Oculomotor synkinesis: an uncommon sequela of paediatric cavernous sinus thrombosis

We report an unusual case of acquired oculomotor synkinesis as a sequela of cavernous sinus thrombosis in a child. A 4-year-old male child presented to our emergency services with sudden onset periorbital swelling with complete ptosis of the left upper eyelid. This was preceded by a febrile episode and a furuncle at the tip of the nose. Computerised axial tomography of the orbit revealed orbital cellulitis in the left eye. The child was started on systemic antibiotics followed by a short course of systemic steroids. MRI of the brain with contrast revealed left cavernous sinus and superior ophthalmic vein thrombosis. Following administration of systemic anticoagulants and antibiotics, the ocular motility and ptosis improved remarkably. However, 6 months post-treatment, the child developed signs of aberrant regeneration of the third cranial nerve (oculomotor synkinesis).