Myasthenia gravis poses a diagnostic problem for the otolaryngologist: a closer look at symptoms may alert the possibility of myasthenia gravis.

A nine-year retrospective study of the new cases of myasthenia gravis (MG) at Ramathibodi Hospital was done to find the incidence, the symptoms, and the physical signs at initial attendance (IA) and at the time of correct diagnosis (CD). In contrast to previous studies on MG, we found an incidence of only 1.1 patient with MG/year in the department of otolaryngology, representing only 3.3% of the new cases of MG seen at Ramathibodi Hospital. Ninety percent of patients with MG had five or more symptoms at the time of IA but only 30% had positive physical signs at the time of IA. However, all the patients had five or more symptoms at the time of CD and all the patients had five or more physical signs at the time of CD. Seven out of 10 patients were diagnosed as MG late, 8-182 days after the time of IA. The presence of five or more symptoms at the time of IA should have alerted the otolaryngologist to consider MG as a possible diagnosis. This emphasis has yet to be written in the otolaryngological literature.