Shivering following retrobulbar block.

A case of a severe but brief period of shivering following a retrobulbar block (RBB) is presented. The shivering occurred within two minutes after completion of the RBB and subsided gradually within five minutes, without specific treatment. The patient remained conscious during the episode of shivering. The shivering was so abrupt and severe as to be misjudged as a seizure, but its onset appeared to be slower than a seizure. The mechanism of shivering appeared to be the central spread of local anaesthetic solution into the brain stem, along the optic nerve. Shivering may be a warning sign of brain stem anaesthesia and demands special care to anticipate life-threatening complications.