Deafness and Hearing Loss
Diseases

Author: Gianpiero Pescarmona
Date: 12/06/2007

Description

DEFINITION

Deafness is a physical condition characterized by lack of sensitivity to sound.

EPIDEMIOLOGY

age, sex, seasonality, etc

SYMPTOMS

DIAGNOSIS

Audiometric tests
histopathology
radiology
NMR
laboratory tests

PATHOGENESIS

The acoustic nerve is one of the most sensitive perypheral sensory nerves. Therefore any condition leading to a decreased ATP synthesis is associated with a ear functional deficit (hearing loss, tinnitus), well before any other peripheral tissue shows signs of failure.

PATIENT RISK FACTORS

Vascular

Endocrinologia
Screening genetico per diabete e sordità
Più di una mutazione può causare la malattia mitocondriale che determina la sordità e il diabete. I pazienti con forme ereditarie di queste patologie ricevono uno screening di routine per la mutazione m.3243A>G nel DNA mitocondriale, ma il presente studio suggerisce di inviare il paziente ad uno specialista anche in caso di risultati negativi. L'associazione fra questa mutazione e la combinazione diabete-sordità è ben nota, ma numerosi pazienti con questa presentazione non riportano la mutazione. Il meccanismo tramite il quale mutazioni nel genoma mitocondriale causino queste caratteristiche cliniche è complesso, ma semplicisticamente le mutazioni di questo DNA influenzano la capacità delle cellule di produrre ATP, anche se non è noto come mai vengano colpite preferenzialmente le cellule pancreatiche e dei nervi uditivi. E' necessario effettuare diagnosi corrette per evitare complicazioni potenzialmente pericolose che possono sorgere nelle malattie mitocondriali, quali cardiopatie, neuropatie ed epilessia. (Diabetes Care 2007; 30: 2238-9)

J Thromb Haemost. 2005 May;3(5):929-34.
Cardiovascular and thrombophilic risk factors for idiopathic sudden sensorineural hearing loss.

Marcucci R, Alessandrello Liotta A, Cellai AP, Rogolino A, Berloco P, Leprini E, Pagnini P, Abbate R, Prisco D.

Dipartimento del Cuore e dei Vasi, University of Florence, Italy. r.marcucci@dac.unifi.it

BACKGROUND: In recent years there has been a significant increase in the diagnosis of sudden sensorineural hearing loss (SSHL) in western, countries with an incidence of 20 of 100,000 people affected every year. No clear causes for this disease have been found thus far, but cochlear ischemia has been hypothesized in patients in whom an infectious episode or acoustic neurinoma have been excluded. OBJECTIVES: The aim of this case-control study was to investigate a number of acquired and inherited thrombophilic risk factors [antithrombin, protein C and S; factor V (FV) Leiden, FII polymorphism; lupus anticoagulant (LA); anticardiolipin (aCL) antibodies; fasting homocysteine (Hcy); lipoprotein(a) (Lp(a)); plasminogen activator inhibitor-1 (PAI-1)] in addition to cardiovascular risk factors in patients with idiopathic SSHL (ISSHL). PATIENTS AND METHODS: We investigated 155 patients (67 male/88 female; age: 55 (range 19-79 years) with a diagnosis of ISSHL within 30 days from the onset of symptoms, and 155 controls (67 male/88 female; age 54 (range 19-78 years). Fasting Hcy levels were significantly higher in patients than in controls [11.6 (6.7-60) micromol/L vs. 8.7 (5.0-24) micromol/L] as well as PAI-1 levels [19 (2-95) mg/dL vs. 14.5 (4.0-87) mg/dL]. Lupus anticoagulant was present in 13 of 155 (8.4%) patients; 20 patients (12.9%) had positivity of aCL (four IgM and 16 IgG). In no patient was a deficiency of physiological clotting inhibitors antithrombin, protein C and protein S found. No significant differences between patients and controls were observed for Lp(a) plasma levels [111 (1-1146) mg/L vs. 103 (11-695) mg/L] and for the presence of FV Leiden (4.5% vs. 4.5%) and FII variant G20210A (3.8% vs. 3.2%). RESULTS AND CONCLUSIONS: Independent risk factors for ISSHL at the multivariate analysis (adjusted for age, sex and the traditional cardiovascular risk factors) were the positivity of aCL: OR 5.6 (95% CI 2.0-15.3); cholesterol levels within the second and third tertiles (with respect to the first tertile): T2 = OR 4.8 (95% CI 1.9-12.6)/T3 = OR 19 (95% CI 7-50.1); PAI-1 and Hcy levels within the third tertile (with respect to the first tertile): OR 20 (95% CI 7.8-78) and OR 4.0 (95% CI 2.0-8.1), respectively. These preliminary data suggest that hypercholesterolemia, hyperhomocysteinemia, elevated PAI-1 levels and anticardiolipin antibodies are associated with ISSHL, so indirectly supporting the hypothesis of a vascular occlusion in the pathogenesis of the disease.
h4. Genetic

Acquired

Hormonal

Chi perde la memoria sente poco
Anche lievi danni a carico della memoria influenzano negativamente la funzionalità uditiva centrale. Con le disfunzioni uditive centrali, il paziente ha difficoltà a sentire quando sono presenti altri fattori che stressano l'udito. L'interazione fra memoria ed udito sembra permanere anche dopo aver escluso l'effetto interferente di età e status uditivo periferico. Sarebbe dunque opportuno prendere in considerazione l'ipotesi di effettuare test uditivi centrali nella valutazione di soggetti anziani con problemi dell'udito quali parte di un programma omnicomprensivo individualizzato onde assisterli nelle loro necessità sia nella riabilitazione uditiva che nella sfera cognitiva. (Arch Otolaryngol Head Neck Surg 2008; 134: 771-7)

Genetic

Acquired

TISSUE SPECIFIC RISK FACTORS

anatomical (due its structure)

vascular (due to the local circulation)

physiopathological (due to tissue function and activity)

COMPLICATIONS

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