累及眼部的肌肉特异性受体酪氨酸激酶抗体(MuSK-Ab)表达阳性的重症肌无力

Ocular involvement in MuSK antibody-po-sitive Myasthenia gravis (Germ)

Background: Antibodies (Ab) against the acetylcholine receptor (AChR) are found in 80-90% of generalized myasthenia gravis (MG),but only in 50% of pure ocular MG. Furthermore,Ab against the muscle-specific receptor tyrosine kinase (MuSK) were detected in 38-54% of patients with AChR-Ab negative (“ seronegative” ) MG,but not in pure ocular MG. Methods: 2 case reports have been analysed: Two patients (42 years old and 61 years old) with primary ocular MG were studied. Both patients complained of fluctuating bilateral ptosis and double vision lasting for 2 to 3 months. Results: AChR-Ab were negative but MuSK-Ab were clearly positive. In spite of treatment with pyridistigmin and prednisolone,the symptoms in patient 1 generalized within 4 weeks causing dysphagia,limb muscle weakness and respiratory crisis. Symptoms immediately responded to plasmapheresis. Patient 2 clearly improved under treatment with pyridostigmine,methylprednisone,and azathioprine. There was no generalizationwithin a course of 12 months. Conclusions: Both cases clearly indicate that MuSKAb can be found in primary isolated ocular MG lasting for 2 to 3 months. In a primary ocular manifestation of MG the detection of MuSK might indicate the risk for subsequent generalization and might have implications for immunosuppressive therapy. Therefore,seronegative MG requires testing for MuSK-Ab.

Background： Antibodies （Ab） against the acetylcholine receptor （AChR） are found in 80-90% of generalized myasthenia gravis （MG）, but only in 50% of pure ocular MG. Furthermore, Ab against the muscle-specific receptor tyrosine kinase （MUSK） were detected in 38-54% of patients with AChR-Ab negative （＂seronegative＂） MG, but not in pure ocular MG. Methods： 2 case reports have been analysed： Two patients （42 years old and 61 years old） with primary ocular MG were studied. Both patients complained of fluctuating bilateral ptosis and double vision lasting for 2 to 3 months. Results： AChR-Ab were negative but MuSK-Ab were clearly positive. In spite of treatment with pyridistigmin and prednisolone, the symptoms in patient 1 generalized within 4 weeks causing dysphagia, limb muscle weakness and respiratory crisis.