Description
A 14-year-old boy presented with mild headache of 20 days duration and three episodes of vomiting over the past 3 days. On clinical evaluation, he had grade I papilloedema along with bilateral partial ptosis (figure 1). Extraocular movements, pupils and the rest of the neurological examination were normal. MRI of the brain showed a thick-walled ring-enhancing lesion with perilesional gross oedema causing obstructive hydrocephalus due to the obstruction of the aqueduct sylvius (figure 2). A magnetisation transfer (MT) image showed brighter than T1-weighted (T1W) contrast image, which favoured the diagnosis of tuberculoma. The patient showed improvement on antituberculous and dexamethasone therapy.
Figure 1.
(A) Bilateral symmetrical partial ptosis and (B) normal upgaze.
Figure 2.
MRI of the brain. (A) T1-weighted (T1W) contrast image showing dorsal midbrain ring-enhancing tuberculoma. (B) T1W magnetisation transfer image with more enhancement compared with T1W contrast image. (C) T2W sagittal image showing perilesional gross oedema causing obstructive hydrocephalus due to the obstruction of the aqueduct sylvius.
Isolated oculomotor nuclear involvement is an uncommon phenomenon. Isolated bilateral ptosis is a rare presentation, because it is usually associated with superior rectus palsy. The subnucleus of the superior rectus and levator palpebrae superioris lie in proximity. Therefore, ptosis due to nuclear lesion is usually associated with upgaze palsy. Isolated bilateral ptosis with sparing of the extraocular muscles and pupils has been described due to mesencephalic lesions.1 Isolated bilateral ptosis without hemiplaegia has also been reported in midbrain haemorrhage.2 Cellular components of lesions show hyperintensity on T1W MT images, which further enhance on contrast.3
Learning points.
Isolated bilateral ptosis is due to a midbrain lesion.
A magnetisation transfer image is helpful in diagnosing ring-enhancing lesions.
Footnotes
Contributors: RS provided the idea, gave guidance and edited the manuscript. SK prepared the manuscript and searched the literature regarding the case.
Competing interests: None.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
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