What is the accuracy of the clinical diagnosis of multiple system atrophy? A clinicopathologic study

BACKGROUND

The presentation of symptoms for multiple system atrophy (MSA) varies. Because there are no specific markers for its clinical diagnosis, the diagnosis rests on the results of the neuropathologic examination. Despite several clinicopathologic studies, the diagnostic accuracy for MSA is unknown.

OBJECTIVES

To determine the accuracy for the clinical diagnosis of MSA and to identify, as early as possible, those features that would best predict MSA.

DESIGN

One hundred five autopsy-confirmed cases of MSA and related disorders (MSA [n=16], non-MSA [n=89]) were presented as clinical vignettes to 6 neurologists (raters) who were unaware of the study design. Raters identified the main clinical features and provided a diagnosis based on descriptions of the patients' first and last clinic visits.

METHODS

Interrater reliability was evaluated with the use of kappa statistics. Raters' diagnoses and those of the primary neurologists (who followed up the patients) were compared with the autopsy-confirmed diagnoses to estimate the sensitivity and positive predictive values at the patients' first and last visits. Logistic regression analysis was used to determine the best predictors to diagnose MSA.

RESULTS

For the first visit (median, 42 months after the onset of symptoms), the raters' sensitivity (median, 56%; range, 50%-69%) and positive predictive values (median, 76%; range, 61%-91%) for the clinical diagnosis of MSA were not optimal. For the last visit (74 months after the onset of symptoms), the raters' sensitivity (median, 69%; range, 56%-94%) and positive predictive values (median, 80%; range, 77%-92%) improved. Primary neurologists correctly identified 25% and 50% of the patients with MSA at the first and last visits, respectively. False-negative and -positive misdiagnoses frequently occurred in patients with Parkinson disease and progressive supranuclear palsy. Early severe autonomic failure, absence of cognitive impairment, early cerebellar symptoms, and early gait disturbances were identified as the best predictive features to diagnose MSA.

CONCLUSIONS

The low sensitivity for the clinical diagnosis of MSA, particularly among neurologists who followed up these patients in the tertiary centers, suggests that this disorder is underdiagnosed. The misdiagnosis of MSA is usually due to its confusion with Parkinson disease or progressive supranuclear palsy, thus compromising the research on all 3 disorders.

What are the obstacles for an accurate clinical diagnosis of Pick's disease? A clinicopathologic study

Several studies have evaluated the reliability and validity of the clinical diagnosis of Alzheimer's disease (AD) using well-defined neuropathologic criteria, but none has attempted to evaluate the diagnostic accuracy of Pick's disease. We determined the accuracy of the clinical diagnosis of Pick's by presenting 105 autopsy-confirmed cases of Pick's (n = 7) and related disorders (non-Pick's, n = 98) as clinical vignettes in randomized order to six neurologists who were unaware of the autopsy findings. The group of raters had moderate to fair agreement for the diagnosis of Pick's as measured by the kappa statistics. The sensitivity for the diagnosis of Pick's for the first visit (mean, 53 months after onset) and last visit (mean, 78 months after onset) was low (range, 0 to 71%), but specificity was near-perfect. Median positive predictive values at both visits were 83 to 85%. False-negative misdiagnoses mainly involved AD. False-positive diagnoses were rare and occurred with corticobasal degeneration (first visit) and with dementia with Lewy bodies (last visit). Pick's was also misdiagnosed by primary neurologists. The best clinical predictors for the early diagnosis of Pick's included "frontal" dementia, early "cortical" dementia with severe frontal lobe disturbances, absence of apraxia, and absence of gait disturbance at onset. However, the first neurologic evaluation in some of the Pick's cases took place in advanced stages of the disease. Our findings suggest that this disorder is underdiagnosed in clinical practice. Although the low sensitivity for the clinical diagnosis of Pick's is disappointing, our data suggest that when clinicians suspect Pick's, their diagnosis is almost always correct. Absence of awareness of the main features of this disorder and of specificity of the frontal lobe syndrome may partially explain the low detection of Pick's disease.

