Autonomic dysfunction in chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVES

Autonomic deficits in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have not been adequately quantitated. The Composite Autonomic Severity Score (CASS) is a validated instrument for laboratory quantitation of autonomic failure derived from standard autonomic reflex tests. We characterized dysautonomia in CIDP using CASS.

METHODS

Autonomic function was retrospectively analyzed in 47 patients meeting CIDP criteria. CASS ranges from 0 (normal) to 10 (pandysautonomia), reflecting summation of sudomotor (0-3), cardiovagal (0-3), and adrenergic (0-4) subscores. Severity of neurologic deficits was measured with Neuropathy Impairment Score (NIS). Degree of small fiber involvement was assessed with quantitative sensation testing. Thermoregulatory sweat test (TST) was available in 8 patients.

RESULTS

Patients (25 men) were middle-aged (45.0 ± 14.9 years) with longstanding CIDP (3.5 ± 4.3 years) of moderate severity (NIS, 46.5 ± 32.7). Autonomic symptoms were uncommon, mainly gastrointestinal (9/47; 19%) and genitourinary (8/47; 17%). Autonomic deficits (CASS ≥1) were frequent (22/47; 47%) but very mild (CASS, 0.8 ± 0.9; CASS ≤3, all cases). Deficits were predominantly sudomotor (16/47; 34%) and cardiovagal (10/47; 21%) with relative adrenergic sparing (4/47; 9%). TST was abnormal in 5 of 8 patients (anhidrosis range, 2%-59%). Sudomotor impairment was predominantly distal and postganglionic. Somatic deficits (disease duration, severity, small fiber deficits) did not predict presence of autonomic deficits.

CONCLUSION

Our data characterize the autonomic involvement in classic CIDP as mild, cholinergic, and predominantly sudomotor mainly as a result of lesions at the distal postganglionic axon. Extensive or severe autonomic involvement (CASS ≥4) in suspected CIDP should raise concern for an alternative diagnosis.

Gastroparesis and functional dyspepsia: excerpts from the AGA/ANMS meeting

BACKGROUND

Despite the relatively high prevalence of gastroparesis and functional dyspepsia, the aetiology and pathophysiology of these disorders remain incompletely understood. Similarly, the diagnostic and treatment options for these two disorders are relatively limited despite recent advances in our understanding of both disorders.

PURPOSE

This manuscript reviews the advances in the understanding of the epidemiology, pathophysiology, diagnosis, and treatment of gastroparesis and functional dyspepsia as discussed at a recent conference sponsored by the American Gastroenterological Association (AGA) and the American Neurogastroenterology and Motility Society (ANMS). Particular focus is placed on discussing unmet needs and areas for future research.

Sudomotor dysfunction in autoimmune autonomic ganglionopathy

BACKGROUND

Autoimmune autonomic ganglionopathy is characterized by impairment of multiple autonomic domains of which sudomotor function is among the most common. Many patients with this disorder have difficulties with thermoregulation and anhidrosis. Our objective was to characterize the distribution and severity of sudomotor dysfunction in this disorder.

METHODS

Sudomotor function was analyzed in a cohort of 21 patients with ganglionic alpha3 nicotinic acetylcholine receptor (nAChR) antibody positive autoimmune autonomic ganglionopathy. Standard measurements of sudomotor function were used including the Thermoregulatory Sweat Test and Quantitative Sudomotor Axon Reflex Test.

RESULTS

The clinical presentation in all patients was characterized by widespread sudomotor dysfunction. Sudomotor impairment was predominantly postganglionic in 17 of the 21 patients studied. Higher ganglionic alpha3 nAChR antibody levels resulted in progressive postganglionic predominant dysfunction (postganglionic, r = 0.637, p = 0.002; mixed ganglionic, r = 0.709, p < 0.001). The pattern of anhidrosis on Thermoregulatory Sweat Testing was consistent with a ganglionopathy in the majority of patients (14 of 21) and a distal pattern in a minority of patients (8 of 21). These patterns of anhidrosis coupled with increasing postganglionic dysfunction in a proximal to distal pattern (foot > distal leg > proximal leg > forearm) indicate lesions at both the ganglia and distal axon of the postganglionic sudomotor sympathetic neuron.

CONCLUSIONS

Our data characterize the unique sudomotor dysfunction in autoimmune autonomic ganglionopathy as widespread, predominantly postganglionic, and a result of lesions at both the ganglia and distal axon. This study provides important support to the hypothesis that this disorder represents a ganglionic neuropathy.

Dopamine cell loss in the periaqueductal gray in multiple system atrophy and Lewy body dementia

BACKGROUND

Experimental studies indicate that dopaminergic neurons in the ventral periaqueductal gray matter (PAG) are involved in maintenance of wakefulness. Excessive daytime sleepiness (EDS) is a common manifestation of multiple system atrophy (MSA) and dementia with Lewy bodies (DLB) but involvement of these neurons has not yet been explored.

