Prediction of functional outcome and tissue loss in acute cortical infarction

OBJECTIVE

To compare the acute Allen's Prognostic Score, Canadian Neurological Score, and subacute Barthel Index as predictors of outcome functional status and infarct size at 3 months in patients with acute cortical infarction.

DESIGN

A prospective study of acute stroke predictors and outcome measurements in a cohort of sequential hospitalized patients.

PATIENTS

Fifty-one patients with acute cortical infarction and without previous disability assessed 24 hours after onset with Allen's Prognostic Score and the Canadian Neurological Score and at 7 days with the Barthel Index.

MAIN OUTCOME MEASURES

Mortality, Barthel Index, and volumetric measurement of infarct size on computed tomography 3 months after stroke.

RESULTS

There were seven deaths. The outcome Barthel Index was measured in all 44 survivors, of whom 29 had computed tomography at the time outcome was determined. In a multivariate analysis, functional outcome was best predicted by Allen's Prognostic Score, a score of less than -15 having a sensitivity of 82% and specificity of 97% in predicting a poor outcome (Barthel Index, < or = 12 or death). Volumetric tissue loss was predicted only by Allen's Prognostic Score (r = .62, P < .001).

CONCLUSIONS

Allen's Prognostic Score is a robust predictor of both functional outcome and tissue loss in acute cortical infarction and has a potentially important role in the analysis of the results of acute stroke intervention trials.

Crossed cerebellar diaschisis and brain recovery after stroke

BACKGROUND AND PURPOSE

Although crossed cerebellar diaschisis is well recognized after stroke, there is controversy concerning its clinical correlations and serial changes, and little is known about its prognostic value.

METHODS

We studied crossed cerebellar diaschisis and cerebral hypoperfusion in 47 patients with acute middle cerebral cortical infarction using 99mTc-hexamethylpropyleneamine oxime and single-photon emission computed tomography within 72 hours of stroke onset. Thirty-one of these patients had outcome studies at 3 months; 15 of the 31 underwent an additional scan after acetazolamide injection. Tissue loss was determined with computed tomography, performed at outcome in 28 patients. Clinical stroke severity was assessed with the Canadian Neurological Scale and Barthel Index. Cerebellar blood flow asymmetry was studied in 22 healthy, age-matched control subjects.

RESULTS

Cerebellar blood flow asymmetry was significant in patients (mean +/- SE, 9.76 +/- 0.78%; P < .001) but not in control subjects (-0.22 +/- 0.56%). Crossed cerebellar diaschisis was strongly associated with infarct hypoperfusion volume at both acute (regression coefficient +/- SEb, b = 6.76 +/- 0.65; P < .001) and outcome stages (b = 6.13 +/- 0.63; P < .001). Cross-sectionally over the first 72 hours, infarct hypoperfusion volume decreased by 2% for each hour from onset (P < .05), while crossed cerebellar diaschisis remained unchanged. Canadian Neurological Scale score at the acute stage was negatively associated with acute crossed cerebellar diaschisis (b = -0.10 +/- 0.05; P < .05) after allowing for infarct hypoperfusion volume. Crossed cerebellar diaschisis did not change between acute-stage, outcome, and postacetazolamide scans. Acute-stage crossed cerebellar diaschisis predicted outcome Barthel Index score (b = -0.28 +/- 0.14; P = .05) and tissue loss (b = 3.81 +/- 0.96; P < .001) but was no longer an independent prognostic factor after allowing for acute-stage infarct hypoperfusion volume.

CONCLUSIONS

This study shows that crossed cerebellar diaschisis is a functional phenomenon that correlates with both stroke severity and infarct hypoperfusion volume and persists despite neurological recovery. Although acute-stage crossed cerebellar diaschisis has no prognostic value independent of acute-stage hypoperfusion volume, it might indicate the proportion of nutritional to nonnutritional perfusion at the infarct site and hence be useful in the evaluation of reperfusion therapies in the acute stage.

Reperfusion after thrombolytic therapy in ischemic stroke measured by single-photon emission computed tomography

BACKGROUND AND PURPOSE

We used 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (SPECT) to study cerebral perfusion in patients treated with streptokinase for acute ischemic stroke in an open and prospective study. Our primary aims were (1) to compare the extent of reperfusion between patients who had received thrombolytic therapy and a control group studied during the same period who were ineligible to receive such therapy and (2) to determine if, among all patients, reperfusion led to improved outcome.

