Consensus statement on the definition of orthostatic hypotension, pure autonomic failure, and multiple system atrophy. The Consensus Committee of the American Autonomic Society and the American Academy of Neurology

Blood pressure regulation, cognition, and depression in response to orthostatic challenge in African American children: an initial investigation

Poor blood pressure regulation (BPR) in response to orthostasis could contribute to cerebral hypoperfusion and cell damage. The authors of this study examined neuropsychological function and mood in relation to BPR following orthostatic challenge in African American children, aged 6 to 9 years. Participants (N = 33) laid supine for 5 minutes, before having their BP taken. Participants then stood and had BP measured again at 1, 3, and 5 minutes. After a rest, the authors administrated neuropsychological and depression tests while the participants were seated. The authors calculated the difference between supine and 1-minute standing systolic blood pressure (SBP) and pulse pressure (PP) scores. In response to orthostatic challenge, smaller increases in SBP were predictive of decreased verbal memory whereas smaller increases in PP were associated with increased depressive symptomatology and poor prospective memory. In conclusion, less effective BPR was associated with increased depression and poor performance on some neuropsychological tests.

Diagnosing multiple system atrophy with greater accuracy: combined analysis of the clonidine-growth hormone test and external anal sphincter electromyography

The clonidine-growth hormone test (CGHT) has been proposed as a means of differentiating multiple system atrophy (MSA) from idiopathic Parkinson's disease (PD). However, it is controversial whether the CGHT is valid. We sought to confirm the validity of the CGHT and to compare the diagnostic accuracy of the CGHT with that of external anal sphincter electromyelography (Sph-EMG) for MSA. We performed the CGHT and the Sph-EMG on 21 PD patients, 23 patients with probable MSA of parkinsonian type (MSA-p), and 22 patients with probable MSA of cerebellar type (MSA-c). We compared the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of CGHT, Sph-EMG, and a combination of the two tests. We also evaluated the correlations of Unified Parkinson's Disease Rating Scale (UPDRS) scores with the results of the two tests. There was no significant difference between the UPDRS scores for the PD and MSA-p groups. Serum growth hormone concentrations after clonidine significantly increased in PD (mean increase +/- SEM, 4.19 +/- 0.92 ng/ml; P < 0.0001), but remained unchanged in both MSA-p (0.83 +/- 0.61 ng/ml) and MSA-c (1.45 +/- 0.58 ng/ml). The growth hormone responses to clonidine in MSA-p were significantly different from those in PD (P < 0.05). Abnormal, denervated Sph-EMG was observed in 95.7% of MSA-p, 86.4% of MSA-c, and 33.3% of PD patients. Compared to Sph-EMG, the CGHT was less sensitive but more specific in both MSA-p and MSA-c. The result of neither test correlated with the severity of parkinsonism. Interestingly, combining the results of the CGHT and Sph-EMG markedly increased the specificity (85.7% in the CGHT and 66.7% in Sph-EMG vs. 95.2% in the combination study) and the PPV in both MSA-p (85.7% and 75.9% vs. 94.4%) and MSA-c (82.4% and 73.1% vs. 91.7%). We confirm that the CGHT can distinguish MSA-p from PD. Its sensitivity is lower and its specificity higher than Sph-EMG. Compared to either test alone, combined testing with the CGHT and Sph-EMG increased specificity and PPV, thereby enhancing accuracy in the diagnosis of MSA.

Neurocardiovascular instability in cognitive impairment and dementia

Neurocardiovascular instability (NCVI, neurally mediated disorders causing hypotension with or without bradycardia) represents abnormal neural control of the cardiovascular system and presents as dizziness, syncope, or falls. The mechanisms underpinning NCVI are incompletely understood. The three most common disorders are carotid sinus syndrome (CSS), orthostatic hypotension (OH), and vasovagal syndrome (VVS): CSS, cardioinhibition > 3 s and/or vasodepressor response > or = 50 mmHg drop in systolic pressure during carotid sinus stimulation; OH: fall in systolic blood pressure > 20 mmHg during standing; VVS: cardioinhibition > 3 s and/or vasodepressor response > 50 mmHg during prolonged head-up tilting. In fallers with cognitive impairment or dementia, the prevalence of NCVI is 70%. Multifactorial interventions, including treatment of NCVI, significantly reduce falls and syncope. The predominant components of NCVI in fallers with cognitive impairment and dementia are CSS and OH. In Lewy body and Alzheimer's dementia, the prevalence of NCVI is up to 60%, again predominantly CSS and OH. The prevalence of cardioinhibitory carotid sinus hypersensitivity is particularly high in Lewy body dementia-41% compared with 12% in Alzheimer's disease and 3% in case controls. In addition, patients with Lewy body dementia have greater heart rate slowing (>2 s) and falls in systolic blood pressure (>20 mmHg) than those with Alzheimer's disease or controls during carotid sinus stimulation. The extent of deep white matter hyperintensities on MRI correlates with systolic fall during carotid sinus stimulation (R = 0.58; p < 0.005), suggesting a possible causal association between bradyarrhythmia-induced hypotension and microvascular pathology. NCVI is common in patients with dementia and may be a reversible cause of falls and syncope. Repeated hypotensive episodes may exaggerate cognitive decline in these patients.

Association between the blood pressure response to a change in posture and the 6-year incidence of hypertension: prospective findings from the ARIC study

The association between the blood pressure response to a change from the supine to the standing position and the 6-year incidence of hypertension was studied in a bi-ethnic, middle-aged cohort of 6951 normotensive men and women free of coronary heart disease at baseline. Postural change in systolic blood pressure (SBP) was categorized into deciles, and the middle four deciles served as the referent (no change) group. In unadjusted analyses, the incidence of hypertension was higher among both those with SBP increases and decreases relative to those in the referent group. Associations were modestly attenuated after controlling for age, ethnicity, and gender and cardiovascular disease risk factors. However, after adjustment for baseline, seated SBP, a modest association with incident hypertension persisted only for SBP decreases. Orthostatic hypotension (upon standing) was associated with incident hypertension and isolated systolic hypertension and, unexpectedly, this increased risk was highest among those with the lowest levels of baseline, resting SBP.

Autonomic neuropathy is associated with increased cardiovascular risk factors: the EURODIAB IDDM Complications Study

AIMS

To assess the prevalence of and risk factors for autonomic neuropathy in the EURODIAB IDDM Complications Study.

METHODS

The study involved the examination of randomly selected Type I (insulin-dependent) diabetic patients from 31 centres in 16 European countries. Neuropathic symptoms and two tests of autonomic function (changes in heart rate and blood pressure from lying to standing) were assessed and data from 3007 patients were available for the present analysis. Autonomic neuropathy was defined as an abnormality of at least one of the tests.

RESULTS

The prevalence of autonomic neuropathy was 36% with no sex differences. The frequency of one and two abnormal reflex tests was 30% and 6%, respectively. The R-R ratio was abnormal in 24% of patients while 18% had orthostatic hypotension defined as a fall in systolic blood pressure > 20 mmHg on standing. Significant correlations were observed between autonomic neuropathy and age (P < 0.01), duration of diabetes (P < 0.0001), HbA1c (P < 0.0001), diastolic blood pressure (P < 0.05), lower HDL-cholesterol (P < 0.01), the presence of retinopathy (P < 0.0001) and albuminuria (P < 0.0001). New associations have been identified from the study: the strong relationship of autonomic neuropathy to cigarette smoking (P < 0.01), total cholesterol/HDL-cholesterol ratio (P < 0.05) and fasting triglyceride (P < 0.0001). As a key finding, autonomic neuropathy was related to the presence of cardiovascular disease (P < 0.0001). All analyses were adjusted for age, duration of diabetes and HbA1c. However, data have been only partly confirmed by logistic regression analyses. Frequency of dizziness on standing up was 18%, while only 4% of patients had nocturnal diarrhoea and 5% had problems with bladder control.