METHODS

We sought to determine whether there is loss of dopaminergic neurons in the ventral PAG in MSA and DLB. We studied the midbrain obtained at autopsy from 12 patients (9 male, 3 female, age 61 +/- 3) with neuropathologically confirmed MSA, 12 patients (11 male, 1 female, age 79 +/- 4) with diagnosis of DLB and limbic or neocortical Lewy body disease, and 12 controls (7 male, 5 female, ages 67 +/- 4). Fifty-micron sections were immunostained for tyrosine hydroxylase (TH) or alpha-synuclein and costained with thionin. Cell counts were performed every 400 mum throughout the ventral PAG using stereologic techniques.

RESULTS

Compared to the total estimated cell numbers in controls (21,488 +/- 8,324 cells), there was marked loss of TH neurons in the ventral PAG in both MSA (11,727 +/- 5,984; p < 0.01) and DLB (5,163 +/- 1,926; p < 0.001) cases. Cell loss was more marked in DLB than in MSA. There were characteristic alpha-synuclein inclusions in the ventral PAG in both MSA and DLB.

CONCLUSIONS

There is loss of putative wake-active ventral periaqueductal gray matter dopaminergic neurons in both multiple system atrophy and dementia with Lewy bodies, which may contribute to excessive daytime sleepiness in these conditions.

Efficacy of immunotherapy in seropositive and seronegative putative autoimmune autonomic ganglionopathy

OBJECTIVE

To evaluate the efficacy of immunotherapy in the treatment of patients with seropositive and seronegative putative autoimmune autonomic ganglionopathy (AAG) using validated autonomic function tests and instruments.

BACKGROUND

AAG is an immune-mediated disorder characterized by prominent and selective involvement of autonomic nerve fibers or ganglia. Treatment with i.v. immunoglobulin (IVIg) or plasma exchange (PE) has been reported to be effective in single case reports.

METHODS

We studied six patients, four with seropositive and two with seronegative putative AAG, who underwent autonomic function tests and completed two validated questionnaires, to assess autonomic symptoms before and after immunomodulatory treatment. Patients were treated with standard doses of IVIg, PE, or immunosuppressants in a specific sequential therapy protocol depending on clinical response.

RESULTS

Of the six patients (all women, mean ages 49.3 +/- 10.6 years), four patients were ganglionic (alpha3) AChR autoantibody positive and two were autoantibody negative. All patients showed clinical improvement after treatment. Sudomotor function assessed by quantitative sudomotor axon reflex test and thermoregulatory sweat test improved in four patients after treatment.

CONCLUSIONS

Immunomodulatory treatment can be effective in both seropositive and seronegative putative autoimmune autonomic ganglionopathy. Plasma exchange or combined therapy with immunosuppressive agents should be considered in patients who do not benefit from i.v. immunoglobulin alone.

Second consensus statement on the diagnosis of multiple system atrophy

BACKGROUND

A consensus conference on multiple system atrophy (MSA) in 1998 established criteria for diagnosis that have been accepted widely. Since then, clinical, laboratory, neuropathologic, and imaging studies have advanced the field, requiring a fresh evaluation of diagnostic criteria. We held a second consensus conference in 2007 and present the results here.

METHODS

Experts in the clinical, neuropathologic, and imaging aspects of MSA were invited to participate in a 2-day consensus conference. Participants were divided into five groups, consisting of specialists in the parkinsonian, cerebellar, autonomic, neuropathologic, and imaging aspects of the disorder. Each group independently wrote diagnostic criteria for its area of expertise in advance of the meeting. These criteria were discussed and reconciled during the meeting using consensus methodology.

RESULTS

The new criteria retain the diagnostic categories of MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia to designate the predominant motor features and also retain the designations of definite, probable, and possible MSA. Definite MSA requires neuropathologic demonstration of CNS alpha-synuclein-positive glial cytoplasmic inclusions with neurodegenerative changes in striatonigral or olivopontocerebellar structures. Probable MSA requires a sporadic, progressive adult-onset disorder including rigorously defined autonomic failure and poorly levodopa-responsive parkinsonism or cerebellar ataxia. Possible MSA requires a sporadic, progressive adult-onset disease including parkinsonism or cerebellar ataxia and at least one feature suggesting autonomic dysfunction plus one other feature that may be a clinical or a neuroimaging abnormality.

CONCLUSIONS

These new criteria have simplified the previous criteria, have incorporated current knowledge, and are expected to enhance future assessments of the disease.

Mesopontine cholinergic neuron involvement in Lewy body dementia and multiple system atrophy

BACKGROUND

The pedunculopontine (PPT) and laterodorsal (LDT) tegmental nuclei are involved in control of REM sleep and thalamocortical arousal. REM sleep behavior disorder (RBD) is a feature of multiple system atrophy (MSA) and dementia with Lewy bodies (DLB), which is also associated with visual hallucinations and cognitive fluctuations. We sought to determine the degree of PPT/LDT involvement in DLB compared to MSA.

METHODS

We counted the cholinergic neurons in the PPT and LDT in 13 patients with neuropathologically confirmed DLB, 11 patients with MSA, and 11 control cases. Five patients with DLB and eight patients with MSA had history or polysomnographic evidence of RBD. Ten patients with DLB and no patient with MSA had history of visual hallucinations or cognitive fluctuations.

