Diagnóstico e tratamento atual das mioclonias: revisão da literatura / Current diagnosis and treatment of myoclonus: literature review

Mioclonias são movimentos involuntários de instalação súbita e de duração breve, de rara ocorrência (2%), mesmo em serviços especializados. São classificadas de acordo com a sua distribuição, origem e etiologia. O diagnóstico se baseia, fortemente, na apresentação clínica associada às alterações eletrofisiológicas. O tratamento medicamentoso deve ser orientado conforme a sua origem anatômica, destacando-se as seguintes drogas: clonazepam, levetiracetam, piracetam e valproato de sódio. A politerapia é mais eficaz do que a monoterapia, particularmente nas mioclonias de origem cortical. O objetivo desta revisão é enfatizar o diagnóstico e o tratamento atual das condições mais expressivas observadas na prática neurológica, tais como: distonia-mioclônica, mioclonia proprioespinhal, epilepsia com ausência mioclônica, síndrome de West, epilepsia mioclônica juvenil, doença por corpos de Lewy, degeneração corticobasal, panencefalite esclerosante subaguda, doença de Creutzfeldt-Jakob, síndrome de Lance-Adams, mioclonia induzida por drogas, mioclonia medular e mioclonia periférica.

Myoclonus are sudden, brief and rare abnormal movements. They can be classified according to their distribution, origin and etiology. The diagnosis is based largely on the clinical features associated with electrophysiological data. The treatment must be guided according to anatomical origin, highlighting the following drugs: clonazepam, levetiracetam, piracetam and sodium valproate. Polytherapies are more effective than monotherapy, particularly in cortical myoclonus. The aim of this review is to emphasize the current diagnosis and treatment of the more expressive morbid conditions seen in neurological practice, such as: myoclonus-dystonia, propriospinal myoclonus, epilepsy with myoclonic absences, West syndrome, juvenile myoclonic epilepsy, Lewy body disease, corticobasal degeneration, subacute sclerosing panencephalitis, Creutzfeldt-Jakob disease, Lance-Adams syndrome, drug-induced myoclonus, spinal myoclonus and peripheral myoclonus.

Síndrome de Lance-Adams: presentación de dos casos / Lance-Adams syndrome: report of two cases

Lance-Adams syndrome was described in 1963 is a rare complication due to recovered hypoxic episodes or prolonged hypotension events. Is characterized by action myoclonus and cerebellar ataxia. We report two patients studied with this syndrome. A 51 year-old men and a 72 years-old men fully recovered after a brief cardiorespiratory arrest they developed intention myoclonus, triggered by voluntary movements, posture, also by sounds, touches and emotional stimuli. It also was accompanied by cerebellar syndrome, ataxia and posture control alterations. They had a Magnetic Resonance (MR), EEG and normal metabolic parameters. Myoclonus was treated with sodium valproate and clonazepam. The neurophysiologic interpretation of this motor imbalance is an abnormal functioning of the Central Pattern Generator Netwoks (CPGN) located in the mesencephalic region. Hypoxic lesions in vermian purkinje and paravermal cerebellum neurons have an inhibitory effect in this system, producing motor control attenuation, generating an imbalance in the motoneurons of the spinal cord contraction sequence, which starts shooting in an uncoordinated way. As in almost all cerebellar lesions with time they tend to compensate and to diminish myoclonus.

El Síndrome de Lance-Adams descrito en 1963, es una rara complicación que sigue tardíamente a episodios hipóxicos o de hipotensión prolongada, ya recuperados. Se caracteriza por mioclonías de acción y ataxia cerebelosa. Se describen dos pacientes estudiados con este síndrome. Son dos hombres de 51 y 72 años que después de un paro cardiorrespiratorio breve, de recuperación completa, iniciaron mioclonías de intención, activadas por movimientos voluntarios, posturas, estímulos sonoros, táctiles y afectivos. Acompañado además de un síndrome cerebeloso, ataxia de la marcha y alteraciones del control postural. Cursaron con RM (Resonancia Magnética), EEG (Electroencefalograma) y parámetros metabólicos sin relevancia patológica. Las mioclonías fueron controladas con ácido valproico y clonazepam. La interpretación neurofisiológica de este desajuste motor es la alteración en el funcionamiento del patrón central de circuitos generadores (PCCG) ubicado en la región mesencefálica. Las lesiones hipóxicas de las neuronas de Purkinje del vermis y paravermianas del cerebelo, que tienen un efecto inhibitorio para este sistema, producen una atenuación del control motor del PCCG, generando desajuste en la secuencia de la contracción de las motoneuronas de la médula espinal, que comienzan a dispararse de manera independientemente. Como ocurre con la mayoría de las lesiones cerebelosas, con el tiempo tienden a compensarse y por consiguiente a disminuir las mioclonías.

