Neurogenic orthostatic hypotension in Parkinson's disease: evaluation, management, and emerging role of droxidopa

Toxin Induced Parkinsonism and Hospitalization Related Adverse Outcome Mitigation for Parkinson's Disease: A Comprehensive Review

Patients with Parkinson's disease admitted to the hospital have unique presentations. This unique subset of patients requires a multidisciplinary approach with a knowledge-based care team that can demonstrate awareness of complications specific to Parkinson's disease to reduce critical care admissions, morbidity, and mortality. Early recognition of toxic exposures, medication withdrawals, or medication-induced symptoms can reduce morbidity and mortality. This review can assist in the critical assessment of new or exacerbating Parkinson's disease symptoms.

Frequency and Factors Associated with Orthostatic Hypotension in Individuals with Parkinson's Disease: A Case-Control Observational Study

Background

Orthostatic hypotension (OH) is a common and considered the most incapacitating non-motor symptom of Parkinson's disease (PD). Little is known about OH in Ethiopian PD patients. The objectives of the present study were to determine the frequency and factors associated with OH in individuals diagnosed with PD compared to a healthy control.

Methods

A multi-center case-control observational study was conducted. A total of 53 PD cases and 53 age and sex matched healthy controls were included. Both descriptive and Chi-square proportional statistical analysis were used.

Results

The mean age distribution was comparable between the two study groups (61.9 vs. 59.9 years). Distribution of male gender was comparable between PD and control groups (71.7% vs. 67.9%). Nearly all the individuals diagnosed with PD were on levodopa treatment, and close to half of them were on anticholinergic drugs. Hypertension was the commonest comorbid disorder in both groups. The prevalence of orthostatic hypotension was higher in PD patients (22.6%) compared to the control group (9.4%). The proportion of constipation (p=0.007), urinary urgency (p=0.007), and nocturia (p<0.0001) was significantly higher among Parkinson's disease patients compared to the healthy control group. Falls and excessive sweating were only reported by PD patients.

Conclusion

The present study shows the frequency of orthostatic hypotension in Ethiopian Parkinson's disease patients is comparable to other regions. The presence of constipation, urinary urgency, and nocturia was associated with Parkinson's disease compared to the control group.

Istradefylline for OFF Episodes in Parkinson’s Disease: A US Perspective of Common Clinical Scenarios

The effective management of OFF episodes remains an important unmet need for patients with Parkinson’s disease (PD) who develop motor complications with long-term levodopa therapy. Istradefylline is a selective adenosine A_2A receptor antagonist for the treatment of patients with PD experiencing OFF episodes while on levodopa/decarboxylase inhibitor. Originally approved in Japan, istradefylline was recently approved in the USA. In this article, we provide a specific review of the four clinical studies that the FDA included in the approval of istradefylline in the USA, and discuss common clinical scenarios, based on our experience, where treatment with istradefylline may benefit patients experiencing motor fluctuations.

Comprehensive telemedicine solution for remote monitoring of Parkinson's disease patients with orthostatic hypotension during COVID-19 pandemic

OBJECTIVE

Orthostatic hypotension (OH) represents a frequent but under-recognized phenomenon in Parkinson's disease (PD). During COVID-19 pandemic, Information and Communication Technologies (ICT) have become pivotal in the management of chronic diseases like PD, not only to assess motor impairment, but also for vital signs monitoring. This pilot study aimed to propose a real-time remote home-monitoring system and protocol for PD patients with OH.

METHODS

Vital parameters were acquired by wireless devices and transmitted to an ICT platform, providing data and smart notifications to the healthcare provider through an interactive web portal. Eight patients with idiopathic PD and OH underwent 5-day monitoring. Data about OH episodes, therapeutic interventions, impact on daily activities, and patient satisfaction were collected and analyzed.