RESULTS

There was a significant loss of PPT and LDT neurons in both DLB and MSA. Cell loss in both the PPT and LDT was more severe in MSA than in DLB. The number of cells/section for the PPT were 148 +/- 21 in controls, 54 +/- 10 in DLB (p < 0.001), and 20 +/- 3 in MSA (p < 0.001), and for the LDT, 112 +/- 16 in controls, 49 +/- 8 in DLB (p < 0.01), and 16 +/- 2 in MSA (p < 0.001). Severity of neuronal loss in MSA or DLB did not relate to the presence or absence of history of RBD.

CONCLUSIONS

Loss of cholinergic pedunculopontine tegmental nuclei/laterodorsal tegmental nuclei neurons occurs in both dementia with Lewy bodies and multiple system atrophy but is probably not the primary mechanism of REM sleep behavior disorder in these disorders.

Rostral raphe involvement in Lewy body dementia and multiple system atrophy

Depression is a feature of both Lewy body disorders and multiple system atrophy (MSA). Since serotonergic neurons of the rostral raphe have been implicated in depression, we sought to determine whether there is a differential involvement of these neurons in cases with clinically diagnosed dementia with Lewy bodies (DLB) or MSA. We studied the brainstem obtained at autopsy from fourteen patients with diagnosis of DLB and pathological limbic or neocortical stage Lewy body disease, 13 patients with clinical and neuropathological diagnosis of MSA, and 12 controls with no history of neurologic disease. The clinical features of these patients were analyzed retrospectively by reviewing their medical records. Serial sections were immunostained for tryptophan hydroxylase (TrOH) and alpha-synuclein and cell counts were performed in the dorsal raphe (DR), median raphe (MR) and medullary raphe nuclei. There was loss of serotonergic cells in both the DR and MR in DLB compared to control cases: For the DR, the number of cells/section were 53 +/- 6 in DLB versus 159 +/- 13 (P < 0.001) respectively, and for the MR 70 +/- 11 in DLB versus 173 +/- 23 (P < 0.001) respectively. In contrast, these cells were relatively preserved in MSA. The caudal raphe groups were affected both in MSA and in DLB. There is a differential involvement of raphe neurons in DLB and MSA. Although loss of rostral raphe neurons may contribute to depression in DLB, this appears to be less likely in MSA. Factors other than the neurochemical phenotype determine neuronal vulnerability in MSA.

Autoimmune autonomic ganglionopathy: IgG effects on ganglionic acetylcholine receptor current

BACKGROUND

Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated form of diffuse autonomic failure. Many patients have serum antibodies that bind to the ganglionic acetylcholine receptors (AChRs) that mediate fast synaptic transmission in autonomic ganglia. Previous clinical studies and observations in animal models suggest that AAG is an antibody-mediated neurologic disorder.

METHODS

Using whole-cell patch clamp techniques, we recorded ganglionic AChR currents in cultured human IMR-32 cells and examined the effects of bath application of IgG derived from patients with AAG.

RESULTS

IgG from seven patients with AAG all produced a progressive decline in whole-cell ganglionic AChR current, whereas IgG from control subjects had no effect. The effect was abolished at low temperature. Fab antibody fragments had no effect unless a secondary antibody was added concurrently. IgG from one patient also produced a more immediate reduction of ganglionic AChR current.

CONCLUSIONS

The characteristics of antibody-mediated inhibition of ganglionic acetylcholine receptor (AChR) current are consistent with modulation and blocking of the membrane AChR, analogous to the effects of muscle AChR antibodies in myasthenia gravis. Our observations demonstrate that antibodies in patients with autoimmune autonomic ganglionopathy (AAG) cause physiologic changes in ganglionic AChR function and confirm that AAG is an antibody-mediated disorder.

Calf venous compliance in multiple system atrophy

In multiple system atrophy (MSA), increased venous compliance with excessive venous pooling is assumed to be a major contributor to orthostatic hypotension (OH); however, venous compliance has never been assessed in MSA patients. We evaluated the severity and distribution of adrenergic, cardiovagal, and sudomotor failure in 11 patients with probable MSA, 14 age- and sex-matched control subjects, and 8 patients with Parkinson's disease (PD) but not OH. Calf venous compliance, venous filling, and capillary filtration were measured using calf plethysmography. The response to the directly acting α-adrenergic stimulation (10 mg midodrine) on calf venous compliance was additionally evaluated. Contrary to our hypothesis, pressure-volume curves in the legs of MSA patients were flatter than in PD patients ( P < 0.05) or controls ( P < 0.001); this indicated reduced calf venous compliance in MSA. The MSA group had reduced venous filling compared with control ( P < 0.001) or PD subjects ( P < 0.001) but had a normal capillary filtration rate ( P = 0.73). Direct α-adrenergic stimulation resulted in a slight but significant reduction of calf venous compliance in controls ( P = 0.001) and PD subjects ( P < 0.001) but not in the MSA group. The compliance change in MSA significantly regressed with autonomic failure (composite autonomic severity scale, r2 = 0.56) but not with parkinsonism (Unified MSA Rating Scale, r2 = 0.12). Our data indicate that MSA patients with chronic OH have reduced, rather than increased, venous compliance in the lower leg. We postulate that chronic venous distension that is associated with OH results in structural remodeling of veins, leading to reduced compliance, a change which may protect patients against orthostatic stress.

The burden of inpatient neurologic disease in two Ethiopian hospitals

OBJECTIVES

To define the burden of inpatient neurologic disease seen in Ethiopian teaching hospitals.

