Isolated trochlear nerve palsy secondary to dural carotid-cavernous sinus fistula.

Ophthalmoplegia associated with dural carotid-cavernous sinus fistula typically involves the third, fourth, and sixth cranial nerves. Occasionally, isolated palsy of the oculomotor or abducens nerve is noted. We report a patient with bilateral dural carotid-cavernous sinus fistulas who presented with an isolated trochlear nerve palsy.

New insights into pathophysiology of vestibular migraine.

Vestibular migraine (VM) is a common disorder in which genetic, epigenetic, and environmental factors probably contribute to its development. The pathophysiology of VM is unknown; nevertheless in the last few years, several studies are contributing to understand the neurophysiological pathways involved in VM. The current hypotheses are mostly based on the knowledge of migraine itself. The evidence of trigeminal innervation of the labyrinth vessels and the localization of vasoactive neuropeptides in the perivascular afferent terminals of these trigeminal fibers support the involvement of the trigemino-vascular system. The neurogenic inflammation triggered by activation of the trigeminal-vestibulocochlear reflex, with the subsequent inner ear plasma protein extravasation and the release of inflammatory mediators, can contribute to a sustained activation and sensitization of the trigeminal primary afferent neurons explaining VM symptoms. The reciprocal connections between brainstem vestibular nuclei and the structures that modulate trigeminal nociceptive inputs (rostral ventromedial medulla, ventrolateral periaqueductal gray, locus coeruleus, and nucleus raphe magnus) are critical to understand the pathophysiology of VM. Although cortical spreading depression can affect cortical areas involved in processing vestibular information, functional neuroimaging techniques suggest a dysmodulation in the multimodal sensory integration and processing of vestibular and nociceptive information, resulting from a vestibulo-thalamo-cortical dysfunction, as the pathogenic mechanism underlying VM. The elevated prevalence of VM suggests that multiple functional variants may confer a genetic susceptibility leading to a dysregulation of excitatory-inhibitory balance in brain structures involved in the processing of sensory information, vestibular inputs, and pain. The interactions among several functional and structural neural networks could explain the pathogenic mechanisms of VM.

Gamma Knife radiosurgery in benign skull base tumors after planned subtotal resection: preliminary results in combined approaches

Aim: The management of large lesions of the skull base, such as vestibular schwanommas (VS), meningiomas (MEN) or pituitary adenomas (PA), is challenging, with microsurgery remaining the main treatment option. Planned subtotal resection is now being increasingly considered to reduce the risk of neurological deficits following complete resection. The residual part of the tumor can then be treated with Gamma Knife Radiosurgery (GKR) to achieve long-term growth control. Methods: This case series documents early results with planned subtotal resection followed by GKR in Lausanne University Hospital, between July 2010 and March 2012. There were 24 patients who underwent surgery, with 22 having already undergone GKR and 2 waiting for GKR. We analyzed clinical symptoms for all patients, as well as audiograms, ophthalmological and endocrinological tests, when indicated. Results: Nine patients had VS surgery (mean diameter 35 mm; range 30-44.5) through a retrosigmoid approach. There were no post-operative facial nerve deficits. Of the 3 patients whom had useful hearing pre-operatively, this improved in 2 and remained stable in 1. Four patients with clinoid MEN (mean diameter 26.5 mm; range 17-42) underwent subtotal resection of the tumor, and the component in the cavernous sinus was later treated with GKR. The visual status remained stable in 3 patients and one had complete visual recovery. 4 patients underwent subtotal resection of petro-clival MEN (mean diameter 36 mm; range 32-42): 3 had House-Brackmann (HB) grade 2 facial function that recovered completely; one continues to have HB grade 4 facial deficit following surgery. Of the 7 patients with PA (mean diameter 34.5 mm; range 20-54.5), 2 had acromegaly, the others were non functional PA. Six patients underwent trans-sphenoidal surgery, while one patient had a transcavernous sinus resection of the tumor (with prior staged trans-sphenoidal surgery). Visual status improved in 3 patients while the others remained stable. Two patients had transient diabetes insipidus following surgery. Up to now, no additional deficit or worsening has been reported after GKR. Conclusions: Our data suggest that planned subtotal resection has an excellent clinical outcome with respect to preservation of cranial nerves, and other neurological functions, and a good possibility of recovery of many of the pre-operative cranial nerve dysfunctions. The results in terms of tumor control following GKR need further long-term evaluation.