METHODS

Fifty-seven patients (22 treated with streptokinase) had two SPECT studies performed, the first before streptokinase administration and the second 24 hours later.

RESULTS

On the first SPECT study hyperfusion was present in the middle cerebral artery or anterior cerebral artery territories in 40 patients (17 treated with streptokinase). Patients in the treatment and control groups with initial hypoperfusion on SPECT were well matched for the volume of the perfusion defect and the severity of neurological deficit. A greater number of patients who received streptokinase developed at least partial reperfusion (streptokinase, 65%; control, 52%) on the second study but not significantly so (P = .43). Similarly, the proportion of each hypoperfused region that reperfused (P = .74) and the reduction in the size of the perfusion defect (P = .06) were higher in the streptokinase group but did not reach statistical significance. When all patients were considered, those who did not reperfuse had higher mortality rates (P = .008), less neurological improvement (P = .016), and more functional disability (P < .001) than patients who had reperfusion or normal perfusion initially.

CONCLUSIONS

These findings suggest that at least some reperfusion during the first 48 hours of ischemic stroke is a common natural occurrence and is of prognostic significance. The observed trend toward better reperfusion indexes among patients treated with streptokinase is encouraging, but larger controlled trials are required to answer this definitively.

Hematologic abnormalities occur in both cortical and lacunar infarction

BACKGROUND AND PURPOSE

Primary hematologic abnormalities are a rare but established cause of ischemic stroke. In addition, activation of hemostatic parameters is often present during the acute phase of stroke. However, it is uncertain whether these abnormalities occur in both cortical and lacunar infarction; this study aimed to further assess this issue.

METHODS

Hematologic parameters (prothrombin, activated partial thromboplastin, thrombin clotting, and euglobulin lysis times; and fibrinogen, fibrinopeptide A, antithrombin III, protein C, protein S, and plasminogen levels) were measured in 19 patients within 48 hours of the onset of acute cerebral infarction. These patients included 10 with cortical infarcts and 9 with lacunar infarcts, as determined by standard clinical and radiological criteria.

RESULTS

Five patients with lacunar infarction and 7 patients with cortical infarction demonstrated raised fibrinopeptide A levels, indicating enhanced thrombin activity. Fibrinolysis, assessed by the euglobulin lysis time, was impaired in 6 of 9 patients with lacunar infarction and in 2 of 10 patients with cortical infarction. Lupus anticoagulants were detected in 3 patients with lacunar infarction and in 1 patient with cortical infarction. Three patients in each group displayed decreased antithrombin III function, and 1 patient with a lacunar infarction had a low protein C level.

CONCLUSIONS

Primary hematologic disorders and secondary hemostatic derangements may occur in patients with either cortical or lacunar infarction.

Cerebral hypoperfusion in stroke prognosis and brain recovery

BACKGROUND AND PURPOSE

The value of acute cerebral blood flow measurements in stroke prognosis is controversial. No previous study has determined whether acute perfusion deficits independently add to a validated clinical prognostic score. We aimed to compare the value of acute hypoperfusion deficits with a quantitative clinical score in stroke prognosis and to correlate the changes in perfusion with brain recovery.

METHODS

Volumetric analysis of regional hypoperfusion was performed in 38 patients with middle cerebral infarction within 72 hours of onset by use of single photon emission computed tomography and 99mTc hexamethylpropylene amine oxime. Stroke severity was assessed by the Canadian Neurological Score and Barthel Index. Allen's prognostic score was determined acutely in all patients. Clinical outcome was evaluated in 36 of 38 patients, of whom 18 had repeat blood flow studies.

RESULTS

Acute hypoperfusion correlated with both the outcome Barthel Index (P < .001, r = -.61) and Canadian Neurological Score (P < .001, r = -.64). Allen's score correlated better with both the outcome Barthel Index (P < .001, r = .80) and Canadian Neurological Score (P < .001, r = .81). Acute hypoperfusion deficits, after allowing for Allen's score, independently predicted neurological but not functional outcome. Despite overall neurological improvement, mean hypoperfusion increased on the repeat blood flow studies (P < .05).

CONCLUSIONS

Volumetric analysis of acute regional hypoperfusion within 72 hours of onset predicts stroke outcome after 3 months, but Allen's score is a better prognostic method. Neurological recovery is not associated with chronic infarct reperfusion.

The potential for elderly donors to increase renal transplantation rates in Australia

OBJECTIVE

To estimate the potential increase in renal donation rates if elderly donors (those over 60 years of age) were considered.