METHODS

We reviewed records of all medical inpatients admitted over a 6-month period to two teaching hospitals, one with and one without neurologists.

RESULTS

Neurologic cases made up 18.0% and 24.7% of all medical admissions. The mortality rates were 21.8% and 34.7%. Noninfectious diseases were 36.7% and 31.7% of neurologic cases, but unknown etiologies made up 42.2% and 29.0% of all cases. Of total cases, only 42.9% and 24.1% had at least a high level of diagnostic certainty.

CONCLUSIONS

Patients with neurologic disease make up a substantial minority of medical inpatients in Ethiopia. Noninfectious neurologic disease is at least as common as infectious neurologic disease. Reaching a well-defined final diagnosis occurs in only a minority of cases. Areas for improving the mortality rate include improving the barriers to diagnostic certainty and increasing treatment options for Ethiopian patients.

The North American Multiple System Atrophy Study Group

The North American Multiple System Atrophy Study Group involves investigators in 12 US medical centers funded by a grant from the National Institutes of Health. The objectives are to examine the environmental and genetic risk factors for MSA; elucidate pathogenic mechanisms underlying the disorder; and refine evaluations used for assessment. During its first year, the group enrolled 87 patients, implemented four cores, and initiated four scientific projects. Most patients among the 87 had parkinsonian features, which frequently began asymmetrically and remained asymmetrical; one-third responded to levodopa and many developed levodopa complications; almost two-thirds of the patients had cerebellar dysfunction, of these 90% had ataxia; urinary incontinence occurred commonly, and sleep disorders affected most. The investigators studied the effects of oxidative and nitrative stress upon the formation of alpha-synuclein inclusions; generated transgenic models of alpha-synuclein accumulation that recapitulate several behavioral and neuropathological features of MSA; and compared the severity of the autonomic features of MSA, Parkinson's disease and dementia with Lewy bodies.

Involvement of vagal autonomic nuclei in multiple system atrophy and Lewy body disease

BACKGROUND

Multiple system atrophy (MSA) and Lewy body disorders (LBDs) are associated with impaired control of gastrointestinal and cardiac functions. The dorsal vagal nucleus (DMV) innervates enteric neurons, whereas the ventrolateral nucleus ambiguus (NAmb) innervates the heart. The relationship between DMV and NAmb involvement and the gastrointestinal or cardiovagal manifestations in MSA and LBD is unclear.

METHODS

The authors counted the cholinergic neurons in the DMV and NAmb in 15 cases of neuropathologically confirmed MSA, 14 of LBD (4 brainstem, 3 limbic, and 7 neocortical), and 12 control cases. All MSA and 8 of the 14 LBD cases had gastrointestinal symptoms; 8 of 12 MSA and 1 of 4 LBD cases had laboratory evidence of cardiovagal failure; 5 of the MSA and no LBD cases had laryngeal stridor.

RESULTS

There was loss of cholinergic DMV neurons in all MSA and LBD cases. The degree of DMV cell loss was similar in LBD patient with or without gastrointestinal symptoms. In MSA but not in LBD cases, there was neuronal loss in the ventrolateral NAmb, with lower counts in patients with cardiovagal failure.

CONCLUSIONS

There is comparable involvement of the dorsal vagal nucleus (DMV) in multiple system atrophy (MSA) and different stages of Lewy body disorders (LBDs). The relationship of DMV involvement and gastrointestinal symptoms is uncertain. Loss of neurons in the ventrolateral nucleus ambiguus may explain the more consistent cardiovagal failure in MSA than in LBD.

Autonomic dysfunction in dementia with Lewy bodies

OBJECTIVE

To assess autonomic function in patients with dementia with Lewy bodies (DLB).

METHODS

The authors compared data from 20 DLB patients evaluated from 1995 to 2000 to 20 age-matched multiple system atrophy (MSA) and Parkinson disease (PD) patients evaluated from 1999 to 2002. Analysis of variance, Fisher exact test, and Student t-test were applied to compare disease characteristics, autonomic symptoms, and function tests on the Composite Autonomic Scoring Scale (CASS) and Thermoregulatory Sweat Test (TST).

RESULTS

In DLB, mean age at onset of autonomic symptoms was 70.3 +/- 8.9 years. Orthostatic symptoms were common and orthostatic hypotension occurred in 10/20 DLB, 17/20 MSA, and 1/20 PD patients (p = 0.023, 0.003). CASS-sudomotor for DLB, MSA, and PD were 1.6 +/- 1.2, 2.5 +/- 0.7, and 0.9 +/- 0.8 (p < 0.00001). CASS-cardiovagal were 1.4 +/- 0.9, 2.1 +/- 0.8, and 0.7 +/- 0.6 (p < 0.00001). CASS-adrenergic function were 2.4 +/- 1.2, 3.5 +/- 0.9, and 0.5 +/- 0.6 (p < 0.00001). Total CASS were 5.2 +/- 2.0, 8.1 +/- 1.3, and 2.2 +/- 1.2 (p < 0.00001). The most common pattern of TST in DLB was distal anhidrosis. Mean duration of follow-up was 3.0 +/- 1.8 years. Six patients needed medication to maintain blood pressure and five had good response.

