The Etiological Spectrum of Dizziness Observed at a Vertigo Clinic: A Study of a Dubai Outpatient Population

There is little data available describing the incidence of vestibular disorders in the Dubai population. This study therefore aims to report the etiological spectrum of vertigo and dizziness from a vertigo speciality clinic in Dubai.

Introduction

Dizziness is a common complaint in medical outpatients, with vestibular disorders being the most common cause of dizziness.1-3 However, there is little data available describing the incidence of vestibular disorders in the Dubai population.4 This study therefore aims to report the etiological spectrum of vertigo and dizziness from a vertigo speciality clinic in Dubai.

Material and methods

The study was conducted at the Vertigo clinic, Aster Specialty Medical Centre, International city, Dubai, which is equipped with Video-Oculography (VOG) goggles. All patients suffering from dizziness who visited the Vertigo clinic during the study period (27th Jan-25th Dec 2019) were included in the study (n=601). Detailed history taking and neurotological examination were performed in every patient. Video-oculography (VOG), Neuroimaging studies and other investigations were also conducted where appropriate.

Results

During the 11 month study period, 601 patients (359 males and 242 females) were evaluated. The mean age was 38 years (Range 14-83 years).

Overall, central causes were responsible for 47% cases; peripheral causes were seen in 31% cases, functional and psychiatric causes in 12% of patients and other causes in 9% of cases. Vestibular

migraine was the most common central cause, Benign paroxysmal positional vertigo (BPPV) was the most common peripheral cause, and persistent-postural- perceptual dizziness (PPPD) was the most common cause of dizziness due to functional aetiology.

1) Vestibular migraine

∑ Vestibular migraine is the leading cause of spon- taneous episodic vertigo.

∑ The International classification of headache dis- orders (ICHD-3) criteria was used to diagnose vestibular migraine.5

∑ Due to the stringent nature of the diagnostic criteria, only 25% patients with vestibular migraine were diagnosed to have ‘definite’ vestibular migraine, and 75% were diagnosed to have ‘probable’ vestibular migraine (Fig 1).

∑ Patients with ‘definite vestibular migraine’ had vertigo as a presenting complaint which affected their quality of life. The duration of the dizziness was more than 5 minutes per episode.

∑ Patients with ‘probable vestibular migraine’ did not have vertigo as a presenting complaint, and many reported that it did not affect their quality of life. A large proportion of patients had a duration of dizziness of less than 5 minutes. Some patients had had fewer than 5 attacks of vestibular symptoms. Of those who had more than 5 attacks, fewer than 50% of the attacks were associated with 2 or more of the four migrainous features mentioned in the diagnostic criteria2. All of these patients were categorized as ‘probable vestibular migraine’.

A statistical analysis showed the following findings.

a. 258 patients were diagnosed with vestibular migraine.

b. 69 patients presented with migrainous positional vertigo mimicking BPPV.

c. 15 patients presented with Meniere’s syndrome.

d. 51 patients presented with pseudo- acute unilateral vestibulopathy, and 5 patients presented with bilateral vestibulopathy (Fig 3).

e. The mean age of onset of vestibular migraine was 38 years.

f. Vestibular migraine can affect children as young as 14 years, and can present as late as 83 years.

g. It is slightly more common in females (53.48% of cases) than in males.

h. Video-oculography showed dizziness and discomfort on optokinetic stimulation in 90% of patients.

i. 13.5% (35/258) patients with vestibular migraine had co- morbid/triggered persistent-postural-perceptual dizziness

j. 22% of patients had a history of motion sickness in child- hood (39/258).

2) BPPV

Overall, BPPV was the second most common cause of vertigo. However, it remains the most common cause of positional vertigo if ‘probable vestibular migraine’ patients are discounted.

108 patients had typical symptoms suggestive of BPPV (Fig 3).

11 patients did not undergo positional testing. Of those who underwent positional testing (97 patients), 49 patients had nystagmus which was characteristic of one of the canal types (objective BPPV).

30 patients had symptoms without any characteristic nystagmus during the positional testing (subjective BPPV).

10 patients with Subjective BPPV (sBPPV) had sitting-up vertigo (or Type 2 BPPV), and 20 patients were classified as having sBPPV forms other than type 2 BPPV.

7 patients did not have symptoms or nystagmus during the positional testing. They were classified as ‘probable BPPV spontaneously resolved’ as per the Barany society criteria.

The most common type of objective BPPV was posterior canal (65%), followed by the lateral canal (24%). Anterior canal BPPV was seen in 10% of patients.

30 out of 32 patients with posterior canal BPPV had a typical form, and two patients had an apogeotrophic form (Fig 4). 10 out of 12 patients with lateral canal BPPV had the geotrophic form, and two patients had the apogeotropic form.

3) Persistent postural perceptual dizziness:

86 patients were diagnosed to have ‘persistent postural perceptual dizziness’ (P3D). P3D presents with chronic vestibular syndrome.

Symptoms are usually triggered in specific situations such as crowded places (malls, supermarkets), which can be classified as agoraphobia. Symptoms can also be triggered in open places during active or passive head motion (especially while driving). The symptoms usually present with the patient in an upright posture, and are relieved in the supine position.

In 34 patients, the precipitating disorder for the P3D could not be established. Fifty-two patients had P3D secondary to another vestibular, neurologic or medical disorder.

The most common precipitating disorder for P3D was vestibular migraine. Other vestibular disorders identified included BPPV, Meniere’s disease, Acute unilateral vestiblopathy and vestibular paroxysmia. However, it was observed that P3D could also be triggered by non-vestibular disorders including epilepsy and depression.

