Thalamic vascular lesions. Risk factors and clinical course for infarcts and hemorrhages

The data of patients with an MRI-confirmed diagnosis of thalamic stroke were analyzed to identify risk factors and to describe the clinical syndromes according to the thalamic arterial territory involved.

We examined the records of all patients with a diagnosis of thalamic stroke confirmed by MRI who attended the National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" from 1987 through 1995. A database containing demographic features, risk factors, clinical course, type and mechanism of stroke, and vascular territory was analyzed.

Twenty-eight patients (19 men and 9 women; mean age, 48.2 years) had MRI-confirmed thalamic stroke. Infarct was present in 22 patients and hemorrhage in 6. Eleven (39.3%) patients were younger than 45 years. In these young patients, cigarette smoking was the main risk factor associated with the development of stroke. In young patients, isolated and multiple thalamic lesions were present in almost equal proportions. The remaining 17 patients were older adults (45 to 84 years of age). In such patients, most lesions were multiple and were associated with atherosclerosis-predisposing factors. The main distinguishing clinical feature for hemorrhages and paramedian infarcts in comparison with infarcts in the other thalamic territories was the presence of an altered level of consciousness. No patient died as a direct result of the stroke.

Thalamic stroke commonly occurs in young adults. and its mechanism is often undetermined. Increased awareness of this type of stroke in young adults should lead to better delineation of its clinical features, course, and management.