[Ocular involvement in MuSK antibody-positive myasthenia gravis].

Abstract

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 pyridostigmine 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 generalization within a course of 12 months.

CONCLUSIONS:

Both cases clearly indicate that MuSK-Ab 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.

• Authors: V Bau, F Hanisch, B Hain, S Zierz
• Journal: Klinische Monatsblatter fur Augenheilkunde (Klin Monbl Augenheilkd) Vol. 223 Issue 1 Pg. 81-3 (Jan 2006) ISSN: 0023-2165 [Print] Germany
• Vernacular Title: Okuläre Beteiligung bei MuSK-Antikörper-positiver Myasthenia gravis.
• PMID: 16418940 (Publication Type: Case Reports, English Abstract, Journal Article)

Chemical References

• Autoantibodies
• Receptors, Cholinergic
• Prednisolone
• MUSK protein, human
• Receptor Protein-Tyrosine Kinases
• Pyridostigmine Bromide
• Azathioprine
• Methylprednisolone

Topics

• Adult
• Autoantibodies (analysis)
• Autoimmune Diseases (diagnosis, drug therapy, immunology)
• Azathioprine (adverse effects, therapeutic use)
• Drug Therapy, Combination
• Female
• Humans
• Methylprednisolone (adverse effects, therapeutic use)
• Middle Aged
• Myasthenia Gravis (diagnosis, drug therapy, immunology)
• Prednisolone (adverse effects, therapeutic use)
• Pyridostigmine Bromide (adverse effects, therapeutic use)
• Receptor Protein-Tyrosine Kinases (immunology)
• Receptors, Cholinergic (immunology)