1/73. Ipsilateral facial weakness in upper medullary infarction-supranuclear or infranuclear origin? We describe two patients with upper medullary infarctions showing ipsilateral facial weakness and relative sparing of the upper facial muscles. Electrophysiological follow-up using transcranial magnetic stimulation of the motor cortex in combination with stimulation of the peripheral facial nerve disclosed a supranuclear (corticofacial) tract lesion in one patient and a partial nuclear/infranuclear intra-axial facial nerve lesion in another. ( info) |
| Ischemic lesions of the brainstem can lead to complex neurologic deficits. Failure of the automatic control of ventilation (Ondine's curse syndrome) is a possible but rare syndrome following localized brainstem dysfunction. We report on a 49-year-old man with intermittent bradycardia, cranial nerves' dysfunctions and a slight right-sided hemiparesis. An acute brainstem ischemia was diagnosed and treated immediately with high-dose heparin. cerebral angiography revealed a proximal occlusion of the left vertebral artery but a normal right vertebral artery and a hyperplastic right posterior inferior cerebellar artery. Cranial Computed tomography and MRI scan demonstrated multiple ischemic lesions in the posterior circulation. During a 4-week treatment course the patient underwent six episodes of acute severe hypoxia and hypercapnia requiring orotracheal intubation twice and manual ventilation by air mask over a few minutes for four times after a tracheostomy had been performed. Twice a short-term episode of hypothalamic diabetes insipidus was observed following hypoventilation. We conclude that both Ondine's curse syndrome and diabetes insipidus were due to transient vertebrobasilar ischemia. ( info) |
| In a patient with unilateral pharyngeal paralysis, rotation of the head to the paralyzed side can effectively close the hemipharynx on that side. However, the exact level or place of closure is unknown. Serial computed tomography of the pharynx in a patient with lateral medullary syndrome showed that hemipharyngeal closing occurred at the level of the hyoid bone, or the hypopharyngeal cavity above the pyriform sinus, and that the entire space of the bilateral pyriform sinuses remained open despite the head rotation. ( info) |
4/73. Acute brainstem symptoms associated with cervical syringomyelia. syringomyelia classically presents with slowly progressing dissociated sensory and upper and lower motor deficits. Atypical and acute manifestations have rarely been described. We report here on 3 patients with syringomyelia, who had acute and atypical brainstem symptoms with regard to the underlying disease. These symptoms occurred after acute elevation of the intrathoracic and intra-abdominal pressure, respectively, and remitted subsequently. Vertebrobasilar ischemia was initially suspected. ( info) |
5/73. Concomitant post-traumatic craniocervical junction epidural hematoma and pontomedullary junction infarction: clinical, neurophysiologic, and neuroradiologic features. STUDY DESIGN: A case report. OBJECTIVES: To report and discuss a case of post-traumatic epidural hematoma of the craniocervical junction with concomitant brain stem infarction. SUMMARY OF BACKGROUND DATA: Post-traumatic epidural hematoma of the cervical spine and brain stem post-traumatic infarction are very rare disorders. Post-traumatic epidural hematoma is usually located dorsally in the epidural space. methods: The clinical, neuroradiologic, and neurophysiologic findings in one patient with post-traumatic epidural hematoma located ventrally at the cervicomedullary junction and associated with medial infarction at the pontomedullary junction are reported. RESULTS: The main clinical finding in this patient was bilateral corticospinal and corticobulbar tract involvement. A magnetic resonance image showed displacement and flattening of the medulla oblongata and of the most cranial portion of cervical cord, which were caused by the epidural hematoma associated with an ischemic lesion of the pontomedullary junction. Results of central motor conduction studies indicated that the abnormality of the central motor pathways was localized at brain stem level, and that there was normal conduction from the cervicomedullary junction to spinal cord. CONCLUSION: This is the first reported case of spinal epidural hematoma located ventrally in the cervical spine at the cervicomedullary junction level and concomitant infarction at the pontomedullary junction resulting from whiplash injury. ( info) |
6/73. Midbrain ptosis caused by periaqueductal infarct following cardiac catheterization: early detection with diffusion-weighted imaging. Isolated infarcts in the periaqueductal region are rare but have been reported after cardiac catheterization. The authors report a case of dorsal midbrain infarct which caused bilateral ptosis, partial upgaze paresis, and internuclear ophthalmoplegia imaged within eight hours with diffusion-weighted imaging (DWI). The lesion was later confirmed on T2-weighted images. diffusion-weighted imaging can rapidly confirm the diagnosis of this rare brain-stem infarct. ( info) |
