Posterior cerebral artery stenosis with midbrain infarction

Benedikt syndrome in a 74-year-old hypertensive woman: A case report

Benedikt syndrome is a rare neurological disorder of the midbrain. Herein, we present a case of Benedikt syndrome, who presented with left-sided body weakness, right oculomotor nerve palsy, cerebellar ataxia, and Holmes tremor in the left upper limb following midbrain infarction. She was treated with aspirin, clopidogrel, and amiodarone.

Crossed brainstem syndrome revealing bleeding brainstem cavernous malformation: an illustrative case

BACKGROUND

Since the nineteenth century, a great variety of crossed brainstem syndromes (CBS) have been described in the medical literature. A CBS typically combines ipsilateral cranial nerves deficits to contralateral long tracts involvement such as hemiparesis or hemianesthesia. Classical CBS seem in fact not to be so clear-cut entities with up to 20% of patients showing different or unnamed combinations of crossed symptoms. In terms of etiologies, acute brainstem infarction predominates but CBS secondary to hemorrhage, neoplasm, abscess, and demyelination have been described. The aim of this study was to assess the proportion of CBS caused by a bleeding episode arising from a brainstem cavernous malformation (BCM) reported in the literature.

CASE PRESENTATION

We present the case of a typical Foville syndrome in a 65-year-old man that was caused by a pontine BCM with extralesional bleeding. Following the first bleeding episode, a conservative management was decided but the patient had eventually to be operated on soon after the second bleeding event.

DISCUSSION

A literature review was conducted focusing on the five most common CBS (Benedikt, Weber, Foville, Millard-Gubler, Wallenberg) on Medline database from inception to 2020. According to the literature, hemorrhagic BCM account for approximately 7 % of CBS. Microsurgical excision may be indicated after the second bleeding episode but needs to be carefully weighted up against the risks of the surgical procedure and openly discussed with the patient.

CONCLUSIONS

In the setting of a CBS, neuroimaging work-up may not infrequently reveal a BCM requiring complex multidisciplinary team management including neurosurgical advice.

Deep brain stimulation of the thalamic ventral intermediate nucleus for Benedikt's syndrome mainly present as tremor: a long-term case observation

Benedikt's syndrome (BS) is caused by the lesion in the midbrain and specifically manifests a series of symptoms, including ipsilateral third nerve palsy, contralateral tremor, hemiataxia, and hyperactive tendon reflexes. Deep brain stimulation (DBS) for BS emerges as a new approach and achieves successfully results. We report a successful case report of thalamic ventral intermediate (VIM) nucleus DBS for a patient with BS. During follow-up of 3 years, DBS successfully control the tremor and greatly improve his living and working quality. We consider that VIM DBS may have sustained benefit for refractory BS that mainly presents as tremor.

Deep brain stimulation as an effective treatment option for post–midbrain infarction-related tremor as it presents with Benedikt syndrome

Benedikt syndrome is a rare but debilitating constellation of symptoms that manifests from infarction of the red nucleus, cerebral peduncle, oculomotor fascicles, and lower oculomotor nucleus. Clinically, it presents as ipsilateral cranial nerve III palsy, contralateral hemiataxia with intention tremor, contralateral hemiparesis, and hyperactive tendon reflexes. Commonly, the tremor upon purposeful movement proves to be the most debilitating manifestation of the infarction with significant impact on the patient's ability to perform activities of daily living and, therefore, quality of life. The authors report the successful management of this debilitating post–midbrain infarction tremor with the insertion of a deep brain stimulator with targets in the contralateral lenticular fasciculus.

Localization of arm representation in the cerebral peduncle of the non-human primate

Motor deficit severity and the potential for recovery in patients with brain injury depend on the integrity of descending corticofugal projections. Clinical assessment of these conditions following subtotal brain trauma requires a comprehensive understanding of the anatomical structures involved in the lesion as well as those structures that are spared. To assist in this endeavor, we investigated motor fiber organization in the crus cerebri of the cerebral peduncle (ccCP) in the rhesus monkey. Fibers originating from the arm representations of the primary (M1), supplementary (M2), rostral cingulate (M3), caudal cingulate (M4), dorsolateral pre- (LPMCd) and ventrolateral pre- (LPMCv) motor cortices were studied. The projections from the frontal and cingulate motor cortices formed descending longitudinal bundles that occupied the medial three-fifths of the ccCP at superior and middle levels. Although considerable overlap characterized these corticofugal projections, a general topography was discernable. Fibers from M1 and M4 occupied the central subsector of the ccCP, and fibers from M3 resided medially. The main distribution of LPMCd, LPMCv, and M2 fibers occupied the centromedial region and overlapped extensively. Progressing inferiorly, all fiber bundles in the central and centromedial sectors gradually extended medially, and overlap increased. A common location of fiber passage occurred at the midbrain-pontine isthmus where all of the fiber bundles overlapped. Our findings indicate that the widespread distribution of corticofugal motor projections may account for the favorable levels of motor recovery that accompany subtotal midbrain injury. At superior and mid-levels of the ccCP anteromedial lesions may disrupt projections from M3, whereas anterolateral lesions may disrupt projections from M1 and M4. Fibers from M2, LPMCv, and LPMCd may be compromised to some degree in both situations. The compact and commixed nature of motor fiber organization at inferior levels and the midbrain-pontine isthmus suggests a vulnerable region of passage for comprehensive disruption of frontal and cingulate corticofugal projection fibers.

Benedikt and "plus-minus lid" syndromes arising from posterior cerebral artery branch occlusion

A 53-year-old man was admitted with diplopia, right ptosis, left lid retraction, mild left sided weakness and involuntary movements. Neurological examination revealed plus-minus lid and Benedikt's syndromes together. Magnetic resonance imaging (MRI) showed two distinct mesencephalic infarctions in territories of paramedian and pedincular perforating arteries. Magnetic resonance angiography (MRA) showed severe stenosis of proximal segment of the right posterior cerebral artery (PCA). Rare clinical presentations such as Benedikt and plus-minus syndromes can be seen together and be due to stenosis of the posterior cerebral artery with specific regional infarctions.

Differing mechanisms between posterior and middle cerebral artery infarctions

Cardiac embolism has been thought to be one of the principal causes of posterior cerebral artery territory infarction. To determine stroke mechanisms and stroke risk factors in patients with posterior cerebral artery infarction, we studied 23 consecutive patients with recent infarcts in the posterior cerebral artery distribution (PCA infarcts) and compared these with a case-control group of 46 patients with recent infarcts in the middle cerebral artery distribution (MCA infarcts). All patients were similarly studied, including angiography and echocardiography. Case controls were age- and sex-matched and were randomly chosen from the most recent MCA infarcts seen at our institutions. All subjects were white. PCA infarcts had significantly more cardiac-source emboli (P=.01), less evident atherothrombosis (P=.003), multiplicity of infarctions (P=.05), and documented branch occlusions in the vessel involved (P=.05). MCA infarcts had more preinfarction transient ischemic attacks (P=.03) and evident occlusion of the appropriate extracranial vessel (P=.03). Different stroke mechanisms should lead to different diagnostic and therapeutic decisions.