CONCLUSION

Cardiovascular reflex tests, even in the form of the two tests applied, rather than a questionnaire, seem to be appropriate for the diagnosis of autonomic neuropathy. The study has identified previously known and new potential risk factors for the development of autonomic neuropathy, which may be important for the development of risk reduction strategies. Our results may support the role of vascular factors in the pathogenesis of autonomic neuropathy.

Supine hypertension during general anesthesia in a patient taking midodrine

IMPLICATIONS

Midodrine, a drug used to treat symptomatic orthostatic hypotension, may cause or exacerbate supine hypertension. We describe a case of a patient taking midodrine who exhibited severe hypertension during general anesthesia. Possible preventive measures to avoid this complication are discussed.

Clinical correlates of the pathology underlying parkinsonism: a population perspective

We correlated the clinical features with pathological findings in an autopsy series of cases of incident parkinsonism. We used the medical records-linkage system of the Rochester Epidemiology Project to identify all incident cases of parkinsonism in Olmsted County, MN, for the years 1976 to 1990. Medical histories were abstracted in a standardized manner. Included in this study were those incident cases who died and underwent autopsy. Brain sections were studied with routine histology and special stainings. A neuropathologist blinded to any clinical information assigned cases to neuropathological categories. We found 364 incident cases of parkinsonism of which 235 were deceased at the time of this study; there were 39 autopsied brains available for analysis (17% of deceased cases). Of the 16 patients diagnosed pathologically with Lewy body disease, documentation indicated that 8 had an early dementia, 3 had prominent dysautonomia, and 2 had prominent ataxia. Of the 7 patients diagnosed pathologically with progressive supranuclear palsy, 4 had no documentation of supranuclear gaze palsy, and 3 had no documentation of early falls. Of the 3 patients diagnosed pathologically with multiple system atrophy, none had prominent ataxia or dysautonomia documented. Of the 5 patients with vascular disease at pathology, none had been given the clinical diagnosis of vascular parkinsonism. Of the 8 cases given the clinical diagnosis of drug-induced parkinsonism, 6 were found to have basal ganglia pathology. The autopsied cases in this study were not representative of all patients with parkinsonism, because atypical cases are more likely to come to autopsy than typical ones. Despite this selection bias, the retrospective data collection, and the small sample size, we made several observations that illustrate the difficulty in achieving an accurate antemortem diagnosis of parkinsonism.

Impaired chemosensitivity to hypoxia is a marker of multiple system atrophy

Sudden death is common in patients with multiple system atrophy (MSA). In its early stages, the cerebellar presentation MSA-C can be indistinguishable from idiopathic late-onset cerebellar ataxia. We studied the hypoxic ventilatory response in MSA-C and idiopathic late-onset cerebellar ataxia patients. Six patients with idiopathic late-onset cerebellar ataxia that later evolved to MSA had impaired hypoxic ventilatory response when minimal autonomic failure was still present, whereas for patients with unimpaired hypoxic ventilatory response their diagnosis remained idiopathic late-onset cerebellar ataxia. The demonstration of impaired hypoxic ventilatory response appears to be a good marker enabling earlier diagnosis of MSA in patients presenting with idiopathic late-onset cerebellar ataxia.

Cerebral metabolic changes in early multiple system atrophy: a PET study

Previous positron emission tomography (PET) studies have shown widespread hypometabolism in the brain of advanced MSA but the time course of these metabolic abnormalities is largely unknown. In order to clarify the principal disease processes in multiple system atrophy (MSA) in the early stage, we investigated regional cerebral glucose metabolism (rCMGglc) and nigral dopaminergic function in nine patients with early stage of MSA using [(18)F]fluorodeoxyglucose (FDG) and 6-L-[(18)F]fluorodopa ((18)F-Dopa) positron emission tomography (PET) (two men and seven women; age, 59.3+/-5.4 years; disease duration, 29.7+/-14.6 months). The rCMRglc in the early MSA patients significantly decreased in the cerebellum, brainstem, and striatum compared with that in nine normal subjects. A significant correlation was found between the severity of autonomic dysfunction and rCMRglc within the brainstem. The severity of extrapyramidal signs also correlated with the decline of F-Dopa uptake but not that of rCMRglc within the striatum. The degree of atrophy on MRI has correlated with neither the clinical symptoms nor rCMRglc at the cerebellum and the brainstem. Our PET studies demonstrated widespread metabolic abnormalities except for the cerebral cortex in the brain of MSA even in the early stage. The hypometabolism in the brainstem was tightly linked to the autonomic dysfunction. Not the striatal dysfunction but the nigral damage may be responsible for the extrapyramidal symptoms in early MSA.

Bionic technology revitalizes native baroreflex function in rats with baroreflex failure

BACKGROUND

We developed a bionic technology for the treatment of baroreflex failure and tested its efficacy in restoration of arterial pressure against head-up tilt (HUT) in rats with baroreflex failure.

METHODS AND RESULTS

The bionic baroreflex system (BBS) was a negative feedback system controlled by a computer, the artificial vasomotor center. It sensed systemic arterial pressure (SAP) through a micromanometer placed in the aortic arch and automatically computed the frequency of a pulse train to stimulate sympathetic efferent nerves. We selected the celiac ganglion as the sympathetic vasomotor interface. To make this system bionic, the operational rule of the artificial vasomotor center (H(BRP-->STM); BRP indicates baroreceptor pressure; STM, electrical stimulation) was actively matched to that of the native center. First, we identified the open-loop transfer functions of the native baroreflex control of SAP (H(Native)) and the response of SAP to electrical stimulation of the celiac ganglion (H(STM-->SAP)). We computed H(BRP-->STM) from H(Native)/H(STM-->SAP) and transplanted the operational rule into the computer. In 10 rats with baroreflex failure, we evaluated the performance of the BBS during rapid hypotension induced by HUT. Abrupt HUT dropped SAP by 34+/-6 mm Hg in 2 seconds and by 52+/-5 mm Hg in 10 seconds. During real-time execution of the BBS, on the other hand, the fall in SAP was 21+/-5 mm Hg at 2 seconds and 15+/-6 mm Hg at 10 seconds after HUT. These arterial responses controlled by the BBS were indistinguishable from those by the native baroreflex.

CONCLUSIONS

We concluded that the BBS revitalized the native baroreflex function in rats with baroreflex failure.

