Atypical presentation of subdural block resulting in Horner's syndrome and loss of consciousness.

Horner's syndrome is a rare side effect for patients receiving epidural anaesthesia. Studies described Horner's syndrome due to cephalic spread of injected anaesthetics, a high spinal anaesthesia, or a sign of an inadvertent subdural block. A 31-year-old woman (Gravida 1 Para 0) at 40 weeks and 2 days had a caesarean section secondary to second stage arrest. Fourteen minutes after she received the lidocaine bolus, she became unresponsive with nystagmus, unequal pupils and no pupillary reflex. Head CT and MRI showed no intracranial haemorrhage and 2 hours later, she had spontaneous resolution of neurological symptoms with no further sequelae. Although Horner's syndrome is a benign, transient process, clinicians should be mindful regarding epidural catheter placement causing subdural blocks resulting in spontaneous, reversible neurological deficits.