DESIGN

Patients dying from acute brain damage resulting from stroke were identified using the Royal Melbourne Hospital (RMH) Stroke Service Register. Their records were retrospectively analysed to assess their eligibility as potential renal donors.

SETTING

One hundred and ninety-eight patients dying from acute brain damage caused by stroke at a large metropolitan teaching hospital (RMH), from May 1987 to December 1990 inclusive. PATIENT ASSESSMENT: Patients were considered "eligible", "ineligible" or "possibly eligible" (requiring further assessment) as donors according to existing strict criteria (see methods) but irrespective of age.

RESULTS

Of 198 stroke patients dying of brain damage, 92 satisfied the criteria of eligibility for renal donation; 51 of these were over 60 years old, yet only one became a renal donor.

CONCLUSION

There is good evidence that elderly donors are acceptable for renal transplantation, yet they are not being referred. The consideration of elderly stroke victims as renal donors could have a dramatic effect on decreasing transplant waiting lists, increasing recipient patient well-being, and reducing hospital costs.

Early seizures after acute stroke. Risk of late seizures

The prognosis of early seizures after stroke is controversial. We assessed the incidence of late seizures in 31 patients with early seizures complicating acute stroke and compared this with the incidence of late seizures in 31 matched patients with stroke without early seizures. Ten (32%) of 31 patients with early seizures had late seizures during a mean follow-up period of 26 months. Only three (10%) of 31 patients without early seizures had late seizures during the follow-up period of 28 months, a significantly lower incidence than in patients with early seizures. The risk of seizure recurrence in patients with early seizures did not correlate with stroke type or lesion size as imaged on the computed tomographic scan. We conclude that early seizures are not benign and are associated with a significant risk of seizure recurrence.

Correlations between cerebral arterial velocities, blood flow, and delayed ischemia after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Elevated middle cerebral erythrocyte velocities and tissue hypoperfusion have been correlated with delayed ischemia after subarachnoid hemorrhage, but few studies have compared serial arterial velocities with cerebral blood flow and neurological deficits.

METHODS

Serial measurements of middle cerebral velocities, using transcranial Doppler ultrasonography, were performed in 34 patients after subarachnoid hemorrhage and correlated with cerebral blood flow, measured in 20 of the 34 using single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime and neurological evidence of delayed ischemia.

RESULTS

In 16 patients without delayed ischemia, eight had evidence of vasospasm (greater than 120 cm/sec), but only one of seven had hypoperfusion, suggesting that vasospasm might be more common than hypoperfusion in this group (p = 0.1). In 10 patients with delayed ischemia and a lateralizing deficit, both asymmetrical middle cerebral vasospasm (eight of nine with vasospasm) and hypoperfusion (six of six studied) were concordant with the clinically ischemic hemisphere (p less than 0.05). Vasospasm occurred with nonlateralized delayed ischemia in seven of eight patients and with hypoperfusion in five of six, affecting the anterior cerebral territory in three.

CONCLUSIONS

Concordant vasospasm and hypoperfusion were most often present in patients with delayed ischemia and lateralizing neurological deficits. Discordant results reflect inherent limitations and the different levels of the circulation monitored by the two techniques.

Stroke topography and outcome in relation to hyperglycaemia and diabetes

In a prospective study to analyse stroke topography and outcome in diabetics and to determine the prognostic value of blood glucose and glycosylated haemoglobin estimation, we evaluated 176 patients with acute stroke. The patients were classified into four groups on the basis of history, fasting glucose, and glycosylated haemoglobin: euglycaemic patients with no history of diabetes, stress hyperglycaemia, newly diagnosed diabetics, and known diabetics. A high prevalence of undiagnosed diabetes was shown. No difference was found in the type or site of stroke between the four groups. No difference was found in the site of symptomatic or incidental lesions on computerised axial tomography. Patients with stress hyperglycaemia and known diabetics had more severe strokes. Mortality was higher in patients with stress hyperglycaemia, newly diagnosed diabetics, and the combined diabetes groups. This increased mortality was evident in the hyperglycaemic and diabetic groups, even after excluding patients with cerebral haemorrhage. Stroke severity and mortality also increased independently with blood glucose in the euglycaemic group. We conclude that there is a correlation between admission glucose concentration, diabetes, and poor stroke outcome, which may not be attributed to stroke type or location.

