Centenary of the UCT Faculty of Health Sciences

The characteristics of juvenile myasthenia gravis among South Africans

Jeannine M Heckmann, Perrin Hansen, Ronald Van Toorn, Elsabeth Lubbe, Elmarie Janse van Rensburg, Jo M Wilmshurst

Abstract


Objectives. To report the characteristics of juvenile-onset (<20 years) myasthenia gravis (MG) in Africa.
Subjects and methods. Six South African centres collected data which included acetylcholine receptor-antibody (AChR-ab) status, delay before diagnosis, MG Foundation of America grade at onset, maximum severity and severity at last visit, therapies, outcomes and complications.
Results. We report on 190 individuals with a 4-year median follow-up (interquartile range (IQR) 1 - 8). The median age at symptom onset was 7 years (IQR 4 - 14). Ocular MG (26%) occurred among younger children (mean 5.1 years), compared with those developing generalised MG (74%) (mean 10.2 years) (p=0.0004). Remissions were obtained in 45% of generalised and 50% of ocular MG patients, of whom the majority received immunosuppressive treatment, mainly prednisone. Children with post-pubertal onset had more severe MG, but deaths were infrequent.
Thymectomies were performed in 43% of those with generalised MG who suffered greater maximum disease severity (p=0.002); there was a trend towards more remissions in the thymectomy group compared with the non-thymectomy group (p=0.057).
There was no racial variation with respect to AChR-ab status, maximum severity, or use of immunosuppression. However, 23% of children of African genetic ancestry developed partial or complete ophthalmoplegia as a complication of generalised MG (p=0.002).
Conclusion. Younger children developed ocular MG and older children generalised MG. Persistent ophthalmoplegia developing as a MG complication is not uncommon among juveniles of African genetic ancestry. A successful approach to the management of this complication that causes significant morbidity is, as yet, unclear.

Authors' affiliations

Jeannine M Heckmann, Division of Neurology, Department of Medicine, Groote Schuur Hospital and University of Cape Town

Perrin Hansen, Department of Paediatrics, Chris Hani Baragwanath Hospital and University of the Witwatersrand, Johannesburg

Ronald Van Toorn, Department of Paediatrics, Tygerberg Children’s Hospital and Stellenbosch University, Cape Town

Elsabeth Lubbe, Department of Paediatrics, Steve Biko Academic Hospital and University of Pretoria

Elmarie Janse van Rensburg, Departments of Neurology and Paediatrics, Universitas Hospital and University of the Free State, Bloemfontein

Jo M Wilmshurst, Departments of Paediatric Neurology and Neurophysiology, Red Cross War Memorial Children’s Hospital and School of Child and Adolescent Health, University of Cape Town

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Keywords

myasthenia gravis, childhood, juvenile, extraocular muscles, ophthalmoplegia

Cite this article

South African Medical Journal 2012;102(6):532-536.

Article History

Date submitted: 2011-10-26
Date published: 2012-05-23

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