Documento descargado de http://www.elsevier.es el 19/11/2016. Copia para uso personal, se prohíbe la transmisión de este documento por cualquier medio o formato. Acta Otorrinolaringol Esp 2006; 57: 196-198 LETTER TO THE DIRECTOR Changes on blood filterability in patients with fluctuant hearing loss F.J. García Callejo, C. de Paula Vernetta, E. Sebastián Gil, J. Marco Algarra Servicio de ORL. Hospital Clínico Universitario. Universidad de Valencia. Valencia. Abstract: We conducted a two-year follow-up of thirteen subjects with fluctuating sensorineural hearing loss, measuring their blood filterability (BF) and correlating it to the onset of episodes of deafness. We observed a decrease in the BF levels of all the patients when they experienced hearing loss. When the patients recovered their normal level of hearing, the BF also increased. The use of reactive techniques to avoid these decreases in BF could potentially prevent or correct fluctuating deafness. Key words: Blood filterability. Sensorineural hearing loss. Erythrocytes. Dear Director: Perceptive hearing disorders have in the last decade gone through an interesting advance in their diagnostic orientation thanks to imaging and neurophysiological tests. Recently, knowledge of immune mediated and vasoactive phenomena and their implications for the labyrinth has enabled measurements of peripheral blood to be validated, offering physiopathological reasons for using specific agents and treatment procedures for types of hearing loss traditionally considered irreversible. Among these the symptoms defined within the context of autoimmune inner ear disease and hearing loss developed as a result of blood hyperviscosity stand out. These laboratory tests have been well-studied in cases of sudden deafness in which accessibility to the patient is high, due to the symptoms being rapidly identified and followed-up, as well as in cases of degenerative and slowly progressive hearing loss, such as presbyacusis, where the disorder proves to be relatively predictable and, therefore, monitorable in the patient. Correspondence F. Javier García Callejo C/ Luis Oliag n º 71 – 8 46006 Valencia E-mail: [email protected] Fecha de recepción: 27-9-2005 Fecha de aceptación: 6-3-2006 196 There are symptoms of a less clear etiopathogeny whose chronobiology, being fluctuating, temporary, repetitive, unpredictable and of rapid (if not sudden) onset, disconcerts the specialist. The tonal audiometry evaluation made during an episode of hearing loss is characteristically sensorineural and cochlear. Treatment is often empirical and includes corticotherapy, hemorheotherapy vasodilators and anti-hemostatics, sometimes in combination. This fluctuating sensorineural hearing loss is well defined as perceptive hearing loss, unilateral or bilateral, - the latter kind can be either symmetrical or asymmetrical, - and of relatively short evolution (weeks or months). It is therefore possible to confirm a drop of more than 10 dB HL at two or more consecutive tonal frequencies over a two-month period in which a total or partial recovery takes place, either spontaneously or following treatment. Between January 2001 and June 2005, 13 cases of subjects who sought medical advice for FHL were collected. With prior informed consent, the patients underwent a Western-blot study with bovine antigenic cochlear extract, which did not identify a band in any of the cases. Furthermore, from the start of the study until the end of the follow-up, the level of hearing was monitored using pure-tone audiometry and peripheral blood for the blood filterability capacity. This was repeated every 2 months for 2 years, with every patient consequently receiving thirteen check-ups. The quantification of the degree of hearing loss followed the specifications that conform to current legislation in Spain1. The BF was calculated by measuring the time it took for the volume of a column containing 1 cc of whole anticoagulated blood to pass through 5µ diameter polycarbonate filters at water pressure of 20cc as per the Reid-Dormandy2 model. The range of normality accepts a range of between 16.9 and 24.5 µ l/sec. Figure 1 reflects the variation in the BF parameter throughout the follow-up of the individual. Although the average value in the group was 20.1±1.9 µl/sec, it varied between 14.2 and 23.7 µl/sec. The fact that the BF value was particularly low during the episodes of temporary hearing loss detected in the pure-tone audiometry as compared to the rest of the Documento descargado de