Short- and long-term survival and function of unilateral intrastriatal dopaminergic grafts in Parkinson's disease

Six patients with Parkinson's disease were followed for 10 to 72 months after human embryonic mesencephalic tissue from four to seven donors was grafted unilaterally into the putamen (4 patients) or putamen plus caudate (2 patients). After 8 to 12 months, positron emission tomography showed a 68% increase of 6-L-[18F]-fluorodopa uptake in the grafted putamen, no change in the grafted caudate, and minor decreases in nongrafted striatal regions. There was therapeutically valuable improvement in 4 patients, but only modest changes in the other 2, both of whom developed atypical features. Patient 4 was without L-dopa from 32 months and had normal fluorodopa uptake in the grafted putamen at 72 months. Overall, the L-dopa dose was reduced by a mean of 10 and 20%, "off" time was reduced by 34 and 44%, and the "off" phase Unified Parkinson's Disease Rating Scale motor score by 18 and 26%, and the duration of the response to a single L-dopa dose increased by 45 and 58% during the first and second years after surgery, respectively. Rigidity and hypokinesia improved bilaterally, but mainly contralateral to the implant. No consistent changes in dyskinesias were observed. We conclude that transplantation of embryonic mesencephalic tissue leads to highly reproducible survival of dopaminergic neurons, inducing clinically valuable improvements in most recipients.

Mitochondrial respiratory chain function in multiple system atrophy

Multiple system atrophy (MSA) is a clinico-pathological entity distinct from idiopathic Parkinson's disease (PD) that is responsible for 5-10% of cases of parkinsonism. Degeneration of nigral neurones is a feature of both diseases. A specific deficiency of mitochondrial complex I activity has been found in PD substantia nigra. We have analysed mitochondrial function in substantia nigra and platelets from MSA patients to identify any respiratory chain defect in this disorder and to determine its tissue specificity. As our MSA patients had been on L-DOPA, we also sought to establish whether this treatment could cause the complex I defect as seen in PD. We found no significant difference in respiratory chain activity corrected for mitochondrial mass between control and MSA patients in either of the tissues studied. These results provide a biochemical dimension to the differences between MSA and idiopathic PD. In addition, the fact that L-DOPA failed to induce a complex I defect in MSA substantia nigra suggests that this treatment is unlikely to cause the complex I deficiency in PD, without additional factors that may operate in PD.

Parkinsonism. Multiple system atrophy

Over the last decade multiple system atrophy (MSA) has been confirmed as a distinct clinicopathological entity. For a long time, overlapping pathology in individual cases with striatonigral degeneration (SND), sporadic olivopontocerebellar atrophy (OPCA) or Shy-Drager syndrome (SDS) had often been a source of confusion. The recently discovered glial and neuronal inclusions indeed confirm that these three disorders represent manifestations of the same disease. Parkinsonism is the most frequent motor disorder of MSA. Early diagnosis of these patients is difficult but important, particularly in clinical trials of potential therapies. Patients with only parkinsonism (+/- autonomic failure) account for much of this diagnostic difficulty, particularly early on. Some features that have been associated with SND such as symmetry or absence of tremor are not helpful, and insistence on a poor levodopa response will miss a sizeable minority of patients. A number of further clinical 'red flags' may be helpful. MRI, MRS, PET and SPECT scanning, autonomic function tests and, especially, external sphincter EMG, may also help differentiate between idiopathic Parkinson's disease (IPD) and MSA. Available medical treatments are usually disappointing, so that good therapy services are all the more important. Better animal models of MSA and evaluation of novel treatment strategies are urgently required, and grafting techniques currently applied to IPD and Huntington's disease (HD) patients might be usefully combined in MSA. Epidemiological and case-control studies are needed to determine the prevalence, incidence and risk factors of MSA. The pathogenesis of MSA remains uncertain. Until the discovery of glial cytoplasmic inclusions (GCIs) previous studies had failed to identify abnormalities relevant to pathogenesis rather than reflecting secondary change. The abundance of GCIs points to a fundamental cytoskeletal alteration in glial cells that may eventually result in neuronal degeneration. Mechanisms of formation and distribution of GCIs as well as disordered glial-neuronal interactions should be studied in more detail in MSA brains.

Multiple system atrophy: a review of 203 pathologically proven cases

We report the clinicopathological features of 203 cases of pathologically proven multiple system atrophy (MSA) from 108 publications up to February 1995. The majority of patients showed symptoms in their early fifties, and men were more commonly affected than women (ratio of 1.3:1). Most patients suffered from some degree of autonomic failure (74%). Parkinsonism was the most common motor disorder (87%), followed by cerebellar ataxia (54%) and pyramidal signs (49%). The response to levodopa was poor in most patients, but there was a subgroup with a good response, who also often developed axial levodopa-induced dyskinesias. Other characteristic features included severe dysarthria, stridor, and, in a few patients, contractures and dystonia (antecollis). Mild or moderate intellectual impairment occurred in some cases, but severe dementing illness was most unusual. The main pathological change comprised cell loss and gliosis in the putamen, caudate nucleus, external pallidum, substantia nigra, locus ceruleus, inferior olives, pontine nuclei, cerebellar Purkinje cells, and intermediolateral cell columns of the spinal cord. However, other neuronal populations were also involved to varying degrees, such as the thalamus, vestibular nucleus, dorsal vagal nucleus, corticospinal tracts, and anterior horn cells. Characteristic glial and/or neuronal cytoplasmic inclusions were identified in all cases in which they were sought, irrespective of clinical presentation. Akinesia correlated with the degree of nigral and putaminal cell loss, whereas rigidity was related only to the later. Tremor was unrelated to cell loss at any site. Ataxia correlated with the degree of olivopontocerebellar atrophy. Pyramidal signs were associated with pyramidal tract pallor. Our analysis also confirmed an association of postural hypotension with intermediolateral cell column degeneration.

