Ethnic variations in risk factor profile, pattern and recurrence of non-cardioembolic ischemic stroke.

BACKGROUND: Ischemic stroke is influenced by ethnic and geographical variations. The aim of this study was to identify the risk factor profiles, subtypes and recurrence of non-cardioembolic ischemic stroke for the two largest subpopulations, the Arab and South Asians, at the only stroke-admitting hospital in Qatar. METHODS: Data on stroke patients admitted to Hamad Medical Corporation from January through December 2001 were reviewed in January 2005. Only patients with non-cardioembolic ischemic stroke and complete work-up were included. RESULTS: A total of 303 patients with ischemic non-cardioembolic stroke fit the entry criteria. Sixty seven percent of the overall patient population (sex ratio 2:6, M/F) was of Arab origin, and 32% were South Asians. Hypertension was the most commonly encountered risk factor followed by dyslipidemia, diabetes mellitus, and obesity. Significant differences between the Arab and South Asian subgroup of patients were observed with respect to number of risk factors and occurrence of obesity and diabetes. Carotid artery stenotic lesions, ventricular wall motion abnormalities and stroke recurrence were observed with a higher frequency in the Arab subgroup of patients compared with the South Asians. The majority of strokes were lacunar hemispheric strokes (68%), followed by lacunar brainstem strokes (15%) and large-vessel hemispheric infarctions (10%). Patients with a previous history of stroke had a higher frequency of carotid artery stenosis (p = 0.05) and risk of stroke recurrence (p = 0.04). CONCLUSIONS: Unlike in other studies originating from the Arabian Gulf, lacunar stroke is the most common subtype of non-cardioembolic ischemic stroke in both the Arabs and South Asians in Qatar. Significant ethnic differences in age of occurrence, risk factor profile, and cardiovascular variables were observed.

Downbeat nystagmus following classical heat stroke.

Cerebellar syndrome following classical heat stroke is rare. We report a case of a 39-year-old man who presented with a cerebellar syndrome including downbeat nystagmus. MRI taken after 3 days of admission was normal. The downbeat nystagmus lasted for 6 days and than gradually disappeared. The ataxia and dysmetria improved gradually over 2 months. A brain CT scan performed 3 months later revealed no cerebellar atrophy. This case is unique as there were no predisposing factors (e.g. hypomagnesemia) and follow-up revealed complete reversibility of the ophthalmological abnormality. It reveals that the vestibulocerebellum is particularly vulnerable to thermal injury.

"Man-in-the-barrel" syndrome as delayed manifestation of extrapontine and central pontine myelinolysis: beneficial effect of intravenous immunoglobulin.

"Man-in-the-barrel" syndrome has been rarely described following osmotic myelinolysis. We report a case of a 45-year-old woman admitted with septicemia and severe hyponatremia. She presented with a "man-in-the-barrel" syndrome which developed more than 10 days after rapid correction of the hyponatremia. There was radiological evidence of central pontine and extrapontine myelinolysis. Three days after completing a course of intravenous immunoglobulin therapy (0.4 g/kg body weight/day for 5 days) there was considerable improvement (Expanded Disability Status Scale score improved 30%). This case, reported for its peculiar mode of development, unusual presentation and challenging therapeutic response to intravenous immunoglobulin, highlights the enigmatic and unpredictable aspects of osmotic myelinolysis.

Schwannoma of the vestibulocochlear nerve presenting as isolated paroxysmal vertigo.

We report a patient with a schwannoma of the eighth cranial (vestibulocochlear) nerve who presented with isolated episodes of paroxysmal vertigo and positive Dix-Hallpike maneuver, and without the common features of hearing loss, disequilibrium and tinnitus. There are no previous reports of paroxysmal episodes of vertigo as the sole manifestation of schwannoma of the vestibulocochlear nerve. Hence, recurrent paroxysmal vertigo should therefore prompt the physician to rule out schwannoma of the vestibulocochlear nerve as a potential cause even in the presence of normal hearing tests.