Abstract:
OBJECTIVES: To report the characteristics of juvenile-onset (<20
years) myasthenia gravis (MG) in Africa.
SUBJECTS AND METHOD: 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.