http://www.elsevier.es el 19/11/2016. Copia para uso personal, se prohíbe la transmisión de este documento por cualquier medio o formato. PERSISTENCE OF THE TIRAD BRANCHIAL ARCH Figure 1. Recording of the evolution of blood filterability in ml/sec, (y axis), in the 13 measurements taken from each patient over the 2-year follow-up period, (x axis in months), with ♦ indicating the period in which hearing loss or an increase in previously recorded hearing loss was detected. measurements taken in the follow-up of each subject is particularly noteworthy. This group of individuals recorded an average of 1.9±0.7 FHL episodes over the 2-year period of the study, which meant 129.6±52.8 days of hearing alteration per patient. At the start of the study, the level of hearing loss was 8.5±5.6%, with variations of between 0 and 0.9%. At the end of the study the average hearing loss recorded was 11.4±8.2%, there being 4 patients whose hearing improved, one whose hearing did not change, and another 8 who experienced increases in their hearing loss ranging from 8.5 to 67.23% of the initial loss. In the 36 audiometric recordings in which the appearance or worsening of hearing loss was apparent, the BF was 16.6±1.1 µl/sec, while in the rest of the measurements taken (n=133) the BF had a value of 21.1 ±1.1 µl/sec, a difference which proved to be statistically significant (Students t test=22.342: p<0.0001). However, when the 169 BF measurements were correlated with the percentage of hearing loss detected, the resulting straight line equation was y=18857x+48.218. This revealed a non-statistically significant tendency (R2=0.3071) to detect greater hearing losses when low BF values are recorded. The BF measurement copies in vitro the conditions of blood flow in microcirculation. The filtration method used generates a shear force over the blood of between 15 and 30 pascals, a similar value to that produced in vivo in terminal and capillary arteries3. This is a polyfactorial variable as the capacity for erythrocytic deformity, leukocytosis and plasmatic factors such as fibrogen, lipoproteins and immunoglobulins all bear an influence4. Any variation in these parameters is susceptible to reducing the BF and with it the debt that accesses organs without vicarious circulation, such as the labyrinth, which would explain the appearance of a hearing disorder of rapid onset. This drop in BF has previously been recorded in cases of sudden deafness5,6, generally finding a prior trigger that modifies the blood’s viscoelastic conditions, turning it into a thicker liquid. However, the evolution of hearing loss with a drop in BF does not necessarily appear to be acute, as the drop coincided with the appearance of 197 Documento descargado de http://www.elsevier.es el 19/11/2016. Copia para uso personal, se prohíbe la transmisión de este documento por cualquier medio o formato. F. J. GARCÍA CALLEJO ET AL. slowly progressive and definitive hearing loss in physiopathological environments with a recognised limitation over this parameter, such as hypertension, diabetes mellitus or senility7-9. The study of variations in the viscoelastic properties of the blood in episodes of FHL had not previously been documented. These results, although limited by the size of the sample, justify treatment alternatives for this hearing deterioration based on physiological reasons such as the use of vasoactive agents, - pentoxifylline, piracetam, naftidrofuryl, etc. or rheopheresis. 4. 5. 6. 7. References 1. 2. 3. 198 Real Decreto 1971/1999,de 23 de Diciembre,de Procedimiento para el Reconocimiento, Declaración y Calificación del Grado de Minusvalía (BOE de 26 de enero y 13 de marzo de 2000),Anexo 1A, Capítulo 13. Reid HL, Barness AJ, Lock P. A simple method for measuring erythrocyte deformability. J Clin Pathol 1976;29:855-861. Lindmark K, Engstrom KG. Theoretical and experimental aspects of erythrocyte filterability testing: flow acceleration 8. 9. and systemic resistance. J Biomech 2002;35:683-688. Evans SA, Adams R, Nash GB. What do measurements of filterability of blood tell us about the effect of red cell aggregation on flow resistance in small vessels? Biorheology 1999;36:453-455. García Callejo FJ, Martínez Beneyto MP, Platero Zamarreño A, Marco Sanz M, Fernández Julián EN, Marco Algarra J. Estudio no intrevencionista de las alteraciones de la filtrabilidad sanguínea en el debut clínico de sorderas súbitas neurosensoriales. Acta Otorrinolaringol Esp 2001;52:556-564. 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