RESULTS

The proposed solution allowed the identification of 65 OH episodes and subsequent medical interventions. Thirty-five episodes were asymptomatic, especially in the postprandial and in the afternoon recordings. Systolic-blood-pressure (SBP) and diastolic-blood-pressure (DBP) were significantly lower in symptomatic episodes, while the pressure drops resulted significantly higher in presence of symptoms. High usability and patient satisfaction scores were observed.

CONCLUSION

The proposed home-monitoring system and protocol have proved to provide useful information and to allow prompt interventions in the management of PD patients with OH during COVID-19 pandemic.

Management Strategies for Comorbid Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension

PURPOSE OF REVIEW

In autonomic failure, neurogenic orthostatic hypotension (nOH) and neurogenic supine hypertension (nSH) are interrelated conditions characterized by postural blood pressure (BP) dysregulation. nOH results in a sustained BP drop upon standing, which can lead to symptoms that include lightheadedness, orthostatic dizziness, presyncope, and syncope. nSH is characterized by elevated BP when supine and, although often asymptomatic, may increase long-term cardiovascular and cerebrovascular risk. This article reviews the pathophysiology and clinical characteristics of nOH and nSH, and describes the management of patients with both nOH and nSH.

RECENT FINDINGS

Pressor medications required to treat the symptoms of nOH also increase the risk of nSH. Because nOH and nSH are hemodynamically opposed, therapies to treat one condition may exacerbate the other. The management of patients with nOH who also have nSH can be challenging and requires an individualized approach to balance the short- and long-term risks associated with these conditions. Approaches to manage neurogenic BP dysregulation include nonpharmacologic approaches and pharmacologic treatments. A stepwise treatment approach is presented to help guide neurologists in managing patients with both nOH and nSH.

Classical and Delayed Orthostatic Hypotension in Patients With Unexplained Syncope and Severe Orthostatic Intolerance

Background: Orthostatic hypotension (OH) is a major sign of cardiovascular autonomic failure leading to orthostatic intolerance and syncope. Orthostatic hypotension is traditionally divided into classical OH (cOH) and delayed OH (dOH), but the differences between the two variants are not well-studied. We performed a systematic clinical and neuroendocrine characterization of OH patients in a tertiary syncope unit.

Methods: Among 2,167 consecutive patients (1,316 women, 60.7%; age, 52.6 ± 21.0 years) evaluated for unexplained syncope and severe orthostatic intolerance with standardized cardiovascular autonomic tests including head-up tilt (HUT), we identified those with a definitive diagnosis of cOH and dOH. We analyzed patients' history, clinical characteristics, hemodynamic variables, and plasma levels of epinephrine, norepinephrine, C-terminal-pro-arginine-vasopressin (CT-proAVP), C-terminal-endothelin-1, mid-regional-fragment of pro-atrial-natriuretic-peptide and pro-adrenomedullin in the supine position and at 3-min HUT.

Results: We identified 248 cOH and 336 dOH patients (27% of the entire cohort); 111 cOH and 152 dOH had blood samples collected in the supine position and at 3-min HUT. Compared with dOH, cOH patients were older (68 vs. 60 years, p < 0.001), more often male (56.9 vs. 39.6%, p < 0.001), had higher systolic blood pressure (141 vs. 137 mmHg, p = 0.05), had lower estimated glomerular filtration rate (73 vs. 80 ml/min/1.73 m², p = 0.003), more often pathologic Valsalva maneuver (86 vs. 49 patients, p < 0.001), pacemaker-treated arrhythmia (5 vs. 2%, p = 0.04), Parkinson's disease (5 vs. 1%, p = 0.008) and reported less palpitations before syncope (16 vs. 29%, p = 0.001). Supine and standing levels of CT-proAVP were higher in cOH (p = 0.022 and p < 0.001, respectively), whereas standing norepinephrine was higher in dOH (p = 0.001). After 3-min HUT, increases in epinephrine (p < 0.001) and CT-proAVP (p = 0.001) were greater in cOH, whereas norepinephrine increased more in dOH (p = 0.045).