Brain perfusion scintigraphy with 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT single-photon emission tomography in dementia of the Alzheimer-type and diffuse Lewy body disease

Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or 99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2 beta-carboxymethoxy-3 beta-[4-iodophenyl]tropane (123I-beta-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of 99mTc-HMPAO or 99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was 2.5 +/- 0.4, with an increase to 5.5 +/- 1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was significantly reduced to 1.7 +/- 0.3, with a modest increase to 2.1 +/- 0.4 18 h after tracer injection (P < 0.05, Scheffe test, ANOVA). These results suggest that 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.

Survival of patients with pathologically proven multiple system atrophy: a meta-analysis

A systematic review of the neurologic literature identified 433 cases of pathologically proven multiple system atrophy over a 100-year period. Earlier case reports included patients younger in age with more frequent cerebellar involvement. Mean age of onset was 54.2 years (range 31 to 78) and survival was 6.2 years (range 0.5 to 24). Survival analysis showed a secular trend from a median duration of 4.9 years for publications between 1887 and 1970 to 6.8 years between 1991 and 1994. Older age of onset was associated with shorter survival; the hazard ratio for patients with onset after 60 years was 1.8 (95% CI 1.4 to 2.3) compared with patients between 31 and 49 years. Cerebellar features were associated with marginally increased survival (6.1 years versus 5.4 years; p = 0.04). There were no difference in survival according to gender, parkinsonian, or pyramidal features or whether the patient was classified as striatonigral degeneration or olivopontocerebellar atrophy type. These results demonstrate the poor prognosis for patients with multiple system atrophy but may be biased toward the worst cases. Future research needs to recruit more representative samples.

[Atypical Parkinson syndrome]

Various clinico-pathological studies have shown that appr. 20% of patients with a clinical diagnosis of idiopathic Parkinson's disease (IPD) may have neuropathological evidence of alternative causes of parkinsonism. Most of these misdiagnosed "IPD" patients meet clinical criteria for either multiple system atrophy (MSA), or progressive supranuclear palsy (PSP), or corticobasal degeneration (CBD). A careful history and physical examination, as well as follow-ups and selected investigations are essential for an accurate clinical diagnosis of these atypical parkinsonian syndromes. The following paper therefore provides a review of clinical features and diagnostic findings in MSA, PSP and CBD, in order to facilitate recognition of these patients.

Accuracy of the clinical diagnosis of corticobasal degeneration: a clinicopathologic study

The accuracy of the clinical diagnosis of corticobasal degeneration (CBD) is unknown. To determine its diagnostic accuracy, we presented 105 cases with known neuropathologic diagnoses, including CBD (n = 10), progressive supranuclear palsy (PSP, n = 24), Parkinson's disease (n = 15), diffuse Lewy body disease (n = 14), multiple system atrophy (n = 16), postencephalitic parkinsonism (n = 7), Pick's disease (n = 7), Creutzfeldt-Jakob disease (n = 4), Alzheimer's disease (n = 4), vascular parkinsonism (n = 3), and Whipple's disease (n = 1), as clinical vignettes to six neurologists unaware of the autopsy findings. Reliability was measured with the kappa statistics. The neurologists' clinical diagnoses were compared with clinicopathologic diagnoses for sensitivity, specificity, and positive predictive values at first and last clinic visits. The group reliability for the diagnosis of CBD significantly improved from moderate for the first visit (mean = 34 months after onset) to substantial for the last (68 months after onset). For the first visit, mean sensitivity for CBD was low (35%), but specificity was near-perfect (99.6%). For the last visit, mean sensitivity minimally increased (48.3%), and specificity remained stable. False-negative misdiagnoses mainly occurred with PSP. False-positive diagnoses were rare. The extremely low sensitivity of the clinical diagnosis of CBD suggests that this disorder is markedly underdiagnosed. Although the validity of the clinical diagnosis might have been improved if neurologists could have examined these patients, more important is that this disorder was misdiagnosed by the primary neurologists. In our data set, the best predictors for the diagnosis of CBD included limb dystonia, ideomotor apraxia, myoclonus, and asymmetric akinetic-rigid syndrome with late onset of gait or balance disturbances.

