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Título

Bilateral thalamic infarction presented as a loss of consciousness

Resumo

CASE REPORT: A 62-year-old female presented in the emergency department with sudden loss of consciousness. At admission, the patient was conscious but confused. She had clinical history of hypertension. On examination, she was somnolent, and the rest of the physical examination was unremarkable. Her electrocardiogram showed a sinus rhythm. Echocardiogram reported concentric remodeling of the left ventricle. A non-contrast CT scan revealed a hypoattenuation in the medial portion of both thalami, corroborated by MRI. Angio-CT demonstrated stenosis in the distal V4 segment of the left vertebral artery. DISCUSSION: The thalamus is part of the diencephalon and is the relay center of the brain, retransmitting information between the cerebral cortex and subcortical structures. The inferolateral, polar, paramedian, and posterior choroidal arteries are the main arteries that supply blood to the thalamus. There is considerable variation in the territory supplied by each artery. Gerard Percheron described four variants of paramedian artery that supply the mediodorsal and intralaminar thalamic nuclei and occasionally the upper brainstem. One of the variants is the artery of Percheron. It arises from P1 segment of the posterior cerebral artery as a single artery and supplies blood to the bilateral paramedian thalamic nuclei and occasionally the rostral mesencephalon. Occlusion of the artery of Percheron can lead to a bilateral paramedian thalamic infarct. It can present with a variety of clinical manifestations such as an altered mental status, increased somnolence, memory impairment, a vertical gaze palsy, aphasia, hemiplegia, movement disorder, cerebellar ataxia and even coma. FINAL COMMENTS: Due to the large number of possible differential diagnoses, vigilance impairment poses a common diagnostic challenge. The occlusion of the artery of Perhceron, an anatomical variation whereby both paramedian arteries arise from a common P1, often leads to a bilateral paramedian thalamic infarction. Thalamic infarcts account for 11% of vertebrobasilar infarcts, of which 4-18% are due to the artery of Percheron occlusion and only 0.6% of cerebral infarctions are bilateral thalamic. In a case with no obvious cause for sudden loss of consciousness, occlusion of the artery of Percheron should be considered as one of the differentials. The severity of vigilance impairment is significantly more pronounced in bilateral paramedian infarction than in unilateral lesions.

Palavras Chave

bilateral thalamic infarct, bilateral stroke, thalamus, artery of percheron