Evaluation of maximal respiratory pressures in myasthenia gravis. Prognostic value.
We assess the prognosis of mild forms of myasthenia gravis (MG) by maximal respiratory pressures (MRP) and single fiber electromyography (SFEMG). Fifty MG patients (12 form I, 21 form IIa and 17 form IIb) are valued by MRP [maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP)] and SFEMG, and are followed-up clinically. We have found in form I patients developing form IIa and form IIa worsening to form IIb, MEP and MIP mean relative values significantly lower than the rest. Inversely, IIb form patients improving to IIa form display MIP mean relative values higher than the rest; no difference appears with MEP. A reduction under 50% of fifth-percentile implies clinical deterioration in forms I and IIa, while its surpassing in IIb form suggests a tendency to improvement. No evident differences are found by SFEMG. MRP allow the follow-up of MG patients and could warn us of a clinical prognosis.
Muñoz  Fernández
Carmen
C
Department of Neurology, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain. cumunfer@gobiernodecanarias.org
Díez Tejedor
Exuperio
E
Frank Garcia
Ana
A
Pino
Jose María
JM
Pérez Conde
Concepción
C
Barreiro Tella
Pablo
P
D004576:Electromyography / Q000379:methods; D006801:Humans; D008451:Maximal Voluntary Ventilation / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009157:Myasthenia Gravis / Q000145:classification / Q000503:physiopathology*; D011312:Pressure; D012119:Respiration; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000294:innervation / Q000503:physiopathology*; D012720:Severity of Illness Index