Ataxic hemiparesis from a midbrain mass

Abstract

A 10-year-old boy with leukemia developed ipsilateral corticospinal and cerebellar signs: the ataxic hemiparesis syndrome. Computed tomography revealed a mass lesion in the contralateral rostral midbrain. Previous reports of this syndrome placed the lesion in the basis pontis. The anatomical substrate of the ataxic hemiparesis syndrome includes the basis pontis, rostral midbrain, and possibly other areas within the central nervous system.

Ataxic hemiparesis in patients with primary pontine hemorrhage.

“…2 8-11 The possible lesions already proposed are small infarction at the upper basis pontis, 2,9 or at the superior portion of the posterior limb of the internal capsule 8 -11 or mass lesion in the rostral midbrain. 10 Although it has been suggest ed that small infarctions at the posterior limb of the internal capsule could produce ataxic hemiparesis on the basis of CT scan, 8 " there might be small coexis tent infarctions in the brainstem which could not be detected by conventional CT scans. Bendheim and Berg 10 reported that interruption of the corticospinal tract and cerebellofugal pathways by a mass lesion situated at the ventrolateral aspect of the rostral mid brain could also produce contralateral hemiparesis and cerebellar signs.…”

“…The lesions in all 3 cases of Fisher and in the present 2 cases were in the right brainstem. Among those 5 patients, 4 showed dysarthria, while ataxic hemiparesis due to left brainstem lesions 10 did not reveal speech disturbance. This is in agreement with the results of Lechtenberg and Gilman,…”

The fallacy of the lacune hypothesis.

“…The site of the lesion does not precisely determine its pathogenesis as infarction, hemorrhage, infection, 23 or neoplasm. 24 CT has established that small intracerebral hemorrhages 25 - 26 and large ischemic infarcts 27 can cause "lacunar syndromes." The cause(s) of "lacunar syndromes" have strayed so far from stroke as to include cysticercosis.…”

Ataxic Hemiparesis

“…Fisher 4,8 described an excellent outcome in his 17 cases. Multiple single case reports 11,12,15,19,21,46,51,63,64 as well as large series 28,29 also suggested that good outcome was the rule, regardless of the type of lesion. Our data concurred, with 77% of our patients returning to normal or mild impairment.…”

“…In 1 case 46 infarction related to cysticercosis-induced meningovasculitis was found. In abundant case reports other etiologic mechanisms, such as hemorrhage, 12,14,16,17,20,28,39,[47][48][49] trauma, 50 and neoplastic infiltration 23,28,51,52 have been well documented. Information from studies in which neuroimaging was used to diagnose small, deep infarcts provides some evidence for diffuse etiologic mechanisms, with 33% of those patients with small deep infarcts on CT scan having either a potential cardiac or carotid embolic source.…”