Project description:IntroductionOculopalatal tremor (OPT) is a late manifestation of a Guillain-Mollaret triangle lesion. Memantine has been shown to improve nystagmus in OPT, but its long-term efficacy and putative distinct effects on each plane of nystagmus and on associated phenomena (e.g., gravity perception) are largely unknown.MethodsWe conducted a 6-month open-label study to evaluate the effect of memantine in OPT patients. Baseline (visit 1), 2 (visit 2), and 6 months (visit 3) assessments included video-oculography, best corrected visual acuity (BCVA), visual function questionnaire (VFQ25), palatal tremor frequency, and subjective visual vertical (SVV). Memantine was titrated to 20 mg per day and stopped after 6 months.ResultsWe included six patients (5 females; mean age 68.5+/-9.7). At visit 2, nystagmus improved >50% only along the horizontal plane in two patients, while worsening >50% along the vertical and horizontal planes in 4 and 1 patients, respectively. At visit 3, previous improvement of nystagmus along the horizontal plane in two patients was not sustained, and it further worsened >50% along the vertical plane in 4. The mean vertical velocity and amplitude of nystagmus in the left eye significantly worsened from visit 2 to visit 3 (p = 0.028). Throughout the study, nystagmus frequency remained unchanged (p = 0.074), BCVA improved in both eyes (p = 0.047, p = 0.017), SVV progression was unpredictable (p = 0.513), and the mean VFQ-25 score (p = 0.223) and mean palatal frequency remained unchanged.ConclusionThe long-term use of memantine 20 mg per day in OPT produced a modest and only transient improvement in nystagmus, predominantly along the horizontal plane. Visual acuity improved, albeit without relevant changes in vision-related quality of life.
Project description:Lesions in multiple sclerosis can involve brain, optic nerve and spinal cord. We here report a patient of multiple sclerosis, who had unilateral vertical pendular nystagmus, because of simultaneous involvement of optic nerve and asymmetric brain stem lesions. This specific combination is rarely seen in other disorders, therefore can be considered as a distinctive neuro-opthalmoloical sign of multiple sclerosis.
Project description:In the kidney, a set of proteins expressed in the epithelial cells of the thick ascending loop of Henle and the distal convoluted tubule directly or indirectly play important roles in the regulation of serum magnesium levels. Magnesium reabsorption in the thick ascending loop of Henle occurs through a passive paracellular pathway, while in the distal convoluted tubule, the final magnesium concentration is established through an active transcellular pathway. The players involved in magnesium reabsorption include proteins with diverse functions including tight junction proteins, cation and anion channels, sodium chloride cotransporter, calcium-sensing receptor, epidermal growth factor, cyclin M2, sodium potassium adenosine triphosphatase subunits, transcription factors, a serine protease, and proteins involved in mitochondrial function. Mutations in the genes that encode these proteins impair their function and cause different rare diseases associated with hypomagnesemia, which may lead to muscle cramps, fatigue, epileptic seizures, intellectual disability, cardiac arrhythmias, and chronic kidney disease. The purpose of this review is to describe the clinical and genetic characteristics of these hereditary kidney diseases and the current research findings on the pathophysiological basis of these diseases.
Project description:Here, we report a patient with persistent positional upbeat nystagmus in a straight supine position with no evident abnormal central nervous system findings. A 43-year-old woman with rotatory positional vertigo and nausea visited our clinic 7 days after the onset. Initially, we observed persistent upbeat nystagmus in straight supine position with a latency of 2 s during the supine head roll test. However, an upbeat nystagmus disappeared on turning from straight to the left ear-down supine position, and while turning from the left to right ear-down position, an induced slight torsional nystagmus towards the right for >22 s was observed. In the Dix-Hallpike test, the left head-hanging position provoked torsional nystagmus towards the right for 50 s. In prone seated position, downbeat nystagmus with torsional component towards the left was observed for 45 s. Neurological examination and brain computed tomography revealed no abnormal findings. We speculated that persistent positional upbeat nystagmus in this patient was the result of canalolithiasis of benign paroxysmal positional vertigo of bilateral posterior semicircular canals.
