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Clinical and laboratory‐reconfirmed myasthenia gravis: a population‐based study
Author(s) -
Ööpik M.,
Puksa L.,
Lüüs S.M.,
Kaasik A.E.,
Jakobsen J.
Publication year - 2008
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.2007.02038.x
Subject(s) - medicine , myasthenia gravis , repetitive nerve stimulation , referral , medical record , physical examination , population , weakness , pediatrics , physical therapy , surgery , family medicine , environmental health
The aim of this study was to compare the clinically based prevalence of myasthenia gravis (MG) with the prevalence of laboratory‐confirmed cases. All patients with a diagnosis of MG living in Estonia as on 1 January 1997 were asked to participate in re‐examination. The criteria for laboratory‐supported MG were weakness and rapid fatigue and a positive outcome of at least one of three laboratory tests: (i) blinded acetylcholinesterase inhibitor test; (ii) determination of antibodies to acetylcholine receptor and (iii) neurophysiological examination using repetitive nerve stimulation and single‐fibre EMG. Eighty‐nine patients were re‐examined and 70 patients (79%) fulfilled the criteria of laboratory‐supported MG. The corrected prevalence ratio was 78 per million. In the non‐confirmed MG group, there was more women (92%) than men (43%) whose diagnosis was established within 1 year from onset of symptoms ( P = 0.016). In all women with non‐confirmed MG the diagnosis was established within 1 year from referral to the physician, whereas 68% of women with confirmed MG was diagnosed within 1 year ( P < 0.0001). Thus, we conclude that, in Estonia the prevalence of MG based on medical records seems overestimated by 21% and women are at higher risk of obtaining an uncertain diagnosis of MG.