'I've been feeling dizzy, doctor," can be one of the most challenging openings to a medical consultation. Has the person experienced postural unsteadiness or imbalance? Was there a sense of impending loss of consciousness? Add the symptoms of light-headedness, giddiness and wooziness and the diagnostic spectrum becomes very broad indeed.
Many people use "dizziness" and "vertigo" interchangeably. To the medical way of thinking, however, vertigo is a discrete symptom. The best question we can ask in an attempt to validate the presence of vertigo is: "when you have dizzy spells, do you feel light-headed or do you see the world spin around you, as if you had just got off a playground roundabout?" Research suggests that about 30 per cent of patients who attend their GPs with "dizziness" have, in fact, got vertigo.
There are three principal causes of vertigo. In MΘniΦre's disease, a condition first described in 1861, by the French physician Prosper MΘniΦre, the patient will usually describe hearing loss, tinnitus - ringing in the ears - and a sensation of fullness or pressure in the ears as well as vertigo. These are the result of increased fluid within the semicircular canals of the inner ear.
In benign positional vertigo (BPV), changes in head position bring on recurrent bouts of vertigo, sometimes accompanied by nausea.
Vestibular neuritis literally means the presence of inflammation in the vestibular nerve, usually in the part that runs from the inner ear to the brain. Confusingly, it is also known as acute labyrinthitis. Most people with the condition have nausea as well as vertigo. In 50 per cent of cases, vomiting occurs; patients also complain of unsteadiness.
Other reasons for vertigo: local infection of the ear; disruption to the blood supply of the inner ear and the base of the brain; rarely, a tumour in the neurological system will emerge as the reason for vertigo.
Making an exact diagnosis of vertigo for the three most common causes is largely a clinical exercise, in which the usefulness of blood tests and scans is minimal. Hearing tests are helpful in confirming MΘniΦre's disease, but otherwise the diagnosis involves teasing out the pattern of vertigo as well as the presence or absence of symptoms such as nausea, vomiting, hearing loss and ear "fullness".
The accompanying panel lists some of the classical features of each of the three main causes. Remember, though, that medicine is not an absolute science and that the patterns are variable.
What about treatment? Pharmacological options include the use of drugs such as prochlorperazine, which suppress both nausea and vertigo. Patients with MΘniΦre's disease generally improve with the use of a drug called betahistine, sometimes combined with a diuretic, or water tablet. Less severe cases of benign positional vertigo respond well to simple repositioning exercises, such as those of the Brandt-Daroff programme. There is a need for further research into the use of repositioning treatment for people with chronic vertigo, as an alternative to drug treatment.
I am indebted to Dr Karena Hanley, a GP in Rathmullen, Co Donegal, Tom O'Dowd, professor of general practice at Trinity College in Dublin, and Niall Considine, consultant ear, nose and throat surgeon at Sligo General Hospital, as sources for this column.
They contributed an excellent review article on vertigo in the August edition of the British Journal Of General Practice. As a result, I shall face my next patient complaining of dizziness with a firmer grasp of the subject. I hope vertiginous readers of this column will have benefited also.
You can e-mail Dr Muiris Houston, Medical Correspondent, at mhouston@irish-times.ie or leave a message on 01-6707711, ext 8511. He regrets he cannot reply to individual medical problems
