Movement disorder emergencies

Akinetic crisis and withdrawal syndromes: guideline "Parkinson's disease" of the German Society of Neurology

The akinetic crisis is a well-known, rare, potentially life-threatening condition in Parkinson's disease with subacute worsening of akinesia, rigidity, fever, impaired consciousness, accompanying vegetative symptoms and transient dopa-resistance. The akinetic crisis was historically supposed to be a "withdrawal syndrome" in the sense of discontinuation of dopaminergic medication. Recently, other "withdrawal syndromes" as the specific "dopamine agonist withdrawal syndrome" or "deep brain stimulation withdrawal syndrome" have been described as emergency situations with specific subacute symptom constellations. All three conditions require immediate start of the adequate therapy to improve the prognosis. Here, the diagnostic criteria and treatment options of these three acute, severely disabling syndromes will be reported along the current guidelines of the German Parkinson Guideline Group.

The akinetic crisis in Parkinson´s disease- the upper end of a spectrum of subacute akinetic states

The akinetic crisis is defined as an acute, potentially life-threatening, levodopa-resistant, severe aggravation of rigidity, severe akinesia, associated with high fever, disturbance of consciousness, dysphagia and autonomic symptoms often due to disruption of dopaminergic medication or infections. The akinetic crisis is a relatively rare event, however subacute mild-moderate motor symptom deterioration in Parkinson´s disease (PD) patients is a frequent cause of hospitalization. In this review, we propose that the akinetic crisis is the upper end of a continuous spectrum of acute akinetic states depending on the degree of the progressive levodopa-resistance. Clinical symptomatology, risk factors, and instrumental diagnostics as the DAT-SPECT reflecting a biomarker of levodopa-resistance will be discussed to evaluate the spectrum of akinetic states. Pathophysiological considerations about the potential role of proinflammatory cytokines on the progressive levodopa-resistance will be discussed and therapeutical, consensus-based guidelines will be presented.

Perioperative Use of Intravenous Levodopa as an Anti-Parkinsonian Drug: A Propensity Score Analysis

Background

Perioperative discontinuation of oral anti-parkinsonian medication can negatively impact the prognosis of abdominal surgery in patients with Parkinson's disease. Although intravenous levodopa may be an alternative, its efficacy has not yet been investigated.

Objectives

To determine the efficacy of intravenous levodopa as an alternative to oral anti-Parkinsonian drugs during gastric or colorectal cancer surgery.

Methods

We identified patients with Parkinson's disease who underwent surgery for gastric or colorectal cancer between April 2010 and March 2020, using the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan. Patients were divided into two groups: those who received intravenous levodopa during the perioperative period and those who did not. We compared in-hospital mortalities, major complications, and postoperative length of stay between the groups after adjusting for background characteristics with overlap weights based on propensity scores.

Results

We identified 648 patients who received intravenous levodopa and 1207 who did not receive levodopa during the perioperative period. In the adjusted cohort, the mean postoperative length of stay was 24.7 and 29.0 days (percent difference, -7.7%; 95% confidence interval, -13.1 to -1.5); in-hospital death was 3.2% and 3.3% (adjusted odds ratio, 0.95; 95% CI: 0.54-1.67); and incidence of major complications were 21.4% and 19.3% (adjusted odds ratio, 0.89; 95% confidence interval, 0.70-1.13) in those with and without intravenous levodopa, respectively.

Conclusions

Intravenous levodopa was associated with a shorter postoperative length of stay, but not with mortality or morbidity. Intravenous levodopa may improve perioperative care in patients with Parkinson's disease.

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.

Current advances in metabolomic studies on non-motor psychiatric manifestations of Parkinson's disease (Review)

Life expectancy has increased worldwide and, along with it, a greater prevalence of age-dependent disorders, chronic illnesses and comorbidities can be observed. In 2019, in both Europe and the Americas, dementias ranked 3rd among the top 10 causes of death. Parkinson's disease (PD) is the second most frequent type of neurodegenerative disease. In the last decades, globally, the number of people suffering from PD has more than doubled to over 6 million. Of all the neurological disorders, PD increased with the fastest rate. This troubling trend highlights the stringent need for accurate diagnostic biomarkers, especially in the early stages of the disease and to evaluate treatment response. To gain a broad and complex understanding of the recent advances in the '-omics' research fields, electronic databases such as PubMed, Google Academic, and Science Direct were searched for publications regarding metabolomic studies on PD to identify specific biomarkers for PD, and especially PD with associated psychiatric symptomatology. Discoveries in the fields of metagenomics, transcriptomics and proteomics, may lead to an improved comprehension of the metabolic pathways involved in disease etiology and progression and contribute to the discovery of novel therapeutic targets for effective treatment options.

