In clinical practice, such rare entities should also be considered for proper management of patients’ ailments.

Background

Seizure disorder usually starts at a young age but its onset is not uncommon in elderly people. Onset of epilepsy in the elderly population is usually secondary; the aetiology can be stroke, tumour, head injury or degenerative disease. As the aetiology varies in different age groups, so does the management and other clinical aspects. We present this case of a rare cause of secondary epilepsy that was earlier missed. It was a considerable challenge to determine how to treat this patient. She had suffered for years before the actual cause was found and treated.

Case presentation

We report a case of a 62-year-old right handed Indian woman with diabetes, hypertension and ischaemic heart disease, who was on regular medication for these comorbidities. She presented to our department, with a history of frequent drop attacks, sometimes associated with unconsciousness and, rarely, with generalised tonic-colonic seizures, for the past 10 years. She had 1–2 attacks per month—the attacks would start with a sinking feeling in the heart, dizziness and sometimes abdominal dragging sensations. Following these, she would collapse and fall down. In 40% of the attacks she would fall unconscious and, rarely, would have a seizure for 1–2 min. She visited many physicians in her home country and abroad. The first consideration was syncopal attack with seizure. She was investigated in detail, with normal results, hence the diagnosis of syncope was sustained, but it was difficult for the physicians to decide on the institution of antiepileptic medication. They started the patient on valproate sodium after discussion and escalated the dose over time, with no benefit. The patient was then seen in another centre, where they considered her to have a case of pseudoseizures and treated her with antidepressants and anxiolytics. Again there was no response. She next consulted a neurologist in Europe. He performed EEG, Video EEG monitoring, MRI of the brain and Holter monitoring—everything was normal. However, the description of seizure was very clear, and the condition did not resemble pseudoseizures, so the neurologist stopped the antidepressants/anxiolytics and started the patient on levitiracetam. She took this medicine for almost 2 years, with no response. She was similarly assessed by many doctors and was given various medicines, but got no relief. Some physicians were of the opinion that her illness was probably linked to paroxysmal cardiac arrhythmias. She was seen by our department when she presented to emergency with H/O sudden drop attack proceeded by unconsciousness and generalised tonic-colonic seizure. On examination, she was initially confused because of a postictal confusional state, but she later became alert and oriented. A detailed neurological examination was unremarkable.

Investigations

The patient's EEG, brain MRI (figure 1), echocardiography and Holter monitoring were unremarkable. A detailed review of her history revealed that sometimes, before such attacks, she would feel a slight pain on the medial side of the left gum and, very rarely, it would radiate to the base of her tongue. Examination of her head and neck was repeated and turned out to be normal. We reviewed the brain MRI and found an enlarged styloid process of the left temporal bone (figure 1). It measured 24.5 mm on the right and 29.3 mm on the left. Later, on speculation, we assumed that the enlarged styloid process was probably irritating the glossopharyngeal nerve and causing neuralgia, which provoked syncopal attacks and seizures. Diagnosis was confirmed clinically when a bimanual palpation manoeuvre of the styloid process through the tonsillar bed triggered her symptoms. The ECG record on the cardiac monitor exhibited bradycardia during this manoeuvre.

Figure 1.

Brain MRI; Upper left image is T1-weighted image (T1WI) sagittal view, which is normal. Upper right is fluid-attenuated inversion recovery axial sequence, which is also normal. Lower image is T2-weighted image coronal, which shows a left sided enlarged styloid process.

Differential diagnosis

As discussed above, the patient was initially considered as having epilepsy, pseudoseizures and cardiac arrhythmia, on different occasions. Investigations and treatment of the aforementioned differentials did not direct the physicians to the correct diagnosis. Finally, we found that the patient had glossopharyngeal neuralgia followed by syncope and seizures.

Treatment

We started the patient on pregabalin, which relieved her pain and drop attacks partially, but it could not cure her completely, so Carbamazepine was added to control her drop attacks. Initially, we planned to perform surgical removal of the styloid process, if medical management failed, but the patient showed good response to medication so the surgical option was deferred.

Outcome and follow-up

The patient was followed up recently through a telephonic conversation, which delineated that she had responded to medical management considerably well in terms of pain, drop attacks, seizures and episodes of unconsciousness. Her pain/drop attacks were reduced gradually to once every 4–5 months and seizures reduced to almost zero.