Le traitement chirurgical de la paralysie faciale définitive [Surgical facial reanimation after persisting facial paralysis].

Facial reanimation following persistent facial paralysis can be managed with surgical procedures of varying complexity. The choice of the technique is mainly determined by the cause of facial paralysis, the age and desires of the patient. The techniques most commonly used are the nerve grafts (VII-VII, XII-VII, cross facial graft), dynamic muscle transfers (temporal myoplasty, free muscle transfert) and static suspensions. An intensive rehabilitation through specific exercises after all procedures is essential to archieve good results.

Isolated IVth (trochlear) nerve palsy due to basilar artery dolichoectasia.

BACKGROUND: Dolichoectasia (elongation, dilatation and tortuosity) of the basilar artery can cause an isolated cranial neuropathy. The trigeminal nerve and facial nerve are most frequently affected. Dysfunction of one of the ocular motor cranial nerves due to basilar artery dolichoectasia is uncommon, and an isolated IVth (trochlear) nerve palsy has not been previously described in the literature. HISTORY AND SIGNS: Two men, ages 70 and 59 years, respectively, presented with vertical diplopia due to a IVth nerve palsy. In one patient, the onset of the IVth nerve palsy was painless and gradual and in the other patient, the onset was acute and associated with periorbital pain. Neuroimaging in both patients revealed pathological tortuosity of the basilar artery around the midbrain and displacement of the artery toward the side of the affected trochlear nerve. THERAPY AND OUTCOME: The patients were observed clinically. One patient had gradual worsening of his palsy for three and one-half years then suffered a stroke. The second patient whose IVth nerve palsy had an acute onset experienced spontaneous resolution of his palsy but later developed dysfunction of other cranial nerves. CONCLUSIONS: Basilar artery dolichoectasia should be considered in the differential diagnosis of an isolated IVth nerve palsy. The clinical course may be variable, and the prognosis is not always benign.

Combined approaches in large vestibular schwannomas: surgical and radiosurgical perspective

Purpose: The management of vestibular schwanommas (VS) is challenging, with microsurgery remaining the main treatment option. Planned subtotal resection is now being increasingly considered to reduce the risk of neurological deficits following complete resection. The residual part of the tumor can then be treated with Gamma Knife surgery (GKS) to achieve long-term growth control. Methods: This case series of 11 patients documents early results with planned subtotal resection followed by GKS in Lausanne University Hospital, between July 2010 and March 2012. We analyzed clinical symptoms and signs for all cases, as well as MRI and audiograms. Results: Mean age in this series was 50.3 years (range 24.1-73.4). Two patients (18.2%) had a stereotactic fractionated radiotherapy, which had failed to ensure tumor control, before the microsurgical intervention. The lesions were solid in 9 cases (81.8%), and mixed (solid and cystic) in 2 patients (18.2%). Presurgical tumor volume was of a mean of 18.5 cm3 (range 9.7-34.9 cm3). The mean duration between microsurgery and GKS was 10.5 months (range 4-22.8). The mean tumor volume at the time of GKS treatment was 4.9 cm3 (range 0.5- 12.8). A mean number of 20.7 isocenters was used (range 8-31). Nine patients received 12 Gy and 2 patients with 11 Gy at the periphery (at the 50% prescription isodose). We did not have any major complications in our series. Postoperative status showed no facial nerve deficits. Four patients with useful pre-operative hearing underwent surgery aiming to preserve the cochlear nerve function. Of these patients, the patient who had Gardner-Robertson (GR) class 1 before surgery, remained in GR class 1. Two patients improved after surgery, one changing from GR 5 to GR 3 and the other with slight improvement, remaining in the same GR 3 class. Mean follow-up after surgery was 15.4 months (range 4-31.2). One patient, who presented with secondary trigeminal neuralgia before surgery, had transitory facial hypoesthesia following surgery. No other neurological deficits were encountered. Following GKS, the patients had a mean follow-up of 5.33 months (range 1-13). No new neurological deficits were encountered. Conclusions: Our data suggest that planned subtotal resection followed by GKS has an excellent clinical outcome with respect to preservation of cranial nerves, and other neurological functions, and a good possibility of recovery of many of the pre-operative cranial nerve dysfunctions

TLR3 deficiency in patients with herpes simplex encephalitis.