Emergency presentations of movement disorders

Movement disorders are typically perceived as being gradually progressive conditions that are managed in outpatient settings. However, they may manifest de novo with an acute severe phenotype or an acute decompensation. A movement disorder becomes an emergency when it evolves acutely or subacutely over hours to days; delays in its diagnosis and treatment may cause significant morbidity and mortality. Here we address the clinical presentation, diagnosis and management of those movement disorder emergencies that are principally encountered in emergency departments, in acute receiving units or in intensive care units. We provide practical guidance for management in the acute setting where there are several treatable causes not to be missed. The suggested medication doses are predominantly based on expert opinion due to limited higher-level evidence. In spite of the rarity of movement disorder emergencies, neurologists need to be familiar with the phenomenology, potential causes and treatments of these conditions. Movement disorder emergencies divide broadly into two groups: hypokinetic and hyperkinetic, categorised according to their phenomenology. Most acute presentations are hyperkinetic and some are mixed.

Drug-induced movement disorders

Many therapeutic and illicit drugs can cause movement disorders Antipsychotics and antiemetics are most commonly implicated

The time of onset of the movement disorder may be acute subacute or chronic The severity can range from mild to severe and life-threatening

Early recognition of a drug-induced movement disorder is essential to allow for prompt intervention This includes stopping the offending drug supportive care and sometimes other pharmacological treatment

Acute Presentation of Nonmotor Symptoms in Parkinson's Disease

There are a few syndromes involving the nonmotor symptoms of Parkinson's disease and other movement disorders that can quickly lead to severe morbidity and mortality, and, as such, need rapid identification and management. Among these are neuroleptic malignant syndrome, serotonin syndrome, dopamine agonist withdrawal syndrome, and dystonic storm. It is important to maintain a high index of suspicion for these disorders as lack of identification can lead to death. Many of these acutely occurring nonmotor syndromes are primarily the result of imbalances in dopaminergic and serotonergic systems due to changes in pharmacologic management of psychiatric disorders or Parkinson's disease. We discuss these acutely occurring nonmotor symptoms in order to raise awareness and also to highlight how these extremes in symptoms may uniquely shed light on the pathophysiology of Parkinson's disease.

The Role of Amantadine Withdrawal in 3 Cases of Treatment-Refractory Altered Mental Status

Amantadine, which was originally developed as an antiviral medication, functions as a dopamine agonist in the central nervous system and consequently is utilized in the treatment of Parkinson disease, drug-induced extrapyramidal reactions, and neuroleptic malignant syndrome. For reasons that are not entirely understood, abrupt changes in amantadine dosage can produce a severe withdrawal syndrome. Existing medical literature describes case reports of amantadine withdrawal leading to delirium, which at times has progressed to neuroleptic malignant syndrome. Amantadine withdrawal may be under-recognized by mental health clinicians, which has the potential to lead to protracted hospital courses and suboptimal outcomes. The goal of this case series is to highlight the role of amantadine withdrawal in the cases of 3 medically complex patients with altered mental status. In the first case, the cognitive side effects of electroconvulsive therapy masked acute amantadine withdrawal in a 64-year-old man with Parkinson disease. In the second case, a 75-year-old depressed patient developed a catatonic delirium when amantadine was discontinued. Finally, a refractory case of neuroleptic malignant syndrome in a 57-year-old patient with schizoaffective disorder rapidly resolved with the reintroduction of outpatient amantadine. These cases highlight several learning objectives regarding amantadine withdrawal syndrome: First, it may be concealed by co-occurring causes of delirium in medically complex patients. Second, its symptoms are likely to be related to a cortical and limbic dopamine shortage, which may be reversed with electroconvulsive therapy or reintroduction of amantadine. Third, its clinical presentation may occur on a spectrum and may include features suggestive of delirium, catatonia, or neuroleptic malignant syndrome.

