The characteristics of juvenile myasthenia gravis among South Africans

Division of Neurology, Department of Medicine, Groote Schuur Hospital.
South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde (Impact Factor: 1.63). 06/2012; 102(6):532-6.
Source: PubMed


To report the characteristics of juvenile-onset (<20 years) myasthenia gravis (MG) in Africa.
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.
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).
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.

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    • "These observations support the postulate that during active MG, patients with severe EOM damage may have inadequate DAF upregulation and therefore less protection against complement-mediated damage. Since some of the patients developed the ophthalmoplegic-MG complication whilst on prednisone, with or without a steroid-sparing agent [12] [13], we were interested in the effect of these drugs on DAF expression. "
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