Acute stroke outcome: effects of stroke type and risk factors

We studied 925 consecutive patients hospitalised with acute stroke to determine how stroke type, age, gender and risk factors influence acute, in-hospital outcome. Stroke types included carotid territory cortical or large subcortical infarction (52%), vertebrobasilar infarction (12%), lacunar infarction (11%), intracerebral haemorrhage (16%), and subarachnoid haemorrhage (9%). Mean age (mean +/- 1 SD) was 66 +/- 15 years, but patients with cerebral infarction were older than those with cerebral haemorrhage. The prevalence of hypertension, diabetes mellitus and cardiac disease increased with age across all stroke types, while the prevalence of smoking decreased with age. Mortality was 19% overall, but varied significantly between stroke types, highest in intracerebral haemorrhage (34%), and lowest in lacunar infarction (1%). Age had a marked adverse effect on mortality, independent of stroke type, the probability of death increasing by 3 +/- 0.5% per year from 20-92 years, whereas gender had no effect. Cardiac disease and diabetes were independent adverse prognostic factors (Odds Ratios 1.6 and 1.5 respectively). Cerebral haemorrhage, age, cardiac disease and diabetes all independently worsen acute stroke outcome.

Effects of 4 percent and 6 percent carboxyhemoglobin on arrhythmia production in patients with coronary artery disease

In this study, we assessed the effects of exposure to 4 percent and 6 percent carboxyhemoglobin on ventricular arrhythmias in 41 subjects (nonsmokers) with documented coronary artery disease. We used a randomized, double-blind, crossover design. On day 1, a training session with no exposure, the baseline carboxyhemoglobin level was measured, and a supine bicycle exercise test was done. On days 2 through 4, subjects were exposed to room air, 100 parts per million (ppm)2 carbon monoxide (target, 4 percent blood carboxyhemoglobin), or 200 ppm carbon monoxide (target, 6 percent blood carboxyhemoglobin), and they then did a supine bicycle exercise test. Radionuclide ventriculography was performed at rest and during exercise. Ambulatory electrocardiogram recordings were made during the four consecutive days to determine the frequency of premature ventricular contractions at various intervals. The frequency of single premature ventricular contractions per hour during exercise was significantly greater on the 6 percent carboxyhemoglobin day than on the room air day (167.72 +/- 37.99 for 6 percent carboxyhemoglobin compared with 127.32 +/- 28.22 for room air, p = 0.03). The frequency of multiple premature ventricular contractions per hour was also significantly greater during exercise on the 6 percent carboxyhemoglobin day compared with the room air day (9.59 +/- 3.70 for the 6 percent carboxyhemoglobin day compared with 3.18 +/- 1.67 for the room air day, p = 0.02). Patients who developed increased arrhythmias during exercise on the 6 percent carboxyhemoglobin day were significantly older than those who had no increased arrhythmia, and, in addition, exercised longer and had a higher peak workload during exercise. No effect of carbon monoxide exposure was seen on the 4 percent carboxyhemoglobin day.

Ethnic and gender differences in Southwestern students' sources of information about health

Students from several rural, Southwestern schools rated family, television, teachers and doctors as the most important of 11 sources of information about various health topics. However, doctors were only the fifth-ranked source of information about sex and reproduction and the seventh-ranked source of information about drugs, with friends being the fourth- and third-ranked sources of information about these two more personal and sensitive topics. American Indians reported even stronger reliance on doctors than did Hispanic and Anglo students, and rated clinic nurses as much more important sources of health information than did the other two ethnic groups. Females showed greater reliance on social sources and less on electronic media than did male students, and high school students relied more on print media and less on television, nurses and family than did younger children. Students felt more knowledgeable about smoking, alcohol and exercise than about diet, the heart-blood system and cancer; however, American Indians felt less informed about smoking and alcohol than did Anglos or Hispanics. These findings (especially when compared to previous results) suggest that effective health education programs must be tailored to particular populations and based on specific knowledge of their attitudes, behavior and environment.