CONCLUSIONS

Autonomic dysfunction is frequent in dementia with Lewy bodies and the severity is intermediate between that of multiple system atrophy and Parkinson disease.

Aphrodisiacs past and present: a historical review

The drug Viagra (sildenafil) has drawn public attention to aphrodisiacs. The search for such substances dates back millennia. Aphrodisiacs can be classified by their mode of action into 3 types: those that increase (1) libido, (2) potency, or (3) sexual pleasure. Various substances of animal and plant origin have been used in folk medicines of different cultures; some have been identified pharmacologically, allowing for understanding of their mechanisms of action. For increasing libido, ambrein, a major constituent of Ambra grisea, is used in Arab countries. This tricyclic triterpene alcohol increases the concentration of several anterior pituitary hormones and serum testosterone. Bufo toad skin and glands contain bufotenine (and other bufadienolides), a putative hallucinogenic congener of serotonin. It is the active ingredient in West Indian "love stone" and the Chinese medication chan su. The aphrodisiac properties are likely of central origin, as are the other effects of the drug. For increasing potency, Panax ginseng used in traditional Chinese medicine, works as an antioxidant by enhancing nitric oxide synthesis in the endothelium of many organs, including the corpora cavernosa; ginsenosides also enhance acetylcholine-induced and transmural nerve stimulation-activated relaxation associated with increased tissue cyclic guanosine monophosphate, hence the aphrodisiac properties. For increasing sexual pleasure, cantharidin ("Spanish fly") is a chemical with vesicant properties derived from blister beetles, which have been used for millennia as a sexual stimulant. Its mode of action is by inhibition of phosphodiesterase and protein phosphatase activity and stimulation of beta-receptors, inducing vascular congestion and inflammation. Morbidity from its abuse is significant. The ingestion of live beetles (Palembus dermestoides) in Southeast Asia and triatomids in Mexico may have a basis similar to cantharidin. It is of paramount importance for the physician to be aware of the options available to help his or her patients, and to advise them in using the correct drugs while avoiding "miracle" remedies that could be potentially harmful.

Autonomic peripheral neuropathies: clinical presentation, diagnosis, and treatment

This brief review was written with the intention of familiarizing the reader with autonomic peripheral neuropathies. We have discussed what we think are the main presenting symptoms of these conditions, briefly outlining some specific autonomic neuropathies. We then provide a general guideline to evaluation and diagnosis by using both widely available, as well as more sophisticated, techniques. Finally, we have addressed management. Whenever possible, specific treatment of underlying disorders leads to the best outcome However, for many autonomic neuropathies, no cure is available, although symptomatic management can effectively improve patients" quality of life.

Involvement of GABA(A) receptors in myoclonus

Alterations in multiple neurochemical systems have been reported in animal and human studies of posthypoxic myoclonus. It is impossible, however, to establish causative relationships between the observed changes and the myoclonic movements from these studies. Therefore, to establish causative links between neurochemical changes and myoclonus, ligands that target neurotransmitter systems that are altered in posthypoxic myoclonus were microinjected into the lateral ventricles of normal rats to identify the changes that can produce myoclonus. Of the ligands that were tested, only the GABA(A) antagonists produced myoclonus after intracerebroventricular administration, suggesting the importance of disinhibition of GABAergic systems in myoclonus. To further examine the role of GABA in myoclonus, GABAergic antagonists were microinjected into the nucleus reticularis of the thalamus (NRT), an area of the brain in which extensive pathologic changes are seen in posthypoxic animals. GABA(A), but not GABA(B), antagonists produced myoclonus after microinjection into the NRT. Earlier investigators have further reported the ability of GABA(A) antagonists to produce myoclonus after microinjection into the caudate. The data therefore suggest that disruption of activity at GABA(A) receptors at any one of a number of levels in the neural axis can produce myoclonus.

Mechanisms of blood pressure alterations in response to the Valsalva maneuver in postural tachycardia syndrome

The postural tachycardia syndrome (POTS) is characterized clinically by orthostatic lightheadedness and tachycardia. When these patients perform a Valsalva maneuver, there is an excessive blood pressure increment after cessation of the maneuver (phase IV) that is sometimes associated with headaches. It is not known whether excessive phase IV is due to excessive peripheral vascular tone (an alpha-adrenergic mechanism) or is a manifestation of increased beta-adrenergic tone (hyperadrenergic state). The authors undertook a pharmacologic study evaluating the effect of intravenous phentolamine (alpha-adrenergic antagonist) and propranolol (beta-adrenergic antagonist) on the different phases of the Valsalva maneuver in a group of patients with POTS and age-matched normal control subjects. Patients with POTS had mean phases, when compared with controls, that were characterized by more negative II_E (p = 0.07), smaller II_L (p = 0.04), and significantly larger phase IV (p = 0.001). The effect of phentolamine was qualitatively and quantitatively different in POTS when compared with controls. Ten mg phentolamine in controls resulted in a significant accentuation of phase II_E (p = 0.001), attenuation of phase II_L (p = 0.002), and increase of phase IV (57.6 vs 30.7 mm Hg; p = 0.025). These changes resembled those of patients with POTS at baseline. In patients with POTS, the phase II abnormalities, already present, were further accentuated (p <0.001), and phase IV became smaller (50.6 vs 73.8 mm Hg; p = 0.09). Propranolol had no significant effect on phases II_E and II_L, but significantly reduced phase IV in both controls (p <0.05) and in patients with POTS (p <0.001) and improved the headache symptoms, when present, during and after phase IV. The authors conclude that phase IV is mainly under beta-adrenergic regulation and that the exaggerated phase IV in POTS is a result of a hyperadrenergic state.