Some Toll and Toll-like receptors (TLRs) provide immunity to experimental infections in animal models, but their contribution to host defense in natural ecosystems is unknown. We report a dominant-negative TLR3 allele in otherwise healthy children with herpes simplex virus 1 (HSV-1) encephalitis. TLR3 is expressed in the central nervous system (CNS), where it is required to control HSV-1, which spreads from the epithelium to the CNS via cranial nerves. TLR3 is also expressed in epithelial and dendritic cells, which apparently use TLR3-independent pathways to prevent further dissemination of HSV-1 and to provide resistance to other pathogens in TLR3-deficient patients. Human TLR3 appears to be redundant in host defense to most microbes but is vital for natural immunity to HSV-1 in the CNS, which suggests that neurotropic viruses have contributed to the evolutionary maintenance of TLR3.

Modern Gamma Knife radiosurgery of vestibular schwannomas: treatment concept, volumetric tumor response, and functional results.

The objective of the present study was longitudinal evaluation of the volumetric tumor response and functional results after Gamma Knife radiosurgery of vestibular schwannomas, performed according to the modern standards of treatment. From October 2003 to September 2007, 133 consecutive patients with vestibular schwannomas were treated according to the concept of robotic Gamma Knife microradiosurgery, which is based on precise irradiation of the lesion, sparing adjacent structures, and delivery of the high radiation energy to the target. Multiple small-sized isocenters located within the border of the neoplasm were applied. The mean marginal dose was 11.5 Gy (range, 11-12 Gy). In total, 126 cases with a minimum posttreatment follow-up of 2 years (range, 2-7 years; median, 4 years) were analyzed. Temporary enlargement was noted in 25 % of tumors at 6 months after radiosurgery. At 3 years of follow-up, tumor shrinkage, stabilization, and increase in volume were marked in 73 %, 23 %, and 4 % of cases, respectively. All progressing lesions spontaneously stabilized later on and did not require additional management. In 3 % of patients, transitory impairment of the facial nerve function was marked; however, neither its permanent dysfunction nor trigeminal neuropathy attributed to radiosurgery was noted. Impairment of hearing compared to its pretreatment level was revealed in 4 %, 12 %, 13 %, and 16 % of patients at 6 months, 1 year, 2 years, and 3 years after radiosurgery, respectively, and this trend was statistically significant (P = 0.0042). Overall, 77 % of patients with serviceable hearing before treatment preserved it 3 years thereafter. In conclusion, modern Gamma Knife radiosurgery provides effective and safe management of vestibular schwannomas. Nevertheless, possible temporary tumor enlargement, delay of its growth arrest, transient dysfunction of the cranial nerves, and gradual deterioration of hearing after irradiation should be always taken into consideration.

Oral implant rehabilitation in a patient with Moebius syndrome

Introduction: Moebius syndrome is a rare congenital disorder characterized by unilateral or bilateral involvement of the sixth and seventh cranial nerves, resulting in a lack of facial expression and eye movements. These patients suffer a series of oral manifestations that may complicate their dental treatment, such as facial and tongue muscle weakness, uncontrolled salivation secondary to defi cient lip sealing, micrognathia, microstomia, bifi d uvula, gothic and fi ssured palate, fi ssured tongue, and glossoptosis. The underlying etiology remains unclear, though vascular problems during embryogenesis appear to be involved. Clinical case: We report the case of a woman with Moebius syndrome and total edentulism. Eight years ago she underwent complete oral rehabilitation with the placement of two implants in each dental arch. Discussion: Moebius syndrome has still an unknown etiology, although it is related to disorders during pregnancy. This kind of patient can be rehabilitated using oral implants.

