Drug-induced and tardive movement disorders.

Drug-induced and tardive movement disorders represent a large number of extrapyramidal disorders seen in neurologic practice. Iatrogenically induced, most commonly by neuroleptics, these disorders can be characterized by any abnormal body movement including tremor, chorea, athetosis, dyskinesias, dystonia, myoclonus, tics, ballismus or akathisia. Parkinsonism, dyskinesias and dystonia tend to be the most common. Management of patients with drug-induced or tardive syndromes is complex. Prognosis is frequently poor as patients usually need the offending agent to manage their underlying psychiatric or medical problem. Neuroleptics and other drugs known commonly to cause movement disorders should be used cautiously and significant consideration of all risks and benefits measured before initiating therapy.     

Drug-induced movement disorders: tardive syndromes

Persistent drug-induced movement disorders (tardive syndromes) remain an important clinical problem and consist of a variety of involuntary movements appearing in a patient exposed to a dopamine-blocking agent. The current state of knowledge on this topic is summarised in this article. Clinical aspects (tardive dyskinesia, tardive dystonia and other forms), prevalence, risk factors, prevention and management are discussed.     

Drug-induced acid-base disorders]

Drug-induced acid-base disorders may be classified into four categories with respect to the mechanism. 1. Metabolic acidosis is induced by a large acid loads incurred from exogenous sources (e.g. NH4Cl, or toxin ingestion) or endogenous acid production (e.g. generation of ketoacids or lactic acids by alcohol or phenformin) or base loss (e.g. abuse of laxatives). 2. Metabolic alkalosis results from exogenous bicarbonate loads (e.g. milk-alkali syndrome) or effective extracellular fluid contraction, potassium depletion plus hyperaldosteronism (e.g. vomiting, diuretics, or licorice). 3. Renal tubular acidosis is induced by the drugs which mainly impair proximal and/or distal tubules (e.g. vitamin D, NSAID, acetazolamide or amphotericin B). 4. Respiratory acidosis or alkalosis results from drug-induced respiratory center depression or neuromuscular impairment (e.g. anesthetic, sedative overdosage or curare) or hyperventilation (salicylates, paraldehyde, epinephrine, or nicotine).     

Drug-induced acute kidney injury

PURPOSE OF REVIEW: The purpose of this review is to describe the most prevalent mechanisms of drug-induced acute kidney injury, to define the risk factors for nephrotoxicity, and to analyze the available evidence for preventive measures. RECENT FINDINGS: Drug toxicity remains an important cause of acute kidney injury that, in many circumstances, can be prevented or at least minimized by vigilance and early intervention. Recent studies have resulted in increased insight into the subcellular mechanisms of drug nephrotoxicity. Further improvement is to be expected from the identification of early markers of nephrotoxicity and an increasing involvement of a clinical pharmacist. SUMMARY: The main mechanisms of nephrotoxicity are vasoconstriction, altered intraglomerular hemodynamics, tubular cell toxicity, interstitial nephritis, crystal deposition, thrombotic microangiopathy, and osmotic nephrosis. Before prescribing a potentially nephrotoxic drug, the risk-to-benefit ratio and the availability of alternative drugs should be considered. Modifiable risk factors should be corrected. The correct drug dosage should be prescribed. Patients should be pre-hydrated and the glomerular filtration rate should be frequently monitored during the administration of a potentially nephrotoxic drug. Studies are needed to further elucidate the mechanisms of nephrotoxicity to design more-rational prevention and treatment strategies. Computer-based prescriber-order entry and an appropriately trained intensive care unit pharmacist are particularly helpful to minimize medication errors and adverse drug events.     

Trimetazidine induces parkinsonism, gait disorders and tremor

OBJECTIVE: To study the adverse effects of trimetazidine on motor functions. DESIGN: A retrospective study was carried out using electronic records to identify all patients seen between January 1990 and August 2003. SETTING: A neurological out-patient clinic. PARTICIPANTS: Of the 10 258 patients who attended the clinic, 130 received trimetazidine. Treatment with this drug was discontinued in 128 patients. Of the 130 patients treated with trimetazidine, 29 also had other drugs capable of inducing parkinsonism withdrawn from their treatment. MAIN OUTCOME MEASURES: Identification of an improvement in motor function after drug withdrawal. RESULTS: In 56 of the 130 patients who were treated with trimetazidine (43%), an adverse effect on motor function was detected that had been induced or aggravated by one of the withdrawn drugs. Indeed, drug-induced parkinsonism was detected in 20 of these patients. Of these, ten were being treated with trimetazidine only, while the remaining ten were simultaneously receiving other drugs potentially capable of inducing parkinsonism. Treatment with trimetazidine worsened previously diagnosed Parkinson's disease in 12 patients, and gait disorders coupled with disequilibrium was observed in 15 patients. Trimetazidine induced tremor in nine patients. CONCLUSION: Trimetazidine can induce parkinsonism, gait disorder and tremor. These adverse effects have not been previously described for this drug.     

