Is stroke incidence related to season or temperature? The Oxfordshire Community Stroke Project

BACKGROUND: A winter excess of ischaemic stroke has been found in mortality and hospital-based studies. It is often assumed that this is due to seasonal variation in stroke incidence and several pathophysiological explanations have been proposed. We studied the incidence of stroke in relation to season and outside temperature. METHODS: The data came from a community-based study of first ever in a lifetime stroke in a defined population of about 105 000. 675 such strokes were registered over four years and the month of inset was analysed separately for cerebral infarction, primary intracerebral haemorrhage, and subarachnoid haemorrhage. FINDINGS: There was no significant seasonal variation. The incidence of primary intracerebral haemorrhage was increased at low temperatures, but there was no significant relation between the incidence of ischaemic stroke or subarachnoid haemorrhage and temperature. INTERPRETATION: The widely reported winter excess of ischaemic strokes may be an artifact due to referral bias in hospital-based studies and increased case fatality during the winter in mortality studies.     

Stroke and intracranial venous thrombosis during pregnancy and puerperium

OBJECTIVES: To determine nationally representative estimates of the incidence of stroke and intracranial venous thrombosis during pregnancy and the puerperium, and to identify potential risk factors for these conditions. METHODS: National Hospital Discharge Survey data were analyzed for the period 1979 to 1991. Nationally representative estimates of risk were calculated by age, race, presence of pregnancy-related hypertension, census region, hospital ownership, and number of hospital beds. Multivariate models were developed using logistic regression. RESULTS: There were an estimated 8,918 cases of stroke and 5,723 cases of intracranial venous thrombosis during pregnancy and the puerperium in the United States among 50,264,631 deliveries, giving risks of 17.7 cases of stroke and 11.4 cases of intracranial venous thrombosis per 100,000 deliveries. In the multivariate models, stroke was associated strongly with pregnancy-related hypertension, larger hospital size, and proprietary hospital ownership, and inversely associated with living in the South. Intracranial venous thrombosis was associated with maternal age. CONCLUSIONS: Stroke and intracranial venous thrombosis are relatively common complications of pregnancy and the puerperium. Collectively, rates for these conditions are about 50% greater for the entire period of pregnancy and the puerperium than for the immediate peripartum period.     

Giant fusiform basilar artery aneurysm: endovascular treatment by flow reversal in the basilar artery

We report a patient presenting with subarachnoid haemorrhage due to rupture of a giant fusiform aneurysm of the proximal basilar artery. The aneurysm was successfully treated by reversing blood flow in the basilar artery by balloon occlusions of both vertebral arteries proximal to the posterior inferior cerebellar artery origins. Substantial thrombosis and regression of the aneurysm was evident 4 months later.     

Hormone replacement therapy and risk of non-fatal stroke

BACKGROUND: The effect of postmenopausal hormone replacement therapy (HRT) on the risk of subtypes of stroke is as yet unclear. To investigate the effect of oestrogen and combined oestrogen-progestagen therapy on the risk of non-fatal haemorrhagic and thromboembolic stroke, we carried out a case-control study. METHODS: From the Danish National Patient Register we identified all Danish women aged 45-64 years who had a non-fatal, first-ever cerebrovascular attack during 1990-92. Two age-matched controls were randomly selected for each case from the Danish National Person Register. Important correlates of hormone use and stroke, on which information was obtained from postal questionnaires, were controlled for by multivariate analyses based on log-linear graphical models. The analyses included data on 1422 cases classified in four subtypes of stroke (160 subarachnoid haemorrhage, 95 intracerebral haemorrhage, 846 thromboembolic infarction, 321 transient ischaemic attack) and 3171 controls. FINDINGS: After adjustment for confounding variables and correction for the trend in sales of HRT preparations, no significant associations were detected between current use of unopposed oestrogen replacement therapy and non-fatal subarachnoid haemorrhage (odds ratio 0.52 [95% CI 0.23-1.22]), intracerebral haemorrhage (0.15 [0.02-1.09]), or thromboembolic infarction (1.16 [0.86-1.58]), respectively, compared with never use. Current use of combined oestrogen-progestagen replacement therapy had no significant influence on the risk of subarachnoid haemorrhage (1.22 [0.79-1.89]), intracerebral haemorrhage (1.17 [0.64-2.13]), or thromboembolic infarction (1.17 [0.92-1.47]). A significantly increased incidence of transient ischaemic attacks among former users of HRT and among current users of unopposed oestrogen may to some extent be explained by selection--HRT users being more aware of symptoms than non-users. INTERPRETATION: Unopposed oestrogen and combined oestrogen-progestagen replacement therapy have no influence on the risk of non-fatal thromboembolic or haemorrhagic stroke in women aged 45-64 years.     

