Drug-induced disorders of the nervous system

Abstract

EncephalopathyDrugs that cause encephalopathy and coma do so either by inducing metabolic disturbances (eg hepatic, hypoglycaemic, hyponatraemic or uraemic encephalopathy) or by direct central nervous system (CNS) toxicity (eg anti-epileptic drugs (AEDs), cephalosporins, penicillins, IVIg). Drug-induced coma most commonly occurs at toxic serum concentrations of drug, typically after overdose (eg tricyclic antidepressants (TCAs), opiates, benzodiazepines, AEDs).Posterior reversible leukoencephalopathy (PRLE) (Fig 3) Extrapyramidal disordersDrug-induced symmetrical akinetic rigid syndromes are thought to result from monoamine oxidase dysregulation and chronic dopamine depletion after prolonged treatment with phenothiazines, haloperidol, TCAs, metoclopramide, lithium and cinnarizine. Hyperkinetic syndromes may be the result of drug interactions with dopamine transporter proteins. Acute dystonia-dyskinesia (including oculogyric crisis) is commonly caused by antipsychotics, TCAs, AEDs and metoclopramide. Choreo-athetosis is sometimes seen with benzhexol, neuroleptics and OCPs. TCAs and antipsychotics can both cause restless leg syndrome, while dextroamphetamine, methylphenidate and haloperidol can cause motor tics.Drug withdrawal is the first step but acute symptomatic treatment is also often required (eg iv procyclidine, benztropine or diphenhydramine and iv benzodiazepines in oculogyric crisis). Tardive dyskinesia, which develops after prolonged treatment with phenothiazines, thioxanthines, butyrophenones, dibenzepines, diphenylbutylpiperidines and metoclopramide, can be irreversible. It may be prevented by concomitant treatment with vitamin E, but the evidence is weak. 5 Patients in whom tardive dyskinesia develops should be converted to alternative antipsychotic medication (eg sulpiride). Symptomatic treatments can also be used (eg tetrabenazine). Patients may complain of akathisia when treated with phenothiazines, butyrophenones, TCAs, L-dopa and monoamine oxidase inhibitors (MAOIs); if severe and persistent, it can be treated with anticholinergics, amantadine or propranolol. 6 Cerebellar disorders and tremor Cranial neuropathiesCytosine arabinoside, ciclosporin and ganciclovir can all induce abducens palsies, but the last two have been described only following allogeneic bone marrow transplantation. Immunological reactions are likely to explain the occurrence of sulfasalazine, insulin-like growth factor-1, didanosine, and HBV vaccine-induced facial palsies. There are several reports of recurrent laryngeal palsy with vincristine chemotherapy, usually in association with peripheral neuropathy; if severe, it can require tracheal intubation. Early withdrawal of therapy is essential to ensure recovery. Special senses VisionBlurred vision is a common side effect of medication. Examples of the more common, more serious and occasionally irreversible causes of visual impairment are given in Fig 4(a). Note that agents known to cause PRLE can also cause cortical blindness. OtotoxicityOtotoxic agents are categorised acc...

Síndrome cerebeloso por mesalamina: reporte de un caso

“…Neuroimágenes por resonancia magnética para descartar lesiones de la fosa posterior causante de síndrome cerebeloso: enfermedades autoinmunes, inflamatorias, vasculares, infecciones, tumores primarios y secundarios, traumas, iatrogénicos, ataxias hereditarias, esporádicas 5,[11][12][13][14][15][16] . La imagen por resonancia magnética normal y la persistencia de la sintomatología cerebelosa nos debe hacer pensar en la posibilidad de factores tóxicos o metabólicos desencadenantes de las manifestaciones clínicas, entre las causas más comunes (tabla 1 5,17,18 ) . 124 Fernández Yépez LJ., Escorcia Barceló O., Montoya Jaramillo M., Herrera Ruiz F. Síndrome cerebeloso por mesalamina: reporte de un caso La buena historia clínica puede descartar causas metabólicas y también guiarnos sobre los tóxicos en este caso los fármacos 15 .…”