Conclusions: One-quarter of patients with unexplained syncope and severe orthostatic intolerance present orthostatic hypotension. Classical OH patients are older, more often have supine hypertension, pathologic Valsalva maneuver, Parkinson's disease, pacemaker-treated arrhythmia, and lower glomerular filtration rate. Classical OH is associated with increased vasopressin and epinephrine during HUT, but blunted increase in norepinephrine.

Managing autonomic dysfunction in Parkinson's disease: a review of emerging drugs

Introduction: Autonomic dysfunction is an integral part of Parkinson disease (PD) complex and can be seen both in early and advanced stages. There is a paucity of medicines available to manage autonomic dysfunction in PD and this adds to the considerable morbidity associated with the illness.Areas covered: The pathophysiology and the available therapeutic options of autonomic dysfunction seen in PD are discussed in detail. The potential targets for novel regimens are reviewed and the available literature on the drugs emerging in management of autonomic dysfunction in PD is highlighted.Expert opinion: In the current scenario, there are several drugs that can be tried for constipation viz stool laxatives, prucalopride, prokinetic agents and a high fiber diet. Bladder dysfunction has been treated with β-agonists and with mirabegron, a selective β-3 agonist, the anticholinergic side effects are minimized, and the drug has been found to be effective. Orthostatic hypotension is managed with midodrine while droxidopa is a new drug with promising efficacy. Botulinum toxin works best for management of sialorrhea, but repeated injections are needed.

Neurogenic Orthostatic Hypotension in Parkinson Disease: A Primer

Parkinson disease (PD) is associated with a variety of motor and non-motor clinical manifestations, including cardiovascular autonomic dysfunction. Neurogenic orthostatic hypotension (nOH) is a potentially serious manifestation of cardiovascular sympathetic failure that occurs in approximately 30% of patients with PD. Here we review the pathophysiology and effects of the condition as well as treatment considerations for patients with PD and nOH. Screening for nOH using orthostatic symptom questionnaires, orthostatic blood pressure measurements, and specialized autonomic testing is beneficial for the identification of symptomatic and asymptomatic cases because cardiac sympathetic denervation and nOH can occur even at early (premotor) stages of PD. Symptoms of nOH, such as orthostatic lightheadedness, in patients with PD, have been shown to adversely affect patient safety (with increased risk of falls) and quality of life and should prompt treatment with non-pharmacologic and, occasionally, pharmacologic measures. Patients with nOH are also at increased risk of supine hypertension, which requires balancing various management strategies. FUNDING: Lundbeck (Deerfield, IL).

Small vessel disease pathological changes in neurodegenerative and vascular dementias concomitant with autonomic dysfunction

We performed a clinicopathological study to assess the burden of small vessel disease (SVD) type of pathological changes in elderly demented subjects, who had clinical evidence of autonomic dysfunction, either carotid sinus hypersensitivity or orthostatic hypotension or both or had exhibited unexpected repeated falls. Clinical and neuropathological diagnoses in 112 demented subjects comprised dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), Alzheimer's disease (AD), Mixed dementia (mostly AD-DLB) and vascular dementia (VaD). Of these, 12 DLB subjects had no recorded unexpected falls in life and therefore no evidence of concomitant autonomic dysfunction. A further 17 subjects were assessed as aging controls without significant pathology or signs of autonomic dysfunction. We quantified brain vascular pathological changes and determined severities of neurodegenerative lesions including α-synuclein pathology. We found moderate-severe vascular changes and high-vascular pathology scores (P < 0.01) in all neurodegenerative dementias and as expected in VaD compared to similar age controls. Arteriolosclerosis, perivascular spacing and microinfarcts were frequent in the basal ganglia and frontal white matter (WM) across all dementias, whereas small infarcts (<5 mm) were restricted to VaD. In a sub-set of demented subjects, we found that vascular pathology scores were correlated with WM hyperintensity volumes determined by MRI in life (P < 0.02). Sclerotic index values were increased by ~50% in both the WM and neocortex in all dementias compared to similar age controls. We found no evidence for increased α-synuclein deposition in subjects with autonomic dysfunction. Our findings suggest greater SVD pathological changes occur in the elderly diagnosed with neurodegenerative dementias including DLB and who develop autonomic dysfunction. SVD changes may not necessarily manifest in clinically overt symptoms but they likely confound motor or cognitive dysfunction. We propose dysautonomia promotes chronic cerebral hypoperfusion to impact upon aging-related neurodegenerative disorders and characterize their end-stage clinical syndromes.