Plasma oestrogens in a pregnancy associated with chronic haemodialysis

Pregnancy in a patient undergoing regular haemodialysis at home is described. The pregnancy was complicated by antepartum haemorrhage due to a Type I placenta praevia, and premature labour occurred at 32 weeks, resulting in spontaneous vaginal delivery of a live infant which survived. Plasma progesterone oestrone, unconjugated oestradiol and oestriol levels were normal during the last two weeks of pregnancy, but failed to show a characteristic fall in the puerperium. The conjugated oestriol fraction was 20 to 30 times the normal mean level and did not fall after delivery. These findings are discussed.     

Aneurysms of the cerebral vessels and pneumococcal infection

Two cases of cerebral aneurysm rupture with repeat subarachnoidal haemorrhage are reported in patients with pneumococcal infection confirmed bacteriologically. It is concluded that in pathogenesis of the aneurysmal rupture in pneumococcal infection a significant role is played not only by pneumococcal tropism to the meninges, but also by affection of the endothelium and cerebral vascular membranes, hemostasis defects, arterial hypertension as manifestations of a general adaptation syndrome.     

Pregnancy, puerperium and cerebrovascular disease

Six patients who presented cerebrovascular disease during puerperium or pregnancy were studied. One of them presented hemorrhagic stroke caused by intracerebral bleeding due to pre-eclampsia. Three patients presented ischemic stroke, they all had positive serologic reactions for Chagas' disease, but only two of them had clinical cardiopathy; one of these patients had anticardiolipin antibody. The other two patients presented cerebral venous thrombosis of sagittal sinus. Both were smokers and one of them used oral contraceptive. We emphasize the importance of clinical investigation to seek for the common causes of cerebrovascular disease in young people, with special attention to Chagas disease in Brazil.     

Effect of subarachnoid haemorrhage on micro-circulation in hypothalamus and brain stem of dogs

In order to investigate the relationship between cerebral vasospasm and microvasculature in the hypothalamus and brain stem, colloidal carbon was infused into the vertebral artery at various time intervals after experimental subarachnoid haemorrhage in dogs. Experiments which demonstrated vasospasm on angiogram were always accompanied by ischaemic changes in serial sections taken from the anterior hypothalamus to the brain stem. However, when it was demonstrated by angiography that the vasospasm had disappeared, the micro-circulation was restored to normal. Electron microscopy of the hypothalamus 48 hours and one week after subarachnoid haemorrhage, demonstrated swelling of the endothelial cells, enlargement of the perivascular glia and increase in number of the pinocytic vesicles in the cytoplasm, thus showing vasogenic oedema in this area. It is assumed that in addition to the vasogenic substance in extravasated blood, changes in irritability of cerebral vessels through the vasomotor pathways in the hypothalamus and brain stem might play an important role in the production of cerebral vasospasm.     

Some observations on the microneurosurgical treatment of intracranial aneurysms

This paper reports a retrospective study of the microneurosurgical management of intracranial aneurysm in 133 patients. Good or fair results were obtained in 76%, 12% of patients had a poor result and the mortality was 12%. Major factors which were found to influence the outcome of surgery were: pre-operatively, the Botterell grade of the patient, pre-existing systemic hypertension and the time interval between the last subarachnoid haemorrhage and surgery. Post-operatively, the development of cerebral vasospasm was associated with a poor outcome from surgery. Better results might be obtained from the surgery of intracranial aneurysm by delaying operation to the second week after subarachnoid haemorrhage and by better management of hypertensive patients pre-operatively and patients who develop cerebral vasospasm post-operatively.     

Safety of carotid ligation and its role in the management of intracranial aneurysms

By using measurements of cerebral blood flow and internal carotid artery pressure it is possible to select patients in whom carotid ligation can be performed with a very low risk of post-operative cerebral ischaemia. A study has been carried out in 100 patients comparing this method with clinical predictions of the type used in aneurysm surgery based on age of the patient, arterial hypertension, time from latest subarachnoid haemorrhage, and neurological status on a modified Botterell scale. These clinical factors were found to be of little value in predicting which patients would and would not develop cerebral ischaemia after carotid occlusion.     

