Third nerve palsy associated with preeclampsia and HELLP syndrome

Preeclampsia can cause myriad organ dysfunction, including cranial nerve palsies that pose diagnostic and management dilemmas. We present an unusual case of third nerve palsy, (presenting as diplopia, ptosis) with hypertension, hyperreflexia, proteinuria, easy bruising in a parturient at 34 + 6/52 weeks of twins gestation. She was treated as for severe preeclampsia and HELLP syndrome; intravenous magnesium sulphate and labetalol commenced and emergent cesarean delivery performed under general anesthesia due to concerns of low platelets and for airway protection should her glascow coma scale (GCS) deteriorate. Postoperatively, stroke, aneurysm and intra-cerebral causes of third nerve palsy were excluded, with subsequent recovery of symptoms upon blood pressure normalization. The eye signs are postulated to be due to two preeclamptic mechanisms involving disordered cerebral autoregulation: (1) hyperperfusion and breakdown of the blood-brain barrier that occurs with rising hypertension, causing fluid/blood product extravasation into brain parenchyma, or (2) focal reactive vasoconstriction and local hypoperfusion, contributed to by endothelial dysfunction.