Role of nurses and nurse practitioners in the recognition, diagnosis, and management of neurogenic orthostatic hypotension: a narrative review

Neurogenic orthostatic hypotension (nOH) is a sustained reduction in blood pressure (BP) upon standing that is caused by autonomic dysfunction and is common among patients with a variety of neurodegenerative disorders (eg, Parkinson's disease, multiple system atrophy, pure autonomic failure). A systolic BP drop of ≥20 mmHg (or ≥10 mmHg diastolic) upon standing with little or no compensatory increase in heart rate is consistent with nOH. Symptoms of nOH include light-headedness, dizziness, presyncope, and syncope; these symptoms can severely impact patients' activities of daily living and increase the likelihood of potentially dangerous falls. Because of their patient contact, nurses and nurse practitioners can play a key role in identifying and evaluating patients at risk for nOH. It is advisable to screen for nOH in patients presenting with one or more of the following characteristics: those who have disorders associated with autonomic failure, those with episodes of falls or syncope, those with symptoms upon standing, those who are elderly or frail, or those taking multiple medications. Initial evaluations should include questions about postural symptoms and measurement of orthostatic BP and heart rate. A review of medications for potential agents that can have hypotensive effects should be performed before initiating treatment. Treatment for nOH may include non-pharmacologic measures and pharmacologic therapy. Droxidopa and midodrine are approved by the US Food and Drug Administration for the treatment of symptomatic nOH and symptomatic OH, respectively. nOH is associated with the coexistence of supine hypertension, and the two disorders must be carefully managed. In conclusion, timely screening and diagnosis of patients with nOH can streamline the path to disease management and treatment, potentially improving patient outcomes.

Parkinson's disease: Mechanisms, translational models and management strategies

Parkinson's disease is a progressive neurodegenerative disorder. The classical motor symptoms include resting tremors, bradykinesia, rigidity and postural instability and are accompanied by the loss of dopaminergic neurons and Lewy pathology. Diminished neurotransmitter level, oxidative stress, mitochondrial dysfunction and perturbed protein homeostasis over time worsen the disease manifestations in elderly people. Current management strategies aim to provide symptomatic relief and to slow down the disease progression. However, no pharmacological breakthrough has been made to protect dopaminergic neurons and associated motor circuitry components. Deep brain stimulation, stem cells-derived dopaminergic neurons transplantation, gene editing and gene transfer remain promising approaches for the potential management of neurodegenerative disease. Toxin or genetically induced rodent models replicating Parkinson's disease pathology are of high predictive value for translational research. This review addresses the current understanding, management strategies and the Parkinson's disease models for translational research. Preclinical research may provide powerful tools to quest the potential therapeutic and neuroprotective compounds for dopaminergic neurons and hence possible cure for the Parkinson's disease.

Health and Functional Determinants of Orthostatic Hypotension in Geriatric Ward Patients: A Retrospective Cross Sectional Cohort Study

OBJECTIVE

Orthostatic hypotension (OH) is a common problem in older people. Although it is indicated that OH can be a marker of frailty there are no studies that evaluate this relationship in hospitalized patients. The aim of the study was to assess the prevalence of OH in geriatric ward patients and its association with health and functional ability characteristics and patients' frailty status.