Vertical transmission of hepatitis C virus infection

BACKGROUND: Cavernous carotid aneurysms are generally benign entities. Certain indications exist for their treatment, however, including transient ischemic events, subarachnoid hemorrhage or risk of subarachnoid hemorrhage, epistaxis or its risk, ophthalmoplegia, pain, and progressive visual loss. We feel certain angiographic features may indicate a greater likelihood that cavernous carotid aneurysms extend into the subarachnoid space, thus making their rupture a life-threatening event. METHODS: A case report of an intracavernous carotid aneurysm, which at surgery extended into the subarachnoid space, is described. RESULTS: In this particular case, deformation of the aneurysm (waisting) as seen at angiography was in retrospect an indication that the cavernous carotid aneurysm extended into the subarachnoid space, either through the dural ring or through the eroded dural roof of the cavernous sinus. This finding was verified at surgery when the lesion was explored and trapped. CONCLUSION: Angiographic waisting of a cavernous carotid aneurysm may indicate that the aneurysm extends into the subarachnoid space. Such extension means that rupture would be a life-threatening event. While deformation of the aneurysm may be secondary to compression against the optic nerve or anterior clinoid process with an intact layer of dura overlying the aneurysm, the neurosurgeon confronted with such findings should analyze such lesions carefully and consider surgical exploration.     

Analysis of human sera for filarial IgM antibody using antigen fractions isolated from immune complexes

OBJECTIVES: To assess the efficacy of nimodipine in preventing delayed ischaemic deficit in aneurysmal subarachnoid haemorrhage. DESIGN: A continuous prospective audit of all patients with aneurysmal subarachnoid haemorrhage admitted to the joint neurosurgery units of Prince Henry's and Alfred hospitals, Melbourne. Patients were divided into two groups--135 in the pre-nimodipine group during 1986 to 1989, and 73 in the nimodipine group during 1989 and 1990. MAIN OUTCOME MEASURES: Outcome was measured according to the Glasgow outcome scale and the incidence of delayed ischaemic deficit was recorded. RESULTS: A substantial reduction in the overall incidence of poor outcome was observed, from 37% of patients in the non-nimodipine group, to 20% in the nimodipine group (P = 0.022). Delayed ischaemic deficit occurred in 41% and 21% (P = 0.005), and poor outcome due to delayed ischaemic deficit occurred in 18% and 8% (P = 0.09) respectively. CONCLUSIONS: In our experience, nimodipine appears to have substantially reduced the incidence of delayed ischaemic deficits in patients with aneurysmal subarachnoid haemorrhage, with a resultant improvement in overall patient outcome.     

Transluminal angioplasty and intra-arterial papaverine for the treatment of cerebral vasospasm after ruptured arteriovenous malformations

BACKGROUND: This is the first report on the use of intra-arterial papaverine and percutaneous transluminal angioplasty in two patients with severe, symptomatic cerebral vasospasm who suffered ruptured arteriovenous malformations (AVMs). CASE DESCRIPTIONS: The source of hemorrhage was a venous aneurysm in the first case and a pedicular aneurysm of the distal posterior inferior cerebellar artery in the second case. In both cases, the AVMs were located in the superior vermis and there was minimal subarachnoid hemorrhage. The first patient underwent removal of the AVM before the period of cerebral vasospasm and the second patient underwent removal of the AVM after the cerebral vasospasm had resolved. The outcome was excellent in the first patient and poor in the second patient. CONCLUSION: Arteriovenous malformation with ruptured aneurysms may be at high risk for cerebral vasospasm even when there is minimal subarachnoid hemorrhage. We recommend early treatment of AVMs with ruptured pedicular, intranidal, or venous aneurysms to avoid rebleeding and to allow for aggressive treatment of cerebral vasospasm. The management of cerebral vasospasm after AVM rupture is discussed.     

