Eur J Transl Myol. 2016 Sep 15;26(4):5962. doi: 10.4081/ejtm.2016.5962. eCollection 2016 Sep 15.

Clinical Features of Neuromuscular Disorders in Patients with N-Type Voltage-Gated Calcium Channel Antibodies.

European journal of translational myology

Andreas Totzeck, Petra Mummel, Oliver Kastrup, Tim Hagenacker

PMID: 28078065 PMCID: PMC5220212 DOI: 10.4081/ejtm.2016.5962

Abstract

Neuromuscular junction disorders affect the pre- or postsynaptic nerve to muscle transmission due to autoimmune antibodies. Members of the group like myasthenia gravis and Lambert-Eaton syndrome have pathophysiologically distinct characteristics. However, in practice, distinction may be difficult. We present a series of three patients with a myasthenic syndrome, dropped-head syndrome, bulbar and respiratory muscle weakness and positive testing for anti-N-type voltage-gated calcium channel antibodies. In two cases anti-acetylcholin receptor antibodies were elevated, anti-P/Q-type voltage-gated calcium channel antibodies were negative. All patients initially responded to pyridostigmine with a non-response in the course of the disease. While one patient recovered well after treatment with intravenous immunoglobulins, 3,4-diaminopyridine, steroids and later on immunosuppression with mycophenolate mofetil, a second died after restriction of treatment due to unfavorable cancer diagnosis, the third patient declined treatment. Although new antibodies causing neuromuscular disorders were discovered, clinical distinction has not yet been made. Our patients showed features of pre- and postsynaptic myasthenic syndrome as well as severe dropped-head syndrome and bulbar and axial muscle weakness, but only anti-N-type voltage-gated calcium channel antibodies were positive. When administered, one patient benefited from 3,4-diaminopyridine. We suggest that this overlap-syndrome should be considered especially in patients with assumed seronegative myasthenia gravis and lack of improvement under standard therapy.

Keywords: 3,4-diaminopyridin; dropped-head syndrome; myasthenia gravis; neuromuscular junction disorders; voltage gated calcium channels

References

1. Neurology. 2009 Jul 14;73(2):150-1 - PubMed
2. J Immunol Methods. 1998 Dec 1;221(1-2):35-41 - PubMed
3. Nat Rev Neurol. 2016 May;12(5):259-68 - PubMed
4. J Neurol Sci. 1997 Mar 20;147(1):35-42 - PubMed
5. Biochim Biophys Acta. 2015 Apr;1852(4):651-7 - PubMed
6. Neurol Sci. 2013 Jul;34(7):1253-4 - PubMed
7. Hum Immunol. 2013 Jul;74(7):849-51 - PubMed
8. Muscle Nerve. 2009 Jul;40(1):134-6 - PubMed
9. Eur J Neurol. 2010 Jul;17(7):893-902 - PubMed
10. Clin Neurophysiol. 2005 May;116(5):1167-71 - PubMed
11. N Engl J Med. 1995 Jun 1;332(22):1467-74 - PubMed
12. J Intern Med. 2014 Jan;275(1):12-26 - PubMed
13. Curr Opin Neurol. 2012 Oct;25(5):523-9 - PubMed
14. J Neurol Neurosurg Psychiatry. 1995 Jan;58(1):85-7 - PubMed
15. BMC Neurol. 2010 Jun 18;10:46 - PubMed
16. Muscle Nerve. 2016 Jan;53(1):20-6 - PubMed
17. J Neurol. 2005 Sep;252(9):1127-8 - PubMed
18. N Engl J Med. 1989 Dec 7;321(23):1567-71 - PubMed
19. Curr Opin Neurol. 2013 Oct;26(5):459-65 - PubMed
20. Lancet Neurol. 2015 Oct;14(10):1023-36 - PubMed
21. Autoimmun Rev. 2013 Jul;12(9):918-23 - PubMed
22. J Neurol Neurosurg Psychiatry. 2002 Dec;73(6):766-8 - PubMed

Publication Types

• Journal Article