Cerebral hemorrhage and apoE

The epsilon4 allele of apolipoprotein E (apoE) is found more commonly among patients with Alzheimer's disease (AD) than in the normal population. ApoE is associated with brain amyloid, a component of cerebral amyloid angiopathy (CAA), which is both a pathological feature of AD and a frequent cause of lobar intracerebral hemorrhage (ICH). We hypothesized that the frequency of epsilon4 allele is higher in patients with CAA-related ICH than in hypertensive ICH and in the normal population. To test this hypothesis we compared the frequency of apoE alleles in four populations: 24 patients with lobar ICH, 24 matched patients with hypertensive ICH, 24 matched normal controls, and 173 population controls. Although there was a tendency to a higher frequency of apoE epsilon4 in lobar ICH patients, we found no significant differences in the frequency of this allele between the four studied populations. In addition we did not confirm the finding of some authors of a higher frequency of apoE epsilon2 in patients with lobar ICH than in the normal population. Previous studies on the subject are discussed. The relationship between apoE polymorphism and lobar CAA-related ICH remains to be clearly defined.

Vascular risk factors for perimesencephalic nonaneurysmal subarachnoid hemorrhage

No data have been published on the role of vascular risk factors for perimesencephalic nonaneurysmal subarachnoid hemorrhage (PMSAH). In a case-control study we compared the prevalence of vascular risk factors in 40 consecutive patients who suffered a perimesencephalic subarachnoid hemorrhage with that in two controls groups: (a) 120 subjects registered with a general practitioner (GP: matched at a 3:1 ratio for age and sex) and (b) 81 proxies of patients of a hospital outpatient clinic. A conditional multivariate logistic regression model was performed taking into account the matched design. Hypertension was more frequent among PMSAH patients than among the two control group subjects for men and women. Among women, smoking was more common in PMSAH than in the GP control group. The conditional multivariate logistic regression model confirmed that hypertension was an independent risk factor for PMSAH (P = 0.036) Hypertension is a preventable risk factor of PMSAH.

Paralytic shellfish poisoning: clinical and electrophysiological observations

In paralytic shellfish poisoning a mollusc contaminated with a toxin (saxitoxin) causes a potentially lethal disease, clinically characterised by gastrointestinal and neurological symptoms, of which possible respiratory depression is the most serious. The toxin acts by blocking the sodium channels. We report 9 Portuguese patients with this disease. The mollusc was identified as Mytilus edulis, contaminated with the dinoflagellate Gymnodinium catenatum, and the toxin saxitoxin. Our patients had a benign clinical course with cerebellar ataxia as the most severe neurological impairment. Eight out of 9 patients had neurophysiological investigations, the largest number so far reported. Motor and sensory conduction velocities and amplitudes were normal. The proximal conduction times, as assessed by F waves, showed delayed conduction and decreased frequency, which returned to normal in few weeks. The somatosensory evoked potentials confirmed normal peripheral and central sensory conduction. The rich vascular supply at root level of the sodium channels of the proximal motor nerves may explain the greater vulnerability to toxin damage. The typically transient and quickly reversible nerve dysfunction caused by ion channel blockade is reported.

[Perimesencephalic hemorrhage]

Among 293 subarachnoid hemorrhages admitted to the Neurology and Neurosurgery departments of Sta Maria Hospital, 108 patients had a normal cerebral angiography. Twenty-three meet the radiological criteria for perimesencephalic hemorrhage (center of the hemorrhage located in front of the mesencephalon, without blood in the interhemispheric and lateral sylvian fissures, nor significant intraventricular hemorrhage). The clinical picture was one of sudden, severe headache with meningeal signs, without focal signs or decreased alertness. Evolution was benign: there was no intrahospital mortality, morbidity or rebleeds on follow-up (3.5 years). In this subgroup of subarachnoid hemorrhage there is no need for a repeated angiogram if the first angiography is considered normal.