DESIGN AND SETTING

A retrospective cross-sectional cohort study was conducted among patients aged 60 or over hospitalized in the geriatric ward.

PARTICIPANTS

Patients' medical records were analyzed and those with Active Standing Test (AST) results were included in the study.

MEASUREMENTS

Orthostatic hypotension was defined by a drop in blood pressure of at least 20mmHg for systolic blood pressure and at least 10mmHg for diastolic blood pressure within 3minutes of standing up in AST. The database included sociodemographic characteristics, nutritional, functional and cognitive state, comorbidity and medical treatment. Frailty syndrome was diagnosed with Clinical Frailty Scale. Correlations with OH were counted and multivariable logistic regression models were built.

RESULTS

416 patients were hospitalized in the study period and 353 (84.9%) were included, 78 (22.1%) men and 298 (84.4%) 75+ year-old. AST was not available in patients significantly more dependent in ADL and more frail. OH was diagnosed in 57 (16.2%) patients, significantly more frequently in men (systolic- 45,5%, systolic-diastolic- 40,0%). The significant independent predictors of OH were lower diastolic blood pressure at admittance, nutritional risk in MNA-SF, Parkinson disease, α1-blockers, neuroleptics and memantine, and not the frailty syndrome diagnosed with Clinical Frailty Scale.

CONCLUSIONS

OH affects a significant percentage of patients in the geriatric ward, although this problem may be underestimated due to limitations in the performance of AST in very frail and functionally dependent patients.

Characterization of the symptoms of neurogenic orthostatic hypotension and their impact from a survey of patients and caregivers

Background

Neurogenic orthostatic hypotension (nOH) results from impaired vasoconstriction due to dysfunction of the autonomic nervous system and is commonly associated with Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure. nOH can increase the risk of falls due to symptoms that include postural lightheadedness or dizziness, presyncope, and syncope. The purpose of this study was to obtain information from patients and caregivers regarding the symptoms and burden of nOH to expand on limited knowledge regarding the impact of nOH on quality of life.

Methods

This author-designed survey included questions regarding nOH (e.g., frequency and impact of symptoms, management) and was conducted online by Harris Poll via distribution to individuals who agreed to participate in Harris Poll online surveys or who were members of relevant disease advocacy organizations. Eligible patients were aged ≥ 18 years with PD, MSA, or pure autonomic failure and ≥ 1 of the following: orthostatic hypotension (OH), nOH, low blood pressure upon standing, or OH/nOH symptoms. Eligible caregivers cared for such patients but were not necessarily linked to any patient participant.

Results

Survey responses were received from 363 patients and 128 caregivers. PD was the most frequent underlying disorder (90% of patients; 88% of individuals managed by the caregivers). Despite meeting survey diagnosis criteria, a formal diagnosis of OH or nOH was reported by only 36% of patients and 16% of caregivers. The most frequent symptoms of nOH were dizziness or lightheadedness, fatigue when standing, and difficulty walking. A negative impact on patient quality of life caused by nOH symptoms was reported by 59% of patients and 75% of caregivers. Most respondents (≥87%) reported that nOH symptoms adversely affected patients’ ability to perform everyday activities (most frequently physical activity/exercise, housework, and traveling). Falls (≥1) in the previous year due to nOH symptoms were reported by 57% of patients and 80% of caregivers.

Conclusions

These survey results support the premise that nOH symptoms have a substantial negative impact on patient function and quality of life. The relatively low rates of formal nOH/OH diagnosis suggest the need for heightened awareness regarding the condition and its symptom burden.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1129-x) contains supplementary material, which is available to authorized users.

Frequency of non-motor symptoms in Parkinson's disease presenting to tertiary care centre in Pakistan: an observational, cross-sectional study

OBJECTIVE

To determine the frequency of non-motor symptoms (NMS) in patients of Parkinson's disease (PD) presenting to a movement disorder clinic at a tertiary care centre in Pakistan, and how frequency of NMS is different in male and female patients.