A subtle mimicker in emergency department: Illustrated case reports of acute drug-induced dystonia

BACKGROUND

Movement disorder emergencies include any movement disorder which develops over hours to days, in which failure to appropriately diagnose and manage can result in patient morbidity or mortality.Movement disorder emergencies include acute dystonia: sustained or intermittent muscle contractions causing abnormal, often repetitive, movements. Acute dystonia is a serious challenge for emergency room doctors and neurologists, because of the high probability of misdiagnosis, due to the presence of several mimickers including partial seizures, meningitis, localized tetanus, serum electrolyte level abnormalities, strychnine poisoning, angioedema, malingering, catatonia, and conversion.

METHODS

We describe 2 examples, accompanied by videos, of acute drug-induced oro-mandibular dystonia, both subsequent to occasional haloperidol intake.

RESULTS

Management and treatment of this movement disorder are often difficult: neuroleptics withdrawal, treatment with benzodiazepines, and anticholinergics are recommended.

CONCLUSION

Alternative treatment options are also discussed.

Critical Illness Neuromyopathy Complicating Akinetic Crisis in Parkinsonism: Report of 3 Cases

Akinetic crisis (AC) is a life-threatening complication of parkinsonism characterized by an acute severe akinetic-hypertonic state, consciousness disturbance, hyperthermia, and muscle enzymes elevation. Injectable dopaminomimetic drugs, high-dose methylprednisolone, and dantrolene are advocated as putative specific treatments. The course of the illness is frequently complicated by infections, pulmonary embolism, renal failure, disseminated intravascular coagulation, and cardiac arrhythmias. Critical illness neuromyopathy (CINM) is an acquired neuromuscular disorder characterized by flaccid quadriparesis and muscle enzyme elevation, often occurring in intensive care units and primarily associated with inactivity, sepsis, multiorgan failure, neuromuscular blocking agents, and steroid treatment. In 3 parkinsonian patients, during the course of AC we observed disappearance of rigidity but persistent hypoactivity. In all, neurological examination showed quadriparesis with loss of tendon reflexes and laboratory investigation disclosed a second peak of muscle enzymes elevation, following the first increment due to AC. Electrophysiological studies showed absent or reduced sensory nerve action potentials and compound muscular action potentials, myopathic changes, and fibrillation potentials at electromyography recordings, and reduced excitability or inexcitability of tibialis anterior at direct muscle stimulation, leading to a diagnosis of CINM in all 3 patients. In 1 patient, the diagnosis was also confirmed by muscle biopsy. Outcome was fatal in 2 of the 3 patients. Although AC is associated with most of the known risk factors for CINM, the cooccurrence of the 2 disorders may be difficult to recognize and has never been reported. We found that CINM can occur as a severe complication of AC, and should be suspected when hypertonia-rigidity subsides despite persistent akinesia. Strict monitoring of muscle enzyme levels may help diagnosis. This finding addresses possible caveats in the use of putative treatments for AC.

Acute movement disorders in children: experience from a developing country

We describe acute movement disorders in 92 children, aged 5 days to 15 years, from an Indian tertiary hospital. Eighty-nine children had hyperkinetic movement disorders, with myoclonus in 25, dystonia in 21, choreoathetosis in 19, tremors in 15, and tics in 2. Tetany and tetanus were seen in 5 and 2 children, respectively. Hypokinetic movement disorders included acute parkinsonism in 3 children. Noninflammatory and inflammatory etiology were present in 60 and 32 children, respectively. Benign neonatal sleep myoclonus in 16 and opsoclonus myoclonus syndrome in 7 accounted for the majority of myoclonus cases. Vitamin B12 deficiency in 13 infants was the most common cause of tremors. Rheumatic fever and encephalitis were the most common causes of acute choreoathetosis. Acute dystonia had metabolic etiology in 6 and encephalitis and drugs in 3 each. Psychogenic movement disorders were seen in 4 cases only, although these patients may be underreported.