Neurophysiologic and vascular studies in erythromelalgia: a retrospective analysis

Erythromelaigia is a poorly understood clinical syndrome characterized by painful, hot, red extremities. We assessed the frequency and types of abnormalities observed during tests of vascular, peripheral neurophysiologic, and autonomic function in patients with erythromelalgia.Methods Of" 163 charts of patients fulfilling the clinical diagnosis of erythromelalgia. 93 patients underwent vascular studies Five of them had detailed vascular studies in 10 affected lower extremities performed before and during symptoms, fifty-four patients underwent neurophysiologic testing, 27 had autonomic reflex screening (ARS). and two had recordings of peripheral autonomic surface potentials (PASP).Results. Measurements in the toes during symptoms revealed a mean temperature increase of 11.6 C (P = 0,00011 along with a laser flow increase from a mean of 6.8 mL/min per 100 g tissue to 76.5 mL/min per 100 g tissue (P<.0.0001). Baseline TcPO; in the feet decreased by 6.7 mmHg (P = 0.032) during symptoms. Twenty-one of 54 electromyographic recordings were abnormal: all fulfilled the criteria for axonal neuropathy. Seventeen of 27 ARSs and one PASP showed severe postganglionic sudomotor impairment; five of 17 additionally had peripheral adrenergic dysfunction.Conclusions During symptoms, an increase in flow and temperature is accompanied paradoxically by a decrease in oxygenation of the affected area; a high proportion of patients have a distal small fiber neuropathy with selective involvement of cutaneous sympathetic fibers; in addition, large fiber neuropathy is often present.

Postural tachycardia syndrome: clinical features and follow-up study

OBJECTIVE

To define the clinical features and outcome of postural tachycardia syndrome (POTS).

MATERIALS AND METHODS

In this cross-sectional study of the autonomic symptom profile, inclusion criteria were orthostatic heart rate increment of 30 beats/min or greater, orthostatic symptoms, completion of a standardized autonomic test battery, and follow-up of 18 months or longer. We used 2 instruments. The first part was a structured and validated autonomic symptom profile (108 patients). The second part was a structured questionnaire focused on autonomic status on prospective follow-up (40 patients) (mean +/- SD follow-up, 67+/-52 months).

RESULTS

Most patients had frequent, persistent, and at least moderately severe symptoms for less than 5 years. The following orthostatic symptoms occurred in more than 75% of subjects: light-headedness or dizziness, lower extremity or diffuse weakness, disequilibrium, tachycardia, and shakiness. Nonorthostatic symptoms included dry eyes or mouth, gastrointestinal complaints of bloating, early satiety, nausea, pain, and alternating diarrhea and constipation. Half of the patients reported an antecedent illness presumed to be of viral origin. On follow-up, 80 % of patients were improved, 60% were functionally normal, and 90% were able to return to work. Patients who had an antecedent event appeared to do better than those with spontaneous POTS. Salt supplementation and beta-blockers were the most efficacious therapies.

CONCLUSION

In the majority of patients, POTS is self-resolving, especially in those with a triggering event.

Complex regional pain syndrome I (CRPS I): prospective study and laboratory evaluation

OBJECTIVE

To relate clinical features to autonomic laboratory indices used in the diagnosis of Complex Regional Pain Syndrome type I (CRPS I) (reflex sympathetic dystrophy) to generate improved diagnostic criteria.

DESCRIPTION

CRPS I is a chronic pain syndrome, characterized by diffuse limb pain with allodynia and prominent vasomotor and sudomotor dysfunction.

METHODS

We conducted a prospective study on 102 patients referred for possible CRPS I. These patients completed a structured questionnaire and underwent neurologic examination, with special attention to the evaluation of clinical features of vasomotor, sudomotor, motor, and sensory, including pain, dysfunction. All patients were tested using a standard autonomic protocol that compared side-to-side skin temperature, resting sweat output, and quantitative sudomotor axon reflex test (QSART) measurements. Composite autonomic clinical (CRPS-Sx) and laboratory (CRPS-LAB) scores were defined. The clinical (subjective and objective) and the laboratory data were analyzed using Pearson's correlation analysis and Bonferroni's probability value to assess concordance and their value in correctly diagnosing CRPS I.

RESULTS

All cases occurred after limb injury. One-third of cases did not fulfill our criteria of CRPS I. Highly significant correlations (p<.001) were found among certain clusters of symptoms and signs that shared unifying pathophysiologies. CRPS-Sx correlated with CRPS-LAB (p = .035). The indices that correlated most reliably with clinical data and with each other were RSO, QSART, and skin temperature reductions.

CONCLUSION

Clinical and autonomic laboratory probability scores correlate in an internally consistent manner. Both CRPS-Sx and CRPS-LAB are sensitive and reliable tools to formulate a correct diagnosis of CRPS I and can be combined to provide an improved set of diagnostic criteria for CRPS I.

