Otoneurological Aspects in Cerebellar Tonsils Extension and Conservative

Otoneurological Aspects in Cerebellar Tonsils' Extension and Conservative Management 23387 Diāna Raumane, MD, Ph. D Pauls Stradiņš Clinical University Hospital, Department of Otorhinolaryngology, Latvia Rīga Stradiņš University, Department of Otorhinolaryngology, Latvia The extension of the cerebellar tonsils into the foramen magnum in the 5 mm and more are known as a Chiari Malformation (CM) type I referring the flow of spinal fluid, the only form of CM presenting in adult life. The compression that is sufficient to cause symptoms can occur even when the cerebellar tonsils protrude by as little as 1 mm or are located in the level of the foramen magnum (Fig. 1). Cerebellar tonsil herniation less than 5 mm (Fig. 2) is found more common 1. Patients frequently are misdiagnosed because they complain about dizziness, vertigo attacks, nausea, pressure like headaches, tinnitus, hearing disturbances, mimicking Meniere disease or migraine 2. Recent evidence suggests an extensive exchange of fluid and solutes between the subarachnoid space and the brain interstitium, involving preferential pathways along blood vessels. Possible routes for bulk fluid drainage, based on the apparently experimental data of the anatomical base for proposed transport channels, among others are related to surrounding leptomeningeal and parenchymal blood vessels 5. The cerebrospinal fluid (CSF) compartment, consisting of the subarachnoid space, cisterns, ventricles, and perivascular spaces, forms a continuous and extensive network that surrounds and penetrates the brain, in which mixing may facilitate exchange between interstitial fluid (ISF) and CSF. Also, the ICF pressure is affected by the heartbeat and respiration 4. Fig. 1. Midsagittal T 1 weighted MRI image demonstrates normal anatomy. Reduction of severity of the symptoms improved significantly in 65% of subjects (R=0. 3009, p<0. 01) in 2 weeks, notably improvement of symptoms after 8 weeks in 81 % of subjects (R=0. 2845, p<0, 01), but during a year remarkable reduction of symptoms had reported 96% of subjects (R=0, 3178, p<0, 01). Analyzing ROC, was concluded that after receiving medication symptom relieve in 81 % of subjects after eight weeks was at 61 % sensitivity and 91% specificity, square below curve AUC=0. 80 (p<0, 001) (left fig. ); and after a year in 96% of subjects symptom relieve was at 88% sensitivity and 73%specificity, square below curve AUC=0, 81 (p<0, 001) (right fig. ). Fig. 2. Midsagittal T 1 weighted MRI image shows herniation of the cerebellar tonsil 3 mm below the foramen magnum. The aims of the study are to characterize the symptom complex at the extension of the cerebellar tonsils less than 5 mm presenting with symptoms, to analyse the reduction of symptom severity in correlation with significance of conservative treatment outcomes. 24 asymptomatic CM 1 subjects (20 females, 4 males, mean age 42 ± 12) and 128 (122 females, 6 males, mean age 48 ± 12) adult subjects have been selected presenting with symptoms and extension of cerebellar tonsils to 5 mm. In symptomatic subjects MR images showed extension of the cerebellar tonsils less than 5 mm, in 75% less than 2 mm, in 25 % around the level of foramen magnum, dilated cerebral fissures. Symptomatic subjects suffer from 5 and more symptoms: vertigo and dizziness in 98%, headaches are present in 96%, pressure in the eyes and forehead in 89%, 100%, sensitivity to the sounds or sensoneural hearing loss (SHL) in 78%, visual disturbances 68%, chronic nausea in 32%, poor memory and concentration in 78%. Subjective symptoms were identified and evaluated during conservative pharmacological treatment in a second week from the beginning of medication, in eight weeks, 12 months. In symptomatic subjects pure tone audiometry showed mild to medium uni/bilateral (SHL)I n 78%; videonystagmoraphy tests: delayed saccades and pursuit in 98%, gaze nystagmus in 88%. Ultrasound duplex scans of the brachiocephalic vessels show venue flow reduction in 98%. Pharmaceutical agents that promote ICF transport, enhance capillary stability and normalizing their permeability, was adjusted: Oral intake of Troxerutin 300 mg 3 times a day for at least 8 weeks to year and Acetazolamidum 250 mg per day in the first 5 days of the treatment and again at the moment of appearance of vertigo or headache synmptoms. Discussion. To the response of the suggestion that part of the CSF is recirculate along perivascular routes along arteries into the brain, where it mixes with brain interstitial fluid and leaves the brain along veins pharmacological treatment was based 3. Moreover, the findings of presence of venous flow disturbances were associated with ICF increased pressure symptoms. Therefore expected relieve of symptoms was significant in the result of medication by decreasing trophic disturbances and other ICP consequence of tension type headache with paroxysmal increase in association with increasing dizziness, tinnitus, hearing disturbances were considerably relieving headache and other subjective symptoms were expected to relieve. The later appearance of symptoms is related to secondary increased ICP and initial cerebellar tonsil extension. The anatomical relations between brain vasculature, cerebrospinal fluid compartments, and perivascular spaces observed in symptomatic subjects could explain improvement of symptoms by conservative treatment. The course of mild symptomatic and asymptomatic CM-1 in adults is relatively possible to manage conservatively 6. Conservative treatment shows efficiency reducing the benign intracranial hypertension conservatively to relieve the symptoms. It is reasonable to observe a patient with mild or asymptomatic symptoms even in the presence of significant tonsils’ descent. Remains question about the duration of the medication and long term efficacy. This could be extremely important to avoid the development of processes that deteriorate processes referred to as the glymphatic pathway, clearance of the brain toxic substances such as amyloid β. References. 1. Iliff JJ, Wang M, Liao Y, et al. A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid beta. Sci Transl Med 2012; 4: 147 ra 11. 2. Bedussi B, van der Wel N, de Vos J, van Veen H, Siebes M, Van. Bavel E, Bakker E NTP. Paravascular channels, cisterns, and the subarachnoid space in the rat brain: A single compartment with preferential pathways. J Cereb Blood Flow Metab. 2017 Apr; 37(4): 1374– 1385. 3. Hladky SB, Barrand MA. Mechanisms of fluid movement into, through and out of the brain: evaluation of the evidence. Fluids Barriers CNS 2014; 11: 26. 4. Langridge B, Phillips E, Choi D. Chiari Malformation Type 1: A Systematic Review of Natural History and Conservative Management. World Neurosurg. 2017 Aug; 104: 213219.