Status dystonicus: a practice guide

Status dystonicus is a rare, but life-threatening movement disorder emergency. Urgent assessment is required and management is tailored to patient characteristics and complications. The use of dystonia action plans and early recognition of worsening dystonia may potentially facilitate intervention or prevent progression to status dystonicus. However, for established status dystonicus, rapidly deployed temporizing measures and different depths of sedation in an intensive care unit or high dependency unit are the most immediate and effective modalities for abating life-threatening spasms, while dystonia-specific treatment takes effect. If refractory status dystonicus persists despite orally active anti-dystonia drugs and unsuccessful weaning from sedative or anaesthetic agents, early consideration of intrathecal baclofen or deep brain stimulation is required. During status dystonicus, precise documentation of dystonia sites and severity as well as the baseline clinical state, using rating scales and videos is recommended. Further published descriptions of the clinical nature, timing of evolution, resolution, and epidemiology of status dystonicus are essential for a better collective understanding of this poorly understood heterogeneous emergency. In this review, we provide an overview of the clinical presentation and suggest a management approach for status dystonicus.

Movement disorder emergencies in childhood

The literature on paediatric acute-onset movement disorders is scattered. In a prospective cohort of 52 children (21 male; age range 2mo-15y), the commonest were chorea, dystonia, tremor, myoclonus, and Parkinsonism in descending order of frequency. In this series of mainly previously well children with cryptogenic acute movement disorders, three groups were recognised: (1) Psychogenic disorders (n = 12), typically >10 years of age, more likely to be female and to have tremor and myoclonus (2) Inflammatory or autoimmune disorders (n = 22), including N-methyl-d-aspartate receptor encephalitis, opsoclonus-myoclonus, Sydenham chorea, systemic lupus erythematosus, acute necrotizing encephalopathy (which may be autosomal dominant), and other encephalitides and (3) Non-inflammatory disorders (n = 18), including drug-induced movement disorder, post-pump chorea, metabolic, e.g. glutaric aciduria, and vascular disease, e.g. moyamoya. Other important non-inflammatory movement disorders, typically seen in symptomatic children with underlying aetiologies such as trauma, severe cerebral palsy, epileptic encephalopathy, Down syndrome and Rett syndrome, include dystonic posturing secondary to gastro-oesophageal reflux (Sandifer syndrome) and Paroxysmal Autonomic Instability with Dystonia (PAID) or autonomic 'storming'. Status dystonicus may present in children with known extrapyramidal disorders, such as cerebral palsy or during changes in management e.g. introduction or withdrawal of neuroleptic drugs or failure of intrathecal baclofen infusion; the main risk in terms of mortality is renal failure from rhabdomyolysis. Although the evidence base is weak, as many of the inflammatory/autoimmune conditions are treatable with steroids, immunoglobulin, plasmapheresis, or cyclophosphamide, it is important to make an early diagnosis where possible. Outcome in survivors is variable. Using illustrative case histories, this review draws attention to the practical difficulties in diagnosis and management of this important group of patients.

Evaluation and management of the non-motor features of Parkinson's disease

Parkinson's disease (PD) is traditionally viewed as a motor disorder with a characteristic triad of tremor, rigidity and bradykinesia. There is now increasing awareness that PD is a complex systemic disorder with many nonmotor symptoms (NMS) which include autonomic dysfunction, sleep disorders, sensory and neuropsychiatric features. NMS become more common in severity and frequency with advancing disease when neuropsychiatric features such as cognitive impairment and psychosis dominate the clinical picture. NMS are strongly correlated with quality of life for patients and their families as well as institutional care placement. Despite their importance, NMS are poorly recognized by clinicians and often undeclared by patients. Use of a validated screening tool NMSQuest followed by specific symptom assessment instruments strengthens the recognition and holistic management of NMS in PD. Some NMS such as mood disturbance, anxiety, pain and insomnia may be improved by optimization of dopaminergic therapy. Conversely, psychosis, excess daytime somnolence or impulse control disorder (ICD) may be triggered by dopaminergic drugs. Other NMS such as dementia and severe depression may be unresponsive to dopaminergic treatment and may reflect perturbations in cholinergic, serotonergic or noradrenergic neurotransmitter function. These symptoms are more challenging to manage but may be ameliorated to some extent by agents such as acetylcholinesterase inhibitor or antidepressant drugs. This contribution reviews the evidence for the evaluation and management of key NMS in PD (apathy, anxiety, depression, psychosis, dementia, ICD, sleep disturbance, autonomic dysfunction, pain) and highlights the urgent need for both novel therapies and more controlled trials for current therapeutic strategies.

