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VERTIGO-A NEUROLOGIST’S PERSPECTIVE
S V Khadilkar*, K Jagiyasi**
*Hon. Neurologist, Bombay Hospital. *Hon. Asst. Prof. Neurology; **Lecturer in Neurology, GMC and Sir JJ Hospital, Mumbai.
INTRODUCTION
We are so used to the basic attribute of balance and equilibrium that we rarely think about it until something goes wrong, and then we find ourselves grappling with words to describe the sensation we feel. The complaint of dizziness can pose a big challenge to even the experienced physician and neurologist. In routine out patient practice, a large proportion of patients complains of dizziness and hence it is important to develop a systematic approach towards this symptom.
APPROACH TO DIZZINESS
The history and clinical examination is directed initially to decide whether the symptom is arising from the vestibular apparatus or is a nonvestibular disorder.
HISTORY
It is very valuable to listen to the patient fully and then try to understand what does he mean by ‘giddy’. Patients use the word to describe a variety of sensations ranging from syncope to seizure. Some patients find it very difficult to accurately decipher their sensation and it is relevant to give choices and help him to choose. The clinician then differentiates vertigo-a sense of rotation, from other non-vertiginous sensations like fainting, sense of fall, imbalance, sinking feeling, fear of impending disaster etc. Vertigo is strongly indicative of vestibular system dysfunction. Some people make the distinction between subjective vertigo (a sense of rotation of self) and objective vertigo (movement of surroundings) but this is probably of not much localizing value. Intermittent vertigo with positional element is most likely to arise from the inner ear. The positional nature is very reassuring to the clinician as most such patients have self-limiting diseases. CNS vertigo, on the other hand, tends to arise slowly and is more persistent. Antecedent events like viral infection point to labyrinthine disease and events like mountain climbing may point to barotrauma. Patients with acute vestibular system disorders are usually more comfortable when they close their eyes. Vertigo that is increased by a loud noise (Tullio phenomenon) and Valsalva manoeuvre suggests perilymphatic fistula. If symptoms increase with exercise, the cause is more likely to be cardiopulmonary and a non vestibular problem.
Associated symptoms like nausea, vomiting and autonomic symptoms are common in vestibular disorders, both central and peripheral. Other than that, associated symptoms are very relevant as they give a good localization of the problem. For example, hiccups in coordination would strongly suggest brainstem involvement as commonly occurs in the Wallenberg’s syndrome. Visual loss, diplopia, and sensory loss would also clearly point to the CNS aetiology of vertigo. Hearing loss, pain in ear, tinnitus are cochlear symptoms and suggest a peripheral disease.
A full review of the medical history is indicated as it may lead to the cause of the vertigo. Medications are notorious for their ability to cause vertigo and more than one thousand drugs are known to produce it. In clinical practice, antiepileptics and aminoglycoside antibiotics are commonly encountered culprits.
CLINICAL EXAMINATION
The clinical examination should cover systemic and the complete neurological examination. However, the only objective sign of vertigo is nystagmus and it is the eyes (and not the ears) that have to be carefully examined. A variety of activating procedures are used by clinicians to elicit an attack and nystagmus at that time. The manoeuvres (Nylen-Barany, Barany, and Dix-Hallpike) involve examiner - controlled change of head position and monitoring of the nystagmus. This helps the differentiation between vertigo of ear origin from that of CNS.
Characteristics of central and peripheral nystagmus Nystagmus Peripheral Central Latency 2-20 seconds none Vertigo + ± Direction to downward ear up or variable Adaptation to position + — Fatigue + — The neurological examination may unearth ‘neighbourhood signs’ of brainstem affectation and cranial nerves and coordination are the particularly relevant parts of the examination to give evidence of the CNS involvement.
Special tests like the postural fall of blood pressure, Valsalva manoeuvre, carotid stimulation, and exercise of the left arm may be useful in clinching diagnosis like postural syncope, perilymphatic fistula, carotid sinus hypersensitivity and subclavian steal syndrome.
Caloric testing is of not much help in a conscious dizzy patient and may be difficult to perform. When the clinical examination points to CNS involvement, MRI or CT scan of brain can be very useful. MRI is preferable as it shows the brainstem area better than CT scan. Brainstem auditory evoked responses can be used in selected cases to study the brainstem function further.
TREATMENT
When the vertigo arises due to a neurological disease, the treatment is basically of the neurological condition. For example, multiple sclerosis attack affecting the brainstem can be treated with injections of methyl prednisolone with good outcome or Wallenberg’s syndrome benefits from antiplatelet therapy. However such instances where there is a clear cause effect relationship are few in clinical practice.
A large proportion of patients complaining of dizziness does not have an identifiable anatomical or functional abnormality and the symptom is notoriously recurrent, making it difficult to provide relief. Reassurance that the symptom is not a harbinger of serious ailment helps. The therapy in such patients is symptomatic and a variety of antihistaminics have been used. As a group, they have similar potency and side effect profile and there is very little to choose amongst them. They need to be used for a few weeks duration and at times, rotating two or three agents may help.
In chronic stable vertigo, when the lesion is not identifiable or when the lesion is not reversible, in addition to pharmacotherapy, physical therapy and balance training is a useful supportive measure.
SUMMARY
The clinical history and examination can separate vestibular system disorders from others. Only a few patients have an identifiable neurological cause. In most patients, the symptom can be persistent and recurrent, and a sympathetic approach, rotating pharmacotherapy and physical training can help the patients cope up with their dizziness.
REFERENCES
- Brandt T. Vertigo and dizziness. In Asbury AK et al. Diseases of nervous system, clinical neurobiology. Phila. WB Saunders. 1986; 42.
- Drachman DA, Hart CW. An approach to the dizzy patient. Neurology 1972; 22 : 323.
- 3. Zee DS. Vertigo In Johnson RT. Current therapy in neurological diseases. St. Louis, CV Mosby. 1985; 8-13.
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