Noise-induced compensation for postural hypotension in primary autonomic failure

Noise can have a beneficial effect on sensory neurological systems, enhancing detection of small afferent signals and thereby improve efferent neural responses. We hypothesized whether a similar mechanism would facilitate impaired neural transmission associated with neurological disease, and tested whether addition of external noise to baroreceptor signaling could improve blunted autonomic efferent responses to a postural challenge in patients with primary autonomic failure (PAF). Five PAF patients were tested, one in duplicate and another triplicate, for their transient responses of heart rate (measured from electrocardiographic RR intervals; RRIs) and systolic (SBP) and diastolic (DBP) blood pressures to either 30 degrees or 60 degrees head-up tilt, with and without continuous application of beat-to-beat Gaussian white noise to the carotid sinus baroreceptors. Also, the effects of noise were compared with those by a continuous positive pressure applied to the carotid sinus baroreceptors. The data were fit to a first order model to evaluate the speed (by the time constant; tau) and the magnitudes (by the steady state gains; Gs) of RRI and blood pressure responses. The PAF patients exhibited marked drops in SBP and DBP and a blunted increase in heart rate upon transition from a supine to a head-up position. Addition of noise, not the continuous positive pressure, to the arterial baroreceptors significantly (P<0.05) increased the G in RRI and diminished the Gs in SBP and DBP, though the time courses (taus) of both the RRI and blood pressure responses were unaffected. The addition of external noise to baroreceptor signaling ameliorated the marked postural hypotension seen in patients with PAF.

Update on anorexia and cachexia

Declining physical, emotional, and social function as a result of anorexia and cachexia are considerable contributors to discomfort for cancer patients and their families, and they impair the patient's ability to express optimal physical and psychosocial potential as long as possible. This decline no longer has to be accepted as an indispensable sequel to advanced cancer, just as pain is no longer considered to be unavoidable. A routine screening for anorexia and cachexia and associated symptoms is necessary, as is a careful, comprehensive assessment, because the condition is not always obvious. Decisions about anorexia and cachexia treatment are guided by prioritizing the different, concurrent physical, psychosocial, and existential problems and by considering the natural course of the cancer and the effects of antineoplastic therapies. Reversible causes for anorexia and cachexia need to be identified and treated, if appropriate. Nutritional interventions are often indicated; patients with a predominant starvation component and without inflammation may profit the most. New pharmacologic therapies for primary anorexia and cachexia syndrome are expected to enter clinical practice soon; however, until then, treatment with corticosteroids, progestins, or prokinetics may be indicated for some patients. To understand a multicausal syndrome, multimodal and interdisciplinary therapy is required. Specialist palliative care services can be helpful to provide, hand-in-hand with the disease specialists [172], assessment and management of psychophysical symptoms and sociospiritual needs of patients during the course of the illness and at the end of life [173]. Research efforts aim to better characterize subgroups of patients suffering from secondary causes of anorexia and cachexia and to elucidate the mechanisms involved in the primary anorexia and cachexia syndrome. Increasingly individualized treatments are expected with combination treatments that involve different mechanisms including nutrition.

Deep brain stimulation for Parkinson's disease: patient selection and evaluation

Critical to the successful application of deep brain stimulation for the treatment Parkinson's disease is the proper selection of patients who will reliably benefit from this procedure and the successful evaluation of the responses obtained. This review will discuss the various factors influencing patient selection and summarize the recommended approach to patient assessment by using the Core Assessment Program for Surgical Interventions and Transplantation in Parkinson's Disease (CAPSIT-PD).

Orthostatic hypotension

A common problem among elderly people, orthostatic hypotension is associated with significant morbidity and mortality, which may be caused by medications, the cumulative effects of age- and hypertension-related alterations in blood pressure regulation, or age-associated diseases that impair autonomic function. Evaluation requires multiple blood pressure measurements taken at different times of the day and after meals or medications. Central and peripheral nervous system disorders should be sought, and the laboratory evaluation should concentrate on ruling out diabetes mellitus, amyloidosis, occult malignancy, and vitamin deficiencies. If orthostatic hypotension is detected, it should be considered a risk factor for adverse outcomes and treated first with nonpharmacologic interventions, including the withdrawal of potentially hypotensive medications. In patients with hypertension and orthostatic hypotension, the judicious treatment of hypertension may be helpful. For persistent, symptomatic orthostatic hypotension caused by autonomic failure, pharmacologic interventions include fludrocortisone, midodrine, and a variety of other agents. The careful evaluation and management of orthostatic hypotension will hopefully result in a significant reduction in falls, syncope, and fractures, and an attenuation of functional decline in elderly patients.

Hypertension in orthostatic hypotension and autonomic dysfunction

Disabling orthostatic hypotension dominates the clinical picture of autonomic failure. Nonetheless, severe supine hypertension is observed in about 50% of patients. In patients with multiple system atrophy (Shy-Drager syndrome), supine hypertension is explained by residual sympathetic tone because it can be eliminated with the ganglionic blocker trimethaphan. The cause of hypertension in patients with pure autonomic failure is not known and its understanding may be relevant to essential hypertension. Supine hypertension complicates the treatment of these patients but can be managed by overnight administration of antihypertensive medications.

Neurally mediated syncope

The prevalence and incidence of syncope increases with advancing years due to age related physiological changes in the neurocardiovascular, endocrine and renal systems. Cardiovascular syncope can present as falls because of amnesia for loss of consciousness or postural instability due to hypotension. Drop attacks or non accidental falls should thus be investigated for causes of syncope. The most common causes of neurally mediated syncope in older adults are carotid sinus syndrome, orthostatic hypotension and vasovagal syncope.

Transient orthostatic hypotension is common in adolescents

OBJECTIVES

We hypothesized that transient hypotension associated with the symptom of lightheadedness with standing is a common phenomenon in healthy adolescents but may be mistaken for orthostatic intolerance.

STUDY DESIGN

We studied 23 healthy adolescents, combining upright tilt to 70 degrees and to 35 degrees (in 12 patients) with continuous heart rate and blood pressure (BP) measurements. We measured peripheral blood flow and venous pressure in the arms and legs by using venous plethysmography.

RESULTS

Healthy subjects with normal vasoconstrictive responses to sustained upright tilt uniformly have a transient fall in BP during 70 degrees upright tilt that varies from almost undetectable to large decreases in BP easily exceeding the 20-mm Hg threshold for orthostatic hypotension. Large decreases are associated with short-lived symptoms of lightheadedness and are most marked in those with the largest calf blood flow. The higher the flow, the lower the BP falls. There is appropriate reflex tachycardia.

CONCLUSIONS

We conclude that transient orthostatic hypotension is common in many healthy adolescents, especially after prolonged recumbency, and is related to dependent vascular tone.

Orthostatic hypotension in patients with Parkinson's disease: pathophysiology and management

Orthostatic hypotension is common in elderly patients, and is now considered to be an important prognostic factor for cognitive decline and mortality. In patients with Parkinson's disease, the prevalence of symptomatic orthostatic hypotension may be as high as 20%. Two factors could explain this high prevalence. First, dopaminergic drugs may induce or worsen orthostatic hypotension. Secondly, Parkinson's disease is a cause of primary autonomic failure with an involvement of the peripheral autonomic system as shown by the ubiquitous distribution of Lewy bodies and reduced iobenguane [metaiodobenzylguanidine (MIBG)] cardiac uptake. These pathological and pharmacological characteristics clearly differentiate autonomic failure of Parkinson's disease from multiple system atrophy. If autonomic abnormalities appear to be present from the first stage of the disease, early onset (within the first year) of symptomatic orthostatic hypotension in the course of parkinsonism can be considered as an exclusion criteria for idiopathic Parkinson's disease. No specific clinical trials have evaluated the effects of antihypotensive drugs in patients with Parkinson's disease and thus no specific therapeutic strategy can be recommended. The management of orthostatic hypotension in patients with Parkinson's disease should always start with patient education and nonpharmacological treatment. Drug therapy should be reserved for symptomatic patients who do not get benefit from nonpharmacological management. Among the available drugs, alpha1-adrenergic agonists (mainly midodrine) or plasma volume expanders (mainly fludrocortisone) are the most frequently used. There are also some drugs that are currently investigational such as yohimbine and droxidopa. Other drugs such as desmopressin or octreotide may be of interest in some situations. Domperidone is widely used in patients with parkinsonism with no proven effect on orthostatic hypotension.