Neuroleptic malignant syndrome: mechanisms, interactions, and causality

This review focuses on new data from recent publications concerning how compounding interactions between different thermoregulatory pathways influence the development of hyperthermia and/or neuroleptic malignant syndrome (NMS), and the fundamental issue of the presumed causal role of antipsychotic drugs. The formal criteria for substantiating cause-effect relationships in medical science, established by Hill, are applied to NMS and, for comparison, also to malignant hyperthermia and serotonin toxicity. The risk of morbidities related to hyperthermia is reviewed from human and experimental data: temperatures in excess of 39.5°C cause physiological and cellular dysfunction and high mortality. The most temperature-sensitive elements of neural cells are mitochondrial and plasma membranes, in which irreversible changes occur around 40°C. Temperatures of up to 39°C are "normal" in mammals, so, the term hyperthermia should be reserved for temperatures of 39.5°C or greater. The implicitly accepted presumption that NMS is a hypermetabolic and hyperthermic syndrome is questionable and does not explain the extensive morbidity in the majority of cases, where the temperature is less than 39°C. The thermoregulatory effects of dopamine and acetylcholine are outlined, especially because they are probably the main pathways by which neuroleptic drugs might affect thermoregulation. It is notable that even potent antagonism of these mechanisms rarely causes temperature elevation and that multiple mechanisms, including the acute phase response, stress-induced hyperthermia, drugs effects, etc., involving compounding interactions, are required to precipitate hyperthermia. The application of the Hill criteria clearly supports causality for drugs inducing both MH and ST but do not support causality for NMS.

Management of the hospitalized patient with Parkinson's disease: current state of the field and need for guidelines

OBJECTIVE

To review the literature and to identify practice gaps in the management of the hospitalized Parkinson's disease (PD) patient.

BACKGROUND

Patients with PD are admitted to hospitals at higher rates, and frequently have longer hospital stays than the general population. Little is known about outpatient interventions that might reduce the need for hospitalization and also reduce hospital-related complications.

METHODS

A literature review was performed on PubMed about hospitalization and PD between 1970 and 2010. In addition, in press peer-reviewed papers or published abstracts known to the authors were included. Information was reviewed by a National Parkinson Foundation workgroup and a narrative review article was generated.

RESULTS

Motor disturbances in PD are believed to be a causal factor in the higher rates of admissions and complications. However, other conditions are commonly recorded as the primary reason for hospitalization including motor complications, reduced mobility, lack of compliance, inappropriate use of neuroleptics, falls, fractures, pneumonia, and other important medical problems. There are many relevant issues related to hospitalization in PD. Medications, dosages and specific dosage schedules are critical. Staff training regarding medications and medication management may help to avoid complications, particularly those related to reduced mobility, and aspiration pneumonia. Treatment of infections and a return to early mobility is also critical to management.

CONCLUSIONS

Educational programs, recommendations, and guidelines are needed to better train interdisciplinary teams in the management of the PD patient. These initiatives have the potential for both cost savings and improved outcomes from a preventative and a hospital management standpoint.

A prospective study of acute movement disorders in children

AIM

The purpose of this study was to report a prospective cohort of children with acute-onset movement disorders.

METHOD

We report on 52 individuals (31 females, 21 males; mean age 6y 5mo, range 2mo-15y) with acute-onset movement disorders managed at a busy tertiary paediatric referral hospital over a 40-month period.

RESULTS

In descending order of frequency, the movement disorders reported were chorea, dystonia, tremor, myoclonus, and parkinsonism. It was possible to divide the participants into three groups: (1) those with inflammatory or autoimmune disorders (n=22), (2) those with non-inflammatory disorders (n=18), and (3) those with psychogenic disorders (n=12). The inflammatory or autoimmune aetiologies included N-methyl-D-aspartate receptor encephalitis (n=5), opsoclonus-myoclonus syndrome (n=4), Sydenham chorea (n=3), systemic lupus erythematosus (n=3), acute necrotizing encephalopathy (n=3), and other types of encephalitis (n=4). Other important non-inflammatory movement disorder aetiologies included drug-induced movement disorder (n=6), post-pump chorea (n=5), metabolic (n=3) and vascular (n=2) disease. The participants with psychogenic movement disorders (n=12) were all over 10 years of age and were more likely to be female. Tremor and myoclonus were significantly over-represented in the psychogenic movement disorder subgroup. The outcomes of the total cohort were variable, and included full recovery, severe morbidity, and death.

