Vascular Risk Factors in the Aetiology of Idiopathic Sudden Sensorineural Hearing Loss in Young Adults.

Abstract

Objective:To investigate the frequency of vascular risk factors in unilateral idiopathic sudden sensorineural hearing loss (ISSHL) in young adults.Materials and Methods:Twenty patients aged 18-50 years when suffering a unilateral ISSHL and 20 age and sex matched controls were examined with contrast-enhanced transcranial doppler to identify venous to arterial circulation shunts (v-aCS), flow mediated dilation of the brachial artery to identify endothelial dysfunction and blood tests for a thrombophilia screen, full blood count, fasting plasma lipids, p-selectin and soluble glycoprotein V.Results:There were no significant differences between cases and controls for any of the investigations performed. There was no difference at all between the larger ("significant" or "major") v-aCS and ISSHL (25% vs 25%). There was a limited association for "small" v-aCS with ISSHL (35% vs 25%; p=0.77); between the presence of v-aCS and severity of hearing loss (no v-aCS 49.0+/- 26 dBHL vs v-aCS 73.4 +/- 34dBHL, p=0.11); for endothelial dysfunction with ISSHL (5.9 +/- 3.2% vs 7.2 +/- 3.2%; p=0.32); and for platelet hypereactivity with ISSHL (glycoprotein V: 67.0+/-22.3ng/ml vs 64.2+/-21.5ng/ml, p=0.605; p-selectin: 81.7+/-40.2ng/ml vs 75.8+/-45.6ng/ml, p=0.590). Only 1 case had an inherited thrombophilia compared with 2 controls. No cases had positive antiphospholipid antibodies. High fibrinogen levels were more prevalent in cases: two cases and one control had hyperfibrinogenaemia with a further 5 cases and 4 controls in the upper quartile range. Hyperlipidaemia was more prevalent in controls.Conclusions:Paradoxical embolism and venous thrombosis are unlikely to be important causes of unilateral ISSHL in young adults. Mildly raised cardiovascular arterial risk factors such as endothelial dysfunction, hyperfibrinogenaemia and p-selectin suggest a possible vascular dysfunction in these patients that may warrant further study. The cause of ISSHL remains a mystery.

Date of Award	1 Aug 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Charles Mccollum (Supervisor) & Shakeel Saeed (Supervisor)