Orthostatic hypotension in pediatrics

Transient orthostatic hypotension is a common experience of many healthy adolescents and is the expected outcome of relatively dilated-dependent vascular tone. These children may experience brief symptoms of orthostatic intolerance when standing up rapidly, but they have no chronic symptoms or diseases. However, persistent orthostatic hypotension and chronic symptoms of orthostatic intolerance indicate postural tachycardia syndrome.

Autoregulatory cerebral vasodilation occurs during orthostatic hypotension in patients with primary autonomic failure

It is unclear whether patients with autonomic failure autoregulate cerebral blood flow during hypotension. The objective in this study was to examine cerebral autoregulatory capacity in patients with autonomic failure by studying changes in middle cerebral artery blood flow velocity using transcranial Doppler ultrasonography before, during, and after tilt-induced hypotension. Nine patients with primary autonomic failure were evaluated. Mean arterial pressure and middle cerebral artery blood flow velocity were simultaneously recorded while the patients were in the supine position, during 60 degrees head-up tilt, and after they were returned to the horizontal position. The results were as follows: during tilt-induced hypotension, mean arterial pressure decreased significantly more than middle cerebral artery mean blood flow velocity (58% versus 36%, p <0.0002). After return to the horizontal position, mean arterial pressure returned to baseline, and middle cerebral artery blood flow velocity transiently increased above pretilt value (p <0.02). It is concluded that cerebral autoregulatory vasodilation occurs in patients with autonomic failure. This was demonstrated by a more pronounced decline in mean arterial pressure than in middle cerebral artery blood flow velocity during hypotension and by a transient increase in middle cerebral artery blood flow velocity (ie, hyperemic response) after blood pressure was restored.

Effect of levodopa on orthostatic and postprandial hypotension in elderly Parkinsonian patients

BACKGROUND

This study describes orthostatic and postprandial hypotension in elderly Parkinsonian patients and evaluates the effect of levodopa therapy on orthostatic and postprandial hypotension in these patients.

METHODS

Seventeen elderly patients with a clinical diagnosis of Parkinson's disease or Parkinsonism based on the U.K. Parkinson's Disease Society Brain Bank criteria (age range, 66-84 years) participated in the study. Blood pressure was continuously monitored during standardized standing and meal tests, after starting 125-mg b.i.d. doses of levodopa/benserazide (Madopar) or placebo, in a double-blind, randomized, cross-over design. Seventeen age- and sex-matched healthy subjects served as controls.

RESULTS

Orthostatic hypotension was infrequently found in Parkinsonian patients (13%) and healthy subjects (6%; p =.58, between groups), whereas postprandial hypotension was more frequent in Parkinsonian patients (82%) than in healthy subjects (41%; p <.05, between groups). Doses of levodopa/benserazide, administered 2 times per day, did not result in significantly larger blood pressure decreases after standing or eating, or in higher frequencies of orthostatic or postprandial hypotension in the Parkinsonian group. Postprandial hypotension was related to disease severity (r = -.56, p <.05).

CONCLUSIONS

Postprandial hypotension, but not orthostatic hypotension, was more common in elderly Parkinsonian patients than in healthy subjects. Therapy with 125-mg b.i.d. doses of levodopa/benserazide did not significantly aggravate orthostatic or postprandial hypotension.

Orthostatic hypotension, 2001

Upright posture requires rapid and effective circulatory and neurologic compensations to maintain blood pressure and consciousness. Although it has been recognized over the past 100 years or more that the act of standing may cause hypotension in patients with autonomic dysfunction, only recently several of the pathophysiologic mechanisms resulting in orthostatic intolerance have been discovered. In patients with orthostatic hypotension, failure of reflex vasoconstriction causes pooling of blood in the legs during standing. Not everyone with a postural blood pressure drop requires treatment, nor does everyone with posturally induced symptoms have orthostatic hypotension. This review will discuss current knowledge of a broad, heterogeneous group of disturbances in the autonomic nervous system, each of which is manifested by hypotension, orthostatic intolerance, and often syncope.

Autonomic insufficiency as a factor contributing to dialysis-induced hypotension

BACKGROUND

Autonomic insufficiency is considered a factor that contributes to dialysis-induced hypotension (DIH). However, the relationship between the two conditions has not been fully elucidated.

METHODS

We investigated 44 haemodialysis patients using [(123)I]-meta-iodobenzylguanidine (MIBG) scintigraphy and power-spectral analysis (PSA) of heart rate variability. The patients were divided into four groups: a diabetic group with DIH, a diabetic group without DIH, a non-diabetic group with DIH, and a non-diabetic group without DIH. In these groups the heart to mediastinum average count rate (H/M), MIBG washout rate, and low- and high-frequency components of PSA were compared.

RESULTS

From the [(123)I]-MIBG scintigraphy, for both early and delayed images, H/M of the groups with DIH were lower than in groups without DIH, in both diabetics and non-diabetics (P<0.05). For the early images, H/M of the diabetic groups were lower than in the non-diabetic groups, in the groups both with and without DIH (P<0.01). For the delayed images, H/M of the diabetic group was lower than in the non-diabetic group, in the groups with DIH (P<0.05). The MIBG washout rate was the highest in the diabetic group with DIH (P<0.05 vs diabetic and non-diabetic groups without DIH). The PSA of heart rate variability showed a good discrimination of the low-frequency component between the non-diabetic patients with and without DIH (P<0.05). Mean ultrafiltration volume and its rate were not different among the four groups.

CONCLUSION

Autonomic insufficiency is more severe in patients with DIH than in those without, and its degree may be enhanced in diabetic patients. For the management of DIH, special care should be addressed not only to dry weight but also to autonomic insufficiency.

[Prevalence of orthostatic hypotension in elderly hypertensive patients in primary care]

OBJECTIVE

To find the prevalence of orthostatic hypotension (OH) and associated factors in elderly hypertensive patients in a primary care setting.

DESIGN

Descriptive cross-sectional study.

SETTING

La Marina Health Centre (an urban centre in Santander).

PATIENTS

A random sample of 295 patients aged 65 years or older regularly assisted from hypertension.

MEASUREMENTS AND MAIN RESULTS

Measurements of sitting and standing blood pressure were obtained. Orthostatic hypotension was defined as 20 mmHg or greater decrease in systolic or 10 mmHg or greater decrease in diastolic blood pressure after 1-minute or 5-minute standing. Associated diseases, symptoms upon standing, medication use, habits and other clinical assessments were also recorded. The prevalence of OH was 14.6%. The prevalence of systolic OH after 1-minute (OH-S1) and after 5-minute (OH-S5) standing was 5.8% in both, and the diastolic OH was 5.1% after 1-minute (OH-D1) and 4.1% after 5-minute (OH-D5) standing. By logistic regression analysis, association between higher level of systolic blood pressure and global OH was found, also with the presence of orthostatic intolerance symptoms (although only 25.6% of the patients with OH showed symptoms) and smoking. Beta-blockers and calcium channel blockers (different from dihydropyridines) use was associated with OH after 1-minute standing and smoking with OH after 5-minute standing.

