Medial Medullary Syndrome

Abstract

With advanced imaging techniques, infarctions occurring in the medulla are now more easily identified. To date, however, only approximately 30 cases of medial medullary infarction syndrome (MMS) have been reported, and the clinical and radiological characteristics of MMS remain to be studied. We studied 18 patients (15 men, 3 women; mean age, 62 years) who had compatible clinical and MRI findings of MMS and reviewed the previously reported cases. Seventeen patients had a unilateral lesion usually involving the upper medulla, and 1 had bilateral lesions. Fifteen patients had unilateral sensorimotor stroke, while 2 presented with pure motor stroke. The face was usually but not always spared. The degree of hemiparesis varied, and a tingling sensation with decreased vibration and position sense was the most common sensory manifestation. Two patients had lingual paresis, and none suffered respiratory difficulties. One patient presented with bilateral gait ataxia without sensorimotor dysfunction. Angiography or MR angiography performed in 9 patients showed vertebral artery disease in 6. Three patients had concurrent lateral medullary infarction, and 1 had a previous history of lateral medullary syndrome. The prognosis was generally good, although residual hemiparesis remained in patients with initially severe hemiparesis. Review of 26 previously reported cases showed that they frequently had bilateral lesions, often presenting with quadriplegia, lingual paresis, respiratory symptoms, and a grave prognosis. Our data illustrate that MMS is most often manifested as benign hemisensorimotor stroke frequently associated with tingling sensation and impaired deep sensation. This benign form of MMS should be much more common than MMS with poor prognosis and may have been frequently misdiagnosed as capsular or pontine stroke before the era of MRI.