Cavernous sinus syndrome due to rhino-orbital-cerebral mucormycosis

The present report describes the case of a 43-year-old diabetic patient with facial pain, protruding eyes, nasal congestion and decreased right vision (involvement of the ipsilateral cranial nerves III, IV and V). Computed tomography showed diffuse sinusitis at right, cribriform plate erosion and presence of a hypodense collection in the frontal lobe with peripheral enhancement. Magnetic resonance imaging confirmed the presence of a cerebral abscess. Samples were collected from the lesion, confirming hyphae compatible with mucormycosis.

Facial paralysis and vestibular syndrome in feedlot cattle in Argentina

This paper reports 6 outbreaks of neurological disease associated with paralysis of the facial and vestibulocochlear nerves caused by intracranial space occupying lesions in feedlot cattle. The clinical signs observed were characterized by head tilt, uni or bilateral drooping and paralysis of the ears, eyelid ptosis, keratoconjunctivitis, and different degrees of ataxia. Morbidity and mortality rates ranged from 1.1 to 50% and 0 to 1%, respectively. Gross lesions observed included yellow, thickened leptomeninges, and marked enlargement of the roots of cranial nerves VII (facial) and VIII (vestibulocochlear). Histopathologically, there was severe, chronic, granulomatous meningitis and, in one case, chronic, granulomatous neuritis of the VII and VIII cranial nerves. Attempts to identify bacterial, viral, or parasitic agents were unsuccessful. Based on the morphologic lesions, the clinical condition was diagnosed as facial paralysis and vestibular syndrome associated with space occupying lesions in the meninges and the cranial nerves VII and VIII. Feedlot is a practice of growing diffusion in our country and this is a first report of outbreaks of facial paralysis and vestibular disease associated with space occupying lesions in Argentina.

Differentiation of autonomic reflex control begins with cellular mechanisms at the first synapse within the nucleus tractus solitarius

Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central integration of these autonomic pathways. The visceral afferent synapse is uncommonly powerful at the NTS with large unitary response amplitudes and depression rather than facilitation at moderate to high frequencies of activation. Substantial signal depression occurs through multiple mechanisms at this very first brainstem synapse onto second order NTS neurons. This review highlights new approaches to the study of these basic processes featuring patch clamp recordings in NTS brain slices and optical techniques with fluorescent tracers. The vanilloid receptor agonist, capsaicin, distinguishes two classes of second order neurons (capsaicin sensitive or capsaicin resistant) that appear to reflect unmyelinated and myelinated afferent pathways. The differences in cellular properties of these two classes of NTS neurons indicate clear functional differentiation at both the pre- and postsynaptic portions of these first synapses. By virtue of their position at the earliest stage of these pathways, such mechanistic differences probably impart important differentiation in the performance over the entire reflex pathways.

Control of respiration in fish, amphibians and reptiles

Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate the air-breathing organ in air-breathing fishes. Some reptiles retain a buccal force pump for use during hypoxia or exercise. All vertebrates have respiratory rhythm generators (RRG) located in the brainstem. In cyclostomes and possibly jawed fishes, this may comprise elements of the trigeminal nucleus, though in the latter group RRG neurons have been located in the reticular formation. In air-breathing fishes and amphibians, there may be separate RRG for gill and lung ventilation. There is some evidence for multiple RRG in reptiles. Both amphibians and reptiles show episodic breathing patterns that may be centrally generated, though they do respond to changes in oxygen supply. Fish and larval amphibians have chemoreceptors sensitive to oxygen partial pressure located on the gills. Hypoxia induces increased ventilation and a reflex bradycardia and may trigger aquatic surface respiration or air-breathing, though these latter activities also respond to behavioural cues. Adult amphibians and reptiles have peripheral chemoreceptors located on the carotid arteries and central chemoreceptors sensitive to blood carbon dioxide levels. Lung perfusion may be regulated by cardiac shunting and lung ventilation stimulates lung stretch receptors.

Examen neurológico

Se realizó un capítulo sobre la descripción del examen neurológico como herramienta principal en el abordaje del paciente con patología neurológica.

Guttural Pouch Diseases Causing Neurologic Dysfunction in the Horse

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)