帕金森病肢体震颤和运动障碍的康复

帕金森病(PD)是一种锥体外系的进行性变性疾病 ,PD的评定方法很多 ,主要有 :神经电生理评定 ,定量肌张力测定 ,手臂稳定度评估 ,平衡和协调性评估 ,步态分析 ,言语功能评定及功能的综合评定(如 :Webster评分 ,Heohn和Yahr分期 ,统一帕金森病评定量表) ,日常生活活动能力评定。PD的康复应是合理选用药物 ,尽理控制或减轻症状 ;积极进行运动功能训练 ,防止关节活动范围受限 ,尽力改善运动、平衡、协调功能 ,纠正姿势、步态异常 ;积极进行作业治疗、言语训练和心理治疗 ;设法维持或提高日常生活活动能力 ,提高生活质量。     

Diagnosing non-parkinson's movement disorders

The risk of developing a movement disorder increases with age. Idiopathic Parkinson's disease (IPD), is probably the most well known. However, essential tremor is the most common movement disorder affecting older people. Although many sufferers can have very disabling symptoms it can be a very mild illness in some. Patients present with a symmetrical tremor of the upper limbs in 95% of cases. The tremor is less evident at rest, unlike the tremor of IPD, and there will be no rigidity or bradykinesia. Essential tremor is a mainly clinical diagnosis. A watchful waiting period may be tried. DaTSCAN can be helpful as the results will be normal in patients with essential tremor and abnormal in those with IPD. Vascular parkinsonism accounts for 4.4-12% of all cases of parkinsonism, although it is likely that many cases remain undiagnosed. The features are usually bilateral and symmetrical and often affect the lower more than the upper limbs. A history of previous stroke is common, as are the presence of cardiovascular risk factors such as hypertension and diabetes. Drug-induced parkinsonism is the second most common cause of parkinsonism behind IPD. All patients thought to have a diagnosis of possible IPD should be referred to secondary care. It would also be prudent to refer any patients whose diagnosis is unclear and where advice would be helpful on future management.     

Hypokinetic movement disorders.

Hypokinesis is the term used to refer to slow or reduced movement. Hypokinetic movement disorders are often referred to as parkinsonisms because they display clinical features of idiopathic Parkinson's disease (IPD). As a result, distinguishing other parkinsonian syndromes from IPD is difficult, and it is often not until post mortem that a misdiagnosis is realized. Conditions displaying features of parkinsonism are extensive. The more commonly encountered are IPD, multiple system atrophy, and progressive supranuclear palsy.     

Drug-induced myocardial ischemia and acute myocardial infarction.

Myocardial infarction generally occurs in the presence of known risk factors and identifiable coronary artery disease. Atypical presentations due to therapeutic and illicit drug use are documented, however, and lead to the consideration of alternative pathophysiologic rationales for myocardial infarction. This article discusses central nervous system stimulants and other drugs that have the potential for myocardial damage and their nursing implications.     

Parasomnias and other sleep-related movement disorders

Parasomnias are common clinical complaints. Formal sleep evaluation including PSG is indicated for parasomnias that are violent and potentially injurious; disruptive to the bed partner or other household members; accompanied by excessive daytime sleepiness; or associated with medical,psychiatric, or neurologic symptoms or findings [2]. Multiple sleep latency testing should be considered for patients who have complaints of excessive daytime sleepiness. An extensive history, including medical, neurologic,psychiatric, and sleep disorder, and a review of medication, alcohol, illicit drug use, and family history of parasomnias, may provide useful clues. Distinguishing between a parasomnia and a seizure may be difficult as both can present as recurrent, stereotypical behaviors. Evaluation may be aided by an expanded EEG montage during overnight PSG studies.