[False negatives in the diagnosis of myasthenia gravis].

INTRODUCTION

Myasthenia gravis is an uncommon disorder with very variable clinical findings. This often leads to errors in diagnosis.

OBJECTIVE

To study the main errors leading to false negatives in the diagnosis of myasthenia gravis.

PATIENTS AND METHODS

We carried out a questionnaire to determine all the doctors and diagnoses made by them in relation to symptoms of myasthenia graves in 109 patients in whom this diagnosis was later confirmed when a specialist was consulted.

RESULTS

Most of the patients went to a general practitioner first. During this initial consultation the disease was only diagnosed in 10 cases (9.2%) and neurosis was the most frequent diagnosis (27.5%). Although most patients had to see from two to four doctors before diagnosis was made, there was no major delay in this. In 84 of the 109 cases the diagnosis was established within the first six months, generally by a neurologist (86.2%) and less frequently by a general physician (11.0%).

CONCLUSION

General practitioners, ophthalmologists, psychiatrists and otorhinolaryngologists are often involved in the evaluation of these cases although they made little contribution to the diagnosis.