Cerebellar presentation of multiple system atrophy

Early diagnosis of multiple-system atrophy (MSA) is important in patients presenting with late-onset cerebellar ataxia because it has a less favourable prognosis than other degenerative ataxic disorders. We report cerebellar presentation of MSA in a series of 16 patients, 3 of whom later developed parkinsonism. Two-thirds of them had early evidence of impaired postural reflexes with a history of recurrent falls. Some of these had a narrow-based, unsteady gait, unlike the more classic broad-based gait ataxia of cerebellar disease. On review of the patients' histories, genitourinary dysfunction (particularly impotence) was present at the onset of, or preceding, cerebellar ataxia in 60% of patients, but this had often been attributed to age, or to urological or gynaecological causes. External striated anal or urethral sphincter electromyography (EMG) demonstrated features of chronic denervation and reinnervation in 14 (93%) of 15 patients, consistent with degeneration in Onuf's nucleus as occurs in MSA. Autonomic function tests were abnormal in 9 (64%) of 14 patients. Our data suggest that close enquiry into genitourinary function and analysis of the gait disorder can be useful pointers to a diagnosis of MSA in patients with an unexplained adult-onset progressive cerebellar syndrome, and that sphincter EMG is the most useful investigation in this context.

The natural history of Parkinson's disease

A large body of evidence indicates that the progression of Parkinson's disease (PD) may be fast in the preclinical stage as well as during the first years of the disease, with a subsequent slowing down of the disease process. As has been shown in the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) study, the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination scores declined at a rate of 8 to 9% per year in untreated patients. A subgroup of levodopa-naive DATATOP patients ("survivors") showed a much slower rate of progression, in the order of 3% per year, suggesting a more benign disease course. A number of clinical factors that may govern the rate of motor decline, such as age at onset, disease duration, gender, and clinical phenotype (akinetic-rigid versus tremulous) have been proposed; however, none of them is proven. In contrast, dopaminergic substitution undoubtedly has had a major impact on the natural history of PD, resulting in a reduction of the mortality ratio from about 3.0 to 1.5. This benefit has been noted particularly in patients in whom levodopa therapy was started early. The positive impact of levodopa is largely derived from its symptomatic action; its influence on the disease process itself remains controversial.

Reversal of behavioural abnormalities by fetal allografts in a novel rat model of striatonigral degeneration

We have developed a rodent model of striatonigral degeneration, one of the core pathologies underlying the disease multiple system atrophy (MSA). 6-Hydroxydopamine (6-OHDA) was administered into the left medial forebrain bundle of male Wistar rats, followed 3-4 weeks later by intrastriatal injection of quinolinic acid into the ipsilateral striatum. The 6-OHDA lesion resulted in ipsilateral rotation to (+)-amphetamine and contralateral rotation to apomorphine. Following the subsequent striatal lesion, amphetamine-induced ipsilateral rotation persisted, but apomorphine-induced contralateral rotation was reduced or abolished. Subsequently, the lesioned striatum was implanted with fetal CNS allografts consisting of cell suspensions derived from striatal primordium alone or combined with cografts of ventral mesencephalon. Cografted rats showed a reduction or reversal of amphetamine-induced rotation. This was not observed in animals receiving striatal grafts alone. Apomorphine-induced contralateral rotation was restored after striatal grafts alone, but only partially in animals receiving sham or cografts. Tyrosine hydroxylase (TH) and dopamine- and cyclic adenosine 3':5'-monophosphate-regulated phosphoprotein (DARPP 32) immunocytochemistry showed mesencephalic and striatal graft survival in most animals. However, dopaminergic outgrowth was restricted to the graft deposit. The latter was surrounded by a markedly gliotic glial fibrillary acidic protein-positive capsule continuous with corpus callosum. Dopaminergic reinnervation of denervated and lesioned adult striatum itself was absent, suggesting that rotational recovery was due to diffuse dopamine release. The study shows that combined unilateral lesioning of rodent medial forebrain bundle and striatum results in a characteristic drug-induced rotational response that can be partly restored by mesencephalic/striatal cografts.

Ataxia without telangiectasia masquerading as benign hereditary chorea

We report a nonconsanguineous family in whom two (of three) sons developed isolated chorea in early childhood, suggesting a diagnosis of benign hereditary chorea (BHC). However, cerebellar ataxia and oculomotor apraxia, without telangiectasia, subsequently developed. Chromosome analysis showed increased radiosensitivity in both brothers and translocations in the younger one. We conclude that ataxia with chromosomal instability may masquerade as BHC in some patients.

