The dizzy patient

A 62 year old man was referred by his general practitioner with a one month history of intermittent dizziness and unsteadiness. He described the dizziness as “light headedness,” occasionally with the sensation of the room spinning. His dizziness had some postural element and the episodes were self limiting, usually lasting a few seconds only. He also admitted to feeling unsteady on his feet, with a tendency to veer to the left.

The patient had no history of headache; nausea or vomiting; tinnitus; hearing loss; syncope; limb weakness; altered sensation; speech or visual disturbance. His medical history included chronic obstructive pulmonary disease, dyspepsia, and depression. He used to smoke (10 a day for 30 years) and denied drinking alcohol to excess.

On examination, the patient’s blood pressure was 133/76 (with no postural drop elicited) and his pulse was 60 beats/min regular. Oxygen saturations were 96% in room air. Cardiovascular, respiratory, and gastrointestinal examinations were within normal limits. Examination of the limbs revealed symmetrical brisk reflexes without weakness. Tests showed coordination to be intact, but the patient had mild gait ataxia manifest on “heel to toe” walking. Sensation, including proprioception, was intact, with no rombergism. Cranial nerve examination was normal and fundoscopy was unremarkable. Baseline blood tests were normal, except for an isolated polycythaemia: haemoglobin 184 g/l (normal range 133-167); haematocrit 0.53 (0.39-0.50); normal white cell and platelet count. Electrocardiogram was normal.

The patient was discharged and an outpatient computed tomography brain scan was arranged. His general practitioner was advised to repeat the full blood count and refer the patient to a haematologist if his haematocrit remained elevated. The scheduled computed tomography was subsequently substituted with magnetic resonance imaging by the radiologist because it provides better images of the posterior fossa.⇓ ⇓