[Acute global amnesia as an exclusive presenting symptom of thalamic infarct: a diagnostic challenge].

Isolated acute amnesia is an exceptional presenting symptom of thalamic stroke. This study analyses the clinical profile, the diagnosis, the treatment and the prognosis of these patients. We conducted a retrospective review of the cases of thalamic infarct that presented exclusively as acute amnesia in our university tertiary hospital (n = 3) and a review of similar cases in PubMed (n = 20). 48% presented at least one risk factor of stroke (arterial hypertension, dyslipidaemia, diabetes mellitus, atrial fibrillation or a previous stroke). Amnesia was anterograde in three cases (13%) and global in the remaining 20 (87%). The infarct was detected in neuroimaging studies carried out within the first 24 hours in one patient (4%) and later in all the others; the average time until a diagnosis was established was 11 days. The initial CT scan was normal in five patients (22%). Eight cases (35%) required magnetic resonance imaging to detect the infarct. Of these, four subjects were studied directly with MR imaging. Amnesia clearly improved in eight patients (35%), and three of them (13%) made a full recovery. Fifteen patients (65%) presented mnemonic sequelae that interfered with their functional capacity. The clinical picture lasted less than 24 hours in two patients (9%). None of the cases received revasculisation therapy in the acute phase. The diagnosis of thalamic infarcts that begin exclusively with amnesia is very difficult and this has negative repercussions on their treatment in the acute phase. These infarcts can produce a functionally disabling memory deficit in a high percentage of patients. Amnesia global aguda como forma exclusiva de presentacion de infarto talamico: un reto diagnostico. Introduccion. La amnesia aguda aislada es una forma excepcional de presentacion del ictus talamico. Se analizan el perfil clinico, el diagnostico, el tratamiento y el pronostico de estos pacientes. Casos clinicos. Revision retrospectiva de los casos de infarto talamico que se presentaron exclusivamente como amnesia aguda en nuestro hospital terciario universitario (n = 3) y revision de casos similares en PubMed (n = 20). El 48% presentaba al menos un factor de riesgo de ictus (hipertension arterial, dislipidemia, diabetes mellitus, fibrilacion auricular o ictus previo). La amnesia fue anterograda en tres casos (13%) y global en los otros 20 (87%). El infarto se detecto en estudio de neuroimagen en las primeras 24 horas en un paciente (4%) y posteriormente en los demas, y la media de dias hasta el diagnostico fue de 11. La tomografia computarizada inicial fue normal en cinco (22%) pacientes. Precisaron estudio por resonancia magnetica ocho (35%) casos para detectar el infarto. De estos, cuatro sujetos se estudiaron directamente con resonancia magnetica. La amnesia presento una mejoria clara en ocho (35%) pacientes, y la recuperacion fue completa en tres (13%). Las secuelas mnesicas que interferian la capacidad funcional se presentaron en 15 pacientes (65%). La clinica persistio menos de 24 horas en dos pacientes (9%). Ningun caso recibio tratamiento revascularizador en fase aguda. Conclusion. Los infartos talamicos que comienzan de forma exclusiva con amnesia presentan notables dificultades diagnosticas que repercuten negativamente en su tratamiento en la fase aguda. Estos infartos pueden producir un deficit mnesico funcionalmente discapacitante en un porcentaje elevado de pacientes.