Asthma in the elderly. A comparison between patients with recently acquired and long-standing disease

To characterize asthma in the elderly, 25 consecutive nonsmoking pulmonary clinic patients over the age of 70 who met the American Thoracic Society criteria for asthma were identified. Of these, 12 patients (48%) had developed asthma at an advanced age (greater than 65 yr). This group with late-onset asthma had a mean duration of disease of 5.1 +/- 2.5 yr. The remaining group with early-onset asthma had a mean duration of illness of 31.4 +/- 14.6 yr. On the day of evaluation each patient underwent pulmonary function testing off all medication for at least 12 h. These two groups were indistinguishable by symptoms and medication requirements. Immediate hypersensitivity skin testing to 43 aeroallergens was uniformly negative in all 25 patients but the histamine control was always positive. IgE levels in both groups were not different from those in elderly control subjects. Those with early-onset asthma had a greater likelihood of previous allergic disease (p less than 0.001) and a significantly greater degree of airflow obstruction in pre- and postbronchodilator pulmonary function testing (p less than 0.05). This study suggests that long-standing asthma may lead to chronic persistent airflow obstruction and thereby mimic chronic bronchitis and emphysema (COPD).

Enrichment for academic success: helping at-risk students

Successful retention of at-risk nursing students is best accomplished through an organized system that addresses their individual needs in the areas of academic, cognitive, and self-enhancement skills. The cooperative endeavors of students, faculty, and administrators in the development of one such system, Enrichment for Academic Success, has resulted in a 95% retention rate among participants. The authors describe the incentive, development, implementation, and value of the system which can be adapted to any setting with adequate human and material resources.

Genetic evidence that Neisseria gonorrhoeae produces specific receptors for transferrin and lactoferrin

Transferrin (TF) and lactoferrin (LF) are probably the major sources of iron (Fe) for Neisseria gonorrhoeae in vivo. We isolated mutants of N. gonorrhoeae FA19 that were unable to grow with Fe bound to either TF (TF-) or LF (LF-) or to both TF and LF ([TF LF]-). The amount of Fe internalized by each of the mutants was reduced to background levels from the relevant iron source(s). The wild-type parent strain exhibited saturable specific binding of TF and LF; receptor activity was induced by Fe starvation. The TF(-)-specific or LF(-)-specific mutants were almost completely lacking in receptor activity for TF or LF, respectively, whereas the [TF LF]- mutants bound both TF and LF as well as the wild-type strain. All mutants utilized citrate and heme normally as Fe sources. These results demonstrate that ability to bind TF or LF is essential for gonococci to scavenge appreciable amounts of Fe from these sources in vitro. In addition, the TF and LF Fe acquisition pathways are linked by the mutual use of a nonreceptor gene product that is essential to Fe scavenging from both of these sources; this gene product is not required for Fe acquisition from other sources.

Epileptic seizures in acute stroke

We evaluated prospectively the incidence of early seizures in 1000 consecutive patients with stroke and transient ischemic attacks to determine whether seizure occurrence correlates with stroke type, pathogenesis, or outcome. Seizures occurred in 44 patients (4.4%; SE, 0.7%), including 10 (15.4%) of 65 (SE, 4.5%) with lobar or extensive hemorrhage, 6 (8.5%) of 71 (SE, 3.3%) with subarachnoid hemorrhage, 24 (6.5%) of 370 (SE, 1.3%) with cortical infarction, and 4 (3.7%) of 109 (SE, 1.8%) with hemispheric transient ischemic attacks. Lacunar infarcts and deep hemorrhages were not associated with seizures. Arteriovenous malformation was a common cause of lobar hemorrhage with early seizures, but in cortical infarcts there was no association between seizure occurrence and pathogenesis. Seizures generally occurred within 48 hours of stroke onset, were usually single, partial, and readily controlled. Seizures were not associated with a higher mortality or worse functional outcome.

Magnetic resonance imaging in posterior circulation infarction: impact on diagnosis and management

To compare the diagnostic yield of magnetic resonance imaging (MRI) with computed tomography (CT) in posterior circulation infarction, we used proton MRI with a 0.3 Tesla magnet and a 3rd generation CT scanner in 25 patients. Age-matched controls were compared in a blinded fashion. Seventeen patients (68%) showed relevant pathology on MRI not seen on CT, 11 with normal CT and six with more extensive lesions, chiefly in the brain stem. Evidence of abnormal vertebrobasilar blood flow was seen in 8/25 (32%) of patients, suggested by vascular high intensity signals on MRI. Two tissue and one flow abnormality were seen in the control group. MRI provides additional information concerning infarct site, extent and pathogenesis in posterior circulation infarction.

Core, secondary, and peripheral foods in the diets of Hispanic, Navajo, and Jemez Indian children

Our results show the importance of a number of regional foods and suggest some differences in the dietary patterns of three ethnic groups in the same region. Dietitians and nutritionists should be aware of the rich ethnic diversity of dietary patterns and use this knowledge in nutrition counseling, program planning, and nutrition education.