Certain cardiovascular indices predict syncope in the postural tachycardia syndrome

Patients with postural tachycardia syndrome (POTS) represent a patient population with orthostatic intolerance; some are prone to syncope, others are not. The underlying neurocardiovascular mechanisms are not completely understood. The current study was undertaken to assess if certain cardiovascular indices are predictive of syncope in POTS. We compared the response to tilt-up and the Valsalva maneuver in four groups: POTS patients who fainted (POTS-f; n = 11;31 +/- 11 years): POTS patients who did not faint (POTS-nf; n = 9; 29 +/- 9 years); normal controls (NLS; n = 13; 39 +/- 11 years); patients with generalized autonomic failure with orthostatic hypotension and syncope (n = 10; 59 +/- 14 years). Beat-to-beat heart rate (HR), systolic arterial pressure, diastolic arterial pressure (DAP) and pulse pressure (PP) were monitored using Finapres. Cardiac output, stroke volume (SV) and end-diastolic volume (EDV), and calculated total peripheral resistance (TPR) were recorded using thoracic electrical bioimpedance. An autonomic reflex screen which quantitates the distribution and severity of autonomic failure was also done. With the patient supine, all POTS patients (POTS-nf; POTS-f) had increased HR (p < 0.001) and reduced SV/EDV (p < 0.001) when compared with NLS. On tilt-up, POTS-f patients were significantly different from both NLS and POTS-nf patients; the most consistent alteration was a fall instead of an increase in TPR; other changes were a greater reduction in PP, a reduction (instead of an increment) in DAP, and a different pattern of changes during the Valsalva maneuver (excessive early phase II, attenuated or absent late phase II). Our results suggest alpha-adrenergic impairment with increased pooling or hypovolemia in POTS-f patients. We conclude that it is possible to identify the mechanism of syncope in POTS patients, and perhaps other patients with orthostatic intolerance and an excessive liability to syncope.

Diphenhydramine is effective in the treatment of idiopathic dystonia

OBJECTIVE

To assess the effectiveness of diphenhydramine hydrochloride (Benadryl) in the treatment of patients with idiopathic truncal dystonia.

DESIGN

Before-and-after trial.

SETTING

University referral center.

PATIENTS

Five consecutive patients with idiopathic truncal dystonia who were poorly treated with conventional pharmacotherapies. No patients were withdrawn from the trial for adverse side effects.

INTERVENTIONS

Treatments with diphenhydramine hydrochloride (50 mg intravenously or up to 500 mg/kg orally). Follow-up for up to 20 months.

MAIN OUTCOME MEASURE

Dystonia evaluation.

RESULTS

Diphenhydramine therapy was associated with minimal side effects, and it was most effective in treating patients with dystonia who experienced lightning jerks. Treatment with intravenous diphenhydramine may have a predictive value on a future response to oral therapy.

CONCLUSION

Diphenhydramine should be considered a therapeutic option for idiopathic truncal dystonia with lightning jerks.

Small fibre involvement in neuropathy associated with IgG, IgA and IgM monoclonal gammopathy

A delta and C fibre function has been investigated in 18 patients affected by neuropathies associated with monoclonal gammopathies. Warm, cold and heat pain thresholds have been determined by means of a Somedic Thermotest, operating on the Peltier principle, in a room at constant temperature. Our results indicate that: 1) there is an involvement of A delta and C fibres in these neuropathies that might be difficult to quantitate only on clinical grounds 2) in IgG and IgA patients, all affected by a subclinical or mild axonal neuropathy, small fibres of both types are always involved 3) in IgM anti-MAG positive severe cases, A delta fibre involvement, suggestive of demyelination is evident, while in one anti-MAG negative patient only C fibres are damaged, probably reflecting a different pathogenetic mechanism.

Readiness to respond in a target detection task: pre- and post-stimulus event-related potentials in normal subjects

Brain potentials were recorded from 12 normal subjects engaged in an auditory target detection task (target stimulus probability of 0.2, stimulus rate of 1 every 2 sec) when instructions were (1) to press a response button with the thumb of the dominant hand to each target or (2) to keep a mental count of each target. A pre-stimulus slow negative potential was identified before every stimulus except non-targets immediately after targets. The amplitude of the pre-stimulus negativity was significantly affected by task instructions and was up to 4 times larger during the button press than the mental count condition. In contrast, the amplitudes and latencies of the event-related components (N100, P200, N200 and P300), when slow potentials were removed by filtering, were not different as a function of press or count instructions. The immediately preceding stimulus sequence affected both the amplitude and onset latency of the pre-stimulus negativity; both measures increased as the number of preceding non-targets increased. The amplitude of the pre-stimulus negative shift to targets also increased significantly as RT speed decreased. The major portion of the pre-stimulus negative potential is considered a readiness potential (RP) reflecting preparations to make a motor response. The amplitude of the RP during the target detection task did not significantly lateralize in contrast to the RP accompanying self-paced movements.

Tremor: classification, diagnosis and management

Tremor can range from imperceptible physiologic movements to severely handicapping shaking. It can be a single entity, or it can occur in association with a disease that affects the basal ganglia, brainstem, cerebellum or peripheral nervous system. Tremors can be classified according to their anatomic location, the circumstances under which they occur, their frequency and amplitude, and whether they are physiologic or pathologic. As an isolated disorder, tremor should be treated only when it impairs the patient's ability to perform activities. Successful treatment requires the identification of precipitating factors, as well as associated signs and symptoms.