Discussion

Glossopharyngeal neuralgia is a globally uncommon entity; the incidence usually increases with age and it most often affects people above the age of 50 years. It is characterised by paroxysms of lancinating pain localised unilaterally in the base of the tongue, soft palate, throat, and lateral and posterior regions of the pharynx, which may radiate to the ipsilateral ear. The pain can be triggered by swallowing, coughing, yawning and chewing, and usually lasts for seconds or minutes. Patients with glossopharyngeal neuralgia have more difficulty in identifying the triggering mechanisms than patients with trigeminal neuralgia, probably because they are incapable of localising the pain in deep structures accurately. Sometimes pain is not as debilitating as other features, as in our patient. Although glossopharyngeal neuralgia is mostly idiopathic, it may occur secondary to cerebellopontine angle tumours, intracranial vascular compression, laryngeal and nasopharyngeal tumours that spread locally, parapharyngeal abscess, trauma, multiple sclerosis, Paget's disease or cranial base tumours, calcified stylohyoid ligament, enlarged styloid process of temporal bone and dental extractions.¹

Glossopharyngeal neuralgia caused by irritation of the glossopharyngeal nerve due to an elongated styloid process is termed as Eagle syndrome. Although approximately 4% of the population is thought to have an elongated styloid process, only a small percentage (4–10.3%) is believed to actually be symptomatic.² In 1937, Eagle described two discrete identifiable categories of this syndrome, the first is proper Eagle syndrome, characterised by pharyngeal pain, localised to the tonsillar fossa and, rarely, radiating to the hyoid bone; the second is termed stylocarotid syndrome, and is manifested by persistent pain radiating to the carotid territory.³ Association between glossopharyngeal neuralgia and syncope is very rare, and is due to short episodes of bradycardia, asystole and hypotension.⁴

The most acceptable mechanism underlying the association between bradyarrhythmias, hypotension and syncope—and glossopharyngeal neuralgia—is the close connection between the vagus nerve and glossopharyngeal nerve, particularly with respect to visceral sensations, which may be explained by understanding of the vago-glossopharyngeal reflex arch.⁴ It seems to not be the usual vaso-vagal reaction to pain, because the somatic pain from other areas of the body did not produce similar changes in BP or heart rate.⁴ It is also not due to hypersensitivity of the carotid sinus, as massage of the carotid sinus in our patient and in most of the reported cases⁵ failed to reproduce the typical cardiovascular manifestation of this syndrome. It has been suggested that the vagus nerve or the carotid sinus reflex arch (ie, parasympathetic system) is responsible for the cardiac manifestations because hypotension and bradycardia during attacks respond well to parasympatholytic drugs rather than sympathomimetics.⁴

The changes in cerebral function are generally considered to be caused by transient cerebral ischaemia secondary to reduced perfusion because of bradycardia and hypotension. However, in the literature, some patients are mentioned who had syncope and convulsions during the paroxysm of glossopharyngeal neuralgia in the absence of a fall in heart rate or blood pressure. It was suggested that such patients might have a ‘cerebral type’ of carotid sinus syncope as described by Weiss.⁶ Such patients with syncopal attacks and convulsions are a dilemma for the physician to work out for aetiology and treatment plan. In such a situation, treating glossopharyngeal neuralgia may benefit, as this is the primary entity to trigger seizures. As the mainstay of neuralgia treatment is also anticonvulsant-use, it works both ways—for seizures and for neuralgia. Carbamazepine, gabapentin, phenytoin and pregabalin are most efficacious in neuralgias and peripheral neuropathic pain. In our patient, carbamazepine and pregabalin worked well.

For Eagle syndrome, both surgical and conservative treatment show promising results. Conservative management also includes injecting steroids or long-lasting anaesthetics into the lesser cornu of the hyoid or the inferior aspect of the tonsillar fossa in order to relieve symptoms.⁷ Surgical methods involve removing the elongated styloid process, for which two different approaches have been proposed: the extraoral or transcervical and the intraoral or transpharyngeal approach.⁷ Starting with conservative management and, if that fails, going for the surgical option, appears to be a sound approach.

Patient's perspective.

• Since these new medicines were started I am feeling comfortable. My pain and attacks of falling down are much reduced in frequency. For the last 8 months I did not have any seizures.

Learning points.

• For the clinical practice, good history-taking and examination are the best tools to reach a diagnosis.

• Late onset epilepsy is usually secondary in aetiology.

• Glossopharyngeal neuralgia leading to syncope can also present with seizures.

• Anticonvulsants play a main role in conservative management of neuralgia.