Olivopontocerebellar pathology in multiple system atrophy

Olivopontocerebellar atrophy (OPCA) is widely accepted as part of the neuropathological spectrum of multiple system atrophy (MSA). The distribution of affected sites in the olivopontocerebellar (OPC) system and their interrelationship remain poorly understood due to lack of quantitative studies. To further investigate the OPC pathology in MSA, we performed a morphometric analysis of 20 MSA cases and eight healthy controls. In the MSA cases, mean neuronal cell densities were significantly reduced in (medial and dorsal) accessory and principal inferior olives, pontine nuclei, cerebellar vermis (except nodulus), and hemispheres. Inferior olives and pontine nuclei were more severely affected than cerebellar Purkinje cells in most cases. Cerebellar Purkinje cells were more severely depleted in vermis rather than in hemisphere. There was a poor topographic correlation between neuronal cell loss in inferior olives and cerebellar cortex. These results suggest a primary degeneration of olivopontine nuclei and cerebellar Purkinje cells in OPCA. Inferior olives, pontine nuclei and cerebellar cortex were all significantly more severely affected in cases with a pure or predominating cerebellar syndrome (OPCA type, n = 4) compared to those with pure or predominating parkinsonism (SND type, n = 14). However, although cerebellar signs had been noted in life in only six cases, morphometry revealed OPCA in 17 of the 20 MSA brains.

Effect of repeated administration of dopamine agonists on striatal neuropeptide mRNA expression in rats with a unilateral nigral 6-hydroxydopamine lesion

Striatal mRNA expression for preproenkephalin (PPE) and preprotachykinin (PPT) was studied in unilateral 6-OHDA lesioned rats treated subchronically with a range of selective and non-selective D-1 or D-2 dopamine (DA) agonists. Apomorphine (5 mg/kg sc), pergolide (0.5 mg/kg sc), SKF 38393 (5 mg/kg sc), SKF 80723 (1.5 mg/kg sc), and quinpirole (5 mg/kg sc), or 0.9% saline (150 microliters sc) were all given twice daily (except pergolide: once daily) for 7 days. The abundance of PPE mRNA was not altered by any of these DA agonists in the intact striatum contralateral to the 6-OHDA lesion. Only apomorphine and quinpirole increased the abundance of PPT mRNA in the intact striatum. In saline treated 6-OHDA lesioned animals PPE mRNA was elevated (+160%, p < 0.005) and PPT mRNA decreased (-36%, p < 0.005) in the denervated striatum. The up-regulation of striatal PPE mRNA in the lesioned striatum was reversed only by pergolide. The downregulation of striatal PPT mRNA in the lesioned striatum was reversed only by apomorphine. The differential sensitivity of the striatal PPE message to the long-acting DA agonist pergolide, and of the striatal PPT message to the mixed D-1/D-2 DA agonist apomorphine suggests that the striatopallidal enkephalinergic pathways are mainly regulated by prolonged DA receptor stimulation, whereas the striatonigral substance P pathways are mainly regulated by mixed D-1/D-2 DA receptor stimulation.

Pain in multiple system atrophy

Pain is a recognized feature of idiopathic Parkinson's disease (IPD) but has never been studied in multiple system atrophy (MSA), the commonest cause of atypical parkinsonism. We retrospectively analysed histories of pain in 100 consecutive cases of clinically probable MSA. Details were obtained from the medical records of 100 patients with MSA, comprising 82 with the striatonigral degeneration (SND) type and 18 with the olivopontocerebellar atrophy (OPCA) type of MSA. Pain was reported in 47% of the MSA patients. It was classified as rheumatic in 64% of MSA patients reporting pain, sensory in 28%, dystonic in 21%, and levodopa-related in 16%, mostly related to off-period or diphasic dystonias. There was a mixed pain syndrome in 19% of these patients. Pain was significantly more commonly reported by females (P = 0.02), and by patients with levodopa-induced dyskinesias (P = 0.02). No other clinical feature differentiated MSA patients who reported pain from those who did not. The mean delay between disease onset and onset of pain was 2.9 years, but pain was reported at the time of, or before, disease onset in about 30% of patients. The overall prevalence of pain in MSA was similar to that reported in IPD, but the distribution of pain categories was different.

A clinical and pharmacokinetic case study of an interaction of levodopa and antituberculous therapy in Parkinson's disease

We studied the relationship between levodopa response and antituberculous treatment in a patient with idiopathic Parkinson's disease whose parkinsonism deteriorated when treatment with rifampicin and isoniazid (Rifinah) for pulmonary tuberculosis was started. A levodopa challenge test with regular recording of motor function was performed during, and again after stopping, antituberculous treatment. Plasma levodopa and levodopa metabolite pharmacokinetic profiles were determined using standard techniques. "On" period duration was 75% longer after antituberculous treatment had been stopped. These clinical findings correlated with a 37% increase in area under the concentration versus time curve (AUC), a 103% increase in apparent elimination half-life (t1/2), a 41% increase in time to maximum concentration (Tmax), and a 33% decrease in maximum concentration (Cmax) of levodopa. A concurrent increase in plasma 3-O-methyldopa (3-OMD) and a decrease in plasma 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the three major metabolites of levodopa, suggests an inhibition of the enzyme dopa decarboxylase, probably by isoniazid.