CONCLUSIONS

The detected prevalence is high and justifies the case finding of OH in elderly hypertensive patients in primary care. The symptoms of orthostatic intolerance are correlated with OH, but only 1 out of 4 patients showed symptoms. Smoking could be related with OH, so beta-blockers and calcium channel blockers (different from dihydropyridines) use.

Blood pressure response to standing in the diagnosis of autonomic neuropathy: the EURODIAB IDDM Complications Study

Autonomic neuropathy is associated with poor prognosis. Cardiovascular reflexes are essential for the diagnosis of autonomic nerve dysfunction. Blood pressure response to standing is the most simple test for the evaluation of sympathetic integrity, however it is still discussed which diagnostic criteria of abnormal response should be considered as optimal. The EURODIAB IDDM Complications Study involved the examination of randomly selected Type 1 diabetic patients from 31 centres in 16 European counties. Data from 3007 patients were available for the present evaluation. Two tests of autonomic function (response of heart rate /R-R ratio/ and blood pressure from lying to standing) just as the frequency of feeling faint on standing up were assessed. R-R ratio was abnormal in 24% of patients. According to different diagnostic criteria of abnormal BP response to standing (>30 mmHg, >20 mmHg, and >10 mmHg fall in systolic BP), the frequency of abnormal results was 5.9%, 18% and 32%, respectively (p < 0.001). The frequency of feeling faint on standing was 18%, thus, it was identical with the prevalence of abnormal blood pressure response to standing when >20 mmHg fall in systolic blood pressure was considered as abnormal. Feeling faint on standing correlated significantly with both autonomic test results (p < 0.001). A fall >20 mmHg in systolic blood pressure after standing up seems to be the most reliable criterion for the assessment of orthostatic hypotension in the diagnosis of autonomic neuropathy in patients with Type 1 diabetes mellitus.

Autonomic dysfunction associated with multiple pelvic ganglioneuromas

We describe the case of a 59-year-old male in which several symptoms of autonomic dysfunction resulted associated with the presence of multiple ganglioneuromas in the adrenal glands and in paravertebral spaces. In a 2-year period, the patient developed sexual dysfunctions, micturitional disturbances and severe orthostatic hypotension and was erroneously diagnosed as having primary autonomic failure. However, the examination of all the autonomic functions showed that papillary function and cardiovascular reflexes were normal. CT scan of the abdomen revealed the presence of several small masses in the adrenal glands and along the lumbar sympathetic chain. Cytologic examination of the adrenal glands showed clusters of ganglionlike cells interspersed with Schwann cells, leading to the diagnosis of ganglioneuromas. Patients with signs and symptoms of autonomic dysfunction need an extensive clinical and laboratory examination of all the autonomic functions in order to exclude secondary causes of the symptomatology.

Multiple system atrophy: new developments in pathophysiology and therapy

There have been substantial advances in the last five years in understanding the basic and clinical pathophysiology underlying multiple system atrophy (MSA). Identification of glial cytoplasmic inclusions has been the most important organizing principle for further elucidation of underlying mechanisms. Recently, several unexpected developments at the clinical level have been reported. In this article, we will focus on two of these: (1) the recognition that substantial autonomic function is retained in MSA but not modulated appropriately, and (2) a potent pressor effect from ingestion of water, which cannot be explained by currently understood physiologic and pathophysiologic mechanisms. In some patients, water has elicited a 50% increase in blood pressure and been more therapeutically effective than any available pressor drug. By careful coordination of the pressor effect of water and the depressor effect of carbohydrate-rich food, many patients with MSA can now have their blood pressure controlled without pharmacological intervention.

Diagnostic value of history in patients with syncope with or without heart disease

OBJECTIVES

We sought to establish what historical findings are predictive of the cause of syncope.

BACKGROUND

The clinical features of the various types of syncope have not been systematically investigated.

METHODS

Three hundred forty-one patients with syncope were prospectively evaluated. Each patient was interviewed using a standard questionnaire. A cause of syncope was assigned using standardized diagnostic criteria.

RESULTS

A cardiac cause of syncope was established in 23% of the patients, a neurally mediated cause in 58% and a neurologic or psychiatric cause in 1%, and in the remaining 18%, the cause of syncope remained unexplained. In a preliminary analysis including age, gender and the presence of suspected or certain heart disease after the initial evaluation, only heart disease was an independent predictor of a cardiac cause of syncope (odds ratio 16, p = 0.00001), with a sensitivity of 95% and a specificity of 45%. In contrast, the absence of heart disease allowed us to exclude a cardiac cause of syncope in 97% of the patients. In patients with certain or suspected heart disease, the most specific predictors of a cardiac cause were syncope in the supine position or during effort, blurred vision and convulsive syncope. Significant and specific predictors of a neurally mediated cause were time between the first and last syncopal episode >4 years, abdominal discomfort before the loss of consciousness and nausea and diaphoresis during the recovery phase. In the patients without heart disease, palpitation was the only significant predictor of a cardiac cause.

CONCLUSIONS

The presence of suspected or certain heart disease after the initial evaluation is a strong predictor of a cardiac cause of syncope. A few historical findings are useful to predict cardiac and neurally mediated syncope in patients with and without heart disease.

Review of orthostatic tests on the safety of tamsulosin, a selective alpha1A-adrenergic receptor antagonist, shows lack of orthostatic hypotensive effects

Two phase III studies with tamsulosin, a selective alpha1A-adrenergic receptor antagonist, were conducted to evaluate the safety and efficacy of the standard treatment doses of 0.4 mg/day and 0.8 mg/day in patients with symptoms of benign prostatic hyperplasia (BPH). These large-scale clinical trials were the first to include extensive testing for possible drug-induced orthostatic hypotension (OH). The frequency of positive orthostatic tests and magnitude of vital sign changes were compared among tamsulosin and placebo-treated groups. The results indicate that tamsulosin up to 0.8 mg/day does not induce higher risk of OH than that of placebo. Data from post-marketing surveillance (PMS) studies of tamsulosin indicate that the incidence of hypotension and syncope is extremely low in community-dwelling elderly men treated for BPH. From the results of the phase III studies, PMS studies and an active-controlled clinical pharmacology study, we conclude that the orthostatic test is a useful and convenient method to evaluate the risk of OH and syncope during the investigational stage.

Neuropsychologische Befunde bei der Diagnostik hirnorganischer Erkrankungen mit Demenz

Zusammenfassung: Auf der Basis einer retrospektiven Untersuchung von 175 Patienten, die im Laufe der letzten 4 Jahre mit der klinischen Verdachtsdiagnose einer Demenz in unserer Abteilung vorgestellt wurden, werden die neuropsychologischen Defizite verschiedener Patientengruppen mit Morbus Parkinson, Chorea Huntington (HD), Multisystematrophien, vaskulärer subcorticaler Encephalopathie, Normaldruck-Hydrocephalus und wahrscheinlicher Alzheimerscher Erkrankung (AD) verglichen. Die Ergebnisse zeigen bei allen Patientengruppen schwere Beeinträchtigungen in den Bereichen Aufmerksamkeit und exekutive Funktionen ohne signifikante Unterschiede zwischen den einzelnen Diagnosegruppen. Eine deutliche Clusterbildung in bezug auf stärkere Beeinträchtigungen zeigt sich hingegen bezüglich längerfristigen Gedächtnisleistungen (HD und AD) sowie bei aphasischen, sprachassoziierten und apraktischen Störungen (AD). Auf Basis dieser Befunde werden die möglichen Implikationen der neuropsychologischen Diagnostik für die Differentialdiagnostik der Demenz diskutiert.