7/73. Abnormal vergence with upper brainstem infarcts: pseudoabducens palsy. BACKGROUND: Infarcts of the rostral brainstem often cause vertical gaze palsies but may also produce inappropriate convergence that manifests as pseudoabducens palsy and convergence-retraction nystagmus (CRN). Although the substrate for vergence has been defined in the monkey as lying dorsal and lateral to the oculomotor nucleus, the human homologue is unknown.Method:- The authors reviewed the clinical features, ocular findings, and CT or MR lesions in seven patients with pseudoabducens palsy and "top-of-the-basilar" infarction. They reviewed the literature for infarcts causing pseudoabducens palsy or CRN with precise autopsy localization. The authors then mapped the location of the infarcts on anatomic templates. RESULTS: The smallest MR infarct produced an ipsilateral pseudoabducens palsy and CRN, and was located just rostral to the oculomotor nucleus, near the midbrain-diencephalic junction. Two patients with only contralateral pseudoabducens palsy had both subthalamic and thalamic infarction. Four patients with bilateral pseudoabducens palsy had larger infarcts involving the midbrain. All patients with pseudoabducens palsy had upgaze palsy. Two patients with CRN from the literature had small infarcts near the midbrain-diencephalic junction at autopsy. CONCLUSIONS: Lesions near the midbrain-diencephalic junction are important for the development of pseudoabducens palsy. Pseudoabducens palsy and CRN are probably both manifestations of abnormal vergence activity. Inhibitory descending pathways for convergence may pass through the thalamus and decussate in the subthalamic region. ( info) |
8/73. Bilateral medial medullary infarction. We present a case of bilateral medial medullary infarction demonstrated by magnetic resonance imaging (MRI) and review 12 previously reported cases. We classify these 13 cases (including the present case) into two groups according to the extent of the ischemic region: type 1, the ischemic lesion developed from the medullary pyramid to the medial longitudinal fasciculus; type 2, the lesion was confined to the medullary pyramid.A 71 year old man presented with slight disturbance of consciousness, dysarthria, disturbance of leftward gaze, no gag reflex and tetraparesis. He developed nearly complete horizontal ophthalmoplegia. MRI revealed upper medial medullary infarction bilaterally that extended to the pontomedullary junction. We propose that the prognosis of type 2 bilateral medial medullary infarction is better than that of type 1. Furthermore, the prognosis of bilateral medial medullary infarction itself may be better than previously indicated. ( info) |
9/73. eye deviation in patients with one-and-a-half syndrome. To understand malalignments of the visual axes in one-and-a-half syndrome, we measured eye positions in 4 patients with this syndrome under two conditions: with Frenzel goggles to prevent eye fixation and without Frenzel goggles. When fixation was prevented with the Frenzel goggles, all patients showed mild outward deviation in both eyes. Removal of the Frenzel goggles elicited adduction of the eye ipsilateral to the side of the lesion for fixation, with greater outward deviation of the contralateral eye (acute stage), or adduction of both eyes to midposition for biocular fixation (convalescent stage). In 3 patients whose outward eye deviation with Frenzel goggles was greater on the ipsilateral side, a transition from one-and-a-half syndrome to ipsilateral internuclear ophthalmoplegia was noted, whereas a transition to ipsilateral gaze palsy was seen in the one patient whose deviation was greater on the contralateral side. These findings suggest that in one-and-a-half syndrome patients, the eyes tend to be in divergent positions when fixation is prevented; ipsilateral eye deviation may result from medial longitudinal fasciculus involvement, and contralateral eye deviation may result from paramedian pontine reticular formation involvement. Viewing a target may lead to a secondary deviation or adaptation of eye positions for fixation. ( info) |
10/73. Limb myorhythmia in association with hypertrophy of the inferior olive: report of two cases. We report on 2 patients who uncommonly developed isolated limb myorhythmia in association with inferior olive hypertrophy (IOH) after an acute stroke in the brain stem. A slow tremor presented in the proximal upper limbs predominantly when at rest. It was aggravated by outstretched arms and by active hand movements. The surface electromyogram (EMG) recorded simultaneous activities over the agonist and antagonist muscles with a rate of 3.5 Hz and 2.5 Hz in 2 patients respectively. In the first patient, bilateral limb myorhythmia presented 12 months after the brain stem stroke, and both inferior olives were hypertrophic. In the second patient, unilateral limb myorhythmia developed in the left hand 7 months after right pontine hemorrhage, and only the right inferior olive was hypertrophic. These findings indicate that limb myorhythmia commencing after brain stem insult is anatomically and temporally related to hypertrophy of the contralateral inferior olive. Based on our 2 patients and previously reported cases, we propose that a possible causal relationship exists between limb myorhythmia and contralateral IOH, although its pathophysiological mechanisms remain to be established. We suggest that, similar to palatal myoclonus, isolated limb myorhythmia is within the clinical spectrum of IOH. ( info) |