JAW MUSCLE WEAKNESS: A DIFFERENTIAL INDICATOR OF NEUROMUSCULAR WEAKNESS-PRELIMINARY OBSERVATIONS

Introduction: Flaccid quadriparesis is a common neurological problem. Guillain-Barre syndrome Guillain-Barre syndrome (GBS), polymyositis/dermatomyositis (PM/DM), generalized myasthenia gravis (MG), and hypokalemic periodic paralysis (HPP) constitute the majority of cases of flaccid quadriparesis. Few patients from any of these disease groups lack the cardinal clinical features. We established clinical marker(s) that might have significant discriminating power for diagnosis. Methods: Forty-six patients satisfied all of our criteria. Cases were evaluated clinically followed by laboratory and electrophysiological study, and, in selected cases, muscle histopathology. Results: Twenty-four patients had GBS, 9 had MG, 7 had PM/DM, and 6 had HPP. Jaw-opening weakness was found in 71.4% of PM/DM, 83.3% of HPP, and 4.1% of GBS cases. Jaw-closing weakness was found in 88.8% of MG cases. Conclusions: Presence of jaw-closing weakness pointed toward MG, whereas presence of jaw-opening weakness suggested muscle disease (PM/DM and HPP). GBS patients very rarely had jaw muscle weakness. Muscle Nerve 43: 807-811, 2011