INTERPRETATION

Acute-onset movement disorders in children are important and may be treatable. Management should focus upon identifying the cause and treating the underlying disease process, as symptomatic treatment of the abnormal movements is variably effective.

Parkinsonism-Hyperpyrexia Syndrome After Deep Brain Stimulation Surgery

OBJECTIVE

Deep brain stimulation is an alternative treatment for advanced Parkinson's disease. Levodopa medications are usually discontinued the night before surgery to localize the optimal response site to intraoperative macrostimulation. However, abrupt withdrawal of medication may result in side effects. We report a case of parkinsonism-hyperpyrexia syndrome (PHS), a rare complication resulting from discontinuation of antiparkinsonian medication, after a deep brain stimulation (DBS) procedure for bilateral subthalamic-nucleus (STN).

CLINICAL PRESENTATION

A 66-year-old woman with an 11-year history of idiopathic Parkinson's disease was admitted for DBS. She had experienced wearing-off symptoms, severe peak-dose dyskinesia, and medication-induced side effects. Antiparkinsonian medication was discontinued 2 days before surgery because of severe drug-related complications. DBS for bilateral STN was performed uneventfully, but the patient was unconscious with fever, tachycardia, and hypertension after surgery.

INTERVENTION

Levodopa and dopamine agonist replacement by nasogastric tube and hydration were immediately administered with conservative treatment for the hypertension, tachycardia, and fever. The patient's serum creatine kinase level increased to 786 U/L 3 days after the surgery and then decreased gradually as the patient's consciousness improved.

CONCLUSION

Physicians should be aware of the possibility of PHS after a deep brain stimulation procedure. If the patient shows unexplained changes in consciousness with hyperpyrexia after surgery, PHS should be considered and adequate treatment should be given immediately to prevent death.

Identification and management of deep brain stimulation intra- and postoperative urgencies and emergencies

Deep brain stimulation (DBS) has been increasingly utilized for the therapeutic treatment of movement disorders, and with the advent of this therapy more postoperative urgencies and emergencies have emerged. In this paper, we will review, identify, and suggest management strategies for both intra- and postoperative urgencies and emergencies. We have separated the scenarios into 1--surgery/procedure related, 2--hardware related, 3--stimulation-induced difficulties, and 4--others. We have included ten illustrative (and actual) case vignettes to augment the discussion of each issue.

The challenge of non-motor symptoms in Parkinson's disease

The non-motor symptoms (NMS) of Parkinson's disease (PD) are often poorly recognized and inadequately treated in contrast to motor symptoms and a modern holistic approach to treatment of PD should, therefore, include recognition and assessment of NMS. Certain aspects of the NMS complex of PD can be improved with currently available treatments, both dopaminergic and non-dopaminergic, but other features may be more refractory illustrating the importance of research into more effective drug therapies for the future. The American Academy of Neurology has recently published the first task force guidelines in relation to treatment of NMS of PD.

Reversible parkinsonism due to chronic bilateral subdural hematomas

Subdural hematoma is a rare cause of secondary parkinsonism. We report a 65-year-old woman with reversible parkinsonism due to bilateral chronic subdural hematomas. Symmetrical parkinsonism evolved acutely 45 days after a trivial head injury. Mild pyramidal signs were also present on her left side. MRI revealed bilateral chronic subdural hematomas. The patient's parkinsonism was completely abolished one month after successful neurosurgical evacuation of the hematomas.

Movement disorders and inborn errors of metabolism in adults: a diagnostic approach

Inborn errors of metabolism (IEMs) may present in adolescence or adulthood with various movement disorders including parkinsonism, dystonia, chorea, tics or myoclonus. Main diseases causing movement disorders are metal-storage diseases, neurotransmitter synthesis defects, energy metabolism disorders and lysosomal storage diseases. IEMs should not be missed as many are treatable. Here we briefly review IEMs causing movement disorders in adolescence and adults and propose a simple diagnostic approach to guide metabolic investigations based on the clinical course of symptoms, the type of abnormal movements, and brain MRI abnormalities.