Ambulatory norepinephrine treatment of severe autonomic orthostatic hypotension

OBJECTIVES

This study was designed to establish a patient-controlled, ambulatory norepinephrine treatment of refractory orthostatic hypotension due to primary autonomic failure.

BACKGROUND

Autonomic dysfunction leads to disabling postural hypotension. Particularly in primary autonomic dysfunction, repeated syncope and immobilization can be the result. Medical treatment of orthostatic hypotension often fails in advanced cases.

METHODS

Ambulatory, patient-controlled norepinephrine therapy was initiated in six patients with orthostatic hypotension due to primary autonomic failure that had been refractory to conventional treatment. Before this therapy, three patients were bedridden; one was immobilized in a wheelchair. All had recurrent syncope and tolerated upright tilt-table testing for less than 15 min despite extensive medical treatment. For ambulatory treatment, a port-a-cath system was implanted and, using a CADD ambulatory infusion pump, norepinephrine was infused in individually adjusted dosages.

RESULTS

Norepinephrine infusion therapy enabled all patients to sit, stay and walk around for more than 45 min. One patient died after a five-year treatment period, another after nine months because of nonhemorrhagic brain stem infarctions, both in the absence of norepinephrine treatment. The remaining four patients are still mobile after a period of 19, 10, 9 and 7 months, respectively. None of them has suffered complications due to arterial hypo- or hypertension, and there has been no infection of the infusion system.

CONCLUSIONS

In these selected patients with refractory orthostatic hypotension due to primary autonomic dysfunction, ambulatory norepinephrine infusion therapy has proved to be a promising new therapeutic option. Further long-term studies including more patients are necessary to assess additional indications, reliability and safety of this new method.

Pure autonomic failure in association with human alpha-synucleinopathy

We studied an autopsy case with pure autonomic failure, using anti-alpha-synuclein antibody. Until now there has been no report about the immunohistochemical properties of alpha-synuclein in pure autonomic failure. In conventional stainings, both pre- and post-ganglionic lesions of the sympathetic and parasympathetic nervous systems were found. Lewy bodies and Lewy neurites were abundant especially in the sympathetic nervous system. These inclusions were immunoreactive to anti-alpha-synuclein antibody. The intensity of alpha-synuclein immunoreactivity was stronger in the halos than in the cores of the Lewy bodies. The edges of the swollen neurites had strong immunoreactivity. The substantia nigra was well preserved, and no cortical Lewy bodies were seen. These findings indicate that pure autonomic failure is one of the Lewy body type alpha-synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies, targeting the peripheral autonomic nervous system.

A two-fold difference in the age-adjusted prevalences of Parkinson's disease between the island of Als and the Faroe Islands

With the aim of comparing the previously found high prevalence of idiopathic Parkinson's disease (PD) in the Faroe Islands with the prevalence of PD in an area of Denmark, we used the same case-finding methods for case ascertainment and the same strict criteria to diagnose PD on the island of Als. During the last year before the prevalence date (1 January 1998), we found in various registries from pharmacies, hospital, private neurologist and general practitioners 121 patients with suspected Parkinsonism out of 56,839 inhabitants on the island of Als. After exclusion of those who had other diseases, a total of 79 patients were left for further examinations. Among these we found 58 with PD. The overall prevalence of PD was estimated to be 102.0 and the age-adjusted prevalence to be 98.3 per 100,000 persons compared with 187.6 and 209.0 in the Faroe Islands. Compared with the previous results from the Faroe Islands (prevalence date 1 July 1995) we found an even lower mean age at onset of PD symptoms and at onset of treatment, a lower proportion of definite PD and a lower average dose of levodopa. We therefore conclude that the two-fold higher prevalence in the Faroe Islands than on the island of Als was not due to an early diagnosis and a higher ascertainment of cases with mild PD, which was suggested as being one possible explanation for our previous finding of a high prevalence of PD in the Faroe Islands.

Orthostatic hypotension as a risk factor for stroke: the atherosclerosis risk in communities (ARIC) study, 1987-1996

BACKGROUND AND PURPOSE

The association between orthostatic hypotension (OH) and stroke has rarely been investigated in longitudinal studies. The purpose of the present study was to determine whether OH predicts ischemic stroke in a middle-aged, biethnic population after adjustment for known stroke risk factors. Diastolic, systolic, and consensus OH were evaluated for baseline associations and for the ability to predict stroke.

METHODS

In 11 707 persons from the Atherosclerosis Risk in Communities (ARIC) cohort who were free of stroke and overt heart disease at baseline, Cox proportional hazards analyses modeled the association between OH at baseline and incident ischemic stroke over 7.9 years of follow-up. OH was defined as a systolic blood pressure drop >/=20 mm Hg (systolic OH), a diastolic blood pressure drop >/=10 mm Hg (diastolic OH), or a drop in either (consensus OH) when a person changed from a supine to standing position.

RESULTS

OH was predictive of ischemic stroke, even after adjustment for numerous stroke risk factors (consensus OH: hazard ratio, 2.0; 95% CI, 1.2 to 3.2). While the baseline characteristics associated with OH varied depending on the type of OH, all types of OH had a similar risk of stroke.

CONCLUSIONS

OH is an easily obtained measurement that may help to identify middle-aged persons at risk for stroke.

Management of postural hypotension

Several mechanisms counteract the gravitational forces on blood and maintain systemic arterial pressure and cerebral perfusion upon assumption of the upright posture. Failure of these mechanisms can lead to a postural decrease in blood pressure. Postural hypotension is defined as a reduction of at least 20 mm Hg in systolic blood pressure or at least a 10 mm Hg decrease in diastolic blood pressure. Acute postural hypotension is usually due to fluid or blood loss and responds well to fluid repletion. Chronic postural hypotension is due to drugs or endocrine or neurogenic disorders. A functional classification based on severity of symptoms is useful in monitoring the patient's condition and documenting improvement with treatment. Whenever possible, the reversible causes of chronic postural hypotension should be treated. For symptomatic treatment, a stepped approach starting with nonpharmacologic measures is recommended. Fludrocortisone, midodrine, indomethacin, and atrial tachypacing are recommended, in that order, for patients in whom nonpharmacologic measures prove insufficient. Other drugs can be added if necessary. The goal of treatment is to make the patient as ambulatory and symptom-free as possible without causing supine hypertension.

Possible locus on chromosome 18q influencing postural systolic blood pressure changes

We conducted a genome-wide scan for quantitative trait loci influencing the systolic blood pressure, diastolic blood pressure, and pulse responses to a postural challenge in 498 white sibling-pairs from the Hypertension Genetic Epidemiology Network, a multicenter study of the genetic susceptibility to hypertension. All participants were hypertensive (systolic blood pressure >/=140 mm Hg, diastolic blood pressure >/=90 mm Hg, or on antihypertensive medications) with diagnosis before age 60. Blood pressure and pulse were measured by an oscillometric method after a 5-minute rest in a supine position and again immediately on standing. The genome scan included a total of 387 autosomal short-tandem-repeat polymorphisms typed by the National Heart, Lung, and Blood Institute Mammalian Genotyping Service at Marshfield. We used multipoint variance-components linkage analysis to identify possible quantitative trait loci influencing postural change phenotypes after adjusting for sex, age, and use of antihypertensive medications. There was suggestive evidence for linkage on chromosome 18q for the postural systolic blood pressure response (maximum logarithm of the odds score=2.6 at 80 centiMorgans). We also observed a maximum logarithm of the odds score of 1.9 for the systolic blood pressure response and 1.7 for the diastolic blood pressure response on chromosome 6p. The marker that demonstrated the strongest evidence for linkage for the systolic blood pressure response (D18S858) lies within 20 centiMorgans of a marker previously linked to rare familial orthostatic hypotensive syndrome. Our findings indicate that there may be 1 or more genes on chromosome 18q that regulate systolic blood pressure during the physiological recovery period after a postural stressor.