STUDY DESIGN

Observational, cross-sectional study.

SETTING

Tertiary care centre.

PARTICIPANTS

Out of 102 patients, 85 were included. Inclusion criteria were patients with PD diagnosed according to the UK Parkinson's Disease Society Brain Bank Clinical Diagnostic Criteria, age ≥18 years, able to give consent and have no difficulty in answering questions. Exclusion criteria were diseases that resemble PD, stroke, dementia, patients unable to provide information and history of antipsychotic use.

RESULTS

The NMSQuest revealed a mean of nearly seven different NMS per patient. Autonomic problems such as constipation (56%) and nocturia (49%) were the most common NMS, while urinary urgency was reported by 35% of patients. Low mood and feeling sad were reported by 47%, whereas feeling anxious/panicky was reported by 36%. Problem with memory was reported by 45% of patients. Feeling of light-headedness and dizziness was reported by 40% of patients. Problems with sexual relationship were reported by 30% of patients. The most common sleep problem was difficulty falling sleep (29%). Pain not related to the musculoskeletal system was reported by 30% of patients. Loss or change in the ability to taste or smell was reported by 29% of patients. The rest of NMS were less than 25% in frequency. Feeling sad or blue, feeling light-headed/dizzy, unexplained pain, unpleasant sensations in the legs, difficulty in swallowing and faecal incontinence were more common in female participants, while problems with sex were more common in male participants.

CONCLUSION

NMS are quite prevalent in PD in our population. Certain NMS are more common in women as compared with men. There is a need for a large-scale study to look for the association of different NMS with sex.

Symptomatic orthostatic hypotension in Parkinson's disease patients: Prevalence, associated factors and its impact on balance confidence

BACKGROUND

Orthostatic hypotension (OH) is a commonly reported sign of the cardiovascular autonomic dysfunctions associated with Parkinson's disease (PD). Patients might suffer from a variety of the clinical symptoms of OH, including dizziness, lightheadedness, or problems with vision and fatigue.

OBJECTIVES

To determine the prevalence of, and factors associated with, symptomatic orthostatic hypotension (OH) in Parkinson's disease (PD) and to identify any relationships between the clinical symptoms of OH and balance confidence in this patient population.

METHODS

Symptomatic OH was defined as a systolic or diastolic BP fall of ≥20 or ≥10mmHg respectively, within 3min of standing and an Orthostatic Hypotension Questionnaire (OHQ) score of more than zero. Factors related to symptomatic OH were identified from a multivariate logistic regression analysis. Pearson's correlation test was used to reveal any relationships between the clinical symptoms of OH and a patient's confidence in their ability to balance, assessed using the Activities-specific Balance Confidence (ABC) scale.

RESULTS

100 Thai PD patients were consecutively recruited into this study. The prevalence of symptomatic OH was 18%, asymptomatic OH was 4%, while 78% were patients without OH. Factors associated with symptomatic OH were age (OR, 95%CI: 1.06, 1.003-1.115, p=0.038) and hypertension (OR, 95%CI: 6.16, 1.171-32.440, p=0.032). A significant and negative correlation (r=-0.229, p=0.022) between OHQ composite scores and item 3 of the ABC scale (picking up slippers from floor), one of the movements in a vertical orientation, was found.

CONCLUSION

Elderly PD patients and with a co-morbidity of essential hypertension should be closely evaluated for the presence of symptomatic OH. In addition, they should be advised to change positions slowly, especially those in a vertical orientation.