Phenytoin-carbamazepine cross-sensitivity

A case of phenytoin-carbamazepine cross-sensitivity is presented. Similar signs and symptoms occurred during administration of both drugs. A common metabolic intermediate is offered as a possible explanation of the mechanism. Clinicians should be careful when choosing alternatives in patients with hypersensitivity reactions to anticonvulsants. Valproic acid may be the safest choice in this setting.

Carotid endarterectomy: why question it now?

Carotid endarterectomy has been accepted widely as an important stroke-prevention tool since the 1950s, in spite of the lack of any proof of its efficacy in randomized, controlled clinical trials in either symptomatic or asymptomatic patients. While surgery for asymptomatic carotid disease always has been controversial, the indications and benefits of carotid endarterectomy in symptomatic patients now are being questioned also, although the available evidence suggests that the operation, when performed in expert hands, reduces the incidence of subsequent strokes in patients with minor, carotid-territorial ischaemic events and significant ipsilateral carotid disease. (A morbidity and mortality rate of more than 3% is unacceptable, and hence the procedure should be undertaken only by those who are skilled in its performance). For each patient, a decision has to be made as to whether the potential reduction of the risk of stroke outweighs the immediate surgical risk of stroke or death. Some large, expensive and important randomized clinical trials are either proposed or under way in North America and Europe to evaluate the precise role of carotid endarterectomy in the prevention of strokes. The basis for the current questioning of carotid endarterectomy and the rationale for these trials are addressed in this review.

Improving the health of Indian teenagers--a demonstration program in rural New Mexico

The health status of Indian teenagers in the United States is below that of the general population. The usual barriers to the use of health care services that young people, including young Indians, encounter are compounded in rural areas by distance, isolation, and lack of appropriate services. To overcome these barriers in rural New Mexico, a public health demonstration project (a) established a single location where adolescents can receive multiple, integrated health care services free of charge; (b) set up the initial program of services at a rural school; (c) established links with existing agencies; and (d) incorporated community action toward creating change. The project began as a joint effort of three communities, the University of New Mexico (UNM), and the Albuquerque Area Indian Health Service (IHS) of the Public Health Service; a secondary level public school soon became a participant. The project is being replicated in two other communities that have formed separate partnerships with UNM and the area IHS; also the New Mexico Health and Environment Department has joined the effort in one community. Preliminary data suggest that the services are being used by a majority of the target population, with the proportions of boys and girls about equal.

Analysis of dynamic computed tomography scan brain images

Dynamic computed tomography (DCT) of the brain can be used to study the transit time of first passage of a bolus injection of intravenous contrast medium. Comparison of cerebral perfusion with corresponding sites in the left and right cerebral hemispheres is of diagnostic interest because a real difference may be indicative of differential damage. A method for estimating the mean transit time and approximating its standard error, by assuming a gamma function for the response curve and an appropriate error structure, is presented. Expressed as log-linear regression, estimation is achieved by maximum likelihood using a statistical package such as GLIM or SPSSX. Statistical comparison of the mean transit time to or between corresponding sites can be made; issues of model fit and biologic interpretation need to be considered as an integral part of statistical inference. These methods enable users of CT equipment (without specific software for estimation of mean transit time) to use any log-linear routine for diagnostic purposes. An example of the fit procedure and interpretation in the light of clinical evidence is given.

Dynamic CT brain scanning in the haemodynamic evaluation of cerebral arterial occlusive disease

Dynamic cerebral CT scanning (DCT) was used to quantitatively analyse the haemodynamic effects of extracranial and intracranial arterial occlusive lesions in 17 patients with TIA's or minor cerebral infarcts. Using DCT and gamma variate curve fitting, mean transit times were determined for the terminal internal carotid arteries, middle cerebral arteries and middle cerebral-supplied Sylvian cortex at the level of the Circle of Willis. Six patients were studied sequentially, four before and after transcranial bypass surgery. No arterial or tissue delays were found in patients without haemodynamic arterial lesions or cortical infarcts. Seven of nine patients with haemodynamic, extracranial carotid lesions showed ipsilateral delays in arterial or tissue transit times. Tissue delays usually correlated with CT or clinical evidence of infarction. Improved haemodynamics in patients re-studied correlated with the effects of surgery or clinical recovery. DCT has several important limitations but has the potential to provide additional haemodynamic information about the cerebral circulation in selected patients with cerebral arterial occlusive disease.