Cerebral oxygenation declines in healthy elderly subjects in response to assuming the upright position

BACKGROUND AND PURPOSE

With increasing age, assuming the upright position is more often accompanied by symptoms such as dizziness and lightheadedness, possibly as a result of a diminished oxygen supply to the brain due to impaired cerebral autoregulation. We aimed to quantify postural changes in cerebral oxygenation and systemic hemodynamics in healthy elderly and young subjects.

METHODS

In 18 healthy elderly subjects (aged 70 to 83 years) and 10 healthy young subjects (aged 22 to 45 years), frontal cortical oxygenation and hemodynamic responses were continuously monitored by near infrared spectroscopy and Finapres, respectively, before and during 10 minutes of active standing.

RESULTS

-Cortical oxyhemoglobin concentration [O(2)Hb] decreased by -4.6+/-2.2 micromol/L (P<0.001) and cortical deoxyhemoglobin concentration increased by 1.5+/-2.4 micromol/L (P<0.05) in the elderly subjects after posture change, whereas these variables did not change significantly in the young subjects. The postural hemodynamic changes tended to be attenuated in the elderly subjects, except for the increases in systolic blood pressure (BP). Smaller postural increases in diastolic BP were related to larger [O(2)Hb] decreases (r=0.53, P<0.01, corrected for the age effect).

CONCLUSIONS

Assuming the upright position evokes an asymptomatic decrease in frontal cortical oxygenation in healthy elderly subjects but not in healthy young subjects. Cortical [O(2)Hb] changes are affected by diastolic BP changes. These findings may indicate that regulation of cerebral oxygenation alters with increasing age.

Do elderly persons need to be encouraged to drink more fluids?

BACKGROUND

A recently published and widely quoted modified food guide pyramid encourages persons over the age of 70 years to ingest eight glasses (2 liters) of fluids per day. We challenge the need for this much fluid intake and even question whether it may do more harm than good.

METHODS

Equal numbers of Hispanic and non-Hispanic white men and women were selected randomly from the Health Care Financing Administration (Medicare) rolls and recruited for a home interview followed by a 4-hour interview/examination in a senior health clinic. Questionnaires and examinations were used to determine usual daily self-reported intake of fluids, lying and standing blood pressures, history of falls over the past year, and the presence of chronic constipation and chronic fatigue or tiredness. Serum samples were obtained for determination of sodium, urea nitrogen (SUN) and creatinine concentrations, and calculation of SUN/creatinine ratios.

RESULTS

Interviews/examinations were conducted on 883 volunteers (mean age of 74.1 years). Most participants (71%) estimated that their usual fluid intake was equal to or exceeded six glasses per day. Evidence of hypernatremia (serum sodium concentration > 146 mEq/l) was not observed in the 227 individuals ingesting less than this. Hyponatremia also was rare in this population. Fluid intake showed no significant associations with lying and standing blood pressures, a history of falling, or the frequency of chronic constipation or fatigue/tiredness.

CONCLUSION

Until we have more evidence-based documentation that fluid intake of eight glasses (2 liters) per day improves some aspect of an elderly person's health, encouraging a fluid intake above a level that is comfortable for the individual seems to serve little useful purpose.

Stridor and death in multiple system atrophy

Patients with multiple system atrophy (MSA) have a mean survival of 8 to 10 years. Nocturnal stridor has been considered a poor prognostic feature. We analyzed demographic, clinical, and polysomnographic data and obtained follow-up information from 42 patients with MSA (30 with follow-up data) seen in a Sleep Disorders Center. Group I consisted of 17 patients with nocturnal stridor, including seven with daytime stridor. Group II consisted of 25 patients without stridor. Analysis of survival curves of 30 patients with follow-up information showed a significantly shorter survival from the sleep evaluation, but not from disease onset, for patients with stridor compared with those without. Nine of 11 patients with stridor died a median of 2 years from presentation and the only two survivors had undergone tracheostomy. Patients with daytime stridor and immobile vocal cords had especially poor prognoses. However, two of four patients with tracheostomies also died, as did six of 19 without stridor. We postulate that central hypoventilation and its complications may have been responsible for many of these other deaths. We conclude that stridor does carry a poor prognosis in patients with MSA but that there are also other causes of death. We recommend consideration of tracheostomy for patients with MSA who have stridor, but also assessment for central hypoventilation and appropriate management if it is present.

Orthostatic tolerance, cerebral oxygenation, and blood velocity in humans with sympathetic failure

BACKGROUND AND PURPOSE

Patients with orthostatic hypotension due to sympathetic failure become symptomatic when standing, although their capability to maintain cerebral blood flow is reported to be preserved. We tested the hypothesis that in patients with sympathetic failure, orthostatic symptoms reflect reduced cerebral perfusion with insufficient oxygen supply.

METHODS

This study addressed the relationship between orthostatic tolerance, mean cerebral artery blood velocity (V(mean), determined by transcranial Doppler ultrasonography), oxygenation (oxyhemoglobin [O(2)Hb], determined by near-infrared spectroscopy), and mean arterial pressure at brain level (MAP(MCA), determined by finger arterial pressure monitoring [Finapres]) in 9 patients (aged 37 to 70 years; 4 women) and their age- and sex-matched controls during 5 minutes of standing.

RESULTS

Supine MAP(MCA) (108+/-14 versus 86+/-14 mm Hg) and V(mean) (84+/-21 versus 62+/-13 cm. s(-1)) were higher in the patients. After 5 minutes of standing, MAP(MCA) was lower in the patients (31+/-14 versus 72+/-14 mm Hg), as was V(mean) (51+/-8 versus 59+/-9 cm. s(-1)), with a larger reduction in O(2)Hb (-11. 6+/-4 versus -6.7+/-4.5 micromol. L(-1)). Four patients terminated standing after 1 to 3.5 minutes. In these symptomatic patients, the orthostatic fall in V(mean) was greater (45+/-6 versus 64+/-10 cm. s(-1)), and the orthostatic decrease in O(2)Hb (-12.0+/-3.3 versus -7.6+/-3.9 micromol. L(-1)) tended to be larger. The reduction in MAP(MCA) was larger after 10 seconds of standing, and MAP(MCA) was lower after 1 minute (25+/-8 versus 40+/-6 mm Hg).

CONCLUSIONS

In patients with sympathetic failure, the orthostatic reduction in cerebral blood velocity and oxygenation is larger. Patients who become symptomatic within 5 minutes of standing are characterized by a pronounced orthostatic fall in blood pressure, cerebral blood velocity, and oxygenation manifest within the first 10 seconds of standing.