Palatal myoclonus: report of two cases

We describe two cases of palatal myoclonus (PM), one essential and another secondary to a stroke. Case 1: a 64 years old female who developed clicking sounds in both ears after a stroke and three years later on noticed a progressive involuntary movement of the throat associated with rhythmic contractions of the soft palate, muscles of tongue and throat. MRI showed an ischemic area in brainstem. The patient had a partial response to the use of sumatriptan 6 mg subcutaneously. Case 2: a 66 years old female who began with ear clicking at left ear that worsed slowly associated with tinnitus and arrhythmic movements of soft palate and an audible click at left ear. Brain MRI was normal; audiometry showed bilateral neurosensory loss. She was prescribed clonazepan 1 mg daily with complete recovery. Primary and secondary palatal myoclonus share the same clinical features but probably have different pathophysiological underlying mechanisms

Essential palatal myoconus accompanied with psychiatric symptoms

Palatal myoclonus is a rare and unique neurological disorder which can be primary or secondary to lesions of the central tegmental tract in the brain stem. This is a case report of a patient who complained of hearing a continuous disturbing noise for many years. Later an affective disorder superimposed on his previous complaints and confounded his auditory complaints. The co-morbidity resulted in attributing the complaint of hearing noise to his psychotic states and as a hallucinatory phenomenon. Thorough clinical and paraclinical examinations revealed that the patient had primary palatal myoclonus and the misattribution of the auditory complaints had resulted injudicious prescription of antipsychotics. Administration of appropriate therapy resulted in improvement of both problems

Panencefalitis esclerosante subaguda de inicio en edad adulta: presentación atípica en 2 pacientes / Adult onset subacute sclerosing panencephalitis: atypical presentation in 2 cases

Subacute sclerosing panencephalitis is an infrequent central nervous system viral disease and is a late manifestation of persistent infection by a mutant form of measles virus. Since it affects mainly children and teenagers, the diagnosis in older ages is difficult. Its main clinical symptoms are cognitive impairment, behavioral disturbances and myoclonia. We report two males, aged 21 and 22 years old, presenting with the disease with atypical manifestations. One had a catatonic syndrome and the other, amaurosis. The recognition of the different presentation forms of the disease, endemic in developing countries, allows an earlier diagnosis and a more efficient treatment, when available

Triptofano y su uso en medicina / Medical uses of tryptophan

Ha habido importantes avances en el conocimiento del metabolismo del triptofano, la síntesis de serotonina y los receptores serotoninérgicos encefálicos. Se ha determinado la efectividad terapéutica del 5-hidroxitriptofano en la depresión, insomnio, dolor crónico, mioclonías, etc. Eso sí, ha surgido inquietud al establecerse, como efecto adverso del tratamiento con L-triptofano, la producción del síndrome de mialgia-eosinofilia con compromiso importante de las fuerzas debido a una polineuropatía

Efecto del fenatanyl y nalbufina sobre las mioclonias inducidas por el etomidato / Effects of Pentanyl and nalbuphine on etomidate inducid myoclonus

Se estudia la acción del fentanyl y nalbufina sobre las mioclonias inducidas por el etomidato con el objeto de poder establecer su mecanismo, para lo cual se estudiaron 30 pacientes adultos sometidos a legrado uterino instrumental; manejados con fentanyl, nalbufina o solución salina IV previa inducción de la anestesia con etomeidato. En cada paciente se valoró la PAM, FC y FR; dolor venoso, mioclonias y náuseas y vómitos postoperatorios. Ambos morfínicos previenen o atenúan significativamente la frecuencia e intensidad de las mioclonias, por lo que apoyamos un efecto más específico probablemente a nivel del sistema nigroestriado

Myoclonus, Delayed Sequelae of Carbon Monoxide Poisoning, Piracetam Trial

One month following carbon monoxide poisoning, a 39 year-old man developed incontinence, memory impairment, disorientation and emotional instability. He was hospitalized 7weeks later, and during hospitalization he exhibited myoclonic movements of the neck and lower limbs. He was given piracetam intravenously for 11 days. The myoclonus was significantly reduced by the third day of treatment and had disappeared by the seventh day. There was no recurrence following cessation of treatment.