A los diecisiete años desaparecen del EEG las polipuntas y polipunta ondas: a propósito del síndrome de Lance-Adams / At the seventeen years they disappear from the EEG The little and little waves: About the Lance-Adams syndrome

Objetivo: la inesperada ausencia del signo de polipunta o de polipunta onda (PPO) en el electroencefalograma (EEG) de dos casos, de 29 y 51 años, respectivamente, del Síndrome Lance Adams (SLA), que hemos visto y publicado con anterioridad, nos motivó a investigar la edad cuando este signo tiende a extinguirse, dejando de ser obligatorio para diagnosticar SLA a pacientes de edad madura. Métodos: de una muestra de 7137 trazados se incluyeron 6939, tras excluir 198 por referimientos no identificables. Estos EEG del Centro de Rehabilitación y el Centro Médico de la Universidad Central del Este (UCE), fueron realizados con electroencefalógrafos Nervus y Cadwell, de manera respectiva. Se revisaron buscando la presencia de PPO para estudiar la edad, la patología sospechada en cada indicación y el género de los pacientes. Resultados: PPO fue encontrada en 293 casos: 4.22 % de la muestra total. En 272 habría ocurrido antes de los 17 años, con la gráfica mostrando una elevación inicial máxima a las nueve. En cambio, de los 18 a los 65 solo apareció la PPO en 18 casos. 14 pacientes mostraron supresión de paroxismo o patrones de electro depresión sin PPO. Conclusión: la polipunta/polipunta onda prácticamente desaparece a los 17 años, a mayor edad, por lo tanto, el signo PPO deja de ser obligatorio para el diagnóstico del SLA en pacientes mayores. Es más frecuente en epilépticos y en varones

Objective: Unexpected absence of polyspike/polyspike & wave sign (PPW) in the EEG of our 29 and 51-year old published cases of Lance Adams Syndrome (LAS), prompted us to investigate the age when this sign may nearly disappear. This in order of considering it not obligatory for late LAS diagnosis. Methods: Inclusion consisted of a sample of 7137 recordings performed at the Rehabilitation Center and the Universidad Central del Este's (UCE) teaching clinic (Nervus and Cadwell respectively). Excluded were 198 for unidentifiable indications. PPW was searched in order to study patient's age, suspected pathology plus gender. Results: PPW was found in 293cases: 4.22% of the total sample: in 275.it occurred before the age of 17 with curve showing an initial tip at nine while between 18 and 65 only 18 cases showed it. Incidentally 14 patients showed Burst suppression or electro-decrement patterns without PPW. The most common indication pathology was Epilepsy followed by learning disability. Finally it was more frequent in 176(63.9%) male vs. 113(36.1%) in female cases: ratio 1.56 to 1. however not significant for the gender ratio in the total EEG sample is 1.55 to 1. Conclusion: PPW nearly disappears after the age of seventeen, perhaps explaining rarity in advanced aged SLA. It is more frequent in Epilepsy EEG indications and in the male

Síndrome de Lance Adams / Lance Adams Syndrome

La mioclonía poshipoxia crónica o síndrome de Lance Adams es una complicación rara que se produce en pacientes que sobreviven a la hipoxia o la hipotensión prolongada, días o semanas después del daño cerebral. Se presentó un caso con este síndrome, secundario a shock hipovolémico por embarazo ectópico roto. El electroencefalograma con ausencia de paroxismos apoya el origen subcortical de las mioclonías, con respuesta favorable al alonazepán. Se detallaron estudios de neuroimagen y potenciales evocados auditivos de tallo cerebral

The chronic poshipoxia myoclonus or Lance Adams syndrome is a rare complication that occurs in patients who survive prolonged hypoxia or hypotension, days or weeks after the complication. A case with this syndrome, hypovolemic shock secondary to a ruptured ectopic pregnancy is presented. EEG with no paroxysms supports the origin of myoclonus subcortical with favorable response to alonazepán. Neuroimaging and auditory evoked potentials and brainstem studies were detailed

Lance-Adams Syndrome

It is not common for a patient who survives cardiac arrest to experience significant neurologic impairment such as acute and chronic post-hypoxic myoclonus, known as Lance-Adams syndrome. This syndrome is predominantly characterized by myoclonus that starts days to weeks after cardiopulmonary resuscitation in patients who regained consciousness. Although several cases of LAS were reported, the decisive treatment method has not been established. We report a 43 year old man with Lance-Adams syndrome who showed long-term improvement through treatment with anti-myoclonic agents and participation in a rehabilitation program.

Lance-Adams Syndrome

Lance-Adams syndrome (LAS) is a rare complication of successful cardiopulmonary resuscitation and is often accompanied by action myoclonus. LAS is seen in patients who have undergone a cardiorespiratory arrest, later regained consciousness, and then developed myoclonus days or weeks after the event. Less than 150 cases of LAS have been reported in the worldwide medical literature. Here, we present a 32-year-old man who suffered from myoclonus after hypoxic brain damage due to hanging himself. This case was diagnosed as Lance-Adams syndrome according to a history of hypoxic brain damage, the clinical features, and the neuroimages such as brain SPECT. Making an early diagnosis and properly managing LAS is positively related to improving the patient's functional outcome. If patients have posthypoxic myoclonus after successful cardiopulmonary resuscitation, we should consider the diagnosis of LAS and initiate a proper rehabilitation program.

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.

A Case of The Successful Treatment of Pentobarbital for Posthypoxic Action Myoclonus(Lance-Adams Syndrome) with Refractory Status Epilepticus / 대한소아신경학회지

Lance-Adams syndrome is a rare complications of cardiorespiratory arrest. We report a 15-month-old child with Lance-Adams syndrome who fell into a refractory status epilepticus after a successful resuscitation after the cardiopulmonary arrest from upper airway obstruction due to the croup. On the day of the admission, he went through a generalized tonic-clonic seizure with poor mental status. His condition became aggravated on 18th day of admission when he developed focal myoclonus in his left arm and leg. The EEG findings before the pentobarbital treatment show partial electrical seizure. The seizures were intractable despite the administration of midazolam, phenobarbital, phenytoin, and valproic acid. Therefore, a pentobarbital(PTB) therapy was required. PTB administered by a continuous infusion pump at a loading dose of 5 mg/kg was sufficient to produce a burst suppression pattern and a seizure control, followed by a maintenance infusion of 0.5-1.5 mg/kg/hour. At that time, the brain MRI showed a diffuse distribution of high signal intensity and swelling in both basal ganglia, thalamus and the temporo-occipital area. The therapy continued for 10 days. Thereafter, PTB was gradually tapered after a minimum 48-hours of a seizure-free status. So we report a case with a brief review of related literature.