Long-term follow-up study of unruptured intracranial aneurysms

OBJECTIVE: The purpose of this study was to clarify the risk of rupture of unruptured intracranial aneurysms among large groups of patients with various underlying diseases or conditions. METHODS: A long-term follow-up study of unruptured intracranial aneurysms was performed with 360 patients who were treated conservatively during the period from April 1969 to December 1992. RESULTS: Follow-up evaluation (between February and June 1994) could be performed for 234 (65%) of the patients. The underlying diseases included multiple aneurysms with subarachnoid hemorrhage for 60 patients, cerebral infarction for 108, intracerebral hemorrhage for 27, and other diseases for 39. Single aneurysms were present in 171 patients and multiple aneurysms in 63. The mean follow-up period was 75 months (range, 3-270 mo). Of the 234 patients, 132 (56.4%) survived, 59 (25.2%) died because of other diseases, 9 (3.8%) underwent surgery, and 34 (14.5%) showed bleeding from unruptured aneurysms, which was fatal for 18 of the patients. The average annual rupture rate for all patients was 2.3% (subarachnoid hemorrhage, 3.2%; cerebral infarction, 2.2%; intracerebral hemorrhage, 3.2%; other diseases, 3.6%). There were no significant differences among the patients according to underlying disease or aneurysm site. The cumulative rate of bleeding for all patients was 20% at 10 years after diagnosis and 35% at 15 years. The cumulative probability of rupture was significantly higher for the multiple aneurysms than the single aneurysms (P < 0.001). CONCLUSION: The risk of rupture of unruptured aneurysms is high, especially for multiple aneurysms, but there are no significant differences in the risk of rupture according to the underlying disease or the aneurysm location. Radical treatment should be considered for patients with unruptured intracranial aneurysms.     

No treatment for low-risk thrombocythaemia: results from a prospective study

Essential thrombocythaemia (ET) is a chronic myeloproliferative disorder characterized by the occurrence of thromboembolic episodes, particularly in patients aged > 60 years or with a previous history of thrombosis, and/or by haemorrhages in patients with an exceedingly high platelet count. In these subgroups of patients the use of cytoreductive therapy is beneficial in terms of risk/benefit ratio. Only limited anecdotal data are available on the thrombotic or haemorrhagic risk and survival in young asymptomatic ET patients with a platelet count < 1500 x 10(9)/l. Therefore the optimal management of these patients is unknown. To assess the incidence of thrombosis and haemorrhages in this group of patients we carried out a prospective observational study in a cohort of 65 patients with ET, aged < 60 years, with no history of thrombosis or haemorrhage and platelet count < 1500 x 10(9)/l, and in 65 age- and sex-matched controls. Patients were not treated with cytoreductive therapy until the occurrence of thrombosis or haemorrhage. Arterial or venous thrombotic events were objectively documented both in cases and in controls. The median follow-up was 4.1 years, with an incidence of thrombosis in patients and controls of 1.91 and 1.50 cases/100 patient-years, respectively. The age- and sex-adjusted risk rate ratio was 1.43 (95% CI 0.37-5.4). Only three minor haemorrhagic episodes occurred in patients, with an incidence of 1.12 cases/100 patient-years. Pregnancy and surgery were not associated with thrombosis in these patients. We conclude that the thrombotic risk in young ET patients, with no thrombotic history and a platelet count < 1500 x 10(9)/l, is not increased compared to the normal population and that a conservative therapeutic approach should therefore be considered in these patients.     

Treatment of mallet finger fractures by the extension-block K-wire technique

OBJECTIVES: This report describes successful anaesthesia and electroconvulsive therapy (ECT) in a patient with an unruptured basilar artery aneurysm. ECT is associated with a hyperdynamic state characterised by arterial hypertension, tachycardia, and considerably increased cerebral blood flow rate and velocity. These responses pose an increased risk for subarachnoid haemorrhage when an intracranial aneurysm coexists. METHODS: A 54 year old woman presented for ECT. She had a 20 year history of major depression which was unresponsive to three different antidepressant drugs. There was also an unruptured 5 mm saccular aneurysm at the basilar tip, which had been documented by cerebral angiography, but its size had remained unchanged for the previous four years. After she declined surgical intervention, she gave informed consent for ECT. During a series of seven ECT sessions middle cerebral artery flow velocity was recorded by a pulsed transcranial Doppler ultrasonography system. She was pretreated with 50 mg oral atenolol daily, continuing up to the day of the last ECT and immediately before each treatment, sodium nitroprusside was infused at a rate of 30 microg/min, to reduce systolic arterial pressure to 90-95 mm Hg. RESULTS: Systolic flow velocity during the awake state ranged from 62-75 cm/s, remaining initially unchanged with sodium nitroprusside infusion. After induction of anaesthesia (0.5 mg/kg methohexitone and 0.9 mg/kg succinylcholine), flow velocities decreased to 39-54 cm/s, reaching maximal values of 90 cm/s (only 20% above baseline) after ECT. These flow velocities recorded post-ECT were considerably below the more than twofold increase recorded when no attenuating drugs were used. Systolic arterial blood pressure reached maximal values of 110-140 mm Hg and heart rate did not exceed 66 bpm. Rapid awakening followed each treatment, no focal or global neurological signs were apparent, and the patient was discharged in remission. CONCLUSION: In a patient with major depression and a coexisting intracerebral saccular aneurysm who was treated with ECT, the combination of beta blockade with atenolol and intravenous infusion of sodium nitroprusside prevented tachycardia and hypertension, and greatly attenuated the expected increase in flow velocity in the middle cerebral artery.     