Fuzzy logic-based risk of fall estimation using smartwatch data as a means to form an assistive feedback mechanism in everyday living activities

This Letter aims to create a fuzzy logic-based assistive prevention tool for falls, based on accessible sensory technology, such as smartwatch, resulting in monitoring of the risk factors of falls caused by orthostatic hypotension (OH); a drop in systolic blood pressure (DSBP) >20 mmHg due to postural changes. Epidemiological studies have shown that OH is a high risk factor for falls and has a strong impact in quality of life (QoL) of the elderly's, especially for some cases such as Parkinsonians. Based on smartwatch data, it is explored here how statistical features of heart rate variability (HRV) can lead to DSBP prediction and estimation of the risk of fall. In this vein, a pilot study was conducted in collaboration with five Greek Parkinson's Foundation patients and ten healthy volunteers. Taking into consideration, the estimated DSBP and additional statistics of the user's medical/behavioural history, a fuzzy logic inference system was developed, to estimate the instantaneous risk of fall. The latter is fed back to the user with a mechanism chosen by him/her (i.e. vibration and/or sound), to prevent a possible fall, and also sent to the attentive carers and/or healthcare professionals for a home-based monitoring beyond the clinic. The proposed approach paves the way for effective exploitation of the contribution of smartwatch data, such as HRV, in the sustain of QoL in everyday living activities.

Nondopaminergic treatments for Parkinson's disease: current and future prospects

Parkinson's disease is primarily caused by dysfunction of dopaminergic neurons, however, nondopaminergic (ND) systems are also involved. ND targets are potentially useful to reduce doses of levodopa or to treat nonlevodopa-responsive symptoms. Recent studies have investigated the role of ND drugs for motor and nonmotor symptoms. Adenosine A2A receptor antagonists, mixed inhibitors of sodium/calcium channels and monoamine oxidase-B have recently been found to improve motor fluctuations. N-methyl-d-aspartate receptor antagonists and serotonin 5HT1B receptor agonists demonstrated benefit in levodopa-induced dyskinesia. Conversely, studies using antiepileptic drugs and adrenoreceptor antagonist had conflicting results. Moreover, metabotropic glutamate receptor antagonists also failed to improve symptoms. The current review summarizes the most recent findings on ND drugs over the last 2 years.

Clinical Relevance of Orthostatic Hypotension in Neurodegenerative Disease

The autonomic nervous system appears to be uniquely susceptible to degeneration in disorders of α-synuclein pathology. Clinically, autonomic dysfunction in these disorders manifests as neurogenic orthostatic hypotension (nOH), a condition that results in substantial morbidity and mortality. nOH results from pathology affecting either the central autonomic pathways or peripheral autonomic nerve fibers. Determining the localization and pathophysiology of nOH is critical in effectively managing this disorder and selecting appropriate treatment options. In this review, we discuss the pathophysiology of nOH with respect to the various α-synuclein-related neurodegenerative conditions. We highlight the associated clinical features, including gait instability, rapid eye movement behavior disorder, and hyposmia. We also review the current pharmacologic treatment options for nOH. Overall, the goals of therapy are to improve symptoms and prevent syncope and falls. Non-pharmacologic interventions should be introduced first, followed by carefully selected pharmacologic therapies. Treatment decisions should be directed by an understanding of the underlying pathophysiology, as well as the comorbidities and potential contributing factors present in each individual patient.

Parkinson's disease between internal medicine and neurology

General medical problems and complications have a major impact on the quality of life in all stages of Parkinson's disease. To introduce an effective treatment, a comprehensive analysis of the various clinical symptoms must be undertaken. One must distinguish between (1) diseases which arise independently of Parkinson's disease, and (2) diseases which are a direct or indirect consequence of Parkinson's disease. Medical comorbidity may induce additional limitations to physical strength and coping strategies, and may thus restrict the efficacy of the physical therapy which is essential for treating hypokinetic-rigid symptoms. In selecting the appropriate medication for the treatment of any additional medical symptoms, which may arise, its limitations, contraindications and interactions with dopaminergic substances have to be taken into consideration. General medical symptoms and organ manifestations may also arise as a direct consequence of the autonomic dysfunction associated with Parkinson's disease. As the disease progresses, additional non-parkinsonian symptoms can be of concern. Furthermore, the side effects of Parkinson medications may necessitate the involvement of other medical specialists. In this review, we will discuss the various general medical aspects of Parkinson's disease.