'Fatigue' in patients with multiple sclerosis. Motor pathway conduction and event-related potentials

Ten patients with a definite diagnosis of multiple sclerosis and complaints of "fatigue" were studied using (1) reaction times and event-related potentials accompanying the performance of auditory memory tasks (target detection, verbal short-term memory) and (2) motor conduction velocities of the pyramidal tract elicited by cerebral and cervical magnetic stimulation. Patients were studied when "rested" and when fatigued. Reaction times of the patients when rested were significantly delayed in the short-term memory but not the target-detection tasks when compared with normal controls. When patients were fatigued, their reaction times became significantly longer in all tasks compared with when they were rested. Event-related potentials in these tasks consist of N1/P2 sensory components and P3a and P3b cognitive components. The N1 component latency was longer and P3a and P3b amplitudes were reduced in patients compared with controls. Fatigue in patients with multiple sclerosis was accompanied by a shortening of P3a latency and an increase in P3a and P3b amplitudes compared with these measures when patients were rested. Pyramidal tract conduction velocities did not differ between rested and fatigued conditions. Thus, fatigue in patients with multiple sclerosis was associated with a slowing of performance (reaction time) on memory tasks, whereas brain potentials reflecting neural events of stimulus encoding and classification were either unchanged or paradoxically speeded up in latency in the fatigued compared with the rested conditions. We postulate that, in patients with multiple sclerosis, fatigue affects neural processes acting after stimulus evaluation but before activation of the primary motor pathways.

Hemianopia, hemianesthesia, and spatial neglect: a study with evoked potentials

We recorded somatosensory or visual evoked potentials (SEPs, VEPs) to stimuli contralateral and ipsilateral to the lesion in three right-brain-damaged patients with left spatial hemineglect and in three left-brain-damaged patients without evidence of neglect, as assessed by visual exploratory tasks. All patients had contralateral homonymous hemianopia or hemianesthesia. The three neglect patients showed normal SEPs or VEPs to stimuli delivered to the left half-field or to the left hand, without conscious perception and verbal report of the stimulation. By contrast, the three left-brain-damaged patients without neglect showed no recognizable cortical evoked response to contralateral visual or somatosensory stimuli. In all patients, the cortical evoked responses to ipsilateral stimulation were normal. In patients with spatial hemineglect, hemianopia and hemianesthesia may be manifestations of the neglect syndrome (visual and somatosensory hemi-inattention), rather than representing primary sensory deficit. Visual and somatosensory hemi-inattention may be due to defective access to the neural processes subserving conscious perception by information that has undergone early sensory processing.

Pharmacological dissection of components of the Valsalva maneuver in adrenergic failure

The arterial blood pressure (BP) components of the Valsalva maneuver (VM) were analyzed to ascertain whether they could be used as an index of adrenergic regulation of the circulation. We studied a control and three age- and sex-matched patient groups. Sympathetic adrenergic failure was graded on the basis of the degree of systolic BP (SBP) reduction during tilt: orthostatic hypotension (OH; SBP greater than 30 mmHg), borderline OH (BOH; 30 less than SBP greater than 10 mmHg), and sympathetic sudomotor failure (SSF). Controls exhibited a biphasic phase II, consisting of a modest decrement (early phase II) followed by a rise in BP (late phase II; II1) above resting values. All the patient groups including SSF exhibited a significant reduction in II1. An excessive BP fall in phase II and an absent phase IV overshoot were observed in the OH group. BOH and, to a lesser extent, SSF groups showed a significant reduction in phase IV overshoot. We conclude that BP changes during VM will detect adrenergic vasoconstrictor failure with greater sensitivity than orthostatic BP recordings.

Autonomic involvement in extrapyramidal and cerebellar disorders

We reviewed the clinical and autonomic features of all patients with extrapyramidal and cerebellar disorders studied in the Mayo Autonomic Reflex Laboratory from 1983 to 1989. Patients were grouped into the following categories (number in parentheses): Parkinson's disease (35); parkinsonism-plus (54); multiple system atrophy (75); hereditary multisystem degenerations (eleven); progressive supranuclear palsy (32); non-familial cerebellar degeneration (eleven); nonspecific sporadic multisystem degeneration (73). Severe autonomic failure occurred in 97% of patients with multiple system atrophy and 53% of the nonspecific sporadic multisystem degeneration patients respectively. Autonomic involvement was mild or absent in Parkinson's disease while parkinsonism-plus and non-familial cerebellar degeneration patients had moderate autonomic failure. Orthostatic blood pressure reduction, percentage of anhidrosis on thermoregulatory sweat test, quantitative sudomotor axon reflex test, forearm response and heart rate response to deep breathing strongly regressed with severity. A response to levodopa treatment in patients with parkinsonism was more likely if cerebellar signs and cognitive deficits were absent. The presence of levodopa induced dyskinesia was also a marker for a clinically favourable levodopa response. We conclude that there is a spectrum of autonomic involvement in these degenerative disorders and that autonomic studies are useful in separating them and monitoring their course.