[Multiple system atrophy with Lewy bodies]

The term multiple system atrophy has been used to define a unique sporadic neurodegenerative disease, usually occurring in midlife, pathologically characterized by degeneration of the nigro-striato-pallidal and olivo-ponto-cerebellar systems and autonomic neurons of the spinal cord, and by the presence of characteristic oligodendroglial inclusions. In many cases, this disease can be readily distinguished, both clinically and pathologically, from idiopathic Parkinson's disease. However, often clinical differentiation is difficult, and in a few autopsied cases the presence of Lewy bodies, the characteristic inclusion of idiopathic Parkinson's disease, can lead to diagnostic confusion. Such a pathological association, named the "transitional variant" by some authors, is of unknown clinical and pathological significance. We here report three new cases of such an association from the United Kingdom Parkinson's Disease Society Brain Bank. Clinical and pathological data derived from these new observations, as well as from literature cases, tend to suggest that this pathological association is of no particular clinical significance. The comparison of the prevalence of Lewy bodies in normal elderly individuals and in multiple system atrophy suggests a chance association of the two pathologies. However, the small number of cases so far studied as well as the heterogeneity of series analyzed does not exclude the presence of common susceptibility factors for both diseases.

Nerve conduction studies, skeletal muscle EMG, and sphincter EMG in multiple system atrophy

Although autonomic failure, parkinsonism, and cerebellar and pyramidal signs are well documented in multiple system atrophy, much less is known about the frequency and severity of involvement of the peripheral nervous system. The frequency and nature of peripheral nerve involvement has therefore been determined in 74 patients with multiple system atrophy using nerve conduction studies and skeletal muscle EMG. These findings were compared with those on sphincter EMG. Ninety per cent of the patients had an abnormal sphincter EMG, indicating denervation and reinnervation consistent with anterior horn cell loss in Onuf's nucleus, but only 40% had either abnormal nerve conduction studies (mixed sensorimotor axonal neuropathy in 17.5%) or abnormal skeletal muscle EMG (suggesting partial denervation in 22.5%). These data indicate a remarkable selective vulnerability of the anterior horn cells of Onuf's nucleus innervating external sphincter muscles relative to those supplying skeletal muscle in patients with multiple system atrophy. If this selective pattern of involvement can be explained it may be a clue to pathogenetic mechanisms in multiple system atrophy.

Olfactory function in atypical parkinsonian syndromes

INTRODUCTION

Olfaction is markedly impaired in patients with idiopathic Parkinson's disease (IPD). This deficit contrasts with reports of preserved or only mildly reduced olfaction in patients with atypical parkinsonism. However, the sensitivity and specificity of olfactory function testing in the differential diagnosis of parkinsonian syndromes has not been studied. In addition, olfactory function in patients with corticobasal degeneration (CBD) is unknown.

MATERIAL AND METHODS

Using the University of Pennsylvania Smell Identification Test (UPSIT) with a test score ranging from 0 to 40 we studied olfactory function in patients with IPD as well as other parkinsonian syndromes including CBD and progressive supranuclear palsy (PSP).

RESULTS

UPSIT scores in 118 patients with IPD, 29 with MSA, 15 with PSP, and 7 patients with CBD, as well as in 123 healthy control subjects revealed a marked impairment in the IPD group in contrast to mild impairment in MSA patients and normal olfaction in PSP and CBD patients. An UPSIT score of 25/40 was associated with a sensitivity of 77% and a specificity of 85% in differentiating IPD from atypical parkinsonism.

CONCLUSIONS

These results indicate that olfactory function is differentially impaired or preserved in distinct parkinsonian syndromes and that it might also have some value as a diagnostic pointer. Thus, preserved or mildly impaired olfactory function in a parkinsonian patient is more likely to be related to atypical parkinsonism such as MSA, PSP or CBD, whereas markedly reduced olfaction is more suggestive of IPD.

Autonomic dysfunction in pathologically confirmed multiple system atrophy and idiopathic Parkinson's disease--a retrospective comparison

INTRODUCTION

Autonomic dysfunction (AD) can be a feature of both multiple system atrophy (MSA) and idiopathic Parkinson's disease (IPD), conditions that are frequently misdiagnosed in life. Most studies on AD in MSA and IPD are based on clinical cases without pathological verification.

