The diagnosis and significance of isolated third nerve palsy in the African.

The clinical spectrum of forty-one cases of isolated third nerve palsy in the African (Negro) population is presented. A high proportion (58%) was due to cerebral aneurysm. Other causes were syphilis (15.5%) diabetes mellitus (11%), and ophthalmoplegic migraine (11%). It is evident from this study that, contrary to accepted thinking on this subject, there are no clinical features which reliably distinguish between these groups. Early cerebral angiography is therefore mandatory.