Project description:BackgroundSome individuals present positional end-point nystagmus when the Dix-Hallpike tests are performed on them if they unintentionally look towards the examined ear.ObjectiveTo describe the prevalence and the characteristics of end-point nystagmus during positional testing in healthy subjects.MethodsSixty healthy subjects were included. Eight positional tests were performed on them, two Pagnini-McClure tests and six Dix-Hallpike tests, while keeping the eyes in different positions; one on each side. Two independent observers filled in a questionnaire about the presence of positional nystagmus, its latency, duration, direction, and sense.Results and conclusionsOf the subjects, 65% showed positional end-point nystagmus. This nystagmus had a short latency and last for as long as the head is maintained in the test position. They can show any direction or sense, but the most common are torsional clockwise in left tests and anticlockwise in right tests. Unlike BPPV, this nystagmus did not appear with the eyes in the straight-ahead position, it is asymptomatic, and its intensity does not decline.
Project description:ObjectiveThis study aims to analyze the clinical characteristics of persistent geotropic and apogeotropic positional nystagmus of LC-BPPV in view of light and heavy cupula discussion.Material and methodThe study group includes 184 patients with LC BPPV (98 apogeotropic, 86 geotropic type) who have been examined between 2009 and 2020. Ninety-nine females and 85 males, aged between 16 and 92 years were included (Ageotropic 49.32 ± 14.12, geotropic 44.49 ± 13.90 years). Average slow phase velocity (SPV) of positional nystagmus was documented and those with persistent direction-changing positional nystagmus lasting more than a minute were grouped separately. Age, gender difference, side of involvement, and recurrence pattern were particularly reviewed. Chi-square and One way ANOVA tests were used to compare the difference between groups. Statistical significance was set at P < 0.05.ResultsThirty-seven patients with apogeotropic nystagmus (30.7%; 37/98) and 18 patients with geotropic nystagmus (20.9%; 18/86) had persistent nystagmus (p ˂0.05). Comparison of slow phase velocity (SPV) of persistent and non-persistent geotropic and apogeotropic positional nystagmus of the affected side was significant (p ˂0.05). Comparison of average age, male to female ratio, side of involvement, and the recurrence rate in patients with persistent and non-persistent geotropic and apogeotropic type positional nystagmus groups were not significant (p = 0.177, p = 0.521, p = 0.891, p = 0.702).ConclusionPersistent geotropic and apogeotropic positional nystagmus is mostly correlated with the size, amount, and position of otoconial debris. It is difficult to justify the light cupula as a new geotropic variant of cupular pathology. Patients with persistent positional nystagmus present similar therapeutic outcomes and recurrence rates.
Project description:Benign paroxysmal positional vertigo of the horizontal semicircular canal may present a differential diagnostic challenge. In addition to the classical positional nystagmus, a persistent nystagmus in a seated position occasionally occurs, so-called pseudo-spontaneous nystagmus (PSN), which can be mistaken for a central or peripheral spontaneous nystagmus. We report a case with cupulolithiasis of the horizontal semicircular canal presenting with horizontal PSN in a sitting position, with implications for a new pathomechanism of PSN.
Project description:The maintenance of magnesium (Mg2+) homeostasis is essential for human life. The Cystathionine-β-synthase (CBS)-pair domain divalent metal cation transport mediators (CNNMs) have been described to be involved in maintaining Mg2+ homeostasis. Among these CNNMs, CNNM2 is expressed in the basolateral membrane of the kidney tubules where it is involved in Mg2+ reabsorption. A total of four patients, two of them with a suspected disorder of calcium metabolism, and two patients with a clinical diagnosis of primary tubulopathy were screened for mutations by Next-Generation Sequencing (NGS). We found one novel likely pathogenic variant in the heterozygous state (c.2384C>A; p.(Ser795*)) in the CNNM2 gene in a family with a suspected disorder of calcium metabolism. In this family, hypomagnesemia was indirectly discovered. Moreover, we observed three novel variants of uncertain significance in heterozygous state in the other three patients (c.557G>C; p.(Ser186Thr), c.778A>T; p.(Ile260Phe), and c.1003G>A; p.(Asp335Asn)). Our study shows the utility of Next-Generation Sequencing in unravelling the genetic origin of rare diseases. In clinical practice, serum Mg2+ should be determined in calcium and PTH-related disorders.