Horner's syndrome following obstetric neuraxial blockade - a systematic review of the literature.

Horner's syndrome is a rarely reported complication of neuraxial blockade. In obstetric practice, the neurological signs of Horner's syndrome may cause anxiety amongst patients and healthcare staff, but more importantly may herald the onset of maternal hypotension. Medline, CINAHL, and EMBASE databases were searched to identify cases of Horner's syndrome following obstetric neuraxial blockade. Anaesthetic technique, clinical features, anaesthetic management of the Horner's syndrome and time to resolution were assessed. Seventy-eight case reports of Horner's syndrome following obstetric neuraxial blockade were identified. Nine cases also had trigeminal nerve palsy and one case had hypoglossal nerve palsy. Amongst the 78 cases, 74% developed Horner's syndrome within one hour of a local anaesthetic bolus. The median time for resolution of Horner's syndrome was two hours, though one case was permanent. One case of Horner's syndrome was found to be due to an internal carotid artery dissection. Some cases of Horner's syndrome resolved spontaneously despite ongoing administration of epidural local anaesthetic. Hypotension was reported in 13%. Horner's syndrome is usually a benign phenomenon, the consequence of high cephalad spread of local anaesthetic, that resolves spontaneously within a few hours. Patients with a persistent Horner's syndrome, or one associated with atypical features such as neck pain, should undergo a diagnostic workup including magnetic resonance angiography of the neck. The dermatomal level of neuraxial blockade, maternal and fetal well-being should be taken into account when making decisions regarding neuraxial blockade. The presence of Horner's syndrome alone should not lead to discontinuation of neuraxial blockade.