Predicting ischaemic stroke subtype from presenting systolic blood pressure: the BASIC Project.

OBJECTIVE: We hypothesized that low presenting systolic blood pressure (SBP) predicted cardioembolic stroke aetiology. DESIGN: Active and passive surveillance were used to identify all ischaemic strokes as part of the Brain Attack Surveillance in Corpus Christi (BASIC) population-based study. Multinomial logistic regression was used to examine the association between stroke subtype and first documented SBP in the medical record. SETTING: Nueces County, TX, USA (313,645 residents in 2000). The community is urban with the majority of the population residing in the city of Corpus Christi. The area is served by seven adult acute care hospitals. PATIENTS: Three hundred and eight cases with completed ischaemic stroke and determined subtype aetiology between January 2000 and December 2002. RESULTS: Lower presenting SBP was associated with stroke subtype (P = 0.001). This association remained significant in the final model adjusted for age and history of coronary artery disease. The odds of cardioembolic versus small vessel occlusion increased by 20% (OR = 1.20, 95% CI: 1.07-1.35) for every 10 mmHg decrease in presenting SBP. Other covariates including race/ethnicity, gender, history of hypertension, and diabetes were neither significant predictors of stroke subtype, nor did they confound the association of SBP and stroke subtype. A 5 year increase in age increased the odds of cardioembolic subtype by 25% (OR = 1.25, 95% CI: 1.07-1.47). CONCLUSIONS: Lower initial SBP and older age at ischaemic stroke presentation were associated with cardioembolic stroke. Suspicion of cardioembolic stroke should be increased in those presenting with low SBP.

Oculosympathetic spasm with cervical spinal cord injury.

A 23-year-old man, involved in a motor-vehicle accident, became quadraparetic due to cervical spinal cord injury at the C-4 to C-6 level. Five months later he was noted to have bilateral, asymmetric pupillary mydriasis precipitated by elevation and stretch of an arm or leg. Pharmacologic pupillary testing and ciliospinal reflex responses suggested that the oculosympathetic pathways were intact. Computed tomographic myelography using metrizamide disclosed a posttraumatic syringomyelic cyst at C-4. This pupillary phenomenon has been termed oculosympathetic spasm, and we reviewed four previous reports. While the cause of oculosympathetic spasm remains speculative, it may represent a localized form of autonomic hyperreflexia.

Lateralization of brainstem lesions by brainstem auditory evoked potentials.

In eight patients with unilateral pontine and midbrain lesions, brainstem auditory evoked potentials (BAEPs) were studied with ipsilateral (Cz-Ai) and contralateral (Cz-Ac) recordings after monaural stimulation. In all cases, the most prominent abnormality was noted in BAEP generated by stimulating the ear ipsilateral to the lesions. The Cz-Ai and Cz-Ac patterns showed similar abnormalities in five of the patients and dissociated abnormalities in two patients. We conclude that: (1) Lateralization of BAEP is possible in unilateral pontine and midbrain lesions. (2) Monaural stimulation with Cz-Ai and Cz-Ac recordings is essential for lateralization. (3) The BAEP in monaural stimulation is predominantly generated from the auditory structures ipsilateral to the stimulated ear.