MATERIAL AND METHODS

We retrospectively analysed AD in 135 pathologically confirmed cases of IPD and in 33 of MSA from the UK PD Society Brain Bank.

RESULTS

MSA started at a younger age than IPD (54.4 +/- 10.7 yrs versus 60.6 +/- 10.8 yrs), and AD began earlier in the course of the illness All MSA patients had some degree of AD in life whereas AD was absent in 24% of IPD patients. Although each of five autonomic domains was affected in variable numbers of IPD patients, AD in MSA generally involved more autonomic domains than in IPD, and to a more severe degree, in particular with regard to inspiratory stridor.

CONCLUSIONS

These results indicate that the presence of autonomic disturbance alone does not distinguish between MSA and IPD in individual cases. However, the presence of severe AD, of AD preceding parkinsonism, or of inspiratory stridor, are all individually suggestive of MSA.

Clinicopathological study of 35 cases of multiple system atrophy

The clinical and pathological features of 35 cases with multiple system atrophy collected in the United Kingdom Parkinson's Disease Society Brain Bank (UKPDSBB) between 1985 and 1992 have been analysed. The median age of onset was 55 (range 33.3-75.8) years and median survival was 7.3 (range 2.1-11.5) years. Parkinsonism, usually asymmetric, occurred in all, and autonomic failure in all but one case. Cerebellar signs were noted in 34% and pyramidal features in 54% of the cases. Glial cytoplasmic inclusions were found in all cases with adequate fixation. Lewy bodies were detected in three cases. The substantia nigra was (usually severely) depleted of cells in all cases. With two exceptions the putamen was atrophic; the caudate and pallidum were less commonly and less severely affected. Overall nigrostriatal cell loss correlated with severity of disease at the time of death. The latest, but not the best, recorded levodopa response tended to be inversely related to the degree of putaminal degeneration. The olivopontocerebellar system was involved in 88% of the cases, the cerebellar vermis usually being more severely affected than the hemispheres. The presence of associated cerebellar pathology was, however, unrelated to the presence of cerebellar signs in life.

Differentiation of multiple system atrophy from idiopathic Parkinson's disease using proton magnetic resonance spectroscopy

Proton magnetic resonance spectroscopy, localized to the lentiform nucleus, was carried out in 7 patients with the pure or predominantly striatonigral variant (SND) of multiple system atrophy (MSA), 5 patients with the olivopontocerebellar variant of MSA, 9 patients with a clinical diagnosis of idiopathic Parkinson's disease (IPD), and 9 healthy age-matched controls. The MSA group with predominantly striatonigral involvement showed a significant reduction in the N-acetylaspartate (NAA)/creatine ratio (median, 1.19; range, 0.96-2.0; p < 0.02) compared with the NAA/creatine ratio from the control group (median, 1.76; range, 1.61-2.0). In contrast, the IPD group had a normal NAA/creatine ratio (median, 1.82; range, 1.19-2.31; p > 0.05). The NAA/creatine ratio was markedly reduced in 6 of the SND patients and in only 1 IPD patient. The choline/creatine ratio was also significantly lower in the SND group (median, 1.02; range, 0.91-1.23; p < 0.04) compared with the control group (median, 1.22; range, 1.05-1.65). The IPD group showed a normal lentiform choline/creatine ratio (median, 1.13; range, 0.89-1.65; p = 0.25) compared with controls. The olivopontocerebellar group also showed a significant reduction in the NAA/creatine ratio from the lentiform nucleus (median, 1.47; range, 1.22-1.68; p < 0.01) compared with the controls as well as a nonsignificant reduction in the choline/creatine ratio (median, 0.93; range, 0.85-1.27; p < 0.4).(ABSTRACT TRUNCATED AT 250 WORDS)

[Pseudotransitory ischemic attacks as the initial symptom of multiple system atrophy]

A 59-year-old man presented with an 18-month history of episodes of visual disturbance and dysphagia in association with gait unsteadiness and leg weakness lasting between 45 and 120 min. These episodes were interpreted as vertebrobasilar transitory ischemic attacks. However, they had been preceded by impotence for 6 months. Autonomic function tests remained normal until the age of 62 years when the patient developed documented orthostatic hypotension. Parkinsonism was precipitated by neuroleptic treatment at the age of 59 years, at which time pyramidal signs were evident. The patient was unable to tolerate levodopa preparations and subsequently developed the full clinical picture of pathologically proven multiple system atrophy, dying at age 65, 7 years after his first symptom.