Orthostatic hypotension: managing a difficult problem

Orthostatic hypotension (OH) leads to a significant number of hospitalizations each year, and is associated with significant morbidity and mortality among affected individuals. Given the increased risk for cardiovascular events and falls, it is important to identify the underlying etiology of OH and to choose appropriate therapeutic agents. OH can be non-neurogenic or neurogenic (arising from a central or peripheral lesion). The initial evaluation includes orthostatic vital signs, complete history and a physical examination. Patients should also be evaluated for concomitant symptoms of post-prandial hypotension and supine hypertension. Non-pharmacologic interventions are the first step for treatment of OH. The appropriate selection of medications can also help with symptomatic relief. This review highlights the pathophysiology, clinical features, diagnostic work-up and treatment of patients with neurogenic OH.

Abnormal Cerebrovascular Reactivity in Patients with Parkinson's Disease

Background. Orthostatic hypotension (OH) is an important nonmotor manifestation of Parkinson's disease (PD). Changes in cerebrovascular reactivity may contribute to this manifestation and can be monitored using transcranial Doppler. Objective. To identify possible changes in cerebrovascular reactivity in patients with OH. Methods. Twenty-two individuals were selected and divided into three groups: with and without OH and controls. Transcranial Doppler was used to assess basal mean blood flow velocity, postapnea mean blood flow velocity, percentage increase in mean blood flow velocity, and cerebrovascular reactivity as measured by the breath-holding index. Results. PD patients had lower values of basal velocity (p = 0.019), postapnea velocity (p = 0.0015), percentage increase in velocity (p = 0.039), and breath-holding index (p = 0.04) than the controls. Patients with OH had higher values of basal velocity (p = 0.09) and postapnea velocity (p = 0.19) but lower values of percentage increase in velocity (p = 0.22) and breath-holding index (p = 0.32) than patients without OH. Conclusions. PD patients present with abnormalities in a compensatory mechanism that regulates cerebral blood flow. OH could be an indicator of these abnormalities.

Designer receptors enhance memory in a mouse model of Down syndrome

Designer receptors exclusively activated by designer drugs (DREADDs) are novel and powerful tools to investigate discrete neuronal populations in the brain. We have used DREADDs to stimulate degenerating neurons in a Down syndrome (DS) model, Ts65Dn mice. Individuals with DS develop Alzheimer's disease (AD) neuropathology and have elevated risk for dementia starting in their 30s and 40s. Individuals with DS often exhibit working memory deficits coupled with degeneration of the locus coeruleus (LC) norepinephrine (NE) neurons. It is thought that LC degeneration precedes other AD-related neuronal loss, and LC noradrenergic integrity is important for executive function, working memory, and attention. Previous studies have shown that LC-enhancing drugs can slow the progression of AD pathology, including amyloid aggregation, oxidative stress, and inflammation. We have shown that LC degeneration in Ts65Dn mice leads to exaggerated memory loss and neuronal degeneration. We used a DREADD, hM3Dq, administered via adeno-associated virus into the LC under a synthetic promoter, PRSx8, to selectively stimulate LC neurons by exogenous administration of the inert DREADD ligand clozapine-N-oxide. DREADD stimulation of LC-NE enhanced performance in a novel object recognition task and reduced hyperactivity in Ts65Dn mice, without significant behavioral effects in controls. To confirm that the noradrenergic transmitter system was responsible for the enhanced memory function, the NE prodrug l-threo-dihydroxyphenylserine was administered in Ts65Dn and normosomic littermate control mice, and produced similar behavioral results. Thus, NE stimulation may prevent memory loss in Ts65Dn mice, and may hold promise for treatment in individuals with DS and dementia.