The excitatory:inhibitory ratio model (EIR model): An integrative explanation of acute autonomic overactivity syndromes

Numerous medical conditions present with acute and severe autonomic and muscular overactivity. These syndromes include Neuroleptic Malignant Syndrome, Serotonin Syndrome, Dysautonomia (or paroxysmal sympathetic storms) following acquired brain injury, Autonomic Dysreflexia, Parkinsonian-Hyperpyrexia Syndrome, Malignant Catatonia, intrathecal baclofen withdrawal, Malignant Hyperthermia, Stiff Man Syndrome and Irukandji Syndrome. In their worst forms, each of these syndromes are relatively rare, are treated by different medical specialties and show widely varying pathophysiology. Most are considered to be medical emergencies and share significant mortality rates. Previous authors have noted similarities between some of these conditions, prompting the suggestion that a single common mechanism may underlie their clinical presentation. However, the development of such an integrative model has not occurred. This paper presents a short review of the clinical syndromes, grouped by the location of pathology and mechanism of action. From this background, an integrative framework termed the excitatory:inhibitory ratio (EIR) model is presented. The EIR model consists of two inter-related networks operating at spinal and brainstem levels. The model is evaluated against pre-clinical scientific research, known pathways, each disorder's pathophysiology (where this is known) and variable severity, and used to explain the reasons behind the efficacy of current treatment regimes. Circumstantial evidence for an expanded aetiology for Malignant Hyperthermia is provided and generic treatment strategies for a number of other conditions are suggested. Finally, minor modifications to this model provide a basis to begin to explain less severe, regional "overlap" syndromes.

Parkinson's disease: background, diagnosis, and initial management

Parkinson's disease is a common neurodegenerative disorder associated with aging. After essential tremor, it is the most common movement disorder of the elderly. Parkinson's disease is the most common disabling movement disorder. This article reviews the major clinical features, differential diagnosis, approach to diagnosis, and initial management of Parkinson's disease.

Non-motor symptoms in Parkinson's disease: an underdiagnosed problem

Parkinson's disease results from degeneration of the substantia nigra pars compacta and the consequent dysfunction of the dopaminergic nigrostriatal pathway. Serotonergic and noradrenergic pathways are also affected. However, It has been recognized that nondopaminergic and non-motor symptoms are sometimes present prior to diagnosis and these inevitably emerge with disease progression, impacting on morbidity, quality of life and mortality. The non-motor symptoms of Parkinson's disease continue to be poorly recognized and inadequately treated in contrast with motor symptoms, and a modern holistic approach to treatment of Parkinson's disease should therefore include recognition and assessment of non-motor symptoms. Certain aspects of the non-motor symptoms complex of Parkinson's disease can be improved with currently available treatments, but other features may be more refractory and require research into effective nondopaminergic drug therapies for the future.

Parkinsonism–hyperpyrexia syndrome: The role of electroconvulsive therapy

Herein, we present a case of a parkinsonism-hyperpyrexia syndrome (PHS) in a 58-year-old man with a 10-year history of Parkinson's disease. The patient presented with a 2-week history of fever and increasing confusion, in the context of a number of changes to his medication regimen. On presentation, he was noted to be febrile with autonomic instability, diaphoresis and marked rigidity. He was disoriented and responding to visual hallucinations. Investigations revealed an elevated creatine kinase and a provisional diagnosis of PHS was made. After the patient failed to respond during a 2-week period to supportive measures, electroconvulsive therapy (ECT) treatment was commenced. A good response to eight bilateral ECT treatments was achieved, with resolution of his confusional state and associated psychotic phenomena. We discuss the nosological and management issues associated with this case and discuss the role of ECT as a treatment modality in this condition.

The catatonic dilemma expanded

Catatonia is a common syndrome that was first described in the literature by Karl Kahlbaum in 1874. The literature is still developing and remains unclear on many issues, especially classification, diagnosis, and pathophysiology. Clinicians caring for psychiatric patients with catatonic syndromes continue to face many dilemmas in diagnosis and treatment. We discuss many of the common problems encountered in the care of a catatonic patient, and discuss each problem with a review of the literature. Focus is on practical aspects of classification, epidemiology, differential diagnosis, treatment, medical comorbidity, cognition, emotion, prognosis, and areas for future research in catatonic syndromes.