Brainstem anaesthesia after retrobulbar block: a rare cause of coma presenting to the emergency department

Abstract

Local anaesthesia, in particular retrobulbar block, is commonly used to perform cataract surgery. Known complications of retrobulbar block include cranial nerve palsies, seizures and cardiorespiratory arrest. We report a case of brainstem anaesthesia causing apnoea and loss of consciousness in a man who received retrobulbar block. The likely mechanism is inadvertent dural puncture of the optic nerve sheath and local anaesthetic injection into the cerebrospinal fluid space. As in this case, the literature reports a short-lived period of anaesthesia with usually no long-term sequelae. Although rare, it is a life-threatening complication if the patient is not appropriately resuscitated. This case highlights the need for trained personnel, with suitable monitoring and adequate resuscitation facilities in order to perform this technique.