Wheezing in the elderly. Asthma and other causes

The evaluation and treatment of patients who complain of wheezing take on special significance in the elderly. Although asthma may begin late in life, it is distinctly uncommon. When it does, it is clinically undistinguishable from asthma present at an earlier age. If severe, the disease may require treatment with corticosteroids as well as bronchodilators. Any side effects are particularly troublesome in the elderly, and careful patient monitoring is essential. Wheezing in the elderly may also signal the onset of other diseases such as chronic obstructive pulmonary disease, congestive heart failure, pulmonary aspiration, pulmonary embolism, and bronchogenic carcinoma. Consideration of these causes of wheezing will lead to appropriate diagnostic studies and specific therapy.

Antishock trousers: a collective review

Antishock trousers have become an integral part of emergency medical care for many traumatic and life-threatening emergencies. This article represents a summary of the current state of knowledge concerning the use of this device. A brief history of the development of antishock garments is discussed. This is followed by a discussion of human clinical studies and results of clinical research on hemodynamics, respiration, use in head injury, and effects on vascular hemostasis. Indications, contraindications, complications, and recommended procedure for use are discussed. Based on randomized prospective studies, antishock garments have not, as yet, been shown to improve patient morbidity or mortality. Proper use of antishock garments requires an understanding of both their function and their limitations.

Intravenous digital subtraction angiography in patients with carotid territory ischemia: a prospective trial

To evaluate the place of intravenous digital subtraction angiography (IV-DSA) in the investigation of patients with carotid territory ischemia, we have compared the IV-DSA and conventional angiographic (CA) findings in 40 patients in a prospective study. Arterial disease was assessed by grading stenosis from zero (normal artery) to six (complete occlusion) and recording any luminal ulceration. In 59 of 66 bifurcations imaged by both techniques, the IV-DSA evaluation of any internal carotid artery origin disease was within one grade of the CA assessment, with three false negatives and four false positives. Luminal ulceration was less reliably predicted, and two clinically important middle cerebral artery lesions were missed by IV-DSA. In 11 patients who had carotid endarterectomy, there was a good correlation between surgical, CA, and IV-DSA findings, although some ulcerations were not detected by either angiographic technique. These results suggest that IV-DSA is a sensitive technique for detection of carotid bifurcation stenosis when the study is of good quality, but that intracranial lesions may be missed.

Positron imaging in ischemic stroke disease

Positron emission tomography (PET) is well suited to the study of ischemic stroke disease. It has the potential to help elucidate pathophysiological mechanisms, differentiate viable from nonviable tissue, and provide a more rational basis for developing specific therapies for ischemic lesions. The different tracer strategies that may be applied to the study of ischemic disease, however, all have relative limitations, which may be related to the physical or biological determinants of the tracer distributions, to the tracer half-lives, or to the methods required for quantitation of the data. Determination of blood flow and oxygen metabolism are useful for characterizing stroke lesions, but other parameters, such as the oxygen extraction fraction, blood volume, and glucose metabolism, can provide important interpretative information. Correlation of the physiological PET data with the clinical presentation and course is a primary requisite for the development of the full potential of PET.

High carboxyhemoglobin level without acute or chronic findings

The clinical effects of carbon monoxide in humans have been well studied and described. Carboxyhemoglobin levels usually correlate with the degree of symptomatology; however, some investigators have noted that there may be a wide disparity between absolute carboxyhemoglobin levels and clinical status. A case is reported here of a young man with a potentially lethal level of carbon monoxide who developed neither significant symptomatology nor long-term sequelae. Until a more sensitive indicator of clinical outcome is found, clinicians must rely on carboxyhemoglobin levels and clinical history and examination to make treatment decisions, realizing that clinical presentation and absolute carboxyhemoglobin levels may correlate poorly.

Adolescents' questions about sex

Male and female Anglo, Hispanic and Native American adolescents from urban and rural areas were given a chance to ask anonymous questions about sex. These questions were then used as the bases for subsequent presentations on sex education. The most popular categories of questions were reproduction, sexuality, and contraception, followed by anatomy, venereal disease, pregnancy, abortion, vocabulary, hygiene, and other diseases. Younger adolescents asked significantly more questions in most categories than older ones. Girls asked significantly more total questions and ones concerning pregnancy, contraception, and anatomy than boys. Students attending rural schools asked more questions about venereal disease than those in urban schools, but no other main effects of urban-rural location were found. There were no ethnic differences found. The adolescents' questions ranged from sophisticated to poignantly ignorant, suggesting that the strategy of adapting sex education sessions to fit the concerns of the specific adolescents involved might be valuable.