Orthostatic hypotension and the incidence of coronary heart disease: the Atherosclerosis Risk in Communities study

We examined the association between orthostatic hypotension (OH) at baseline examination (1987-1989) and the incidence of coronary heart disease (CHD) over an average of 6 years, among 12,433 black and white middle-aged men and women participating in the Atherosclerosis Risk in Communities (ARIC) study. OH was defined as a SBP decrease > or = 20 mm Hg or a DBP decrease > or = 10 mm Hg after changing from supine to standing. CHD events included definite or probable myocardial infarctions (MI), silent MI, and fatal CHD. Five percent of participants had OH. Prevalence increased with advancing age and was more common among those with cardiovascular disease (CVD)-related comorbidities and risk factors. Those with OH had an increased risk of CHD (hazard ratio [HR] = 3.49, 95% confidence interval [CI] = 2.58, 4.73). This association was attenuated after controlling for age, ethnicity, gender, comorbid conditions, and CVD risk factors (HR = 1.85, 95% CI = 1.31, 2.63).

Orthostatic Hypotension in Multiple System Atrophy

There is no known way to cure multiple system atrophy or even to slow its insidious progression, but there are opportunities to treat many of its symptoms and complications. Of all the autonomic disturbances it causes, orthostatic hypotension is associated with one of the better chances for successful intervention. Milder symptoms may be treated by nonpharmacologic means (eg, changes in diet and activities and compressive maneuvers and devices). Syncopal patients will require treatment with medications. Midodrine is the most effective drug. It is more physiologic and better tolerated, but much more expensive, than fludrocortisone. The latter is often beneficial but frequently causes lower limb edema. Low-dose propranolol is occasionally useful. Other drugs worth trying are indomethacin and intranasal desmopressin. The variety of measures available to treat orthostatic hypotension in multiple system atrophy affords physicians some prospect of easing the suffering of many patients with this otherwise disabling and discouraging disorder.

Methodology of head-up tilt testing potentiated with sublingual nitroglycerin in unexplained syncope

Shortened head-up tilt testing (HUT) potentiated with sublingual nitroglycerin (60 degrees passive standing for 20 minutes followed, if negative, by 400 microg of sublingual nitroglycerin spray with the test continuing for another 20 minutes) differs from conventional nitroglycerin HUT for a shorter drug-free phase (20 vs 45 minutes). To compare the positivity rate of the 2 protocols, both tests were performed in a randomized sequence in 10 patients with unexplained syncope (study 1), and another 42 patients were randomly assigned either to conventional or to shortened nitroglycerin HUT (study 2). To evaluate the reproducibility of the shortened nitroglycerin HUT, another 38 patients with unexplained syncope underwent 2 consecutive tests within a 7+/-8 day interval (study 3). Finally, to evaluate the specificity of the test, 47 control subjects underwent shortened nitroglycerin HUT (study 4). Seven positive responses were observed during shortened nitroglycerin HUT, and there were 8 positive responses during conventional nitroglycerin HUT (p = NS) in the study 1 group. Fifteen positive (71%) responses, 5 negative responses, and 1 exaggerated response were observed during shortened nitroglycerin HUT; 16 positive (76%, p = NS vs. shortened nitroglycerin HUT), 3 negative, and 2 exaggerated responses were observed during conventional nitroglycerin HUT in the study 2 group. During the first test, 21 patients (55%) had a positive, 15 patients had a negative, and 2 patients had an exaggerated response in study group 3. During the second test, 15 positive (39%), 19 negative, and 4 exaggerated responses were observed. Thus, the reproducibility was 67% for a positive and 94% for a negative test. In control subjects, 2 positive (4%) responses, 38 negative, and 7 exaggerated responses were observed with a specificity of 96% in study group 4. In patients with unexplained syncope, shortened nitroglycerin HUT allowed a positivity rate similar to that of the conventional test. Moreover, the shortened test provided a high specificity and adequate reproducibility for both the positive and the negative responses.

Altered expression of calcium- and apoptosis-regulating proteins in multiple system atrophy Purkinje cells

The expression patterns of the calcium binding proteins calbindin and parvalbumin and of the apoptosis modulating proteins Bcl-2, Bax, and Bcl-x were studied in the cerebellum of patients with multiple system atrophy (MSA). Calbindin and parvalbumin immunoreactivity was markedly decreased in MSA Purkinje cells whereas Bax and Bcl-x protein expression was increased. Bcl-2 expression was restricted to a subpopulation of granule neurons, but no decrease of Bcl-2 was evident in MSA. Additional DNA end-labeling (ISEL) studies revealed only one possible apoptotic Purkinje cell nucleus, but nuclei in the cerebellar white matter, probably oligodendrocytes, in the cerebellum of patients with MSA. The present results suggest that a diminished calcium binding capacity of MSA Purkinje cells might lead to a change in the regulation of proteins of the bcl-2 family that could favor the pathologic initiation of apoptosis.

Rapid eye movement sleep behaviour disorder: demographic, clinical and laboratory findings in 93 cases

We describe demographic, clinical, laboratory and aetiological findings in 93 consecutive patients with rapid eye movement (REM) sleep behaviour disorder (RBD), which consists of excessive motor activity during dreaming in association with loss of skeletal muscle atonia of REM sleep. The patients were seen at the Mayo Sleep Disorders Center between January 1, 1991 and July 31, 1995. Eighty-one patients (87%) were male. The mean age of RBD onset was 60.9 years (range 36-84 years) and the mean age at presentation was 64.4 years (37-85 years). Thirty-two per cent of patients had injured themselves and 64% had assaulted their spouses. Subdural haematomas occurred in two patients. Dream content was altered and involved defence of the sleeper against attack in 87%. The frequency of nocturnal events decreased with time in seven untreated patients with neurodegenerative disease. MRI or CT head scans were performed in 56% of patients. Although four scans showed brainstem pathology, all of these patients had apparently unrelated neurodegenerative diseases known to be associated with RBD. Neurological disorders were present in 57% of patients; Parkinson's disease, dementia without parkinsonism and multiple system atrophy accounted for all but 14% of these. RBD developed before parkinsonism in 52% of the patients with Parkinson's disease. Five of the 14 patients with multiple system atrophy were female, and thus the strong male predominance in RBD is less evident in this condition. Psychiatric disorders, drug use or drug withdrawal were rarely causally related to RBD. Clonazepam treatment of RBD was completely or partially successful in 87% of the patients who used the drug. We conclude that RBD is a well-defined condition and that descriptions from different centres are fairly consistent. It is commonest in elderly males and may result in serious morbidity to patients and bed partners. There is a strong relationship to neurodegenerative disease, especially Parkinson's disease, multiple system atrophy and dementia, and neurologists should explore the possibility of RBD in patients with these conditions. RBD symptoms may be the first manifestations of these disorders and careful follow-up is needed. Neuroimaging is unlikely to reveal underlying disorders not suspected clinically. We confirm the effectiveness of clonazepam, but note that attention to the safety of the bed environment may be sufficient for patients with contraindications to the drug.

Patients' choice of portable folding chairs to reduce symptoms of orthostatic hypotension

Patients with neurogenic orthostatic hypotension may use portable folding chairs to prevent or reduce symptoms of low blood pressure. However, a concomitant movement disorder may limit the use of these chairs in daily living. In this prospective study, 13 patients with orthostatic hypotension, balance disturbance associated with motor disability, or both examined three commercially available portable folding chairs. A questionnaire was used to document the characteristics in chair design that were relevant for satisfactory use to these patients. Armrests, seat width, and an adjustable sitting height were found to be important features of a portable folding chair. One chair was selected by 11 of 13 patients to fit most needs.