[Pathogenesis of Wallenberg's syndrome].

In 1895 Wallenberg described a syndrome characterized by neurological symptoms produced by unilateral softening of the dorsolateral medulla oblongata. In the majority of cases the softening was caused by an arteriosclerotic-thrombotic occlusion of the homolateral intracranial vertebral artery or posterior inferior cerebellar artery, respectively. Occasionally an occlusion of the basilar artery or of the distal extracranial vertebral artery was responsible. In contradiction to the original thesis of Wallenberg, an embolic arterial occlusion could rarely be diagnosed. In particular cases the syndrome was caused by syphilitic vascular changes, tumors, metastases or encephalitis in the region of the dorsolateral medulla oblongata. This paper describes two cases of Wallenberg's syndrome. In the first case (70-year-old-male) the softening of the dorsolateral medulla oblongata was caused by occlusive thrombosis of the homolateral posterior inferior cerebellar artery with concomitant severe arteriosclerosis of the extracerebral brain arteries. The latter variation is characteristic for hypertensive vascular diseases. Thus Wallenberg's syndrome must be classified in similar cases as a complication of hypertensive peripheral cerebral arteriosclerosis. The second observation refers to a 51-year-old-male with bronchiectasis and chronic bronchitis. Metastatic encephalitis was found in several parts of the mid-brain, including the medulla oblongata. The dorsolateral medulla oblongata was destroyed by septic softenings (pneumococci). In this case, however, arteriosclerotic stenosis or thrombosis of the cerebral arteries could not be found. According to the literature metastatic encephalitis, as described in the last case, is an extremely rare cause of Wallenberg's syndrome.