Clinical features and natural history of multiple system atrophy. An analysis of 100 cases

The clinical features and natural history of 100 patients diagnosed as probable multiple system atrophy (MSA) are described. In all 14 (of 41 deceased) cases who underwent post-mortem examination of the brain, the diagnosis was confirmed pathologically, providing some validation of the clinical diagnostic criteria used. There were 67 men and 33 women. Median age at onset (at time of first reported symptom) was 53 (range 33-76) years. Autonomic symptoms were the initial feature in 41% of the patients, but had subsequently developed in 97% at latest follow-up. The most frequent autonomic symptom in men was impotence, and in women was urinary incontinence. Symptomatic orthostatic hypotension, although present in 68%, was severe in only 15% of patients. Parkinsonism was the initial feature in 46%, but had subsequently developed in 91% of subjects at latest follow-up. It was the predominant motor disorder [striatonigral degeneration (SND) type] in 82% of the patients, and was usually asymmetric (74%). Although akinesia and rigidity predominated, tremor was present at rest in 29% of patients, but in only 9% had a classical pill-rolling parkinsonian rest tremor been recorded. Twenty-nine percent of MSA patients had a good or excellent levodopa response at some stage. However, only 13% maintained this response. Prominent orofacial dyskinesias and dystonias occurred in a quarter of treated patients with MSA. Early onset (before age 49 years) MSA patients tended to have a good levodopa response. Cerebellar symptoms or signs were the only initial feature in 5%. Although subsequently developing in a further 47% of cases, in only 18% was a cerebellar syndrome the only (9%) or predominant (9%) motor disorder [olivopontocerebellar (OPCA) type]. Pyramidal involvement at latest follow-up was noted in 61% of all cases. In a further seven patients the initial features involved more than one system, and one other had presented as a parasomnia. Multiple system atrophy of the OPCA type most commonly presented with gait ataxia. Tremor, pyramidal signs and myoclonus were less common than in MSA of the SND type. Cerebellar signs were present in 42% of patients with MSA of the SND type and parkinsonian signs in 50% of patients with MSA of the OPCA type. Disease progression was faster than in idiopathic Parkinson's disease, so that > 40% of patients were markedly disabled or wheelchair bound within 5 years of onset of motor disturbance. Median survival of the whole group as calculated by Kaplan-Meier analysis was 9.5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Is cranial computerized tomography useful in the diagnosis of multiple system atrophy?

Cranial computer tomographic (CT) images of 33 patients with multiple system atrophy (MSA) and of 40 age-matched controls were blindly analyzed by two neuroradiologists. All patients had autonomic dysfunction, all but one had parkinsonism, and 13 had cerebellar signs. The scans were judged entirely normal in 21%. Moderate or severe infratentorial atrophy was found in 42%. Cerebellar atrophy was present in 39%, and pontine atrophy was present in 18%. Of the 13 patients with cerebellar signs, only eight had cerebellar atrophy. Of the 20 patients without cerebellar signs, five had cerebellar atrophy. Supratentorial involvement was much less common and less severe. Thus, CT demonstrated system involvement that was not evident clinically in five of 33 cases (15%). However, in all five the clinical diagnosis was already evident from the presence of both autonomic and pyramidal signs in addition to parkinsonism. We conclude that CT imaging is of limited diagnostic use in individual patients with MSA.

Recovery of the hypothalamic-pituitary-adrenal axis from suppression by short-term, high-dose intravenous prednisolone therapy in patients with MS

We have studied the recovery of the hypothalamic-pituitary-adrenal (HPA) axis from inhibition by short-term, intravenous high-dose, corticosteroid therapy (IVHDCT) without subsequent oral replacement therapy in 10 patients with relapsing-remitting or progressive multiple sclerosis (MS) using the human corticotrophin-releasing hormone (hCRH) test. There was significant HPA suppression with profoundly decreased basal and peak plasma ACTH and cortisol levels 24 h after cessation of therapy. However, at 48 h the pituitary response was greatly enhanced with peak ACTH concentrations rising by more than 100% over baseline values in 7 of 10 patients. Basal and stimulated ACTH concentrations returned to pre-treatment levels at 120 h. Basal and stimulated plasma cortisol levels remained subnormal in 6 patients 120 h after IVHDCT. We conclude that IVHDCT without oral replacement therapy in MS patients is endocrinologically safe.

"Minimal change" multiple system atrophy

We describe the pathological findings in two patients who developed atypical parkinsonism and autonomic failure, leading to a diagnosis of multiple system atrophy (MSA). Postmortem examination of the brain showed cell loss restricted to substantia nigra and locus coeruleus. However, glial cytoplasmic inclusions (GCIs) were present in both cases. We propose that GCIs are highly suggestive of a pathological diagnosis of MSA in the absence of detectable cell loss outside pigmented brain stem nuclei and that brains from cases of atypical parkinsonism should routinely be examined for their presence.