Cerebral blood flow and cerebrovascular CO2 reactivity in stroke-age normal controls

We used the noninvasive 133-xenon inhalation technique to determine cerebral hemodynamics in 55 normal volunteers aged 18 to 88. Values for cerebral blood flow and cerebrovascular CO2 reactivity in fast-clearing tissue (flow gray) and slow-clearing tissue (flow white) were examined as functions of age and in relation to hematocrit, blood pressure, and evidence of extracranial vascular disease. Flow gray declined linearly with age, but no corresponding change was found in flow white or in CO2 reactivity. The data suggest that the progressive fall in flow gray is due to a physiologic aging process.

The effect of amyl nitrite on the mitral valve echocardiogram in presumably healthy young adults

We analyzed the use of amyl nitrite as a provocative factor in the diagnosis of mitral valve prolapse in a population of healthy young adults. Sixty-five men and 11 women underwent continuous M-mode echocardiographic and phonocardiographic monitoring before, during and after the administration of inhaled amyl nitrite. All of the 76 subjects had normal baseline echocardiograms, and all had a satisfactory hemodynamic response to amyl nitrite. Mitral valve prolapse, defined by echocardiography and phonocardiography, was not provoked in any of the subjects. Therefore, we concluded that, although this technique may be difficult, significant false-positive results should not occur if adherence to strict diagnostic criteria takes place.

Estimation of the local statistical noise in emission computed tomography

A simple modification of the filtered backprojection algorithm is presented for the computation of the local statistical noise in emission computed tomography. The technique is general in that any distribution of radioactivity may be accommodated. When applied to positron emission tomography, it is shown that the effects of photon absorption, random coincidences, radioactive decay, and detector nonuniformity may be included. Calculations have shown the effects of resolution, object size, and photon absorption on the statistical noise of disk-shaped emitters. Comparison of calculation and experiment show close agreement both in magnitude and spatial variation. Measurements of the noise level in tomograms of the brain obtained during continuous inhalation of 150-CO2 demonstrate that estimates of radioactivity concentration with a precision of a few percent are readily attainable.

Stimulus-sensitive spinal myoclonus

Two cases of spinal myoclonus are described; in both patients myoclonus was responsive to stimuli and absent during sleep. The first patient was considered to have viral neuronitis and the condition resolved spontaneously. The second patient had spinal cord ischaemia; there was electro-physiological evidence of abnormal alpha motor neurone activity and histological study of the spinal cord revealed a severe reduction in small and intermediate neurones. This supports the theory that spinal myoclonus may result from abnormal activity of alpha motor neurones released from control by spinal internuncial neurones.

Disordered pigmentation, spastic paraparesis and peripheral neuropathy in three siblings: a new neurocutaneous syndrome

Three siblings in a Jordanian family presented with a distinctive syndrome consisting of disordered skin and hair pigmentation, progressive spastic paraparesis and peripheral neuropathy. Sural nerve biopsy revealed axonal degeneration and skin biopsy showed abnormal epidermal pigmentation. Skin fibroblast repair studies were normal. No underlying biochemical defect has been found in this previously undescribed neurocutaneous syndrome.

Biofeedback theory and application in allied health: speech pathology

The implementation of biofeedback procedures represents a new approach to clinical management of speech disorders. Thus far, results of experiments utilizing biofeedback techniques have suggested positive effects in the remediation of speech disorders. The purpose of this paper is to provide the reader with the principles of biofeedback; to survey areas of clinical application including voice, fluency, and other clinical disorders; and to explore potential applications of biofeedback procedures for the speech and language pathologist.

Auditory fusion in children

"Auditory fusion" was defined in terms of a listener's ability to distinguish paired acoustic events from single acoustic events. Children from the ages of 3-12 years listened to 270 pairs of tones controlled for frequency, intensity, and duration. Stimuli consisted of numerous pairs of tone pulses, separated by interpulse intervals that varied systematically from 0 through 40 msec. Results indicate that (a) auditory fusion improves rapidly and in an orderly fashion between 3 and 8 years of age, (b) signal intensity affects the fusion point, and (c) stimulus frequency--253 hertz through 4,000 hertz, at 5-octave intervals--does not affect the fusion point.