Treatment of acute apoplexy at a medical department with a specialized rehabilitation unit

The aim of this retrospective study was to describe the occurrence of acute stroke and the effect of treatment measured as mortality, length of hospital stay and discharge to the home in a medical department with a specialized rehabilitation unit. During the period 1.9.1992-31.5.1995 110 patients were discharged to their own home after transient cerebral ischaemia, 23 after subarachnoid haemorrhage, 62 after documented intracerebral haemorrhage and 574 after acute stroke due to infarction or unknown cause. The 636 patients in the last two groups had an in hospital mortality of 18%, a 30-day mortality 18% and a six month mortality of 25%. In the same group the length of hospital stay was 25.6 days and 68% were discharged to their own home. In conclusion the results of treatment of acute stroke in a medical department with a specialized rehabilitation unit were similar to those reported from acute stroke units in Denmark and abroad, but the patients admitted to our department were younger and fewer were single, which may itself reduce mortality and length of hospital stay.     

Comparing the severity of obstructive sleep apnea in patients referred by urban and rural physicians

The occurrence of a subdural hematoma caused by the rupture of an intracranial aneurysm is rare. In our case, the patient is a 43-year-old woman who suffered from sudden onset of severe headache. Computed tomographic (CT) scan disclosed a subdural hematoma associated with subarachnoid hemorrhage. CT angiography and digital subtraction angiography revealed an elongated aneurysm adhering to the dura in the left Sylvian fissure. The subdural hematoma was evacuated and the aneurysm clipped. The patient made a full recovery.     

Prenatal diagnosis of 22q11 microdeletion

It has been recognised that the level of superoxide dismutase (SOD) significantly increases in CSF as the result of cerebral ischaemic damage. The aim of this study was to correlate the CSF levels of SOD enzymatic activity to the patterns of subarachnoid haemorrhage with regards to ischaemic complications due to vasospasm. A series of 78 patients operated on for intracranial aneurysms was studied; all patients were monitored with serial TCD measurements every second day after SAH. CSF samples were obtained at surgery by cisternal puncture of the subarachnoid cistern nearest to the aneurysm. SOD activity was assayed spectrophotometrically. Mean cisternal CSF level of SOD in 12 control cases (12.99 +/- 2.33 U/ml) is significantly higher (p < 0.01) than in 26 patients operated on between day 1 and 3 from last SAH episode (4.44 +/- 0.7 U/ml) and in 40 patients treated by delayed surgery (7.64 +/- 0.92 U/ml). In 13 patients presenting neurological deterioration related to arterial vasospasm mean cisternal SOD level was 12.23 +/- 1.86 U/ml; in 27 cases without vasospasm mean level was 5.43 +/- 0.7 U/ml (p < 001). The present results suggest that (a) cisternal CSF levels of SOD significantly decreases after SAH, probably in relation to an impaired synthesis in the brain compartment and that (b) a substantial elevation of SOD levels is evident in patients suffering ischaemic complications vasospasm-related. Biochemical events in the brain compartment could influence the expression and release of anti-oxidant enzymes in CSF after SAH.     

Treatment of severe, drug resistant obsessive compulsive disorder with the 5HT1D agonist sumatriptan

Many risk factors operate in both coronary heart disease and stroke, especially ischaemic stroke--age, sex, social class, blood pressure, pre-existing vascular disease (angina, myocardial infarction, cardiac failure, diabetes and peripheral vascular disease, transient ischaemic attack and stroke), atrial fibrillation and fibrinogen, smoking, alcohol and height. Total cholesterol has also recently been recruited to this list. The various mechanisms involved in stroke and its subtypes and the epidemiological problems in evaluating aetiological factors in stroke make the comparison with coronary heart disease more difficult. The recent discrepancy between much of the epidemiology and the clinical trials evaluating the role of lipids in stroke has spurred the systematic review (meta-analysis) of major prospective observational studies. These will provide a clearer assessment about the quantitative comparison of some of the more important risk factors for stroke and coronary heart disease in the near future.