Dissection of the posterior inferior cerebellar artery in a young adult with cerebellar infarct.

The posterior inferior cerebellar artery (PICA) is frequently involved in dissection of the vertebral artery (VA); however, isolated PICA dissection has rarely been reported. A 37-year-old man experienced acute and progressive drowsiness, vertigo, occipital headache, vomiting, and ataxia. There was no precedent trauma or chiropractic manipulation. Neurologically, he had dysmetria of the left extremities. His NIHSS score was 3. Brain magnetic resonance imaging showed an acute cerebellar infarct in the left PICA territory. Magnetic resonance angiography showed a faint signal adjacent to the junction of the left VA and PICA, suggesting a vascular shadow. Catheter angiography showed focal stenosis with a post-stenotic fusiform aneurysmal dilatation of the left proximal PICA that was highly suggestive of dissection with pseudoaneurysm formation. He was treated with clopidogrel and was free of neurological symptoms 3 months after the stroke event. Isolated PICA dissection may be considered in patients with PICA territory infarct or subarachnoid hemorrhage. Treatment depends on the manifestations; ruptured dissecting aneurysms are often treated with surgery or embolization, and infarcts are usually treated with antithrombotic agents.

Chiropractic manipulation: reasons for concern?

Chiropractic's popularity is rising among the general population. Moreover, few studies have been conducted to properly evaluate its safety. We report three cases of serious neurological adverse events in patients treated with chiropractic manipulation. The first case is a 41 years old woman who developed a vertebro-basilar stroke 48 h after cervical manipulation. The second case represents a 68 years old woman who presented a neuropraxic injury of both radial nerves after three sessions of spinal manipulation. The last case is a 34 years old man who developed a cervical epidural haematoma after a chiropractic treatment for neck pain. In all three cases there were criteria to consider a causality relation between the neurological adverse events and the chiropractic manipulation. The described serious adverse events promptly recommend the implementation of a risk alert system.

Neurophysiological monitoring of brainstem function in a patient with Wallenberg syndrome, using Vestibular Evoked Myogenic Potentials.

PURPOSE: We evaluated the use of Vestibular Evoked Myogenic Potentials (VEMPs) in the assessment of neural function, following medullary lesions. METHODS: A 54-year-old male presented with symptoms and signs typical of right lateral medullary (Wallenberg) syndrome. He underwent brain MRI and three successive neurophysiological investigations, which included VEMPs, Brainstem Auditory Evoked Responses (BAERs) and the blink reflex. RESULTS: VEMPs amplitude on the left (unaffected) side was 256.8 microv in the first investigation and remained approximately equal to that value in the following two ones. Their amplitude on the right (affected) side was 37.9 microv, 154.2 microv and 235.2 microv correspondingly. At the same time vertigo, diplopia and nystagmus gradually improved. Right blink reflex comprised a normal R1, but delayed R2 ipsilateral and R2 contralateral responses, which remained unaltered during the follow-up period. Brain MRI disclosed a right dorsolateral medullary infarct. CONCLUSIONS: VEMPs amplitude progressively increased, parallel to the improvement of vestibular symptoms. The blink reflex evolved differently, while BAERs were not affected. As the three evoked responses are mediated by separate neural circuits, they provide information on different aspects of brainstem function. Thus, VEMPs seem to be a useful method that complements existing ones in the assessment of brainstem lesions.

[Wallenberg's syndrome secondary to dissection of the vertebral artery caused by chiropractic manipulation]. / Sindrome de Wallemberg secundario a disección de la arteria vertebral por manipulación quiropráctica.

INTRODUCTION: Chiropractic manipulations of the cervical region are techniques that are used more and more frequently to treat a number of osteomuscular pathologies, but can give rise to important complications, such as the dissection of the cervical arteries. Dissection of the vertebral artery generally presents as alternating syndromes, of which Wallenberg s syndrome, either complete or incomplete, is the most frequent. In this paper we review the literature published to date on the pathogenesis, risk factors, clinical features, chronopathology, diagnosis, treatment and prognosis of this complication. CASE REPORT: We describe the case of a young patient who suffered from incomplete Wallenberg s syndrome a few hours after a single session of cervical chiropractic manipulation, and we also show the resonance images that were used to support the diagnosis. CONCLUSIONS: The appearance of a pain in the neck and neurological symptoms in a patient who has undergone chiropractic manipulation in the last few hours or days must lead us to consider a possible dissection of the cervical arteries. Dissection of the vertebral artery usually gives rise to alternating syndromes, the most frequent of which is lateral bulbomedullary infarction or Wallenberg s syndrome due to proximal occlusion of the posteroinferior cerebellar artery. Magnetic resonance angiography of the supra aortic trunks and cranial magnetic resonance scanning are valid techniques for demonstrating the dissection of the artery and the associated ischemic lesion.

[Click-evoked myogenic potential as a new diagnostic tool for the vestibular disorders].

In accordance with Colebatch's method, click-evoked myogenic potential(VEMP: vestibular evoked myogenic potential) was studied to evaluate 11 healthy subjects and 24 patients with peripheral and central vestibular disorders such as sensorineural hearing loss, peripheral vestibular disorder, endolymphatic hydrops(Meniere disease), cerebellopontine (CP) angle tumor, and Wallenberg's syndrome. Surface electromyograms(EMG) were recorded from both sides of the sternocleidomastoid muscles, with a reference over the jugular notch. The EMG were averaged from 500 responses to 135 dB SPL, 3 c/s(0.1 ms) through one side of a headphone, with 115 dB masking noise in the other side. The average potentials were collected at 20 ms before the clicks to 80 ms afterwards. All healthy subjects showed typical biphasic complex responses(P 13-N 23-N 34-P 44) bilaterally by unilateral stimulation, predominantly on the ipsilateral side. The average latencies were as follows: P 13(13.3 ms +/- 2.1 SD); N 23(22.2 ms +/- 2.7 SD); N 34(32.2 ms +/- 3.1 SD); and P 44(43.6 ms +/- 3.1 SD). The average P 13-N 23 peak amplitude was 20.4 +/- 3.3 microV. In 5 cases of sensorineural hearing loss, in which pure tone audiograms showed thresholds higher than 80 dB, latencies of VEMP were within normal limits of the deaf side. In contrast, VEMP could not be evoked in the affected side in 4 patients with peripheral vestibular disorders or patients with 7 cerebello-pontine angle tumors. In 4 patients with endolymphatic hydrops, latencies of VEMP were within normal limits on the affected side. The P 13-N 23 peak amplitude, however, was remarkably enlarged after 500 ml of glycerol drip infusion(glycerol test). In 2 patients with Wallenberg's syndrome, the latency of P 13 was prolonged on the affected side. Thus, it is concluded that the present study would provide additional information about the vestibular function, especially the otolith function, and clinical usefulness of detecting both central and peripheral vestibular disorders.

Wallenberg's syndrome following neck manipulation.

We describe 4 patients ages 28 to 41 with lateral medullary infarction (Wallenberg's syndrome) following chiropractic neck manipulation. In 3 patients, angiography documented dissection of the extracranial 3rd segment of the vertebral artery near the atlantoaxial joint. The onset of neurologic symptoms following manipulation varied from immediate to 4 days. All had good recovery with minor residual deficits. Although the association between chiropractic neck manipulation and vertebral-basilar artery distribution infarction is well known, we emphasize its occurrence in young healthy individuals without commonly regarded predisposing factors.