The most common oculographic finding in patients with P3D was ‘dizziness during a hyperventilation test without any characteristic nystagmus.’

4) Meniere’s disease:

30 patients were diagnosed with Meniere’s disease. This can trigger persistent-postural-phobic dizziness. It closely mimics vestibular migraine and differentiation from vestibular migraine can sometimes be challenging.

5) Acute unilateral vestibulopathy

18 cases were diagnosed with acute unilateral vestibulopathy due to peripheral aetiology (p-AUV). Patients with p-AUV presented with acute vestibular syndrome. Following the HINTS examination protocol is essential in these cases to exclude central causes. All patients had a positive head impulse test, unidirectional nystagmus without fixation, absence of skew deviation and absence of acute hearing loss.

The nystagmus of p-AUV is not seen under light during a routine clinical examination, or is of mild intensity when gazing contralateral to the side of a vestibulopathy.

Examination of the eyes in the dark (especially with videonystagmography (VNG) goggles and visor), or with Frenzel lenses, is the key to the diagnosis of a unidirectional nystagmus.

Three cases were diagnosed to have Ramsay Hunt syndrome presented with an acute unilateral vestibulopathy. They had ipsilateral facial weakness and herpetic lesions in-ear (Fig 5).

6) Post-traumatic vertigo-

16 cases of dizziness were secondary to trauma. 8 were diagnosed with BPPV and 5 had a labyrinthine concussion. Patients with labyrinthine concussion presented with ‘acute vestibular syndrome’. Two patients had both BPPV and labyrinthine concussion.

7) Psychiatric causes

Dizziness of psychiatric origin was seen in 14 out of 601 patients (2.3%). The most common cause was anxiety disorder.

8) Vestibular paroxysmia

13 cases were diagnosed with vestibular paroxysmia. They commonly presented with a spontaneous episodic syndrome of chronic onset.

All patients had stereotypical symptoms lasting less than one minute per episode.

Two cases had co-existent trigeminal neuralgia.

Two cases had positionally triggered attacks of vertigo.

3 out of 6 patients who underwent VNG showed hyperventilation nystagmus.

MRI brain showed an arterial loop in 9 patients (Fig 6), a venous loop in 1 patient and 3 cases of secondary paroxysmia (multiple sclerosis, vertebral dolichoectasia and an arachnoid cyst in the cerebello-pontine angle respectively)

All patients with vestibular paroxysmia showed a complete response to carbamazepine and/or gabapentin.

9) Posterior circulation stroke

9 cases had vestibular symptoms originating from a vascular cause. 4 patients had an infarction in the vertebro-basilar distribution. Three cases had transient ischaemic attacks; one patient had a cerebellar bleed, and one case had vertebral artery compression syndrome.

10) Tumours

6 patients were diagnosed to have posterior fossa tumours. Three had a cerebellopontine angle tumour; the three remain- ing cases were respectively diagnosed to have an arachnoid cyst, a colloid cyst of the third ventricle and retro-cerebellar meningioma.

11) Drug-induced

6 patients had drug-induced dizziness. The incriminating drugs were as follows.

∑ Pregabalin

∑ Combination of gabapentin and tramadol

∑ Amitriptyline

∑ Budesonide inhaler

∑ Phenytoin

∑ Combination of candesartan, dutasteride and alfuzosin

12) Syncopal dizziness

20 patients had syncopal (Type-2) dizziness. The causes were as follows:

∑ Pre-syncope- 6

∑ Neuro-cardiogenic syncope -4

∑ Micturition syncope- 2

∑ Orthostatic hypotension- 2

∑ Carotid sinus hypersensitivity- 1

∑ Defecation syncope-1

∑ Postural orthostatic tachycardia syndrome- 3

∑ Migraine- 2

13) Other disorders

16 patients were diagnosed to have other disorders as follows.

∑ Migraine with brainstem aura- 6

∑ Rotational vertebral artery syndrome- 2

∑ Vitamin B12 deficiency – 1

∑ Cervical myelopathy – 1

∑ Otolith dysfunction- 1

∑ Veisalgia (Alcohol hangover) – 1

∑ Diabetic neuropathy – 1

∑ Chronic fatigue syndrome- 1

∑ Essential head tremor – 1

∑ Parkinson’s disease -1

14) Unknown causes

The cause could not be established in 21 cases, despite a detailed history and relevant investigations.

CONCLUSION:

Vestibular migraine is one of the most common causes of spontaneous dizziness. BPPV is the most common cause of positional vertigo. This study is probably one of the most extensive studies of vertigo patients in a Dubai population from a neurology clinic. The etiological spectrum of vertigo seen in this study is similar to spectra reported from other countries3-5.

REFERENCES:

1. Sen K, Sarkar A, Raghavan A. The vertigo spectrum: A retrospective analysis in 149 walk-in patients at a specialised neurotology clinic. Astrocyte 2016;3:12-4.

2. Das S, Chakraborty S, Shekar S. Dizziness in a Tertiary Care Centre in Sikkim: Our Experience and Limitations. Indian J Otolaryngol Head Neck Surg. 2017;69(4):443-448.

3. Edlow JA, Newman-Toker D. Using the Physical Examination to Diagnose Patients with Acute Dizziness and Vertigo. J Emerg Med. 2016;50(4):617- 628.

4. Desai TD, Amini SS, Asad F, Kutty H. Prevalence of vestibular migraine in Dubai. Hamdan Med J 2019;12:19-22.

5. Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition. Cephalalgia 2018;38(1):1-211

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